tag:theconversation.com,2011:/global/topics/philae-12095/articlesPhilae – The Conversation2016-12-27T21:02:25Ztag:theconversation.com,2011:article/698732016-12-27T21:02:25Z2016-12-27T21:02:25Z2016: the year in space and astronomy<figure><img src="https://images.theconversation.com/files/150695/original/image-20161219-24299-7yv6gh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The discovery of the year was the first detection of gravitational waves.</span> <span class="attribution"><span class="source">LIGO/T. Pyle</span></span></figcaption></figure><p>The achievements of astrophysicists this year were as groundbreaking as they were varied. From reuniting a lander with a mothership on a comet, to seeing the most extreme cosmic events with gravitational waves, 2016 was truly out of this world for science.</p>
<p>Here are some of the highlights of the year that was.</p>
<h2>1. Gravitational Waves</h2>
<p>The spectacular announcement that ripples in the very fabric of spacetime itself had been found (and from surprisingly massive black holes colliding) sent similarly massive ripples through the <a href="https://theconversation.com/gravitational-waves-discovered-top-scientists-respond-53956">scientific community</a>. The discovery was made using the <a href="https://www.ligo.caltech.edu/">Laser Interferometer Gravitational-Wave Observatory</a> (LIGO) and represents a <a href="https://theconversation.com/explainer-gravitational-waves-and-why-their-discovery-is-such-a-big-deal-53239">fundamentally new sense</a> with which to see the universe.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/zLAmF0H-FTM?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Animation showing how colliding black holes cause a ripple in spacetime that moves outwards into the universe as a gravitational wave.</span></figcaption>
</figure>
<p>The gravitational waves cause one arm of the LIGO detector to stretch relative to the other by less than a thousandth of the width of a proton in the centre of the atom. Relatively speaking, that’s like measuring a hair’s-width change in the distance to the nearest star. </p>
<p>This discovery was the end of a century-long quest to prove Einstein’s final prediction that these gravitational waves are real. It also allows us to directly “see” that famously and fundamentally invisible entity: the black hole (as well as definitively proving its existence). The fact that the two black holes collided 1.3 billion years ago and the waves swept through Earth just days after turning the detector on only add to the <a href="https://theconversation.com/gravitational-waves-found-the-inside-story-54589">incredible story of this discovery</a>.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/QyDcTbR-kEA?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The ‘sound’ of the black holes colliding where the measured signal from LIGO is converted to audio, the rising chirp sound towards the end is the two black holes spiralling together ever more quickly. A surprisingly wimpy sound for the most extreme collision ever detected.</span></figcaption>
</figure>
<h2>2. SpaceX lands (and crashes) a rocket</h2>
<p>The year started so well for <a href="http://www.spacex.com/">SpaceX</a> with the incredible achievement of sending a satellite into orbit, which is no mean feat itself at such low cost, before then <a href="https://theconversation.com/how-to-launch-a-rocket-into-space-and-then-land-it-on-a-ship-at-sea-57675">landing that launch rocket on a barge</a> in the ocean. A seemingly unstoppable sequence of launches and landings made it appear that a new era of vastly cheaper access to space through rockets that could be refuelled and reused was at hand. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/4jEz03Z8azc?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">A Falcon 9 first-stage automatically returns to the barge/droneship ‘Of Course I Still Love You’ in the middle of the Atlantic ocean.</span></figcaption>
</figure>
<p>Unfortunately, with the <a href="http://www.wsj.com/articles/spacex-leads-probe-into-falcon-9-rocket-explosion-1473376404">explosion of a Falcon 9 on the launchpad</a>, the <a href="https://theconversation.com/spacex-explosion-shows-why-we-must-slow-down-private-space-exploration-until-we-rewrite-law-65019">company was grounded</a>, but <a href="http://www.spacex.com/news/2016/09/01/anomaly-updates">apparently hopes for a resumed launch</a> in early January.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/0qo78R_yYFA?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">SpaceX outlines a vision for travel to Mars with planned Interplanetary Transport System.</span></figcaption>
</figure>
<p>Add to that the visionary plans to <a href="http://www.spacex.com/mars">settle Mars outlined by Elon Musk</a>, albeit <a href="https://theconversation.com/how-feasible-are-elon-musks-plans-to-settle-on-mars-a-planetary-scientist-explains-66341">not without some audacious challenges</a>, and it’s been a year of highs and lows for SpaceX.</p>
<h2>3. Closest star may harbour Earth-like world</h2>
<p>Proxima Centauri is our Sun’s nearest neighbour at just over four light years away, and <a href="https://theconversation.com/possibly-habitable-planet-found-around-our-nearest-neighbour-star-64321">it appears that its solar system</a> may contain an Earth-like world. Until this year, astronomers weren’t even sure that <em>any</em> planets orbited the star, let alone ones that might harbour the best extrasolar candidate for life that spacecraft could visit within our lifetime.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/4uBG_Xowyp4?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">What a trip to the Sun’s closet neighbour would look like.</span></figcaption>
</figure>
<p>The planet, creatively named “Proxima b”, was <a href="http://www.nature.com/nature/journal/v536/n7617/full/nature19106.html">discovered by a team</a> of astronomers at Queen Mary University in London. Using the light of Proxima Centuari, the astronomers were able to detect subtle shifts in the star’s orbit (seen as a “wobble”), which is the telltale sign that another massive object is nearby.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/149582/original/image-20161212-31385-1gvtn6z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/149582/original/image-20161212-31385-1gvtn6z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=389&fit=crop&dpr=1 600w, https://images.theconversation.com/files/149582/original/image-20161212-31385-1gvtn6z.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=389&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/149582/original/image-20161212-31385-1gvtn6z.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=389&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/149582/original/image-20161212-31385-1gvtn6z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=489&fit=crop&dpr=1 754w, https://images.theconversation.com/files/149582/original/image-20161212-31385-1gvtn6z.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=489&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/149582/original/image-20161212-31385-1gvtn6z.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=489&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">An artist’s impression of Proxima b’s landscape.</span>
<span class="attribution"><span class="source">ESO/M. Kornmesser</span></span>
</figcaption>
</figure>
<p>While Proxima Centuari is barely 10% the size of our Sun, Proxima b’s orbit is only <a href="https://www.eso.org/public/usa/images/eso1629c/zoomable/">11 days long</a>, meaning it is very close to the star and lies just within the so-called habitable zone. However, follow-up with either Hubble or the upcoming James Webb Space telescope is necessary to determine if the exoplanet is as well suited for life as Earth. </p>
<h2>4. Breakthrough Listen listening and Starshot star-ted</h2>
<p>With a potential Earth twin identified in Proxima b, now the challenge is to reach it within a human lifetime. With the breakthrough initiative <a href="https://breakthroughinitiatives.org/Initiative/3">starshot</a>, which has been funded by Russian billionaire Yuri Milner and endorsed by none other than Stephen Hawking, lightweight nanosails can be propelled by light beams to reach speeds up to millions of kilometres an hour. </p>
<p>Such speeds would allow a spacecraft to <a href="https://theconversation.com/why-sailing-to-the-stars-has-suddenly-become-a-realistic-goal-57762">arrive at Proxima b</a> in about 20 years, thus enabling humans to send information to another known planet for the first time. </p>
<p>However, there are many challenges ahead, such as the fact that the technology doesn’t exist yet, and that high-speed collisions with gas and dust between stars may destroy it before it can reach its target. </p>
<p>But humans have proven to be resourceful, and key technology is advancing at an exponential rate. Incredibly the idea of sailing to another world is no longer science fiction, but rather an outrageously ambitious science project.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/RoCm6vZDDiQ?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">One of the founders of the Breakthrough initiatives, Yuri Milner, discusses the technology needed for breakthrough starshot.</span></figcaption>
</figure>
<p>Perhaps, aliens are already sending out their own information in the form of radio transmissions. In another breakthrough initiative called <a href="https://breakthroughinitiatives.org/Initiative/1">Listen</a>, also championed by Hawking, astronomers will be searching the habitable zones around the million closest stars to try to detect incoming radio transmissions. Involving Australia’s very own Parkes telescope (as well as the Green Bank Telescope and Lick Observatory at visible wavelengths of light), observations have been running through 2016 and the search for alien signals will continue for the next decade.</p>
<h2>5. Philae reunited with Rosetta</h2>
<p>In 2014 the Philae lander became the first space probe to land on a comet, and even though its crash landing dictated that its science transmission would be a one-off, its recent rediscovery by Rosetta has allowed it to continue to contribute to analysis of comet 67P. </p>
<p><a href="https://theconversation.com/philae-has-been-found-heres-why-its-important-64978">Philae’s crash location</a>, as well as the orientation of the doomed probe, has allowed astronomers to accurately interpret data taken by Rosetta regarding the composition of the comet.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/149591/original/image-20161212-31364-1uzyx16.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/149591/original/image-20161212-31364-1uzyx16.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=375&fit=crop&dpr=1 600w, https://images.theconversation.com/files/149591/original/image-20161212-31364-1uzyx16.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=375&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/149591/original/image-20161212-31364-1uzyx16.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=375&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/149591/original/image-20161212-31364-1uzyx16.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=471&fit=crop&dpr=1 754w, https://images.theconversation.com/files/149591/original/image-20161212-31364-1uzyx16.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=471&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/149591/original/image-20161212-31364-1uzyx16.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=471&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Where’s Philae?</span>
<span class="attribution"><span class="source">ESA</span></span>
</figcaption>
</figure>
<p>While Philae has literally been living under (crashed on) a rock for the past two years, Rosetta has been the busy bee, taking numerous images, spectroscopy and other data of the comet. </p>
<p>In fact, data taken from Rosetta’s spectrometer has been analysed and revealed that the <a href="http://www.esa.int/Our_Activities/Space_Science/Rosetta/Rosetta_s_comet_contains_ingredients_for_life">amino acid, glycine, is present in the comet’s outgassing</a>, which breaks away from the surface of the comet as it becomes unstable from solar heating. Glycine is one of the fundamental building blocks of life; necessary for proteins and DNA, and its confirmed extraterrestrial confirms that the ingredients for life are unique to Earth, and that we may have comets to thank for providing our microbial ancestors with those crucial ingredients.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/149592/original/image-20161212-31352-1ludihc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/149592/original/image-20161212-31352-1ludihc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=375&fit=crop&dpr=1 600w, https://images.theconversation.com/files/149592/original/image-20161212-31352-1ludihc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=375&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/149592/original/image-20161212-31352-1ludihc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=375&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/149592/original/image-20161212-31352-1ludihc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=471&fit=crop&dpr=1 754w, https://images.theconversation.com/files/149592/original/image-20161212-31352-1ludihc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=471&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/149592/original/image-20161212-31352-1ludihc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=471&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Dust and gas emitted from comet 67P reveal an amino acid.</span>
<span class="attribution"><span class="source">ESA</span></span>
</figcaption>
</figure>
<h2>Outlook for Down Under</h2>
<p>The future for astrophysics in Australia in 2017 looks particularly bright, with two ARC Centres of Excellence: <a href="http://www.anu.edu.au/news/all-news/anu-to-lead-australian-exploration-of-the-universe-0">CAASTRO-3D</a> studying the build of atoms over cosmic time; and <a href="http://ozgrav.org/">OzGRav</a> exploring the universe with gravitational waves; as well as <a href="http://theconversation.com/digging-for-cosmic-gold-the-hunt-for-dark-matter-at-the-bottom-of-a-gold-mine-69890">SABRE</a>, the world’s first dark matter detector in the Southern Hemisphere, installed by end of the year. </p>
<p>If you thought 2016 was a great year in space, then you’re in for a treat in 2017.</p><img src="https://counter.theconversation.com/content/69873/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alan Duffy is an Associate Investigator in the ARC Centre of Excellence for Gravitational Wave Discovery (OzGRav) and an Associate Investigator in the ARC Centre of Excellence for All-sky Astrophysics (CAASTRO-3D) and member of SABRE.</span></em></p><p class="fine-print"><em><span>Rebecca Allen does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Colliding black holes to exploding spacecraft, 2016 was an incredible year for astrophysics.Alan Duffy, Research Fellow, Swinburne University of TechnologyRebecca Allen, PhD candidate researching galaxy formation and evolution, Swinburne University of TechnologyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/663432016-09-30T15:38:57Z2016-09-30T15:38:57ZEmotion and tears in mission control as Rosetta comes to a silent end<figure><img src="https://images.theconversation.com/files/139922/original/image-20160930-8922-132ci5n.jpg?ixlib=rb-1.1.0&rect=3%2C585%2C2035%2C1453&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Comet 67P taken with a wide-angle lens from an altitude of about 15.5km above the surface during the spacecraft’s final descent on September 30.</span> <span class="attribution"><span class="source">ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>It’s over. Really over. The Rosetta spacecraft has taken its last image, sniffed its last gasp and <a href="http://www.esa.int/Our_Activities/Space_Science/Rosetta/Mission_complete_Rosetta_s_journey_ends_in_daring_descent_to_comet">held its final press conference</a>. To a chorus of sighs from the assembled scientists and engineers, the mission came to a quiet end. Immediately, the audience of 300 or so gathered in the European Space Operation Centre’s auditorium, got to its feet and gave a spontaneous standing ovation to the flight team in mission control who had overseen the delicate and, ultimately, terminal manoeuvre.</p>
<p>It was an emotional moment. For 40 minutes, we had been listening to different speakers connected with Rosetta, hearing brief reports of <a href="https://theconversation.com/swansong-for-rosetta-as-it-lands-on-the-duck-shaped-comet-66301">mission highlights</a>. Holger Sierks, the principal investigator of the OSIRIS camera team, showed the most recent images of comet 67P, taken on the final 19km flight to the surface. The images were crisp and clear, showing beautifully detailed landscapes.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/139876/original/image-20160930-9905-1orbd2h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/139876/original/image-20160930-9905-1orbd2h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/139876/original/image-20160930-9905-1orbd2h.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/139876/original/image-20160930-9905-1orbd2h.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/139876/original/image-20160930-9905-1orbd2h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/139876/original/image-20160930-9905-1orbd2h.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/139876/original/image-20160930-9905-1orbd2h.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Comet seen from an altitude of about 16km during the spacecraft’s final descent on September 30.</span>
<span class="attribution"><span class="source">ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Then, with five minutes to go, the chairwoman of the event said that we were going to go over to mission control, and watch with the flight engineers as Rosetta landed. We weren’t going to see any live pictures of the touchdown – the camera focused on the computer screen showing the communications signal. <a href="http://www.esa.int/spaceinimages/Images/2016/09/Understanding_Rosetta_s_final_signal">When the trace winked out</a>, Sylvain Lodiot, ESA’s spacecraft operations manager, symbolically removed his headset, through which he had been listening to the steady beat of Rosetta’s electronic heart. “This is the end of the Rosetta mission,” he said, adding “thank you and goodbye”. He turned to the rest of the team, and as they hugged each other, tears were shed.</p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/139924/original/image-20160930-7750-1b893n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/139924/original/image-20160930-7750-1b893n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/139924/original/image-20160930-7750-1b893n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/139924/original/image-20160930-7750-1b893n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/139924/original/image-20160930-7750-1b893n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/139924/original/image-20160930-7750-1b893n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/139924/original/image-20160930-7750-1b893n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Static received by the ground station after Rosetta’s radio signal disappeared.</span>
<span class="attribution"><span class="source">ESA</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>But science waits for no one, and within less than a minute, the audience was rapt as Sierks revealed the final few images transmitted before communications ceased. With a wry grin at the one taken 360 metres above the surface, he commented that it would keep the boulder counters occupied for quite some time. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/139930/original/image-20160930-8472-1biley4.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/139930/original/image-20160930-8472-1biley4.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/139930/original/image-20160930-8472-1biley4.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/139930/original/image-20160930-8472-1biley4.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/139930/original/image-20160930-8472-1biley4.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/139930/original/image-20160930-8472-1biley4.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/139930/original/image-20160930-8472-1biley4.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Comet from 360 metres.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>The final image, taken a mere five seconds before landing, was out of focus. Out of focus – how dare it be! The camera was taking a picture that it had not been designed to capture, and we were shown the unprocessed, raw image. Maybe we just expect too much sometimes. Many angular boulders of different sizes, between 30-70cm across can clearly be seen, sitting on a more fine-grained soil.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/139921/original/image-20160930-3330-fwk6kd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/139921/original/image-20160930-3330-fwk6kd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/139921/original/image-20160930-3330-fwk6kd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/139921/original/image-20160930-3330-fwk6kd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/139921/original/image-20160930-3330-fwk6kd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/139921/original/image-20160930-3330-fwk6kd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/139921/original/image-20160930-3330-fwk6kd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Last image, taken shortly before impact at an estimated altitude of 51 metres. Wide-angle camera.</span>
<span class="attribution"><span class="source">ESA</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>When emotions have calmed down, it will be time to reflect on <a href="https://theconversation.com/why-rosetta-is-the-greatest-space-mission-of-our-lifetime-33763">Rosetta’s legacy</a>. The science will speak for itself, and will keep analysts and theoreticians occupied for at least the next decade. But beyond that? Rosetta, like all space missions, acts as a technological and engineering springboard for the next series of missions. Advances in electronics, optics and communications, as well as design and engineering generally, ensure that Rosetta will be remembered, with new instruments developed based on those flown to the comet.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/trljrwTbr4w?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Rosetta cartoon.</span></figcaption>
</figure>
<p>But perhaps Rosetta’s greatest legacy will be the students, still at school, who have followed the adventures of Rosetta and Philae, and who are inspired to take up science and engineering with the aspiration of themselves being part of future space missions. And that is certainly a legacy of which to be proud.</p><img src="https://counter.theconversation.com/content/66343/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Monica Grady works for the Open University. She receives funding from the STFC and the EU Horizon 2020 Programme. She is a Co-Investigator of the EURO-CARES project and a Trustee of Lunar Mission One.</span></em></p>A moment of sadness with tears shed … then it was on with the work.Monica Grady, Professor of Planetary and Space Sciences, The Open UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/663012016-09-30T05:09:13Z2016-09-30T05:09:13ZSwansong for Rosetta as it lands on the duck-shaped comet<figure><img src="https://images.theconversation.com/files/139856/original/image-20160930-9905-za3e08.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Artist's impression of Rosetta's descent.</span> <span class="attribution"><span class="source">ESA</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>It has been an epic journey, much more than 12 years in the making, but Rosetta is just about to <a href="http://www.esa.int/Our_Activities/Space_Science/Rosetta/Rosetta_finale_set_for_30_September">go out in a blaze of glory.</a> The final commands were uploaded to the spacecraft mid-morning on September 29 – and now there is no going back. Rosetta is programmed to touch down on comet 67P sometime in the late morning of September 30. </p>
<p>It is not a suicide crash, as some have described the manoeuvre, but should (we all hope) be a graceful, slow-motion glide onto the comet’s surface. </p>
<p>So what has been achieved by this mission? What do we know now that we didn’t know before? For a start, a new discipline has been invented: cometary morphology – the study of a comet’s surface. The images sent back, first by the navigation cameras and then by the <a href="http://www.esa.int/Our_Activities/Space_Science/Rosetta/Ride_along_with_Rosetta_through_the_eyes_of_OSIRIS">higher resolution Osiris instrument</a>, have been unbelievable. Take a black and white picture of a dried up river bed, or the layers of rock exposed in the walls of a narrow, steep-sided canyon on Earth, and compare them with <a href="https://planetgate.mps.mpg.de:8114/Image_of_the_Day/public/OSIRIS_IofD_2016-07-22.html">some of the landscapes we have seen on 67P</a>, and you could be looking at the same features. </p>
<p>But we know that rivers have never carved their way across the surface of a comet, or sediments laid down in shallow seas. So how do we interpret these landscapes if we do not understand the processes that have caused them?</p>
<p>There have been other discoveries, too. Scientists analysing the data from the comet discovered <a href="https://theconversation.com/building-blocks-of-life-found-among-organic-compounds-on-comet-67p-what-philae-discoveries-mean-45379">molecules that can form sugars and amino acids</a> – which are the building blocks of life as we know it. Another paper unveiled the <a href="https://theconversation.com/rosetta-scientists-unveil-the-source-of-ice-and-dust-jets-on-comet-67p-48122">source of ice and dust jets</a> on the comet.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/139858/original/image-20160930-9894-jvuany.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/139858/original/image-20160930-9894-jvuany.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/139858/original/image-20160930-9894-jvuany.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/139858/original/image-20160930-9894-jvuany.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/139858/original/image-20160930-9894-jvuany.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/139858/original/image-20160930-9894-jvuany.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/139858/original/image-20160930-9894-jvuany.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Close up view of the comet as Rosetta is coming down to surface.</span>
<span class="attribution"><span class="source">ESA</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Of course, perhaps the most spectacular achievement of the Rosetta mission was the <a href="https://theconversation.com/scientists-at-work-from-rosetta-mission-control-as-philae-lands-34152">landing of Philae</a> on the surface of 67P. Although the lander bounced a couple of times before finally coming to rest on its side, in the dark, under a cliff – rather than in the middle of a flat, open, sunlit plain – the instruments on-board Philae managed to achieve <a href="https://theconversation.com/explainer-what-philae-did-in-its-60-hours-on-comet-67p-34289">almost all the planned science goals.</a> Those that were not completed required specimens to be retrieved by the drill – which was not possible, given that Philae was not upright. </p>
<p>More than a year ago, the Philae teams were resigned to the idea that their direct involvement in the Rosetta mission was over and that the lander was <a href="https://theconversation.com/farewell-to-philae-54676">consigned to eternal hibernation</a>. But, at the beginning of September, months of close and careful investigation of images of 67P’s surface paid off and <a href="https://theconversation.com/philae-has-been-found-heres-why-its-important-64978">Philae’s resting place was discovered</a>. </p>
<p>The delight of the instrument teams was not merely an emotional response to locating the missing lander – finding Philae has enabled additional information to be recovered from data acquired by the lander’s instruments, as the physical context in which the data were gathered is now known. This will enable a more complete interpretation of structural and environmental data, which had been recorded without knowing the conditions under which they were collected.</p>
<h2>Dangerous mission</h2>
<p>Rosetta’s sojourn close to the cometary nucleus has not been without peril – <a href="https://theconversation.com/that-sinking-feeling-could-cavities-on-comet-pose-yet-another-risk-to-philae-44155">sudden jets from the pits described as “goosebumps”</a> released bursts of gas and dust which, on several occasions, confused Rosetta. This was because the spacecraft navigated by the stars – and a cloud of dust grains reflecting sunlight bears a close resemblance to a star field of many thousands of stars, resulting in sending Rosetta’s star tracker astray.</p>
<p>Each time this happened, Rosetta might have crashed into 67P, or sent itself flying off into the deep unknown – but each time, swift response by engineers back on Earth were able to rescue the craft from the brink of danger. </p>
<p>During its closest approach to the sun, Rosetta wove a convoluted path around the comet – sometimes nearer, sometimes further away, depending on surface activity. This behaviour ensured that there was always at least one very happy instrument team – and one very irritated one. This is because some of the scientists are interested in dust, so are happy to see it. To other teams, however, dust gets in the way of images, and is a concern for navigation.</p>
<p>Downloading and reducing results from Rosetta and Philae’s instruments is well underway and <a href="https://theconversation.com/rosetta-will-teach-us-more-about-comets-than-we-have-learnt-in-50-years-30295">efforts are in progress</a> to interpret the data and understand their significance. But it will be some time yet before we manage to integrate all the findings into updated models of solar system formation. Maybe we will have got it finished before the next cometary mission launches?</p><img src="https://counter.theconversation.com/content/66301/count.gif" alt="The Conversation" width="1" height="1" />
<h4 class="border">Disclosure</h4><p class="fine-print"><em><span>Monica Grady works for the Open University and receives funding from the STFC and the EU's Horizon 2020 programme. She is a Trustee of Lunar Mission One, and a Co-I of the EURO-CARES project</span></em></p>It has been an epic journey, much more than 12 years in the making, but Rosetta is just about to go out in a blaze of glory. The final commands were uploaded to the spacecraft mid-morning on September…Monica Grady, Professor of Planetary and Space Sciences, The Open UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/650162016-09-27T06:43:19Z2016-09-27T06:43:19ZScience in crisis: from the sugar scam to Brexit, our faith in experts is fading<figure><img src="https://images.theconversation.com/files/138870/original/image-20160922-22530-1de1ybr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Under the microscope.</span> <span class="attribution"><span class="source">www.shutterstock.com</span></span></figcaption></figure><p><em>This is a Foundation Essay for The Conversation Global. Our series of Foundation Essays provide an in-depth investigation of a particular global challenge. In this piece, Andrea Saltelli asks what’s behind the worldwide crisis in science.</em></p>
<p>Worldwide, we are facing a joint crisis in <a href="http://cspo.org/publication/the-rightful-place-of-science-science-on-the-verge/">science and expertise</a>. This has led some observers to speak of a <a href="http://www.ft.com/cms/s/2/82a1a548-3b93-11e6-8716-a4a71e8140b0.html#axzz4Hzb9D6Ql">post-factual democracy</a> – with Brexit and the rise of Donald Trump the results. </p>
<p>Today, the scientific enterprise produces somewhere in the order of <a href="http://www.stm-assoc.org/2012_12_11_STM_Report_2012.pdf">2m papers a year, published in roughly 30,000 different journals</a>. A blunt assessment has been made that perhaps <a href="http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(15)60696-1/fulltext?rss%25253Dyes">half</a> or more of all this production “<a href="http://circres.ahajournals.org/content/116/1/116.long">will not stand the test of time</a>”. </p>
<p>Meanwhile, science has been challenged as an authoritative source of knowledge for both policy and everyday life, with noted major misdiagnoses in fields as disparate as <a href="https://www.ncjrs.gov/pdffiles1/nij/grants/228091.pdf">forensics</a>, <a href="http://www.nature.com/nature/journal/v483/n7391/full/483531a.html">preclinical</a> and <a href="http://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1002049">clinical</a> medicine, <a href="http://www.nature.com/news/bloggers-put-chemical-reactions-through-the-replication-mill-1.12262">chemistry</a>, <a href="http://www.nature.com/news/over-half-of-psychology-studies-fail-reproducibility-test-1.18248">psychology</a> and <a href="http://www.sciencemag.org/news/2016/03/about-40-economics-experiments-fail-replication-survey">economics</a>.</p>
<p>Perhaps nutrition is the field most in the spotlight. It took several decades for <a href="https://www.theguardian.com/society/2016/apr/07/the-sugar-conspiracy-robert-lustig-john-yudkin">cholesterol</a> to be absolved and for sugar to be re-indicted as the more serious health threat, thanks to the fact that the sugar industry sponsored a research program in the 1960s and 1970s, which successfully <a href="http://archinte.jamanetwork.com/article.aspx?articleid=2548255">cast doubt</a> on the hazards of sucrose – while promoting fat as the dietary culprit. </p>
<h2>Destructive trend</h2>
<p>We think of science as producing truths about the universe. Triumphs of science, like the recent confirmation of the existence of <a href="https://theconversation.com/gravitational-waves-discovered-top-scientists-respond-53956">gravitational waves</a> and the <a href="https://theconversation.com/small-glitches-but-rosetta-comet-mission-is-achieving-major-scientific-goals-34228">landing of a probe on a comet</a> flying around the sun, bring more urgency to the need to reverse the present crisis of confidence in other areas of the scientific endeavour.</p>
<p>Science is tied up with our ideas about democracy – not in the cold war sense of science being an attribute of open democratic societies, but because it provides legitimacy to <a href="http://press.princeton.edu/titles/9440.html">existing power arrangements</a>: those who rule need to know what needs to be done, and in modern society this knowledge is provided by science. The science-knowledge-power relationship is one of the master narratives of modernity, whose end was announced by philosopher <a href="https://www.britannica.com/biography/Jean-Francois-Lyotard">Jean-François Lyotard</a> four decades ago. The contemporary loss of trust in expertise seems to support his views. </p>
<p>Still, techno-science is at the heart of contemporary narratives: the convictions that we will innovate our way out of the economic crisis, overcome our planetary boundaries, achieve a dematerialised economy, improve the fabric of nature, and allow universal well-being. </p>
<p>The appeal of reassuring narratives about our future depends on our trust in science, and the <a href="http://www.nature.com/news/misplaced-faith-1.17684">feared collapse of this trust</a> will have far-reaching consequences. </p>
<p>The cult of science is still adhered to by many. Most of us need to believe in a neutral science, detached from material interests and political bargaining, capable of discovering the wonders of nature. For this reason, no political party has so far argued for a reduction in science funding on the basis of the crisis in science, but this threat could soon materialise.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/139296/original/image-20160926-31847-1oh41sm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/139296/original/image-20160926-31847-1oh41sm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/139296/original/image-20160926-31847-1oh41sm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/139296/original/image-20160926-31847-1oh41sm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/139296/original/image-20160926-31847-1oh41sm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/139296/original/image-20160926-31847-1oh41sm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/139296/original/image-20160926-31847-1oh41sm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Landing Philae on a comet was no mean feat.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/dlr_de/15307538379/">DLR German Aerospace Center Follow</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>The crisis we saw coming</h2>
<p>The crisis in science is not a surprise – some scholars of history and philosophy of science had predicted it four decades ago. </p>
<p>Derek de Solla Price, the father of <a href="http://link.springer.com/journal/11192">scientometrics</a> – literally the scientific study of science – feared the quality crisis. He noted in his 1963 book, <a href="http://derekdesollaprice.org/little-science-big-science-full-text/">Little Science, Big Science</a>, that the exponential growth of science might lead to saturation, and possibly to senility (an incapacity to progress any further). For contemporary philosopher <a href="https://global.oup.com/academic/product/the-great-endarkenment-9780199326020?cc=es&lang=en&">Elijah Millgram</a>, this disease takes the form of disciplines becoming alien to one another, separated by different languages and standards. </p>
<p>Jerome R Ravetz noted <a href="https://en.wikipedia.org/wiki/Scientific_knowledge_and_its_social_problems">in 1971</a> that science is a social activity, and that changes in the social fabric of science – once made up of restricted clubs whose members were linked by common interests and now a system ruled by impersonal metrics - would entail serious problems for its quality assurance system and important repercussions for its social functions. </p>
<p>Ravetz, whose <a href="http://www.sciencedirect.com/science/article/pii/S0016328710002296">analysis of science’s contradictions</a> has continued to the present day, noted that neither a technical fix would remedy this, nor would a system of enforced rules. Scientific quality is too delicate a matter to be resolved with a set of recipes. </p>
<p>A perfect illustration of his thesis is the recent debate about the <a href="https://theconversation.com/goodbye-p-value-is-it-time-to-let-go-of-one-of-sciences-most-fundamental-measures-38057">P value</a> – commonly used in experiments to judge the quality of scientific results. The inappropriate use of this technique has been strongly criticised, provoking alarm – and <a href="https://www.amstat.org/newsroom/pressreleases/P-ValueStatement.pdf">statements of concern</a> – at the highest levels in the profession of statistics. But no clear agreement has been reached on the nature of the problem, as shown by the high number of <a href="https://theconversation.com/give-p-a-chance-significance-testing-is-misunderstood-20207">critical comments</a> in the ensuing debate. </p>
<p>Philip Mirowski’s <a href="http://www.hup.harvard.edu/catalog.php?isbn=9780674046467">recent book</a> offers a fresh reading of the crisis in terms of the commercialisation of science’s production. Scientific research deteriorates when it is entrusted to contract research organisations, working on a short leash held by commercial interests. </p>
<p>The present trajectory will result in an impasse in many areas of science, where it may become impossible to <a href="http://www.nature.com/news/sluggish-data-sharing-hampers-reproducibility-effort-1.17694">sort out the good papers from the bad</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/139300/original/image-20160926-31853-1f993ww.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/139300/original/image-20160926-31853-1f993ww.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/139300/original/image-20160926-31853-1f993ww.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/139300/original/image-20160926-31853-1f993ww.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/139300/original/image-20160926-31853-1f993ww.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/139300/original/image-20160926-31853-1f993ww.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/139300/original/image-20160926-31853-1f993ww.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/139300/original/image-20160926-31853-1f993ww.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">See me after class.</span>
<span class="attribution"><a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Science-based narratives and the social functions of science will then lose their appeal. No solution is possible without a change in the prevailing vision and ideology, but can <a href="https://www.theguardian.com/science/political-science/2016/jul/14/six-leading-scientists-give-perspectives-on-uk-science-after-brexit?CMP=share_btn_tw">scientific institutions offer one</a>?</p>
<h2>The supremacy of expertise</h2>
<p>Here the stakes are high and perverse systems of incentives entrenched. Many scientists are highly defensive of their work. They adhere to the deficit model, in its standard or glorified form, whereby if only people understood science – or at least <a href="http://papers.ssrn.com/sol3/papers.cfm?abstract_id=2794799">understood who the true experts were</a> – then progress would be achieved. </p>
<p>Scientists often subscribe to the myth of one science, and promote actions for or against a policy based on their position as scientists. In a recent case, more than 100 Nobel laureates <a href="https://www.washingtonpost.com/news/speaking-of-science/wp/2016/06/29/more-than-100-nobel-laureates-take-on-greenpeace-over-gmo-stance/">took a side in a dispute over a genetically modified rice</a>, a rather complex case where more prudence would have been in order. </p>
<p>Climate is another battlefield where the idea that “<a href="http://cspo.org/publication/the-rightful-place-of-science-science-on-the-verge/">science has spoken</a>” or “doubt has been eliminated” have become common refrains.</p>
<p>Many scientists defend the supremacy of expertise; if lay citizens disagree with experts, it is the former who are wrong. This because scientists are <a href="https://www.newscientist.com/article/mg23030693-400-scientists-have-the-tools-to-fix-the-reported-crisis-in-science/">better than bankers and politicians</a>, or simply better human beings, who need <a href="http://www.npr.org/sections/13.7/2016/08/17/490245464/20-science-questions-for-the-presidential-candidates">protection from political interference</a>. </p>
<p>There is an evident tension between this view and what takes place in the arena of evidence-based (or informed) policy. Here <a href="http://www.eenews.net/stories/1060037292">legislation developed to fight racketeering</a> is used by activists and scientists to target their peers in the opposing faction, in hot fields from climate to <a href="http://www.biotech-now.org/food-and-agriculture/2015/09/foia-attacks-against-biotech-scientists-get-personal">biotechnologies</a>.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/138867/original/image-20160922-22518-ehdvq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/138867/original/image-20160922-22518-ehdvq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/138867/original/image-20160922-22518-ehdvq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=586&fit=crop&dpr=1 600w, https://images.theconversation.com/files/138867/original/image-20160922-22518-ehdvq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=586&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/138867/original/image-20160922-22518-ehdvq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=586&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/138867/original/image-20160922-22518-ehdvq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=736&fit=crop&dpr=1 754w, https://images.theconversation.com/files/138867/original/image-20160922-22518-ehdvq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=736&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/138867/original/image-20160922-22518-ehdvq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=736&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Perhaps not the most helpful attitude.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/dana-k/5334363735/in/photolist-98o1ux-4Lsxny-o6f7yW-8urJtd-5LLtpk-3bgN8-fL6Be3-4CvVS4-3bgN7-pCLTqZ-aWYDyi-fsqmNy-aWZ5G8-9Xh8kF-otW1kT-aWYNZr-9AV8XN-qJb9hP-djaDX1-aWYT72-6zVcHt-8uoEQT-s5FUxc-aWZ6Ja-aWYEQv-mxy1Wd-8WjUcd-e4rvge-fKP1Yv-pVR3eU-aWZ4pn-aWYR8P-aWYV9n-4mfNmo-aWYVZa-5dG1WJ-aWZ2bD-5FNsQF-4xYzsZ-hDRVXA-hDQycW-aWZ7Cc-6zZirh-HvvUMV-aWYPYH-nLJ5gy-eUJs3s-bPe7qi-qAhVyf-hDQ58P">DanaK~WaterPenny</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>The science of economics is still in control of the master narrative. The same craft that failed to predict the latest great recession – and worse, directly engineered it thanks to its financial recklessness – is still dictating market-based approaches to overcome present challenges. By its own admission, the discipline, which supported austerity policies with a <a href="http://www.newyorker.com/news/john-cassidy/the-reinhart-and-rogoff-controversy-a-summing-up">theorem based on a coding error</a>, has little clue as to what to do if the global economy will face another downturn. </p>
<p>The economic historian Erik Reinert notes that economics is the only discipline impermeable to paradigm shifts. For economics, <a href="http://www.e-elgar.com/shop/globalization-economic-development-and-inequality">he says</a>, the earth is round and flat at the same time, all the time, with fashions changing in <a href="http://www.andreasaltelli.eu/file/repository/Full_Circle_scholasticism_2.pdf">cyclical shifts</a>. </p>
<p>One can see in the present critique of finance – as something having <a href="https://profilebooks.com/other-people-039-s-money.html">outgrown its original function</a> into a self-serving entity – the same ingredients of the social critique of science. </p>
<p>Thus the ethos of “little science” reminds us of the local banker of old times. Scientists in a given field knew one another, just as local bankers had lunch and played golf with their most important customers. The ethos of techno-science or mega-science is similar to that of the modern Lehman bankers, where the key actors know one another only through performance metrics.</p>
<p>Change takes place at an ever-accelerating pace; the number of <a href="http://www.nature.com/news/go-forth-and-replicate-1.20473?WT.ec_id=NATURE-20160825&spMailingID=52137465&spUserID=MjA1NTM1Nzc4OAS2&spJobID=984506081&spReportId=OTg0NTA2MDgxS0">initiatives to heal science’s diseases</a> multiply every day from within the house of science. </p>
<p>Increasingly, philosophers warn that not all is well in our ever-stronger symbiotic relation with technology. The effects of <a href="http://secondmachineage.com/">innovation on jobs</a>, on <a href="http://www.jaronlanier.com/futurewebresources.html">inequality</a>, on our <a href="http://books.wwnorton.com/books/The-Internet-of-Us/">way of knowing</a> and of <a href="https://global.oup.com/academic/product/the-great-endarkenment-9780199326020?cc=es&lang=en&">making sense of reality</a>, are all becoming problematic. Everything moves at a pace that frustrates our hope of control. </p>
<h2>What can we do?</h2>
<p>If this wave of concern will merge with the science crisis, then important facets of our modernity might be up for discussion. Will this lead to a new humanism as hoped by some philosophers or to a new dark age, as feared by others?</p>
<p>The conflicts described thus far involve values in conflict, of the type dealt with in something called “<a href="http://www.uu.nl/wetfilos/wetfil10/sprekers/Funtowicz_Ravetz_Futures_1993.pdf">post-normal science</a>”. Many dislike the name of this approach for its postmodern associations, but appreciate its model of <a href="http://isecoeco.org/pdf/pstnormsc.pdf">extended peer communities</a>. These communities bring together experts from across disciplines – as different disciplines see through different lenses – and anyone affected or concerned with the subject at hand, with possibly different views about what the problem is. </p>
<p>Today, extended peer communities are set up by some <a href="https://www.theguardian.com/science/political-science/2016/may/12/to-confront-21st-century-challenges-science-needs-to-rethink-its-reward-system">activist citizens and scientists</a>. This format encourages a humbler, more reflexive attitude. It suggests to citizens a more critical and participatory attitude in matters of science and technology, with less deference towards experts. </p>
<p>New media provides fertile ground for these communities. “Could the internet be to science what the printing press was to the church?” asks the <a href="http://www.andreasaltelli.eu/file/repository/PeerRevieQualityControl.pdf">science and technology philosoper Silvio Funtowicz</a>. </p>
<p>If this process leads to reform in science and challenges the monopoly of knowledge and authority – as to some extent we see <a href="https://www.patientslikeme.com/">happening in health</a> - then we might go some way to rebuilding trust in one of the most important facets of modern life.</p><img src="https://counter.theconversation.com/content/65016/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andrea Saltelli does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Science’s quality control processes are under question. Scientists should think about changing the rules and extending their peer communities.Andrea Saltelli, Researcher at the Centre for the Study of the Sciences and the Humanities (SVT) , University of BergenLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/649782016-09-06T10:34:03Z2016-09-06T10:34:03ZPhilae has been found – here’s why it’s important<figure><img src="https://images.theconversation.com/files/136696/original/image-20160906-6121-sm4e3j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The red box clearly shows where the lander is hiding. </span> <span class="attribution"><span class="source">ESA.</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p><a href="https://theconversation.com/explainer-why-rosetta-comet-mission-is-such-a-big-deal-34037">Rosetta’s mission</a> to comet 67P/Churyumov-Gerasimanko is coming to an end – plans are already in place for a grand finale on September 30, when the orbiter will land gracefully (erm, crash) on the surface of the target it has been following so closely for more than two years. In preparation for the landing, Rosetta has been approaching ever closer to the surface. High resolution images of the surface have been returned, showing in great detail the stark and pitted landscape, ragged cliffs and boulder-strewn plains.</p>
<p>But what is that, under that rock – could it be? Could it possibly be? It is – it’s Philae! The lost comet lander <a href="http://www.esa.int/Our_Activities/Space_Science/Rosetta/Philae_found">was identified</a> in images taken by Rosetta’s OSIRIS camera on September 2, from a height of only 2.7km above the surface. It was emotional for me to see the lander sheltering below a cliff, thinking back to the last sight we had of it, in freefall towards the surface of 67P. There have been several false alarms, with unusually shaped or shadowed rocks thought to be Philae, but the new identification is very clear – “unequivocal”, in the words of the European Space Agency. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/1wbDqv6HNyg?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">A happy landing.</span></figcaption>
</figure>
<p>Philae was delivered to the comet on November 12 2014, but bounced on landing, settling a short (but significant) distance away from its designated landing site. Philae <a href="https://theconversation.com/explainer-what-philae-did-in-its-60-hours-on-comet-67p-34289">returned data from its instruments for 60 hours</a> until its main batteries died. It was thought, at the time, that Philae had landed on its side, under an overhang, preventing its secondary, solar-powered batteries to be recharged. In June and July 2015, when the comet had moved much closer to the sun, Philae <a href="https://theconversation.com/philae-phones-home-but-the-mission-is-about-to-get-riskier-43261">made sporadic contact</a> with Rosetta, suggesting that a communications antenna had been damaged.</p>
<h2>Important data at stake</h2>
<p>Now, we can see that the supposition was correct – Philae is on its side, wedged underneath an overhanging cliff in the Abydos region of the comet. It is, of course, great to see the lander that produced so much interesting data in its shortened active lifetime. But why has so much effort been put in to <a href="https://theconversation.com/eureka-weve-found-beagle2-now-where-did-philae-go-36375">trying to find Philae</a>? There is no chance that any of its instruments could be operational – the comet is too far away from the sun to power them, which is why the Rosetta mission is coming to an end. The reason is that we can now put the acquired data into context. The <a href="http://www.open.ac.uk/science/research/rosetta/mission/philae-lander/mupus">MUPUS team</a>, in charge of a multipurpose sensor package on board Philae, will be able to identify which rock its penetrator hammered into, giving the team a much clearer idea of which part of the surface was so hard.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/136701/original/image-20160906-6130-17u30cv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/136701/original/image-20160906-6130-17u30cv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/136701/original/image-20160906-6130-17u30cv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/136701/original/image-20160906-6130-17u30cv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/136701/original/image-20160906-6130-17u30cv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/136701/original/image-20160906-6130-17u30cv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/136701/original/image-20160906-6130-17u30cv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Philae close up.</span>
<span class="attribution"><a class="source" href="http://www.esa.int/spaceinimages/Images/2016/09/Philae_close-up_labelled">ESA</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Now that we know where Philae is, images from cameras on the lander can be orientated relative to images from Rosetta by matching surface features that the two sets of images have in common. The surface of the comet has been mapped, by an instrument on Rosetta, into areas with different composition, based on how light is reflected from the comet’s surface. By looking in more detail at the structure of Philae’s landing site, the compositional data can be corrected, taking into account the shape of the landscape. This will enable a better idea of the composition of the rocks around Philae, which in turn will help interpret data from the other instruments.</p>
<p>One particular instrument team may be rejoicing more loudly than others. <a href="http://www.esa.int/Our_Activities/Space_Science/Rosetta/CONSERT">CONSERT (Comet Nucleus Sounding Experiment by Radiowave Transmission)</a> was designed to analyse radio waves that bounced between Rosetta and Philae, to determine the interior structure of 67P. The team has been liaising with the imaging teams to search for Philae, as the data they had could help locate Philae to within an area of a few square metres. Now, in combination with the close-up pictures, the location has been tied down precisely. This is surely a great relief to the CONSERT team, because without knowing exactly where Philae landed, their data could not be interpreted fully. Now they know where Philae is, they can go ahead and gain a more accurate determination of the <a href="https://theconversation.com/building-blocks-of-life-found-among-organic-compounds-on-comet-67p-what-philae-discoveries-mean-45379">comet’s interior</a>. </p>
<p>The CONSERT should be able to derive something that is almost like a CT scan of 67P, identifying small structural variations in the interior of the comet. We might even be able to find out how well the two lobes of the comet are joined together – and if they might break apart again.</p>
<p>Although it is not currently planned to land Rosetta close to Philae, there will be a few more opportunities to take images from even closer over the remaining time of the mission. Philae was gone, but not forgotten. Now that we know the lander’s final resting place, we can picture it in <a href="http://www.esa.int/Our_Activities/Space_Science/Rosetta/Rosetta_s_lander_faces_eternal_hibernation">eternal hibernation</a> circling the sun for the lifetime of its cometary ride.</p><img src="https://counter.theconversation.com/content/64978/count.gif" alt="The Conversation" width="1" height="1" />
<h4 class="border">Disclosure</h4><p class="fine-print"><em><span>Monica Grady is a Trustee of Lunar Mission One and receives funding from the STFC and the EU</span></em></p>Philae has finally been found but what was the point of putting so much effort into the search? None of its instruments will actually be working …Monica Grady, Professor of Planetary and Space Sciences, The Open UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/546762016-02-12T16:06:50Z2016-02-12T16:06:50ZFarewell to Philae?<figure><img src="https://images.theconversation.com/files/111327/original/image-20160212-29198-1x6nyk4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Lander Philae on Comet P Churyumov Gerasimenko.</span> <span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Philae_%28spacecraft%29#/media/File:Rosetta%27s_Philae_on_Comet_67P_Churyumov-Gerasimenko.jpg">wikipedia</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>How do you say goodbye to a valued colleague with whom you have worked closely for almost two decades? Maybe there is a farewell party, a collection for a gift, a bunch of flowers? If the colleague is moving to an exciting new post, the affair is usually joyful, possibly tinged with envy as well as regret. The same is true if the colleague is retiring – depending how close you are to retirement yourself. But what are those who <a href="https://theconversation.com/scientists-at-work-from-rosetta-mission-control-as-philae-lands-34152">worked on developing the comet lander Philae</a> supposed to feel now their colleague faces “eternal hibernation” after a decision was made <a href="http://www.bbc.co.uk/news/science-environment-35559503">to give up trying to contact it</a>?</p>
<p>The Rosetta spacecraft released Philae onto comet 67P/Churyumov Gerasimenko on November 12 2014. Although the landing didn’t go quite as planned, Philae was still <a href="https://theconversation.com/explainer-what-philae-did-in-its-60-hours-on-comet-67p-34289">able to operate</a> for almost 70 hours before its main batteries ran out, fulfilling almost all of its scientific goals. The awkward landing prevented Philae’s solar panels from charging-up the secondary batteries, but it was hoped that as 67P drew closer to the sun, the increasing levels of light would revive the sleeping lander. And this happened – on June 13 2015, Rosetta received a signal from Philae, indicating that the batteries were charged, and the lander was all set for another phase of investigation.</p>
<p>Unfortunately, in order for Philae to work effectively, there had to be a stable connection with Rosetta. And that did not happen, possibly because Philae’s transmitter became damaged as it landed. Only intermittent communication was possible – and then even that ceased when Rosetta had to move away from 67P as it came closer to the sun. This was because the amount of dust flowing away from the nucleus was a danger to Rosetta. Imagine having to steer a vehicle through a howling blizzard with no way of clearing the windscreen – that was the effect the dust was having. The spacecraft had to retreat to a safe distance of about 300km from the surface – too great to hear Philae’s signals.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/111332/original/image-20160212-29180-wzi6ah.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/111332/original/image-20160212-29180-wzi6ah.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/111332/original/image-20160212-29180-wzi6ah.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/111332/original/image-20160212-29180-wzi6ah.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/111332/original/image-20160212-29180-wzi6ah.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/111332/original/image-20160212-29180-wzi6ah.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/111332/original/image-20160212-29180-wzi6ah.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Where’s Philae hiding?</span>
<span class="attribution"><span class="source">ESA/Rosetta/NAVCAM</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>There was a second opportunity for communication when Rosetta went through <a href="https://theconversation.com/night-sky-puts-on-a-meteor-shower-to-celebrate-rosettas-closest-approach-to-the-sun-45962">its closest approach to the sun</a> and then started to move away, and the comet’s activity decreased. Rosetta has been listening for Philae, but sadly not a chirp or a tweet has been heard. Partly this has been because the distance between Rosetta and the nucleus was too great – but since about January, Rosetta has been within hailing distance, and still no word has been received.</p>
<h2>Fried, buried or frozen?</h2>
<p>We are not certain why Philae has not been able to communicate. As well as potential damage to its transmitter, the communications antenna might have been displaced and could be pointing in the wrong direction. Or the copious quantities of dust released by the comet have covered the solar panels, preventing them charging up. Or some of the dust has found its way into the inner workings of the lander, and jammed an essential component. Or ice could have sublimated – vaporising without turning into a liquid first – below the lander, causing it to fall even further over. </p>
<p>Yet other possible causes are an overhanging ice cliff crashing down on top of Philae or too much sunlight frying the electronics. Unfortunately, because nothing much can (or could) be done to fix the communication problem, it doesn’t really matter what is causing the radio silence. It is disappointing that there was no opportunity for additional science from the lander – but so much information was returned from the initial campaign that the Philae scientists will be kept busy for plenty of time yet.</p>
<p>And never say never. Over the next six months, Rosetta will orbit the comet more closely – and by about August could be in a position to see Philae directly. If this happens, we should be able to deduce why communication couldn’t be established. It will also help us interpret the data acquired by the instruments, as we will be able to see the landscape in which Philae is sitting.</p>
<p>There will not be any retirement parties for Philae yet – not until Rosetta makes its controlled landing on 67P in September. And that will be a glorious ending to an unforgettable mission.</p>
<p>Mind you, I suspect it was the <a href="https://theconversation.com/gravitational-waves-found-the-inside-story-54589">gravitational waves</a> that knocked the antenna off-beam …</p><img src="https://counter.theconversation.com/content/54676/count.gif" alt="The Conversation" width="1" height="1" />
<h4 class="border">Disclosure</h4><p class="fine-print"><em><span>Monica Grady receives funding from the STFC and is a Trustee of Lunar Mission One.</span></em></p>Ground control says it is time to give up hope of regaining communication with comet lander Philae. But never say never.Monica Grady, Professor of Planetary and Space Sciences, The Open UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/525312015-12-23T15:51:33Z2015-12-23T15:51:33ZThe magical Solar System discoveries we made in 2015<figure><img src="https://images.theconversation.com/files/106971/original/image-20151223-27875-10fe10l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Comet 67P/Churyumov-Gerasimenko, as seen from Rosetta.</span> <span class="attribution"><a class="source" href="http://www.esa.int/spaceinimages/Images/2015/11/Comet_on_17_November_2015_-_NAVCAM">ESA/Rosetta/NAVCAM</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>It has been a busy year for Solar System exploration – and particularly our galactic neighbourhood’s small icy bodies. Comets, asteroids, <a href="http://pluto.jhuapl.edu/Participate/learn/What-We-Know.php?link=The-Kuiper-Belt">Kuiper Belt Objects</a> and planetary satellites have all been in the news – from stunning images of comet <a href="http://sci.esa.int/rosetta/14615-comet-67p/">67P Churyumov-Gerasimenko</a> at the start of the year, to the recent close-up of Saturn’s moon, Enceladus, via Ceres and Pluto. </p>
<p>Early January was a continuation of the stream of data from <a href="http://www.esa.int/Our_Activities/Space_Science/Rosetta">Rosetta</a>, as comet 67P drew closer to the sun. Images were released of jets emanating from the <a href="http://www.esa.int/spaceinimages/Images/2015/01/Comet_activity_22_November_2014">sun-facing surface</a>, from which it could be seen that sublimation of water-ice increased during the daytime, and died down at night. But because the dark surface of the comet retained some heat, the comet was not completely inactive at night – it was possible that fluid might exist for very short periods, leading to sub-surface hydrous activity.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/106984/original/image-20151223-27880-1m1k3oh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/106984/original/image-20151223-27880-1m1k3oh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/106984/original/image-20151223-27880-1m1k3oh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/106984/original/image-20151223-27880-1m1k3oh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/106984/original/image-20151223-27880-1m1k3oh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/106984/original/image-20151223-27880-1m1k3oh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/106984/original/image-20151223-27880-1m1k3oh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Activity on Comet 67P.</span>
<span class="attribution"><a class="source" href="http://www.esa.int/spaceinimages/Images/2015/01/Comet_activity_22_November_2014">ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>One of the other significant results from Rosetta was recognition from magnetic measurements that the two lobes of the comet had been separate bodies, presumably brought together by collision. </p>
<p>Closest approach to the sun was in mid-August, a few weeks after the <a href="http://blogs.esa.int/rosetta/tag/philae-2/">Philae lander</a> signalled that it had woken up after its enforced hibernation. Unfortunately, communication between Rosetta and Philae could not be established reliably, leaving a certain amount of frustration that additional data could not be acquired from the surface. </p>
<h2>Welcome to Pluto (and Charon)</h2>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/106974/original/image-20151223-27863-s0qf68.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/106974/original/image-20151223-27863-s0qf68.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/106974/original/image-20151223-27863-s0qf68.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/106974/original/image-20151223-27863-s0qf68.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/106974/original/image-20151223-27863-s0qf68.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/106974/original/image-20151223-27863-s0qf68.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/106974/original/image-20151223-27863-s0qf68.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Composite image of Pluto and Charon.</span>
<span class="attribution"><a class="source" href="http://www.nasa.gov/image-feature/charon-and-pluto-strikingly-different-worlds">NASA/JHUAPL/SwRI</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>July brought us a close-up of Pluto. The images have been tremendous, turning Pluto from a fuzzy grey blob into a fascinating body of mountains, plains and valleys. Pluto’s closest, and largest, moon, Charon was also captured by the New Horizon mission cameras in similar detail. <a href="https://www.nasa.gov/image-feature/charon-and-pluto-strikingly-different-worlds">The two worlds are very different</a> in their characteristics. Parts of Pluto’s icy surface are crumpled into <a href="https://www.nasa.gov/image-feature/plutos-incredible-diversity-of-surface-reflectivities-and-geological-landforms">mountains and ridges</a>. The “heart” of Pluto, around 1500km across, is a flat and featureless plain, presumably resurfaced relatively recently, showing that Pluto is more active than anticipated.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/106975/original/image-20151223-27851-10v23di.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/106975/original/image-20151223-27851-10v23di.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=541&fit=crop&dpr=1 600w, https://images.theconversation.com/files/106975/original/image-20151223-27851-10v23di.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=541&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/106975/original/image-20151223-27851-10v23di.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=541&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/106975/original/image-20151223-27851-10v23di.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=679&fit=crop&dpr=1 754w, https://images.theconversation.com/files/106975/original/image-20151223-27851-10v23di.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=679&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/106975/original/image-20151223-27851-10v23di.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=679&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Dark areas on Pluto.</span>
<span class="attribution"><a class="source" href="https://www.nasa.gov/image-feature/plutos-incredible-diversity-of-surface-reflectivities-and-geological-landforms">NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Charon, with approximately half the diameter of Pluto, is also a <a href="https://www.nasa.gov/feature/pluto-s-big-moon-charon-reveals-a-colorful-and-violent-history">world of contrasts</a>. The southern hemisphere is flat, relatively smooth and low-lying, broken mainly by impact craters, while the northern regions are fractured with much more topography. Separating the two halves of the moon is an extensive system of canyons, perhaps akin to the Valles Marineris on Mars, probably caused by tectonic stress. Mission scientists have suggested that the southern region is younger than the northern, and has been resurfaced by cryovolcanism – instead of lava, cryovolcanos eject substances such as water, methane or ammonia – implying a frozen ocean below Charon’s crust.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/106976/original/image-20151223-27880-1vw2axp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/106976/original/image-20151223-27880-1vw2axp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/106976/original/image-20151223-27880-1vw2axp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/106976/original/image-20151223-27880-1vw2axp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/106976/original/image-20151223-27880-1vw2axp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/106976/original/image-20151223-27880-1vw2axp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/106976/original/image-20151223-27880-1vw2axp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Charon.</span>
<span class="attribution"><a class="source" href="https://www.nasa.gov/feature/pluto-s-big-moon-charon-reveals-a-colorful-and-violent-history">NASA/JHUAPL/SwRI</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>It should be remembered that the wealth of data now returning to Earth from the New Horizon’s spacecraft was acquired during a fly-by of Pluto that lasted a mere 15 minutes. Imagine what could be learnt with an orbiter.</p>
<h2>A new dawn</h2>
<p><a href="http://dawn.jpl.nasa.gov">The Dawn mission</a> to Asteroid (1) Ceres was a bright spot – literally – in the planetary exploration calendar. At the start of the year, the spacecraft began to orbit the dwarf planet, and images revealed several patches of <a href="http://dawn.jpl.nasa.gov/multimedia/images/image-detail.html?id=PIA20180">highly reflective material</a>. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/106979/original/image-20151223-27894-z2s7i6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/106979/original/image-20151223-27894-z2s7i6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/106979/original/image-20151223-27894-z2s7i6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/106979/original/image-20151223-27894-z2s7i6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/106979/original/image-20151223-27894-z2s7i6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/106979/original/image-20151223-27894-z2s7i6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/106979/original/image-20151223-27894-z2s7i6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Ceres from Dawn.</span>
<span class="attribution"><a class="source" href="http://dawn.jpl.nasa.gov/multimedia/images/image-detail.html?id=PIA20180">NASA/JPL-Caltech/UCLA/MPS/DLR/IDA</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>At first it was suggested that the patches may be of water-ice. This would be unexpected, since the surface of Ceres is too warm for water-ice to be stable at the surface. It is now thought that the bright spots might be salts remaining <a href="https://theconversation.com/dawn-breaks-over-distant-ceres-and-perhaps-reveals-signs-of-habitability-38967">following evaporation (or sublimation of water)</a>.</p>
<h2>A ball of mud</h2>
<p>Ceres is currently thought to be like a ball of compressed mud, possibly with a layer of water-rich slurry below a thin crust of mud – not an attractive description for the largest of the asteroids, but one which clearly shows that the minor planet has had a lengthy history of aqueous activity. </p>
<p>This is important because, like comets, asteroids have played a significant role in the delivery of water and other volatile compounds to Earth. The Dawn spacecraft spent most of 2015 orbiting Ceres at gradually decreasing altitudes – settling, at the beginning of December, in its lowest orbit about 400km above the surface. </p>
<p>Images have shown that Ceres is crossed by troughs and grooves reminiscent of those present on other (larger) <a href="http://dawn.jpl.nasa.gov/multimedia/images/image-detail.html?id=PIA20186">planetary bodies</a>. Some of the features are impact-related, but some seem to have been produced by stress fracturing of the crust, another example of Ceres’ puzzling and sometimes contradictory history.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/106981/original/image-20151223-27858-psoq2w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/106981/original/image-20151223-27858-psoq2w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/106981/original/image-20151223-27858-psoq2w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/106981/original/image-20151223-27858-psoq2w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/106981/original/image-20151223-27858-psoq2w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/106981/original/image-20151223-27858-psoq2w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/106981/original/image-20151223-27858-psoq2w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Ceres: time for your close-up.</span>
<span class="attribution"><a class="source" href="http://dawn.jpl.nasa.gov/multimedia/images/image-detail.html?id=PIA20186">NASA/JPL-Caltech/UCLA/MPS/DLR/IDA</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<h2>The oceans of Enceladus</h2>
<p>Although the <a href="http://saturn.jpl.nasa.gov">Cassini mission</a> has been operational within the Saturnian system for over a decade, and is coming to the end of its life, it is still returning exciting data from the icy moon, Enceladus. In October, the spacecraft took a dive through the plume at the south pole, flying only about 50km above the surface. Then, only last week, Cassini completed its final close encounter with Enceladus, giving us pictures of <a href="http://www.ciclops.org/view_media/41440/Frozen-Fractures">frozen fractures and ridges</a>. We know that Enceladus has a sub-surface global salty ocean – placing it with Jupiter’s moon, Europa, as a possible host to an ocean-floor ecosystem.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/106985/original/image-20151223-27890-fagymy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/106985/original/image-20151223-27890-fagymy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/106985/original/image-20151223-27890-fagymy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/106985/original/image-20151223-27890-fagymy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/106985/original/image-20151223-27890-fagymy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/106985/original/image-20151223-27890-fagymy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/106985/original/image-20151223-27890-fagymy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The surface of Enceladus.</span>
<span class="attribution"><a class="source" href="http://photojournal.jpl.nasa.gov/catalog/PIA17209">NASA/JPL-Caltech/Space Science Institute</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<h2>What next?</h2>
<p>The amazing images that have come from the missions to icy bodies have generated a great increase in public interest in Solar System exploration. A quick trawl through social media sites such as Twitter shows how avidly the missions are followed and results discussed, almost in real time. If 2015 was a Golden Age for the exploration of small icy bodies, we can only hope that among the legacies of the missions is a generation of students enthused to continue investigation of our neighbourhood. </p>
<p>But what may be in store for small icy bodies in 2016? Work has only just started for the cameras on board Dawn, as the spacecraft starts its mapping of Ceres. There will be more images and information from Pluto and its satellites, especially Charon. Cassini has made its final close fly-by of Enceladus, and the images will be returned throughout the coming year. Rosetta will watch 67P’s activity die down as the comet moves further and further away from the sun. But before we say a complete goodbye to comet Churyumov-Gerasimenko, maybe, just maybe, we will hear from Philae …</p><img src="https://counter.theconversation.com/content/52531/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Monica Grady receives funding from the STFC and is a Trustee of Lunar Mission One.</span></em></p>Prepare to be amazed …Monica Grady, Professor of Planetary and Space Sciences, The Open UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/453792015-07-30T21:26:10Z2015-07-30T21:26:10ZBuilding blocks of life found among organic compounds on Comet 67P – what Philae discoveries mean<figure><img src="https://images.theconversation.com/files/90114/original/image-20150729-30862-5706p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The building blocks of life are lurking on the dark and barren surface of Comet 67P.</span> <span class="attribution"><a class="source" href="http://www.esa.int/spaceinimages/Images/2015/04/Comet_on_28_March_2015_NavCam_mosaic">ESA/Rosetta/NAVCAM</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>Scientists analysing the latest data from <a href="https://theconversation.com/explainer-what-philae-did-in-its-60-hours-on-comet-67p-34289">Comet 67P Churyumov-Gerasimenko</a> have discovered molecules that can form sugars and amino acids, which are the building blocks of life as we know it. While this is a long, long way from <a href="https://theconversation.com/theres-no-evidence-to-suggest-there-is-life-on-comet-67p-44384">finding life itself</a>, the data shows that the organic compounds that eventually translated into organisms here on Earth existed in the early solar system. </p>
<p>The results are <a href="http://www.sciencemag.org/lookup/doi/10.1126/science.aab0689">published</a> as two independent <a href="http://www.sciencemag.org/lookup/doi/10.1126/science.aab0673">papers</a> in the journal <em>Science</em>, based on data from two different instruments on <a href="https://theconversation.com/philae-phones-home-but-the-mission-is-about-to-get-riskier-43261">comet lander Philae</a>. One comes from the German-led <a href="http://www.open.ac.uk/science/research/rosetta/mission/philae-lander/cosac">Cometary Sampling and Composition</a> (COSAC) team and one from the UK-led <a href="http://sci.esa.int/rosetta/31445-instruments/?fbodylongid=896">Ptolemy team</a>. </p>
<p>The data finally sheds light on questions that the European Space Agency posed 22 years ago. One of the declared goals of the <a href="http://www.esa.int/Our_Activities/Space_Science/Rosetta">Rosetta mission</a> when it was approved in 1993 was to determine the composition of <a href="http://sci.esa.int/rosetta/47366-fact-sheet/">volatile compounds</a> in the cometary nucleus. And now we have the answer, or at least, an answer: the compounds are a mixture of many different molecules. Water, carbon monoxide (CO) and carbon dioxide (CO<sub>2</sub>) – this is not too surprising, given that these molecules <a href="http://www.space.com/2010-water-ice-detected-comet-surface.html">have been detected many times before</a> around comets. But both COSAC and Ptolemy have found a very wide range of additional compounds, which is going to take a little effort to interpret.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/90113/original/image-20150729-30882-4surgi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/90113/original/image-20150729-30882-4surgi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=565&fit=crop&dpr=1 600w, https://images.theconversation.com/files/90113/original/image-20150729-30882-4surgi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=565&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/90113/original/image-20150729-30882-4surgi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=565&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/90113/original/image-20150729-30882-4surgi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=710&fit=crop&dpr=1 754w, https://images.theconversation.com/files/90113/original/image-20150729-30882-4surgi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=710&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/90113/original/image-20150729-30882-4surgi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=710&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">New images show Philae’s landing spots on comet when bouncing around and taking measurements.</span>
<span class="attribution"><span class="source">ESA/ROSETTA/NAVCAM/SONC/DLR</span></span>
</figcaption>
</figure>
<p>At this stage, I should declare an interest: I am a co-investigator on the Ptolemy team – but not an author on the paper. But the principal investigator of Ptolemy, and first author on the paper, is my husband <a href="https://theconversation.com/profiles/ian-wright-114049">Ian Wright</a>.</p>
<p>Having made this clear, I hope that readers will trust that I am not going to launch into a major diatribe against one set of data, or a paean of praise about the other. What I am going to do is look at the conclusions that the two teams have reached – because, although they made similar measurements at similar times, they have interpreted their data somewhat differently. This is not a criticism of the scientists, it is a reflection of the complexity of the data and the difficulties of disentangling mass spectra.</p>
<h2>Deciphering the data</h2>
<p>What are the two instruments? And, perhaps more to the point, what exactly did they analyse? Both COSAC and Ptolemy can operate either as <a href="http://teaching.shu.ac.uk/hwb/chemistry/tutorials/chrom/gaschrm.htm">gas chromatographs</a> or <a href="https://www.abrf.org/ABRFNews/1996/September1996/sep96iontrap.html">mass spectrometers</a>. In mass spectrometry mode, they can identify chemicals in vaporised compounds by stripping the molecules of their electrons and measuring the mass and charge of the resulting ions (the mass-to-charge ratio, m/z). In gas-chromatography mode they separate the mixture on the basis of how long it takes each component in the mixture to travel through a very long and thin column to an ionisation chamber and detector.</p>
<p>Either way, the result is a mass spectrum, showing how the mixture of compounds separated out into its individual components on the basis of the molecular mass relative to charge (m/z).</p>
<p>Unfortunately, the job doesn’t end there. If it were that simple, then organic chemists would be out of a job very quickly. Large molecules break down into smaller molecules, with characteristic fragmentation patterns depending on the bonds present in the original molecule. Ethane, C<sub>2</sub> H<sub>6</sub> for example, has an m/z of 30, which was seen in the spectra. So the peak might be from ethane, or it might be from a bigger molecule which has broken down in the ionisation chamber to give ethane, plus other stuff. </p>
<p>Then again, it might be from CH<sub>2</sub>O, which is formaldehyde. Or it might be from the breakdown of polyoxymethylene. Or it might be from almost <a href="http://webbook.nist.gov/cgi/cbook.cgi?Value=30&VType=MW&Formula=&Units=SI">any one of the other 46 species</a> which have an m/z of 30. Figuring out what it is exactly is a tough job and the main reason why I gave up organic chemistry after only a year – far too many compounds to study.</p>
<p>Of course, the teams didn’t identify every single peak in isolation, they considered the series of peaks which come from fragmentation. This helps a bit, in that there are now many more combinations of compounds and fractions of compounds which can be matched. </p>
<p>So where does this leave us? Actually, with an embarrassment of riches. Have the teams come to the same conclusions? Sort of. They both detected compounds which are important in the pathway to producing sugars – which go on to form the <a href="http://www.sparknotes.com/biology/molecular/structureofnucleicacids/section2.rhtml">“backbone” of DNA</a>. They also both note the very low number of sulphur-bearing species, which is interesting given the <a href="http://www.compoundchem.com/2014/07/25/planetatmospheres/">abundance of sulphur in the solar system</a>, and the ease with which it can become integrated into organic compounds. </p>
<p>The COSAC team suggests that nitrogen-bearing species could be relatively abundant, whilst Ptolemy found fewer of them. This is important because nitrogen is an essential element for life, and is a fundamental <a href="http://www.ncbi.nlm.nih.gov/books/NBK22475/">part of the amino acids</a>. Conversely, the Ptolemy team has found lots of CO<sub>2</sub>, whilst COSAC hasn’t detected much. </p>
<p>These differences are probably related to sampling location: COSAC ingested material from the bottom of Philae, while Ptolemy sniffed at the top. Did Ptolemy breathe in cometary gases, whilst COSAC choked on the dust kicked up during the brief touchdown? If so, then the experiments have delivered wonderfully complementary sets of data. </p>
<p>Most importantly, both of those sets of data show that the ingredients for life were present in a body which formed in the earliest stages of solar system history. Comets act as messengers, delivering water and dust throughout the solar system – now we have learnt for certain that the ingredients for life have been sown far and wide through the 4.567 billion years of solar system history. The challenge now is to discover where else it might have taken root.</p>
<p>What else is certain is that both teams are keeping fingers crossed that the Philae-Rosetta communications link stabilises, so that they can get on with their analyses. This is just the start.</p><img src="https://counter.theconversation.com/content/45379/count.gif" alt="The Conversation" width="1" height="1" />
<h4 class="border">Disclosure</h4><p class="fine-print"><em><span>Monica Grady is a co-investigator on the Ptolemy team, and wife of Professor Ian Wright, the Principal Investigator, but is not an author on the Science paper discussed in the article, and neither was she involved in its preparation. She receives funding from the STFC and is a Trustee of Lunar Mission One.</span></em></p>Two independent teams have found compounds including nitrogen and carbon dioxide on Comet 67P, which can form sugars and amino acids.Monica Grady, Professor of Planetary and Space Sciences, The Open UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/441582015-07-15T05:22:46Z2015-07-15T05:22:46ZFrom comets to planets near and far, space probes reveal the universe<figure><img src="https://images.theconversation.com/files/88370/original/image-20150714-21701-xe0wt3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="http://solarviews.com/cap/vss/VSS00041.htm">NASA/JHUAPL/SwRI</a></span></figcaption></figure><p>If space is humankind’s ultimate challenge, then the first step starts close to home – we have still to explore much of our solar system that spans across enormous distances, never mind those galaxies and stars more distant still. </p>
<p>To learn more we must get closer, dispatching spacecraft such as New Horizons – which has <a href="http://www.bbc.co.uk/news/science-environment-33524589">just returned our first ever close-up images of Pluto</a> after a nine year journey. Here are my top five missions that are chipping away at what we don’t know and building up a better sense of universe around us.</p>
<h2>1. New Horizons</h2>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/88373/original/image-20150714-21719-1dnittw.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/88373/original/image-20150714-21719-1dnittw.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/88373/original/image-20150714-21719-1dnittw.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/88373/original/image-20150714-21719-1dnittw.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/88373/original/image-20150714-21719-1dnittw.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/88373/original/image-20150714-21719-1dnittw.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/88373/original/image-20150714-21719-1dnittw.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/88373/original/image-20150714-21719-1dnittw.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Time for your close-up, Pluto.</span>
<span class="attribution"><a class="source" href="http://pluto.jhuapl.edu/Multimedia/Science-Photos/image.php?gallery_id=2&image_id=222">NASA/JHU APL/SwRI</a></span>
</figcaption>
</figure>
<p>Rocketing past at 14km/s, the New Horizons spacecraft has provided our first close view of Pluto which will enormously improve our understanding of this distant body. Our facts regarding this icy dwarf are sketchy at best. Just knowing what Pluto looks like makes it much more real.</p>
<p>The probe’s brief two-hour visit captured images of parts of Pluto and its largest moon Charon at high resolution, improving our understanding of planet formation. This is an amazing feat, considering the signals take more than 4.5 hours to reach Earth and that the sun is so weak at this extreme distance that solar power is not an option. </p>
<p>But the mission doesn’t end here: in 2019 New Horizons will visit a small object in the Kuiper belt, a region of space filled with small rocky planetoids, giving us a chance to examine the make-up of these remnants of the early solar system. And by 2026, it will reach the outer edges of the solar system. </p>
<h2>2. Rosetta</h2>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/87345/original/image-20150703-20478-13i4cyi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/87345/original/image-20150703-20478-13i4cyi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=534&fit=crop&dpr=1 600w, https://images.theconversation.com/files/87345/original/image-20150703-20478-13i4cyi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=534&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/87345/original/image-20150703-20478-13i4cyi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=534&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/87345/original/image-20150703-20478-13i4cyi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=671&fit=crop&dpr=1 754w, https://images.theconversation.com/files/87345/original/image-20150703-20478-13i4cyi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=671&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/87345/original/image-20150703-20478-13i4cyi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=671&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Comet 67P/Churyumov-Gerasimenko, as seen from Rosetta 20km above.</span>
<span class="attribution"><a class="source" href="http://www.esa.int/spaceinimages/Images/2014/12/Comet_on_10_December_2014_NavCam">ESA</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Conceived decades ago, Rosetta flew alone through space for years before it reached the tiny comet that was its target and swung into orbit around it. Given the comet’s highly irregular shape this is an outstanding feat by itself.</p>
<p>The lander Philae managed to touch down and collect surface data of the comet, and while it was forced to shut down from lack of sunlight falling on its solar panels, it has now awoken and is transmitting data again. The Rosetta orbiter mission has also been extended to 2016 when it will also attempt to land on the comet.</p>
<p>The missions have improved our understanding of comets which contain <a href="http://blogs.esa.int/rosetta/2015/06/24/exposed-water-ice-detected-on-comets-surface/">frozen, icy rocks</a>, and have measured the <a href="http://blogs.esa.int/rosetta/2015/06/02/ultraviolet-study-reveals-surprises-in-comet-coma">gas composition of jets streaming off the comet</a> before they are altered by solar radiation.</p>
<p>But more than just hard numbers, this mission has been capturing images that speak for themselves, showing an ambitious mission conceived by many nations working together. Images such as Rosetta’s pictures of Philae descending resonates with us more than just hard facts and figures.</p>
<h2>3. Dawn</h2>
<p>Dawn is another mission expanding our knowledge of dwarf planets, in this case Ceres. It is now orbiting this interesting object having spent 2011 conducting similar work around nearby Vesta. Both Vesta and Ceres in the asteroid belt are protoplanets but of quite different composition.</p>
<p>Dawn has illustrated how powerful imagery can be. The most intriguing image is a crater that contains a <a href="http://dawn.jpl.nasa.gov/news/news-detail.html?id=4633">handful of bright white spots</a> on a surface otherwise darker than coal – unexpected, unexplored, challenging terrain.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/87351/original/image-20150703-20462-1tdeqzs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/87351/original/image-20150703-20462-1tdeqzs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=328&fit=crop&dpr=1 600w, https://images.theconversation.com/files/87351/original/image-20150703-20462-1tdeqzs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=328&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/87351/original/image-20150703-20462-1tdeqzs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=328&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/87351/original/image-20150703-20462-1tdeqzs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=412&fit=crop&dpr=1 754w, https://images.theconversation.com/files/87351/original/image-20150703-20462-1tdeqzs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=412&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/87351/original/image-20150703-20462-1tdeqzs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=412&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">What is the bright spot on the surface of Ceres? Dawn will find out.</span>
<span class="attribution"><a class="source" href="http://dawn.jpl.nasa.gov/news/news-detail.html?id=4619">NASA</a></span>
</figcaption>
</figure>
<h2>4. Messenger</h2>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/88366/original/image-20150714-21701-nnpb7n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/88366/original/image-20150714-21701-nnpb7n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/88366/original/image-20150714-21701-nnpb7n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/88366/original/image-20150714-21701-nnpb7n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/88366/original/image-20150714-21701-nnpb7n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/88366/original/image-20150714-21701-nnpb7n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/88366/original/image-20150714-21701-nnpb7n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Incredibly detailed images from Messenger’s visit to Mercury.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:PIA19419-Mercury-Messenger-MASCS-20150416.jpg">NASA/JHU APL/Carnegie Institution of Washington</a></span>
</figcaption>
</figure>
<p>Messenger is still in my list of impressive space probes even though the mission ended with its controlled crash on Mercury’s surface this April. Sent to explore a planet of which we had barely any imagery of its surface, in four years Messenger managed to not only give us high-resolution maps of the innermost planet, it <a href="http://www.space.com/29281-messenger-spacecraft-mercury-crash.html">discovered water in its dark polar craters</a>. On a planet baked by the sun this could only arrive from comets and water-rich asteroids – objects currently under investigation by Rosetta and New Horizons.</p>
<h2>5. Curiosity</h2>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/88368/original/image-20150714-21701-bgp637.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/88368/original/image-20150714-21701-bgp637.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/88368/original/image-20150714-21701-bgp637.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/88368/original/image-20150714-21701-bgp637.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/88368/original/image-20150714-21701-bgp637.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/88368/original/image-20150714-21701-bgp637.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/88368/original/image-20150714-21701-bgp637.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Curiosity Rover’s famous off-world self-portrait from Mars.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:PIA16239_High-Resolution_Self-Portrait_by_Curiosity_Rover_Arm_Camera_square.jpg">NASA/JPL-Caltech/Malin Space Science Systems</a></span>
</figcaption>
</figure>
<p>The last is the Curiosity rover. For me it sums up the efforts to explore our neighbour, Mars. These missions went in search of life and traces of water, carrying a complex laboratory, drills, laser and high resolution cameras.</p>
<p>Curiosity particularly illustrates the challenges we are capable of mastering to land a probe on Mars – described by NASA themselves as “seven minutes of terror”.</p>
<p>These rovers have achieved an outstanding feat, where now those exploring beyond Earth are not astronomers but geologists, the rovers’ equipment replacing the hammer and microscope used during fieldwork. The missions have added Mars to the “territory” that humans have access to. It’s even on <a href="http://www.google.co.uk/mars/">Google Maps</a> – imagery so good that we can see its surface as if we were there and can <a href="http://www.huffingtonpost.com/2014/09/02/11-rocks-on-mars-illusions_n_5697695.html">look at rocks in such detail</a> as if we were picking up pebbles at the beach.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/Ki_Af_o9Q9s?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<h2>It’s out there waiting for us</h2>
<p>Probes have witnessed solar eclipses and comet fly-bys that provide an entirely different view than is possible from Earth – something that adds a feel of awe and wonder, like looking back on Earth from the moon.</p>
<p>The sort of incredible images provided by these probes connects us with the solar system, bringing it closer to home. Famous images of Earth from space, such as the <a href="http://visibleearth.nasa.gov/view_cat.php?categoryID=1484">Blue Marble</a> and the <a href="https://www.youtube.com/watch?v=p86BPM1GV8M">Pale Blue Dot</a> catalysed our ecological conscience, reminding us of the fragility of our world in comparison to the vast, cold emptiness of outer space. </p>
<p>Such images lead us on to explore the universe and ourselves, and the findings of these remarkable spacecraft that have travelled millions, sometimes billions of miles through space over many years remind us that it’s out there to be discovered. The challenge and rewards await, as J F Kennedy said: we choose to go to space not because it is easy, but because it is hard.</p><img src="https://counter.theconversation.com/content/44158/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Daniel Brown does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Everything in space is so far away, but probes bring us closer.Daniel Brown, Lecturer in Astronomy, Nottingham Trent UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/443842015-07-07T16:35:01Z2015-07-07T16:35:01ZThere’s no evidence to suggest there is life on Comet 67P<figure><img src="https://images.theconversation.com/files/87658/original/image-20150707-1281-1txf5b.jpg?ixlib=rb-1.1.0&rect=3%2C225%2C1020%2C594&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">No green little men as far as the eye can see.</span> <span class="attribution"><a class="source" href="http://www.esa.int/spaceinimages/Images/2015/06/Comet_on_21_May_2015_NavCam"> ESA/Rosetta/NavCam </a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span></figcaption></figure><p>As far as underwhelming headlines go: “No Alien Life Found on Comet” must rank very close to the top. <a href="http://www.theguardian.com/science/across-the-universe/2015/jul/06/no-alien-life-on-philae-comet">An article with this title</a> appeared in the Guardian on July 6 in <a href="http://www.theguardian.com/science/2015/jul/06/philae-comet-could-be-home-to-alien-life-say-top-scientists?CMP=share_btn_tw">response to a story</a> claiming that there could be life on comet <a href="http://sci.esa.int/rosetta/14615-comet-67p/">67P/Churyumov-Gerasimenko</a>. </p>
<p>But there simply isn’t enough evidence behind this theory. The chance that life could flourish on a freezing body with no sunlight or oxygen is in fact vanishingly small.</p>
<p>The claims were made at the National Astronomy Meeting in Llandudno, Wales, as well as in a <a href="https://www.ras.org.uk/news-and-press/2654-do-micro-organisms-explain-features-on-comets">press release</a> ahead of the conference. I was asked to comment on the press release, and remarked that I found the claim ‘highly unlikely’ Nevertheless, the story got picked up by the media and naturally created a storm on social media.</p>
<p>Of course, there has been enormous interest in reports about the comet, which is the target of the <a href="http://www.esa.int/Our_Activities/Space_Science/Rosetta">European Space Agencey’s Rosetta mission</a>, before. <a href="https://theconversation.com/that-sinking-feeling-could-cavities-on-comet-pose-yet-another-risk-to-philae-44155">Other discoveries</a> about the comet have been published in peer-reviewed journals and many <a href="http://www.wired.com/2014/11/rosetta-philae-comet-surface-photos/">amazing images</a> of the comet’s surface have been reproduced on websites and in newspapers across the globe. </p>
<p>But in all this coverage, there has until now not been one sniff of a hint of a rumour that the comet, currently speeding towards the Sun (and coming closer to Earth), might be bearing alien life.</p>
<h2>Shaky ground</h2>
<p>So what is the story behind the headline? It comes from interpretation of images of features on 67P’s surface in terms of production by microbial organisms. In fact, the press release was entitled: “Do micro-organisms explain features on comets”, a question which, in my opinion, leads to the succinct answer “No”. </p>
<p>The authors, astrobiologists <a href="http://cardiff.academia.edu/Maxwallis">Max Wallis</a> from the University of Cardiff and <a href="http://www.buckingham.ac.uk/directory/professor-chandra-wickramasinghe/">Chandra Wickramasinghe</a> from the University of Buckingham, propose that the environment of the comet might be suitable for microbes to survive.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/87659/original/image-20150707-1274-1jgm5s5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/87659/original/image-20150707-1274-1jgm5s5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=333&fit=crop&dpr=1 600w, https://images.theconversation.com/files/87659/original/image-20150707-1274-1jgm5s5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=333&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/87659/original/image-20150707-1274-1jgm5s5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=333&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/87659/original/image-20150707-1274-1jgm5s5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=419&fit=crop&dpr=1 754w, https://images.theconversation.com/files/87659/original/image-20150707-1274-1jgm5s5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=419&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/87659/original/image-20150707-1274-1jgm5s5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=419&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Alien life in the eye of the beholder?</span>
<span class="attribution"><a class="source" href="http://www.esa.int/spaceinimages/Images/2015/04/Comet_on_28_March_2015_NavCam_mosaic">ESA/Rosetta/NAVCAM</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>They argue that some micro-organisms on Earth can survive temperatures as low as -40°C (although most studies suggest <a href="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0066207">that -20°C is the limit</a>). And the comet’s temperature should have heated up to around that now that it is closer to the Sun, meaning micro-organisms could be active. In particular, they argue that the presence of <a href="https://theconversation.com/rosetta-is-making-a-splash-again-but-results-show-comets-water-not-the-same-as-earths-35411">water ice</a> and <a href="https://theconversation.com/the-rosetta-lander-detects-organic-matter-the-seeds-of-life-34413">organic compounds</a> on the surface of the comet – along with cracks and fissures which bacteria could colonise – are all signs that life could be present. </p>
<p>Indeed, it is not completely impossible. The lack of light and no atmosphere does not necessarily mean that living organisms can’t exist on a comet. Abundant fauna thrive in the dark of Earth’s deep ocean floor. Similarly, bacteria and other micro-organisms can survive at low temperatures – and have been preserved and <a href="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0066207">found to be viable following freezing</a>.</p>
<p>But one of my greatest problems with this argument is that there are many non-biological mechanisms which can produce organic compounds: organic molecules, which are precursors for life, are not necessarily biotic (created by living organisms). Also, photosynthesis is out, as there is no light. What chemical reactions are taking place that might drive an ecosystem? I am not certain that there is one.</p>
<p>Leaving all that aside and accepting that microbes might survive on the comet in some form of hibernation, one very significant question remains. Where have they come from? That is one of the main issues I have with the authors’ <a href="https://helix.northwestern.edu/article/origin-life-panspermia-theory">version of Panspermia</a>, which states that life came to Earth via bodies from outer space. </p>
<p>The origin of life on Earth is not fully understood, but we are making great strides towards recognising the mechanisms that make up each stage. Placing those mechanisms in an unknown environment and suggesting that life on Earth was seeded by microbes on comets solves nothing. It merely moves the problem further away, making it even harder to study.</p>
<p>Is it a slow summer? Are we already fatigued by the heatwave which lasted a couple of days? I suppose if there is nothing else to worry about, then we can ponder the chances of finding alien life beyond the Earth. Now, what’s that Curiosity Rover up to on Mars?</p><img src="https://counter.theconversation.com/content/44384/count.gif" alt="The Conversation" width="1" height="1" />
<h4 class="border">Disclosure</h4><p class="fine-print"><em><span>Monica Grady receives funding from the STFC and is a Trustee of Lunar Mission One.</span></em></p>As far as underwhelming headlines go: “No Alien Life Found on Comet” must rank very close to the top. An article with this title appeared in the Guardian on July 6 in response to a story claiming that…Monica Grady, Professor of Planetary and Space Sciences, The Open UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/441552015-07-01T19:23:35Z2015-07-01T19:23:35ZThat sinking feeling – could cavities on comet pose yet another risk to Philae?<figure><img src="https://images.theconversation.com/files/86980/original/image-20150701-31858-4yw7zc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Sinkholes on comet 67P could be a great thing for science -- but not if they they bury Philae.</span> <span class="attribution"><a class="source" href="http://www.eurekalert.org/multimedia/emb/94628.php?from=300087">Vincent et al., Nature Publishing GroupVincent et al., Nature Publishing Group</a></span></figcaption></figure><p>Images of the surface of comet <a href="http://sci.esa.int/rosetta/14615-comet-67p/">67P/Churyumov-Gerasimenko</a> have been decorating the front pages of newspapers and journals for the last few months. They have allowed us to see the full magnificence of the comets’ cratered terrain. Now a study suggests that <a href="http://nature.com/articles/doi:10.1038/nature14564">these craters are actually sinkholes</a>, created in a similar way to those on Earth when the surface layer of the ground suddenly collapses. While these pits could help us map the terrain of the comet, they could also pose a risk to the Philae spacecraft.</p>
<p>As the comet moves closer towards the sun, its activity has increased, leading to greater amounts of material from the exterior being turned into gas through the process of sublimation (where solid turns to a gas without first turning to liquid). It is clear, though, from the <a href="http://sci.esa.int/rosetta/54523-cometwatch-navcam-images/">images of the navigation camera</a>, that 67P is not equally active across all of its surface, and that jets of gas and dust can appear very quickly in <a href="http://sci.esa.int/rosetta/54523-cometwatch-navcam-images/">sudden bursts of activity</a>. This is not consistent with a gradual erosion of ice from across the comets’ surface as temperature increases. </p>
<p>The high resolution camera, <a href="http://sci.esa.int/rosetta/35061-instruments/?fbodylongid=1642">OSIRIS</a>, has shown panoramic images of <a href="http://www.esa.int/spaceinimages/Missions/Rosetta">craters, crevasses and valleys on the comet</a> – including craters from which <a href="http://blogs.esa.int/rosetta/2015/04/20/osiris-catches-activity-in-the-act/">jets are emanating</a>. That these are instead sinkholes is interesting but also slightly worrying, as such pits have the awkward habit of <a href="http://www.dailysabah.com/nation/2015/06/25/nine-sinkholes-in-3-months-scare-locals-in-central-town">opening up in the most inconvenient of places</a> at the most inconvenient of times.</p>
<h2>The science of sinkholes</h2>
<p>Sinkholes are caused when (usually) water washes away sub-surface rock and sediment, leaving a cap of material above a cavern. The cap can collapse at any time, becoming particularly vulnerable in times of increased rain or flooding. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/87041/original/image-20150701-27138-1811rhv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/87041/original/image-20150701-27138-1811rhv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/87041/original/image-20150701-27138-1811rhv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/87041/original/image-20150701-27138-1811rhv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/87041/original/image-20150701-27138-1811rhv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=500&fit=crop&dpr=1 754w, https://images.theconversation.com/files/87041/original/image-20150701-27138-1811rhv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=500&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/87041/original/image-20150701-27138-1811rhv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=500&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">More than 110 sinkholes formed in the Dover area of Florida during a freeze event in January 2010.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/usgeologicalsurvey/18050124324/in/photolist-tv2B75-85ESzU-85ETtE-by6GnX-2hD9UZ-8zLT7h-53Pxcj-5mCjbm-2NGmT7-7a4nJk-nJ9UFV-dTAPgd-86HVKB-68SWkm-a6G1tx-4nqDJK-4nuJQY-hg1BYi-d2ADzQ-d2ADrY-nJaZZX-o1DvHx-o1wwqW-hfZexa-bugHmQ-tEViyh-5xztWm-nJa8dN-nJa8nY-hfWBvf-nJbAfd-hg1MHi-bHbw1T-bugHom-bugHjG-3nLN56-hBtNnT-a3EG26-d4hr4u-hg1DJH-hfZb5i-a3EFGT-a3HwJo-d2ADDW-dTAPju-hfZLQQ-pXLLbY-6Qg5fr-6CPGvh-qYi1hi">U.S. Geological Survey</a></span>
</figcaption>
</figure>
<p>The researchers believe that sinkhole formation on 67P may be a consequence of sudden collapse of a ceiling overlying a buried cavity. They speculate that the cavities might have formed by collisions between metre-sized bodies at slow speeds, early in the Solar System’s history. Alternatively, they might be caused by sublimation of subsurface ice. </p>
<p>Whatever the cause of the underlying cavities, images from OSIRIS show that clusters of sinkholes with different depths and diameters across the surface of 67P. After the ceiling of a sinkhole has collapsed, fresh surfaces are exposed to solar radiation, following which jets form by sublimation of ice from the walls of the freshly opened hole.</p>
<p>Newly-formed, active sinkholes are deeper and have narrower diameters than ancient, dormant ones. If we could peer down into one of these holes, we would probably see layers of rock and ice, gradually becoming darker as more of the ice sublimated – leaving rock and dust behind. Dormant holes, on the other hand, seem to be filled in with debris, presumably of dust and rock from the sides of the hole which have collapsed.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/86978/original/image-20150701-31919-l18zw1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/86978/original/image-20150701-31919-l18zw1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=653&fit=crop&dpr=1 600w, https://images.theconversation.com/files/86978/original/image-20150701-31919-l18zw1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=653&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/86978/original/image-20150701-31919-l18zw1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=653&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/86978/original/image-20150701-31919-l18zw1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=820&fit=crop&dpr=1 754w, https://images.theconversation.com/files/86978/original/image-20150701-31919-l18zw1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=820&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/86978/original/image-20150701-31919-l18zw1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=820&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Image of the most active pit, known as Seth_01.</span>
<span class="attribution"><a class="source" href="http://www.eurekalert.org/multimedia/emb/94629.php?from=300087">Vincent et al., Nature Publishing Group</a></span>
</figcaption>
</figure>
<p>What is intriguing about the sinkholes is the opportunity they provide to determine the regional geology and history of 67P’s surface.
Sinkholes on similar terrain have similarly-sized holes. That means we can map the entire terrain of the comet based on the size of these pits. Similarly, the depth of sinkholes also matters. Since more shallow and debris-filled sinkholes tend to be older than deep ones, we can establish a chronology based on the depth.</p>
<p>What we all have to hope is that Philae is not perched precariously on the ceiling of one of these sub-surface cavities. It would be too cruel if the increasing sunlight, <a href="https://theconversation.com/philae-phones-home-but-the-mission-is-about-to-get-riskier-43261">finally charging Philae’s batteries</a>, also removed the ice supporting the lander, leaving sufficient power for Philae to broadcast its last message: “Help, I’m falling…”</p><img src="https://counter.theconversation.com/content/44155/count.gif" alt="The Conversation" width="1" height="1" />
<h4 class="border">Disclosure</h4><p class="fine-print"><em><span>Monica Grady receives funding from the STFC and is a Trustee of Lunar Mission One.</span></em></p>Sinkholes on comet 67P/Churyumov-Gerasimenko could teach us a lot about the geology and history of the body, but they could also spell the end for Philae.Monica Grady, Professor of Planetary and Space Sciences, The Open UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/380102015-02-25T06:27:59Z2015-02-25T06:27:59ZEarth’s other ‘moon’ and its crazy orbit could reveal mysteries of the solar system<figure><img src="https://images.theconversation.com/files/72955/original/image-20150224-25689-41frxe.png?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Cruithne's wacky orbit around the sun</span> <span class="attribution"><a class="source" href="https://www.youtube.com/watch?v=dsHsYjuudVo">YouTube</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>We all know and love the moon. We’re so assured that we only have one that we don’t even give it a specific name. It is the brightest object in the night sky, and amateur astronomers take great delight in mapping its craters and seas. To date, it is the only other heavenly body with human footprints.</p>
<p>What you might not know is that the moon is not the Earth’s only natural satellite. As recently as 1997, <a href="http://www.nature.com/nature/journal/v387/n6634/index.html">we discovered that</a> another body, 3753 Cruithne, is what’s called a quasi-orbital satellite of Earth. This simply means that Cruithne doesn’t loop around the Earth in a nice ellipse in the same way as the moon, or indeed the artificial satellites we loft into orbit. Instead, Cruithne scuttles around the inner solar system in what’s called a “horseshoe” orbit.</p>
<p><strong>Cruithne’s orbit</strong></p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/BmbuSR-fOZM?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>To help understand why it’s called a horseshoe orbit, let’s imagine we’re looking down at the solar system, rotating at the same rate as the Earth goes round the sun. From our viewpoint, the Earth looks stationary. A body on a simple horseshoe orbit around the Earth moves toward it, then turns round and moves away. Once it’s moved so far away it’s approaching Earth from the other side, it turns around and moves away again. </p>
<p>Horseshoe orbits are actually quite common for moons in the solar system. Saturn <a href="http://curious.astro.cornell.edu/our-solar-system/59-our-solar-system/planets-and-dwarf-planets/moon/241-how-can-two-moons-of-saturn-share-the-same-orbit-intermediate">has a couple</a> of moons in this configuration, for instance. </p>
<p>What’s unique about Cruithne is how it wobbles and sways along its horseshoe. If you look at Cruithne’s motion in the solar system, it makes a messy ring around Earth’s orbit, swinging so wide that it comes into the neighbourhood of both Venus and Mars. Cruithne orbits the sun about once a year, but it takes nearly 800 years to complete this messy ring shape around the Earth’s orbit.</p>
<h2>Cruithne close up</h2>
<p>So Cruithne is our second moon. What’s it like there? Well, we don’t really know. It’s only about five kilometres across, which is not dissimilar to the dimensions of the comet 67P/Churyumov-Gerasimenko, which <a href="http://theconversation.com/timeline-rosetta-mission-from-inception-to-landing-bid-34104">is currently</a> playing host to the Rosetta orbiter and the Philae lander. </p>
<p>The surface gravity of 67P is very weak – walking at a spirited pace is probably enough to send you strolling into the wider cosmos. This is why it was so crucial that Philae was able to use its harpoons to tether itself to the surface, and why their failure meant that the lander bounced so far away from its landing site. </p>
<p>Given that Cruithne isn’t much more to us at this point than a few blurry pixels on an image, it’s safe to say that it sits firmly in the middling size range for non-planetary bodies in the solar system, and any human or machine explorers would face similar challenges as Rosetta and Philae did on 67P.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/72957/original/image-20150224-25664-tj0ae6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/72957/original/image-20150224-25664-tj0ae6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/72957/original/image-20150224-25664-tj0ae6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/72957/original/image-20150224-25664-tj0ae6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/72957/original/image-20150224-25664-tj0ae6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/72957/original/image-20150224-25664-tj0ae6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/72957/original/image-20150224-25664-tj0ae6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/72957/original/image-20150224-25664-tj0ae6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Possible clash: Venus.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/47738026@N05/8262562988/in/photolist-84KDia-dPLCg-dA8N7y-dixbcG-bkDozd-bnQ1MG-qkpqw7-qnUXVq-r7VPuy-cbYnRJ-azJDth-fNhc4J-oDXsbP-4GEYTp-bpALpE-perBx7-6Rx2uK-bUhx7o-58tn1B-cya4NE-qMsPgR-djZzWS-dkQx5b-8NkL9-kv1Kjz-bCt7cT-8brTfL-3aMGQz-G9QHh-9QhiNE-9GksBw-ksGKxB-fMZtmr-4q46Lx-5mc4Gi-qKFpWV-eHuXAQ-bjuCc8-bzrCbx-b7EWnB-bCjiok-nwXHog-b2SZPn-fsgg29-fsq5Pu-ct8yyd-5FKAcV-eyLWda-bQBgs6-izGz4K">J.Gabás Esteban</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>If Cruithne struck the Earth, though, that would be an extinction-level event, similar to what <a href="http://blog.everythingdinosaur.co.uk/blog/_archives/2013/03/23/american-researchers-suggest-chicxulub-crater-made-by-comet.html">is believed</a> to have occurred at the end of the Cretaceous period. Luckily it’s not going to hit us anytime soon – its orbit is tilted out of the plane of the solar system, and astrophysicists have shown using simulations that while it can come quite close, it is extremely unlikely to hit us. The point where it is <a href="http://www.nature.com/nature/journal/v387/n6634/index.html">predicted to</a> get closest is about 2,750 years away. </p>
<p>Cruithne is <a href="http://www.nature.com/nature/journal/v387/n6634/index.html">expected to</a> undergo a rather close encounter with Venus in about 8,000 years, however. There’s a good chance that that will put paid to our erstwhile spare moon, flinging it out of harm’s way, and out of the Terran family.</p>
<h2>It’s not just Cruithne</h2>
<p>The story doesn’t end there. Like a good foster home, the Earth plays host to many wayward lumps of rock looking for a gravitational well to hang around near. Astronomers have actually <a href="http://www.arm.ac.uk/press/2011/aac_horseshoe_orbit.html">detected</a> several <a href="http://arxiv.org/abs/1409.5588">other</a> quasi-orbital satellites that belong to the Earth, all here for a little while before caroming on to pastures new.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/72959/original/image-20150224-25698-afgsfj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/72959/original/image-20150224-25698-afgsfj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/72959/original/image-20150224-25698-afgsfj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/72959/original/image-20150224-25698-afgsfj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/72959/original/image-20150224-25698-afgsfj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/72959/original/image-20150224-25698-afgsfj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/72959/original/image-20150224-25698-afgsfj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/72959/original/image-20150224-25698-afgsfj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Secrets: solar system.</span>
<span class="attribution"><a class="source" href="http://www.shutterstock.com/cat.mhtml?lang=en&language=en&ref_site=photo&search_source=search_form&version=llv1&anyorall=all&safesearch=1&use_local_boost=1&search_tracking_id=diLPjz4t_y796qQUnZAg7A&searchterm=solar%20system&show_color_wheel=1&orient=&commercial_ok=&media_type=images&search_cat=&searchtermx=&photographer_name=&people_gender=&people_age=&people_ethnicity=&people_number=&color=&page=1&inline=254113813">Tashal</a></span>
</figcaption>
</figure>
<p>So what can we learn about the solar system from Cruithne? Quite a lot. Like the many other asteroids and comets, it contains forensic evidence about how the planets were assembled. Its kooky orbit is an ideal testing
ground for our understanding of how the solar system evolves under gravity. </p>
<p>As I said before, it wasn’t until the end of the 20th century that we even realised that bodies would enter such weird horseshoe orbits and stay there for such a long time. The fact they do shows us that such
interactions will have occurred while the solar system was forming. Because we think terrestrial planets grow via collisions of bodies of
Cruithne-size and above, this is a big new variable. </p>
<p>One day, Cruithne could be a practice site for landing humans on asteroids, and perhaps even mining them for the rare-earth metals our new technologies desperately crave. Most importantly of all, Cruithne teaches us that the solar system isn’t eternal – and by extension, neither are we.</p><img src="https://counter.theconversation.com/content/38010/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Duncan is supported by the ECOGAL program, which is funded by a
European Research Council Advanced Grant. He is a member of the
Royal Society of Edinburgh's Young Academy of Scotland, and a founding
member of the UK SETI Research Network.
</span></em></p>It’s the satellite you probably didn’t know that Earth has. If we could land on it, it could be pretty usefulDuncan Forgan, Research Fellow, University of St AndrewsLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/363752015-01-16T15:37:24Z2015-01-16T15:37:24ZEureka! We’ve found Beagle2 – now, where did Philae go?<figure><img src="https://images.theconversation.com/files/69257/original/image-20150116-5185-5ymffw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">All that's left.</span> <span class="attribution"><span class="source">HiRISE/NASA/Leicester</span></span></figcaption></figure><p>Landing a spacecraft on a celestial body, whether it be the moon, Mars or a comet, is not easy. The European Space Agency found out the hard way in 2003 when its robot Beagle2, which was supposed to send back a signal after landing on Mars, didn’t do so.</p>
<p>But more than a decade after it went missing, the UK Space Agency has announced that the <a href="http://beagle2.open.ac.uk/index.htm">Beagle2</a> the elusive lander has been re-discovered. </p>
<p>Beagle2 was ejected from the Mars Express spacecraft on December 19, 2003, and was scheduled to land on December 25. The landing had Beagle2 protected by inflated airbags, which would be released from the lander and roll away before deflating. Beagle2 would then deploy its solar panels, before communicating with orbiting craft. Unfortunately, no signal was received, and after desperate attempts to communicate with Beagle2, it was sadly concluded that the lander had been lost.</p>
<p>The subsequent inquiry found that the most likely causes of the loss were either a problem with the Entry, Descent and Landing System (EDLS) or sheer bad luck. It now looks as though the EDLS worked – so that leaves bad luck. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/69258/original/image-20150116-5198-2nevwu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/69258/original/image-20150116-5198-2nevwu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=779&fit=crop&dpr=1 600w, https://images.theconversation.com/files/69258/original/image-20150116-5198-2nevwu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=779&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/69258/original/image-20150116-5198-2nevwu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=779&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/69258/original/image-20150116-5198-2nevwu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=979&fit=crop&dpr=1 754w, https://images.theconversation.com/files/69258/original/image-20150116-5198-2nevwu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=979&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/69258/original/image-20150116-5198-2nevwu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=979&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
<span class="attribution"><span class="source">UKSA</span></span>
</figcaption>
</figure>
<p>The images that have sparked the news come from the <a href="https://hirise.lpl.arizona.edu/ESP_039308_1915">HiRise camera</a> on board NASA’s Mars Reconnaissance Oriter. This is an instrument which is able to take very high resolution images of Mars’ surface. The scientists leading the search for the missing Beagle2 were looking for “something that wasn’t red, and wasn’t a pointy rock”. Given that this doesn’t narrow the field down very much, it is testament to the amazing perseverance and talents of the individuals concerned that they have managed to locate the lander.</p>
<p>It is poignant that the information comes at this time – Colin Pillinger was very much the driving force behind Beagle2, and one of the leaders of the Rosetta mission. His <a href="https://theconversation.com/colin-pillinger-was-not-one-to-compromise-or-toe-the-line-26481">premature death</a> last year deprived the scientific community of one of its most charismatic members. How he would have gloried in the re-discovery of Beagle2.</p>
<p>In contrast to the finding of Beagle2 comes news of another of ESA’s landers: Philae. Getting Rosetta spacecraft to drop Philae was an <a href="https://theconversation.com/scientists-at-work-from-rosetta-mission-control-as-philae-lands-34152">exciting and nerve-wracking time</a> – the lander successfully sent an arrival signal, but subsequent information showed that Philae <a href="https://theconversation.com/sleep-now-for-rosettas-comet-probe-after-a-bouncy-landing-34122">hadn’t landed where it was supposed to</a>. </p>
<p>Since the mid-November landing, there have been several possible sightings of Philae from cameras on-board Rosetta. But none has been confirmed as the lander. Rosetta is continuing its science mission – which means that it has moved further away from the nucleus of comet 67P Churyumov-Gerasimenko. It is now taking wider-field images of the comet’s nucleus, to search for signs of developing surface activity, rather than the more narrow, specific area images that were being acquired in the search for Philae. </p>
<p>Even though the exact location of Philae is unknown, the lander is not lost. It is misplaced, and there is hope that when Rosetta next approaches close to the nucleus, in mid-February, it will once again be able to resume scanning for its delinquent child.</p>
<p>And what of ESA’s third lander – the hugely successful Huygens spacecraft? This is also celebrating its anniversary. It landed on Saturn’s moon, Titan, in January 2005. It did everything that was asked of it, landed where it was supposed to land, acquired the data it was supposed to acquire, and then, on time and with no fuss, quietly went to sleep. A lesson for other landers to learn?</p>
<p>So if you kept score, ESA Landers: Mission accomplished 1, Lost 1, Found 1.</p><img src="https://counter.theconversation.com/content/36375/count.gif" alt="The Conversation" width="1" height="1" />
Landing a spacecraft on a celestial body, whether it be the moon, Mars or a comet, is not easy. The European Space Agency found out the hard way in 2003 when its robot Beagle2, which was supposed to send…Monica Grady, Professor of Planetary and Space Sciences, The Open UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/353702014-12-29T21:27:52Z2014-12-29T21:27:52ZNear Earth and far away, it’s been an exciting year in space<figure><img src="https://images.theconversation.com/files/67615/original/image-20141218-31052-1wb459e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Not yet, but soon ... we're getting closer to sending people to Mars.</span> <span class="attribution"><a class="source" href="http://www.flickr.com/photos/samanntran/4884193472">Samantha T./Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span></figcaption></figure><p>It was an exciting year in space exploration, with mind-blowing triumphs and heart-breaking failures. On Earth, new rockets and spacecraft were tested by space agencies and commercial ventures. </p>
<p>SpaceX, a private company which has sent supplies to the International Space Station (<a href="https://theconversation.com/explainer-the-international-space-station-12565">ISS</a>) on its Dragon/Falcon spacecraft, unveiled a prototype for a <a href="http://www.spacex.com/news/2014/05/30/dragon-v2-spacexs-next-generation-manned-spacecraft">crewed vehicle</a> to much excitement in May.</p>
<p>In July, Russia successfully launched the <a href="http://www.space.com/26872-russia-angara-rocket-launch-vehicle-industry.html">Angara rocket</a> in a sub-orbital flight from Plesetsk. Angara is the first rocket built from scratch since the Soviet era. </p>
<p>NASA tested its <a href="http://www.nasa.gov/orion/">Orion vehicle</a> – uncrewed – in an orbital flight which culminated in a successful splashdown in early December. For many it was a heartening sign that human spaceflight would not be stalled in Low Earth Orbit indefinitely.</p>
<p>The Orion vehicle was not entirely empty, though. On board were a number of objects including a <em>Tyrannosaurus rex</em> fossil, and <a href="http://www.nasa.gov/content/sesame-street-characters-on-board-with-orion/">props</a> from children’s television show Sesame Street: the Cookie Monster’s cookie and Ernie’s rubber duck.</p>
<h2>Don’t take space safety for granted</h2>
<p>Some impediments to spaceflight came not from outer space but the ocean. At NASA’s launch site on Wallops Island, stray boats repeatedly delayed rocket launches. In October, a boat in the exclusion zone caused Orbital Science Corporation’s Antares rocket launch <a href="http://spaceflightnow.com/2014/10/27/errant-boat-scrubs-antares-launch-from-virginia/">to be scrubbed</a>. </p>
<p>The next day, the unthinkable happened. The rocket, carrying the Cygnus craft with over 2000kg of supplies for the ISS, exploded on the launch pad only seconds after lift-off – see the video below. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/aL5eddt-iAo?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>A disaster by some lights, but as many commentators pointed out, the fact that no-one was hurt indicated the effectiveness of range safety procedures.</p>
<p>Others were not so lucky. </p>
<p>A test flight of SpaceShipTwo, Virgin Galactic’s suborbital passenger vehicle, <a href="https://theconversation.com/pilots-of-virgin-galactic-spaceshiptwo-deserve-our-admiration-and-honour-33710">exploded</a> after it detached from the launch jet. One pilot parachuted to safety, but another, sadly, did not survive.</p>
<h2>Venus and Mars</h2>
<p>We learnt more about our nearest neighbours, Mars and Venus, in 2014. </p>
<p>The European Space Agency’s Venus Express carried out an audacious dive into previously uncharted areas of the upper atmosphere, and returned safely to orbit. Its watching brief of our planetary twin sister has now <a href="http://www.esa.int/Our_Activities/Space_Science/Venus_Express/Venus_Express_goes_gently_into_the_night">come to an end</a> with the last of its fuel. It’s expected to drift down into Venus’ sulphuric acid clouds over the next few weeks.</p>
<p>Over at Mars, the comet Siding Spring (named after the Australian observatory) hurtled just 140,000km from the red planet in a “<a href="https://theconversation.com/comet-siding-springs-close-encounter-with-mars-draws-near-33083">near miss</a>”. The international fleet of orbiters and rovers was primed to capture images from this rare event.</p>
<p>It was a big year for the <a href="https://theconversation.com/au/topics/curiosity">Curiosity</a> and <a href="https://theconversation.com/an-opportunity-for-life-finding-mars-most-liveable-mud-22168">Opportunity</a> rovers too. On its tenth anniversary, Opportunity became the most-travelled space rover in history, passing the previous record set by Russia’s Lunakhod on the moon. The off-world robotic distance record currently stands at 40km.</p>
<p>For its part, Curiosity was busy gathering evidence that Mars might yet harbour life – geological traces of ancient water, organic carbon molecules, and a <a href="https://theconversation.com/curiosity-catches-a-whiff-of-methane-on-mars-and-a-possibility-of-past-life-35595">surprising sniff of methane</a>.</p>
<h2>Out and about in the solar system</h2>
<p>After ten years of hibernation, the European Space Agency’s comet-chaser Rosetta <a href="https://theconversation.com/relief-as-rosetta-wakes-up-but-still-we-hold-our-breath-22137">woke up</a> and went into orbit around 67P Churyamov-Gerasimenko. The world held its breath as the Philae lander was dropped onto the surface of the comet. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/67618/original/image-20141218-31046-11yo1oa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/67618/original/image-20141218-31046-11yo1oa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/67618/original/image-20141218-31046-11yo1oa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=412&fit=crop&dpr=1 600w, https://images.theconversation.com/files/67618/original/image-20141218-31046-11yo1oa.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=412&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/67618/original/image-20141218-31046-11yo1oa.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=412&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/67618/original/image-20141218-31046-11yo1oa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=517&fit=crop&dpr=1 754w, https://images.theconversation.com/files/67618/original/image-20141218-31046-11yo1oa.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=517&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/67618/original/image-20141218-31046-11yo1oa.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=517&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">From left to right, images show Philae descending towards and across the comet.</span>
<span class="attribution"><span class="source">ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA</span></span>
</figcaption>
</figure>
<p>Philae’s <a href="https://theconversation.com/sleep-now-for-rosettas-comet-probe-after-a-bouncy-landing-34122">epic bounce</a> across the rough terrain left it in a shaded position under a cliff, with too little sunlight to sustain the solar cells for long. Despite this, both segments of the mission returned <a href="https://theconversation.com/explainer-what-philae-did-in-its-60-hours-on-comet-67p-34289">astonishing data</a> that changed our view of both comets and the Earth. </p>
<p>It’s long been thought that much of the Earth’s oceans are derived from impacts with icy comets; but the composition of 67P’s ice does not match that of Earth.</p>
<p>(And yes, there was <a href="http://zoharesque.blogspot.com.au/2014/11/the-spacecraft-shirt-and-scandal.html">that shirt</a>.)</p>
<p>And finally, another snoozing spacecraft, <a href="https://theconversation.com/rise-and-shine-new-horizons-35332">New Horizons</a>, was woken. The next leg of its mission is a flyby of Pluto, the <a href="http://www.usatoday.com/story/tech/2014/10/02/pluto-planet-solar-system/16578959/">on-again off-again</a> planet we’ve never seen in detail before. In July 2015 we’ll have our first chance to get up close and personal with Pluto before New Horizons travels onwards to the Kuiper Belt.</p>
<h2>Back on earth: power to the people</h2>
<p>The crowd-funding of public space projects gathered pace in 2014 with the launch of Lunar Mission One. </p>
<p>Lunar Missions Ltd proposes to fund a deep-drilling <a href="http://www.lunarmissionone.com/">lunar probe</a> by selling digital “memory boxes”, which will be sent to the moon. This entitles the purchaser to have a say in project decisions. </p>
<p>The <a href="https://theconversation.com/big-brother-on-mars-reality-tv-thats-out-of-this-world-7847">Mars One project</a>, which plans to establish a colony on Mars in 2025, is preparing to select just 24 candidates from the current 600 hopefuls. They’re funding the ambitious project by selling rights to a reality television show like no other, where the “housemates” may actually perish live on air. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/Fk0LLX47deA?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Hear from some of the candidates.</span></figcaption>
</figure>
<p>The project has received some <a href="http://www.businessinsider.com.au/astronauts-thoughts-on-mars-one-colony-mission-2014-12">vigorous criticism</a> from space professionals such as astronaut <a href="https://theconversation.com/speaking-with-canadian-astronaut-chris-hadfield-30032">Chris Hadfield</a>. But for aspiring Martians like Australian comedian <a href="http://www.abc.net.au/local/stories/2014/10/02/4099026.htm">Josh Richards</a>, it’s about “doing something for humans as a species”. </p>
<h2>Looking forward</h2>
<p>In the next few years, it seems clear that public and private space endeavours will continue to develop in sophistication. </p>
<p>It’s an interesting prospect, as existing <a href="https://theconversation.com/who-owns-space-33222">space treaties</a> weren’t really established with this sort of scenario in mind. But it’s vital that we have more diverse players around the table when determining the future of long term access to space.</p>
<p>We can also look forward to the revision of many of our ideas about the history of this modest solar system we call home. </p>
<p>Already this year we’ve seen the deep terrestrial past opened up with the revelation that human ancestors made symbolic marks <a href="https://theconversation.com/marks-on-an-ancient-shell-lead-to-a-re-think-of-human-history-34957">500,000 years ago</a>. New results from space will open windows into even deeper time.</p>
<p>Perhaps it’s appropriate to finish this wrap-up with a thought from 2014’s science fiction blockbuster, <a href="https://theconversation.com/interstellar-gives-a-spectacular-view-of-hard-science-33991">Interstellar</a>. In the words of Dr Amelia Brand (played by Anne Hathaway), </p>
<blockquote>
<p>Love is the one thing that we’re capable of perceiving that transcends dimensions of time and space. Maybe we should trust that, even if we can’t understand it.</p>
</blockquote><img src="https://counter.theconversation.com/content/35370/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alice Gorman is a member of the National Executive Council of the Space Industry Association of Australia.</span></em></p>It was an exciting year in space exploration, with mind-blowing triumphs and heart-breaking failures. On Earth, new rockets and spacecraft were tested by space agencies and commercial ventures. SpaceX…Alice Gorman, Lecturer, Flinders UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/351632014-12-29T19:13:17Z2014-12-29T19:13:17ZFrom comet chasing to gravity waves: 2014 in six science stories<figure><img src="https://images.theconversation.com/files/66540/original/image-20141208-20492-ksgibl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">2014: the year crystallography went mainstream.</span> <span class="attribution"><a class="source" href="http://commons.wikimedia.org/wiki/File:CSIRO_ScienceImage_296_Protein_Crystals_Use_in_XRay_Crystallography.jpg">CSIRO</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>’Tis the season for listicles rounding up the stories of the year. So with, the authority vested in me, here is a selection of six top, bottom and forgotten science stories of 2014.</p>
<h2>Bounciest landing</h2>
<p>The Rosetta drama reached fever pitch in November with the descent of Philae to the surface of a comet. But let’s not forget the slow build to the plot, starting with a launch back in 2004 setting <a href="https://theconversation.com/uk/topics/rosetta">Rosetta</a> on a path that involved four gravitational “slingshots” around Earth and Mars, three orbits of the Sun, two close encounters with asteroids and a rendezvous with 67P/Churyumov–Gerasimenko in August. Chasing down the four kilometre-wide comet travelling at 135,000 km/hr and then touching down on its surface was a staggering feet of precision, roughly equivalent to a marksman hitting a bulls-eye on a one metre target from a million kilometres away (three times the distance from the Earth to the Moon).</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/66537/original/image-20141208-20498-1u6ripd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/66537/original/image-20141208-20498-1u6ripd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/66537/original/image-20141208-20498-1u6ripd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=351&fit=crop&dpr=1 600w, https://images.theconversation.com/files/66537/original/image-20141208-20498-1u6ripd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=351&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/66537/original/image-20141208-20498-1u6ripd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=351&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/66537/original/image-20141208-20498-1u6ripd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=441&fit=crop&dpr=1 754w, https://images.theconversation.com/files/66537/original/image-20141208-20498-1u6ripd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=441&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/66537/original/image-20141208-20498-1u6ripd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=441&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Philae hangs on … just.</span>
<span class="attribution"><a class="source" href="http://www.esa.int/spaceinimages/Images/2014/11/Welcome_to_a_comet">ESA</a></span>
</figcaption>
</figure>
<p>Be prepared for a potential 2015 sequel which may see the hibernating Philae awaken as its ride approaches the Sun and the little probe’s solar panels eke enough power out of the rays to spring back to life.</p>
<h2>Best quiet achiever</h2>
<p>The year 2014 was observed, by the UN, as an <a href="http://www.un.org/en/events/observances/years.shtml">international year</a> for small island developing states, family farming and of crystallography. <a href="https://theconversation.com/explainer-what-is-x-ray-crystallography-22143">Crystallography</a> wins out. It is a technique that usually gets little mainstream attention despite its importance to chemistry, physics and biology. Its implementation has led to no less than 27 Nobel prizes, not to mention the <a href="https://theconversation.com/the-little-known-science-that-improved-everything-around-us-22452">development of countless</a> medical advances, technological discoveries and engineering innovations. </p>
<p>And so 2014 saw an <a href="http://richannel.org/celebrating-crystallography">effort</a> from <a href="http://www.nature.com/news/specials/crystallography-1.14540">major</a> science and <a href="http://www.theguardian.com/science/occams-corner/2014/jan/14/dorothy-hodgkin-year-of-crystallography">media</a> <a href="http://science.time.com/2014/01/09/crystallography-100-years/">outlets</a> to highlight the importance of the 100 year old technique to today’s world.</p>
<h2>Biggest story</h2>
<p>The <a href="https://theconversation.com/uk/topics/ebola">Ebola</a> epidemic started in Guéckédou in Guinea, where a <a href="edition.cnn.com/2014/10/28/health/ebola-patient-zero/index.html?iid=article_sidebar">two-year-old girl</a> who died in late 2013, is believed to be the first case. In March the <a href="http://www.cdc.gov/">CDC</a> announced <a href="http://edition.cnn.com/2014/04/11/health/ebola-fast-facts/">the outbreak</a> and since then the virus and the resting hemorrhagic fever has dominated the science news. By the <a href="http://www.economist.com/blogs/graphicdetail/2014/12/ebola-graphics">end of November</a>
more than 17,000 people had been infected resulting in more than 6,000 deaths. </p>
<p>The ramifications could be felt worldwide, with <a href="http://www.bbc.co.uk/news/health-29549722">health screening</a> at international airports, <a href="http://www.theguardian.com/us-news/2014/dec/02/us-ebola-treatment-hospital">western hospitals prepping</a> to handle Ebola victims, <a href="http://www.telegraph.co.uk/news/worldnews/ebola/11202797/American-Ebola-nurse-wins-court-battle-to-avoid-quarantine-order.html">court rulings</a> on the quarantine of infected health workers and <a href="http://www.bbc.co.uk/news/health-28663217">unprecedented circumvention of drug trials</a> in an attempt to rush experimental drugs and vaccines into use.</p>
<h2>Quickest u-turn</h2>
<p>In 1916 Einstein predicted the existence of waves and a corresponding particle, the graviton, that are responsible for gravity. But almost a century later and despite a plethora of massive experiments, direct evidence of either the waves or particles is sorely lacking. Without this evidence the two dominating pillars of physics, general relativity and quantum mechanics, remain at odds.</p>
<p>So in March the science world was aflutter with the news of the <a href="http://www.theguardian.com/science/2014/mar/17/primordial-gravitational-wave-discovery-physics-bicep">discovery</a> of these allusive gravitational waves. The BICEP2 telescope in the heart of Antarctica peering into the distant Universe and back to the afterglow of the Big Bang found tantalising signs of the long sought gravity waves.</p>
<p>Before the talk of <a href="http://www.theguardian.com/science/2014/mar/21/gravitational-waves-nobel-prize-inflation">Nobel prizes</a> could die down, the evidence <a href="http://physicsworld.com/cws/article/news/2014/sep/22/bicep2-gravitational-wave-result-bites-the-dust-thanks-to-new-planck-data">disappeared in a cloud of dust</a>. The data that looked so promising turned out to be the result of fine matter scattered throughout our galaxy.</p>
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<a href="https://images.theconversation.com/files/66533/original/image-20141208-20507-zfqpid.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/66533/original/image-20141208-20507-zfqpid.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/66533/original/image-20141208-20507-zfqpid.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/66533/original/image-20141208-20507-zfqpid.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/66533/original/image-20141208-20507-zfqpid.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/66533/original/image-20141208-20507-zfqpid.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/66533/original/image-20141208-20507-zfqpid.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/66533/original/image-20141208-20507-zfqpid.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">BICEP2 flexes at the South Pole.</span>
<span class="attribution"><a class="source" href="http://en.wikipedia.org/wiki/BICEP_and_Keck_Array#mediaviewer/File:South_pole_spt_dsl.jpg">Amble</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>But in science there is no shame in a u-turn. Theories and interpretations are adapted in the face of evidence. And so the hunt for the source of gravity continues.</p>
<h2>Most overlooked innovation</h2>
<p>In the decade that Rosetta was homing in on its target, research into a far less dramatic topic was gaining traction.</p>
<p><a href="http://www.nature.com/articles/504S1a.epdf?shared_access_token=WMGAb3ONLaX--bfGK-8EGtRgN0jAjWel9jnR3ZoTv0NYaB9RDJcu38wBR5pnw6QRFGDQdXK7XdS3I0siGEr0-DRJ5W0NXUI6g2n2ccND_QBIgx75tyg8dJQsg_RxKBSI1Lg7ZAgG3i1P7K41yO71cfuBg7ZsXMQRIUHPLLi9Tn1nLK0fB4sa8oBVA1h9rxZzdiHH-kfgOcOJiq4b7gzb5Q%3D%3D">Cancer immunotherapy</a> went mainstream this year. It may not have had the same media coverage as space science and medical epidemics, but its likely to have a greater impact on many of our lives.</p>
<p>The therapy exploits subtle differences between the surface proteins on cancer and normal cells, then persuades our own immune system to recognise these differences and attack the cancer cells.</p>
<p>The fruits of this research ripened in 2014, with <a href="http://www.tandfonline.com/doi/abs/10.4161/onci.27048#.VIRLFGSsX9c">trials</a> <a href="http://www.cancer.org/treatment/treatmentsandsideeffects/treatmenttypes/immunotherapy/immunotherapy-whats-new-immuno-res">underway</a> and promising successes reported in top the journal <a href="http://www.sciencemag.org/content/344/6184/641">Science</a> and Nature Cancer reviews published <a href="http://www.nature.com/search/executeSearch?pub-date-mode=exact&sp-q-3=&sp-q-2=&siteCode=nrc&sp-q-9%5BNRC%5D=1&sp-c=25&shunter=1416997528296&sp-advanced=true&sp-q=immunotherapy&sp-p=all&sp-s=&sp-date-range=0&sp-q-10=&sp-q-11=&sp-q-12=2014&sp-start-month=&sp-start-year=&sp-end-month=&sp-end-year=">24 articles</a> on the subject.</p>
<h2>Losses</h2>
<p>The year saw the passing of some truly great and <a href="http://www.telegraph.co.uk/news/obituaries/science-obituaries/">influential scientists</a>. To name three:</p>
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<a href="https://images.theconversation.com/files/66532/original/image-20141208-20504-1v4if3w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/66532/original/image-20141208-20504-1v4if3w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/66532/original/image-20141208-20504-1v4if3w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=725&fit=crop&dpr=1 600w, https://images.theconversation.com/files/66532/original/image-20141208-20504-1v4if3w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=725&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/66532/original/image-20141208-20504-1v4if3w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=725&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/66532/original/image-20141208-20504-1v4if3w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=911&fit=crop&dpr=1 754w, https://images.theconversation.com/files/66532/original/image-20141208-20504-1v4if3w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=911&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/66532/original/image-20141208-20504-1v4if3w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=911&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Chemistry pioneer Stephanie Kwolek.</span>
<span class="attribution"><a class="source" href="http://en.wikipedia.org/wiki/Stephanie_Kwolek#mediaviewer/File:Stephanie_Kwolek_at_Spinning_Elements_by_Harry_Kalish.TIF">Chemical Heritage Foundation</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Chemist <a href="http://www.telegraph.co.uk/news/obituaries/10923157/Stephanie-Kwolek-obituary.html">Stephanie Kowlek</a> was most well known for her work on a compound beloved by soldiers and cyclists alike. For she invented the kevlar used in bullet-proof vests and puncture-resistant tires. Kowlek’s chemical was patented by Dupont for whom she served for 40 years.</p>
<p><a href="http://blogs.scientificamerican.com/cross-check/2014/05/22/my-testy-encounter-with-the-late-great-gerald-edelman/">Gerald Edelman</a> received a Nobel prize for discovering the structure of antibodies. His work resolved questions about how our bodies deal with invaders. An understanding on which cancer immunotherapy now hangs. He passed away in May aged 84.</p>
<p><a href="http://www.theguardian.com/science/2014/sep/14/dame-julia-polak">Julia Polak</a> was a pioneer in stem cell and tissue engineering. Her own need for a lung transplant triggered her desire to research growing artificial implants. She died aged 75, almost 20 years after her transplant.</p>
<p>Their achievements, of course, live on. So here’s looking forward to a <a href="http://www.light2015.org/Home.html">bright 2015</a>.</p><img src="https://counter.theconversation.com/content/35163/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mark Lorch does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>’Tis the season for listicles rounding up the stories of the year. So with, the authority vested in me, here is a selection of six top, bottom and forgotten science stories of 2014. Bounciest landing The…Mark Lorch, Senior Lecturer in Biological Chemistry, University of HullLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/355092014-12-19T06:16:33Z2014-12-19T06:16:33ZAfter Rosetta, Japanese mission aims for an asteroid in search of origins of Earth’s water<p>The <a href="http://www.esa.int/ESA">European Space Agency</a>’s <a href="http://www.esa.int/Our_Activities/Space_Science/Rosetta">Rosetta mission</a> to land on comet 67P was one of the most audacious in space history. The idea of landing on a small chunk of icy rock 300m kilometres away from Earth and hurtling towards the sun at speeds approaching 135,000km/hour is incredible – made more so by the fact they <a href="http://www.bbc.co.uk/news/live/science-environment-29985988">actually achieved it</a>.</p>
<p>What scientists have learned from the data returned by Rosetta supports the need for another ambitious space mission that has just begun: the Japanese Aerospace Exploration Agency (JAXA) <a href="http://www.jspec.jaxa.jp/e/activity/hayabusa2.html">Hayabusa2</a> mission will intercept not a comet, but an asteroid, landing on its surface no fewer than three times.</p>
<p>Data returned by the Rosetta mission has already provided us with many surprises, including <a href="http://www.sciencemag.org/content/early/2014/12/09/science.1261952">the results now published</a> in the journal Science, which reveal that the nature of the water found on comet 67P does not match that found on Earth. </p>
<p>Examining the vaporous cloud that encloses the comet nucleus, Rosetta measured the ratio of hydrogen to its heavier form, <a href="http://www.britannica.com/EBchecked/topic/159684/deuterium">deuterium</a>, and found it was <a href="http://www.esa.int/Our_Activities/Space_Science/Rosetta/Rosetta_fuels_debate_on_origin_of_Earth_s_oceans">three times higher</a> than that found on Earth. This is an important discovery, since while water is vital to our existence on Earth, it is not at all obvious where it came from.</p>
<h2>In the beginning</h2>
<p>The Earth was formed from small rocky <a href="http://www.britannica.com/EBchecked/topic/463084/planetesimal">planetesimals</a> that circled the young sun, coalescing into a planet that was most likely born a dry world. Ices are not found in the planetary formation process until we reach lower temperatures much further out into the solar system. This means that the Earth must have had a water delivery at a later time.</p>
<p>One hypothesis is that water came via <a href="https://solarsystem.nasa.gov/faq/index.cfm?Category=Comets#q3">comet impacts</a>. Comets are formed in the chilly reaches around the giant planets of Jupiter, Saturn, Uranus and Neptune and are heavy in ice. During the end of our solar system’s formation, a large number of these were scattered towards the inner planets via gravitational kicks from their mammoth planetary neighbours. Striking our dry world, their icy contents could have begun the formation of our oceans. </p>
<p>But Rosetta’s analysis of comet 67P suggests that our oceans are not filled with fresh comet water. What we need is an alternative source, which leads us to Hayabusa2’s mission to the asteroids. </p>
<h2>Answers from asteroids</h2>
<p>The <a href="http://spaceflightnow.com/2014/12/03/hayabusa-2-launches-on-audacious-asteroid-adventure/">JAXA Hayabusa2</a> mission, which launched in early December, aims to intercept <a href="http://iopscience.iop.org/1538-3881/146/2/26">asteroid 1999 JU3</a>, touch down on its surface three times, deploy a lander with a trio of rovers and return to Earth with the asteroid samples in 2020. In short, it is a worthy successor to Rosetta. </p>
<p>Both comets and asteroids are left-over rocky parts from the planet formation process, but asteroids sit much closer to the Earth. The majority form a band orbiting the sun beyond Mars, known as the <a href="http://space-facts.com/asteroid-belt/">asteroid belt</a>, but Hayabusa2’s target is far closer, currently orbiting the sun between the Earth and Mars. </p>
<p>Asteroids come in <a href="http://www.astronomysource.com/tag/s-type-asteroids/">different flavours</a>. The S-type group have been heated during their lifetime in processes that alter their original composition, while C-type asteroids – the target of Hayabusa2 – are thought to have changed very little since their original formation. </p>
<p>As its name implies, Hayabusa2 has a predecessor that visited the S-type asteroid, <a href="http://global.jaxa.jp/article/special/hayabusa_sp3/index_e.html">Itokawa</a>, which showed evidence of experiencing heating up to 800°C. While its exploration illuminated much about the evolution of such space rocks, it held no answers as to the arrival of water on Earth.</p>
<h2>Answers in clay</h2>
<p>At only around 1km across, 1999 JU3 has insufficient gravity to hold liquid water, but observations suggest it contains clays, which require water to form. This, and its current unstable orbit, implies that it was once part of a larger object that broke apart.</p>
<p>After completing an initial analysis, Hayabusa2’s first touchdown will be at the site of the discovered clays. While Rosetta deployed a lander to reach the comet surface, Hayabusa2 will itself make contact with the asteroid, firing a bullet as it descends to break up surface material that it can gather. It will do this twice more at different locations; the third descent will preceded by the firing of a larger missile to bring up rocky debris from beneath the surface of the asteroid. While making a direct landing is risky, the advantage is that these samples can be brought back to Earth for thorough analysis. </p>
<p>Despite touching down itself, Hayabusa2 will also deploy a lander. Developed by the same German and French teams that built the Rosetta lander, Philae, Hayabusa2’s MASCOT (<a href="http://www.dlr.de/irs/en/desktopdefault.aspx/tabid-5960/10970_read-34316/">Mobile Asteroid Surface SCout</a>) will run on a 15-hour battery and dispatch three small rovers to explore the surface. </p>
<h2>Life’s building blocks in space</h2>
<p>However, water may be only one part of the secrets to be discovered on 1999 JU3. Previous <a href="http://www.newscientist.com/article/dn22127-meteorites-lefthanded-molecules-a-blow-to-et-search.html">research has suggested</a> that reactions with water on asteroids are linked to the production of amino acids: the organic building blocks for life. Not only this, but these amino acids seem to be predominantly <a href="http://www.nasa.gov/topics/solarsystem/features/life-turned-left.html">left-handed</a>; a distinctive feature of those in life on Earth.</p>
<p>While amino acids created in the laboratory appear equally as both left- and right-handed mirror images, biology strongly favours the left-handed version. We don’t know the reason for this preference, making the suggestion that such selectivity could have begun in space extremely exciting. If this turns out to be true, then scientists opening Hayabusa2’s sample jar in six years time may not only find the source of our water, but perhaps also the very beginnings of life.</p><img src="https://counter.theconversation.com/content/35509/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Elizabeth Tasker does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The European Space Agency’s Rosetta mission to land on comet 67P was one of the most audacious in space history. The idea of landing on a small chunk of icy rock 300m kilometres away from Earth and hurtling…Elizabeth Tasker, Assistant Professor, Hokkaido UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/342892014-11-17T15:47:01Z2014-11-17T15:47:01ZExplainer: what Philae did in its 60 hours on Comet 67P<figure><img src="https://images.theconversation.com/files/64700/original/cy5gcg86-1416217894.png?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">It's all science.</span> <span class="attribution"><a class="source" href="http://homepages.laas.fr/ehebrard/rosetta.html">Emmanuel Hebrard</a></span></figcaption></figure><p>The drama of Philae’s <a href="https://theconversation.com/scientists-at-work-from-rosetta-mission-control-as-philae-lands-34152">slow fall</a>, <a href="https://theconversation.com/how-rosetta-made-an-epic-journey-through-space-and-overcame-incredible-challenges-34162">bounce</a> and <a href="https://theconversation.com/small-glitches-but-rosetta-comet-mission-is-achieving-major-scientific-goals-34228">unfortunate slide into hibernation</a> was one of the most thrilling science stories of a generation. But what in its short 60 hours of life on Comet 67P did it achieve? </p>
<p>The short answer is analytical chemistry.</p>
<p>Philae’s payload included three instruments that are quite common in chemistry labs, but when deployed on a comet could answer questions about the origins of the solar system and life itself.</p>
<h2>Right- or left-handed life</h2>
<p>Four billion years ago the solar system was an unsettled place. Earth was undergoing heavy bombardment by asteroids and comets. This continuous shower may have delivered a significant amount of water to our planet. But the comets weren’t just dirty snowballs. A third of their contents was probably complex organic (that is, carbon-based) molecules. These compounds may well have triggered the chemistry that led to life on our planet. </p>
<p>One of Philae’s goals is to provide evidence that the organic chemicals on a comet are sufficiently similar to the building blocks of life to support the comet impact theory for <a href="http://www.britannica.com/EBchecked/topic/1790122/abiogenesis">abiogenesis</a>. A key factor is whether Comet 67P (and by extension other comets) contain predominantly right- or left-handed molecules. </p>
<p>Many molecules come in one of two forms, known as stereoisomers, which chemists designate as left- or right-handed. These two forms are identical apart from the fact that they are mirror images of each other. </p>
<p>Your hands are a perfect analogy. Structurally, they are the same except for the fact that you can’t superimpose one on the other. And so it is with stereoisomers.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/64702/original/sgtmddsc-1416219973.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/64702/original/sgtmddsc-1416219973.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=407&fit=crop&dpr=1 600w, https://images.theconversation.com/files/64702/original/sgtmddsc-1416219973.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=407&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/64702/original/sgtmddsc-1416219973.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=407&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/64702/original/sgtmddsc-1416219973.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=512&fit=crop&dpr=1 754w, https://images.theconversation.com/files/64702/original/sgtmddsc-1416219973.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=512&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/64702/original/sgtmddsc-1416219973.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=512&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Life on Earth is based on only left-handed molecules, such as the amino acid on the left.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Chirality_with_hands.svg?uselang=fr">Inconnu</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Strangely, life on Earth is based entirely on left-handed molecules. It is perfectly possible to make the right-handed versions, but life just doesn’t. Where this preference for left-handedness comes from is a <a href="http://www.space.com/20888-earth-life-amino-acids-asteroids.html">mystery</a>. One theory is that the bias came from within the chemistry of comets. In the comets, right-handed molecules may have been preferentially destroyed by a combination of sunlight (to provide energy to trigger chemical reactions) and liquid water (with which the organic compounds could react). </p>
<p>Philae’s <a href="http://www.researchgate.net/publication/225710128_Cosac_The_Cometary_Sampling_and_Composition_Experiment_on_Philae/links/09e4150ea9a8d260bf000000">COSAC instrument</a> is designed to sniff away at the comet’s organic contents and figure out whether they look like the building blocks of life and, importantly, whether the comet contains the same preference for lefty chemistry as Earth-bound life.</p>
<h2>Homegrown detritus or alien debris</h2>
<p>Most theories hold that comets were formed from the same nebula that gave birth to rest of the solar system. But this need not be the case. It could be that they are truly ancient bodies that entirely, or in part, pre-date the solar system, or perhaps they have congregated here much more recently? Philae’s <a href="http://link.springer.com/article/10.1007%2Fs11214-006-9001-5">Ptolemy instrument</a> aims to answer this question by comparing the ratios of different isotopes within Comet 67P. </p>
<p>A given element is defined by the number of protons in its nucleus. For example carbon always has six protons. However the number of neutrons can vary giving rise to carbon-12 (six protons and six neutrons), carbon-13 (with seven neutrons) and carbon-14 (with eight neutrons). All these different variations are known as isotopes. The ratio of these isotopes in any given body will vary depending on its origins. And since the material in the solar system came from more or less the same place, the isotopic carbon ratios for the Sun, the Earth and asteroids are pretty much the same.</p>
<p>But comets might be different, in fact <a href="http://www.sciencedirect.com/science/article/pii/0273117789902548">remote measurements</a> of comet Hale-Boop suggest that it may be an extra-solar alien. The problem is there were large uncertainties in these readings, so we can’t be sure of their accuracy. By sending the Ptolemy instrument to the surface of a comet this should all be resolved, as its isotopic measurements are meant to be as accurate as those performed on Earth, and the solar or alien origins of Comet 67P can be confirmed.</p>
<h2>The snowball factories</h2>
<p>If comets came from the same stock as the rest of the solar system where and how were they produced? The Hubble telescope spotted comets in the Kuiper belt just beyond Neptune, meanwhile the Oort Cloud (another 10,000 times further away) is thought to contain icy bodies that may, paradoxically, have condensed nearer to Jupiter and Saturn.</p>
<p>Figuring out where 67P may have originated is the job of <a href="http://link.springer.com/article/10.1007%2Fs11214-006-9137-3">APXS</a>, an instrument designed to determine the elemental composition of dusty parts of the comet. By comparing this to material on Earth, the origins of which we are more confident about, we should be able to figure out the birth place of 67P.</p><img src="https://counter.theconversation.com/content/34289/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mark Lorch does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The drama of Philae’s slow fall, bounce and unfortunate slide into hibernation was one of the most thrilling science stories of a generation. But what in its short 60 hours of life on Comet 67P did it…Mark Lorch, Senior Lecturer in Biological Chemistry, University of HullLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/341692014-11-14T15:23:20Z2014-11-14T15:23:20ZScientists at work: the day after Philae lands<figure><img src="https://images.theconversation.com/files/64518/original/ktpf59rg-1415920641.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Hang on? Oh, there you are...</span> <span class="attribution"><span class="source">ESA</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Phew, what a day it was yesterday. Ended up having a quiet drink at the hotel. Last drink of the day – a nice cup of tea!</p>
<p>Slept well – no nightmares about flying through space looking for somewhere to land. Open my eyes, open my twitter feed. Don’t usually launch into social media so quickly, but had to see what I had missed overnight. And I’d missed some good news – radio link to Philae had been restored more-or-less on schedule – that Philae is still alive. Joy, and first coffee of the day.</p>
<p>Share in quick conversation between Ian and Ptolemy team. All well – more data downloaded. Get a brief update about the other instruments and hear that there are images! So the cameras are working. Images embargoed until official release later in the morning. But unofficially, apparently they are cracking! Again, relief that Philae is at least operational, even if not optimal – or nominal.</p>
<p>Pitch up at ESOC. Settle down for a quiet(er) morning than yesterday. Get a coffee, and start to scroll through the tweets that have been piling up. Loads of smiling faces. Some embarrassing ones of me <a href="http://www.buzzfeed.com/richardhjames/professors-emotional-reaction-to-european-probe-landing-on-a?bftw=uk">appearing fairly happy</a> at news of the successful landing. Start to catch up with e-mail. Look at the ones that are important. Or urgent. Can’t remember which I’m supposed to process first. Better re-do the time management course.</p>
<h2>We seek it here …</h2>
<p>Grab a coffee before meeting colleagues. This place is Rumour Central. Philae is on its side. Philae is in a cave. Philae is on its side in a cave. At least no rumours that Philae is dead, or upside down, so reasonable optimism is the prevailing mood.</p>
<p>Do a couple of interviews. Manage to sneak in a quick coffee. Tickled when presenter on BBC World News introduces me as a “Professor of Interplanetary Space”. Get a text from the Ptolemy team. They are re-defining the Ptolemy operation command sequence, as it is clear that the preliminary science schedule is no longer valid.</p>
<p>This isn’t a quick job. Ten instruments sharing a low amount of power have to work together to find the most effective solution to enable the greatest amount of science to be obtained. European co-operation at its best!</p>
<p>Now hearing about Philae’s bumpy landing. As they say, you wait for one comet landing, and three come along at once. The first bounce sent Philae about a kilometer up, and it took two hours for the craft to land a second time. Glad I didn’t know this last night.</p>
<p>Second bounce was a much shorter hop – it took ten minutes to land again. Philae is in a precarious state – the harpoon didn’t fire, the screws on the feet didn’t actuate, so the lander is not anchored to the comet, just resting on the surface. A good gust of wind would blow it over. Good job it isn’t windy … yet</p>
<p>First image released. Speechless. Nearly spill my coffee. What a fantastic picture. What a worrying picture. One of Philae’s feet is dangling – I nearly wrote “in mid-air” – in mid-space. We can see the comet. It looks like a jagged cliff face, partly illuminated.</p>
<h2>X marks the spot</h2>
<p>Time for the press conference. More amazing images. We know where Philae is – about a kilometre from where Philae should be. That has blown our departmental sweepstake: “Put the X on the Philae landing site” out of the water, since we were only choosing within the predicted landing ellipse. Then again, Philae’s first landing seems to have been right on target. So maybe we go with that.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/64586/original/ns6zqpsn-1415976919.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/64586/original/ns6zqpsn-1415976919.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/64586/original/ns6zqpsn-1415976919.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=614&fit=crop&dpr=1 600w, https://images.theconversation.com/files/64586/original/ns6zqpsn-1415976919.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=614&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/64586/original/ns6zqpsn-1415976919.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=614&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/64586/original/ns6zqpsn-1415976919.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=772&fit=crop&dpr=1 754w, https://images.theconversation.com/files/64586/original/ns6zqpsn-1415976919.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=772&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/64586/original/ns6zqpsn-1415976919.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=772&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">And the view is spectacular!</span>
<span class="attribution"><span class="source">ESA</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Ought to concern myself with weightier matters than sweepstake. Actually very concerned about illumination. Philae looks to be up against a cliff and will only receive about 1.5 hours sunlight. Needs six hours to keep batteries charged. Main batteries will die soon.</p>
<p>Ptolemy needs the drill to deliver sample to get data on the dust. Not sure whether drill can work in Philae’s current position. And if they start to drill, without Philae being anchored, the action might push Philae over. More worries.</p>
<p>Anyway, I’m off home. Tomorrow, back to the other part of the day job. Workload planning. Curriculum team meeting. Got to find an excuse why I haven’t finished writing my bit of the second-level chemistry module, which includes a section on “Comets and the origin of life”. Wonder if trip to Darmstadt can be passed off as gathering fresh material…</p>
<p><em>Monica Grady would like to thank Ian and the Ptolemy team for allowing her to share their journey. She is looking forward to seeing them with their <a href="https://www.justgiving.com/Simon-Sheridan1">new haircuts</a>. She is, however, glad that she is not part of the instrument team, and thus does not have to have her head shaved….</em></p><img src="https://counter.theconversation.com/content/34169/count.gif" alt="The Conversation" width="1" height="1" />
Phew, what a day it was yesterday. Ended up having a quiet drink at the hotel. Last drink of the day – a nice cup of tea! Slept well – no nightmares about flying through space looking for somewhere to…Monica Grady, Professor of Planetary and Space Sciences, The Open UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/342282014-11-13T20:17:16Z2014-11-13T20:17:16ZSmall glitches, but Rosetta comet mission is achieving major scientific goals<figure><img src="https://images.theconversation.com/files/64513/original/23pc45ck-1415907018.jpg?ixlib=rb-1.1.0&rect=0%2C436%2C1451%2C1092&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">First panorama of a comet.</span> <span class="attribution"><a class="source" href="http://www.esa.int/spaceinimages/Images/2014/11/Comet_panoramic_lander_orientation">ESA/Rosetta/Philae/CIVA</a></span></figcaption></figure><p>The landing of Rosetta’s Philae on comet 67P/Churyumov–Gerasimenko was a <a href="https://theconversation.com/how-rosetta-made-an-epic-journey-through-space-and-overcame-incredible-challenges-34162">triumph of engineering</a>. Many <a href="https://theconversation.com/video-the-amazing-rosetta-spacecraft-and-philae-lander-34116">spectacular scientific firsts</a> will follow now, but small glitches during the landing make it more difficult to obtain all of the scientific goals. </p>
<p>The harpoons did not fire to anchor the lander and as a result the lander bounced off the surface twice before coming to rest at its “third landing”. It is as yet unclear, where exactly Philae landed but it is not the flat, safe surface of the targeted <a href="https://theconversation.com/marriage-of-ancient-and-modern-makes-rosetta-mission-a-true-space-odyssey-34031">Agilkia landing site</a>. </p>
<p>The lander now sits in a position partly shaded from the sun, which limits the ability to charge its secondary battery. Therefore the Philae teams are now scrambling to give each scientific instrument on the lander a measurement slot within the 60 hours of power available from the primary battery. </p>
<p>This cuts the time available for individual measurements to do their experiments. The APXS (Alpha Particle X-ray Spectrometer) instrument, for example, can measure X-ray spectra which yield the elemental composition of cometary dust. It can achieve that fairly quickly for heavier elements (magnesium and above) but needs more time to acquire meaningful information to analyse the abundance of lighter elements such as carbon. </p>
<p>The APXS and MUPUS (the MUlti-PUrpose Sensors for Surface and Sub-Surface Science) instruments have to be moved close to the surface to make their measurements. This consumes energy – and risks moving the still not safely anchored Philae into an even more unfavourable position. </p>
<p>Nevertheless, it seems that a <a href="https://twitter.com/Philae_MUPUS/status/532968586005217280">decision has been made to deploy these instruments</a>. The Drill, Sample and Distribution (SD2) subsystem consumes by far the most energy and poses the greatest risk of moving the lander. However, two instruments depend on sample delivery from the SD2 system: the British Ptolemy instrument, an evolved gas analyser, as well as the COSAC (COmetary SAmpling and Composition) instrument, which is a combined gas chromatograph and time-of-flight mass spectrometer, which detects and identifies complex organic molecules from their elemental and molecular composition in soil and volatiles. </p>
<p>These are <a href="https://theconversation.com/rosetta-lander-will-seek-a-close-encounter-with-comets-primordial-soup-30741">key investigations</a> to better understand comets and their composition. This is why they will probably justify the risk to deploy the drill, even if the outcome is uncertain.</p>
<p>It seems that most instruments on board Philae will achieve their full science goals making this mission a remarkable and outstanding achievement, whatever else might happen. And there is still hope that the lander may even be moved into a more favourable position facing towards the sun, or that – as the comet comes closer to the sun – power output and the charge of the secondary battery increase to enable some kind of extended mission. Even if some instruments will not be able to make measurements, the mission remains a giant success and will deliver a <a href="https://theconversation.com/rosetta-will-teach-us-more-about-comets-than-we-have-learnt-in-50-years-30295">wealth of new and exciting scientific insights</a> into the physical and chemical make-up of comets, the history of the solar system and, ultimately, the origins of life.</p><img src="https://counter.theconversation.com/content/34228/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Christian Schroeder is affiliated with UCU.</span></em></p>The landing of Rosetta’s Philae on comet 67P/Churyumov–Gerasimenko was a triumph of engineering. Many spectacular scientific firsts will follow now, but small glitches during the landing make it more difficult…Christian Schroeder, Impact Research Fellow, Cross-fertilisation between Environmental Science and Planetary Exploration, University of StirlingLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/341162014-11-12T06:30:44Z2014-11-12T06:30:44ZVideo: the amazing Rosetta spacecraft and Philae lander<figure><img src="https://images.theconversation.com/files/64351/original/54zj9422-1415775151.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Conquering a comet.</span> <span class="attribution"><a class="source" href="http://www.esa.int/spaceinimages/Images/2014/02/Philae_separation">ESA/ATG medialab</a></span></figcaption></figure><p>Rosetta is a first-class mission, because it is a mission of firsts. First to fly-by asteroid Steins, a rare metal-poor asteroid. First to travel past asteroid Lutetia, which might be related to a class of rare, metal-rich meteorites. First to attempt to detect an atmosphere on an asteroid. First to catch up to a comet and travel alongside it. First to listen to the plasma “wind” from a comet. First to orbit a comet. First to capture high resolution images of the surface of a comet. First to see the boulders, canyons and cliffs that cover the surface of the oddest-shaped comet yet observed. </p>
<p>These are what the mission has achieved so far. Still to come, we hope: the first mission to travel with a comet as it develops its tails. The first mission to travel around the sun with a comet. The first mission to observe a comet returning to dormancy. And of course, the Rosetta mission is the first in which there will be an attempt to land on the nucleus of a comet. Not just land there, but stay there, sample the comet and analyse its water and dust, checking for the building blocks of life. </p>
<p><em>In the video below, space scientist Monica Grady, a member of the Rosetta mission’s science team, talks to science editor Akshat Rathi about humanity’s fascination with these dirty iceballs and explains how Rosetta hopes to answer some of the most fundamental questions about life on Earth.</em></p>
<iframe src="https://facultimedia.com/embedded-facultimedia/?media_url=https://facultimedia.com/wp-content/uploads/2014/11/CONESA.mp4" height="373" width="100%" scrolling="no" frameborder="0" marginwidth="0" marginheight="0"></iframe>
<p><strong>So, Monica, humans have been fascinated by comets for a very long time. Can you tell me more about it?</strong></p>
<p>Ever since the Chinese astronomers from 2,000 years ago observed the night sky, comets have been harbingers of doom and disaster. There is a picture of a comet in the Bayeux apestry which commemorates the Battle of Hastings from 1066. There are pictures of comets in one of Giotto’s famous pictures. There’s connections, or connections have been made, between comets and the Star of Bethlehem; between comets and battles, disasters, the birth of kings, the death of kings. All this is in sorts of history, mythology and religion going on for thousands and thousands of years.</p>
<p>Edmund Halley predicted that comets came into and out of the solar system and in regular orbits and there is a comet which takes his name, Halley’s Comet, which comes round every 76 years.</p>
<p>One of the most famous of cometary scientists was somebody called Fred Whipple, who described them as “dirty snowballs”, the idea that they were a mixture of rock and snow. Now we call them more like “icy dirtballs”. It’s actually more dust there than there is ice.</p>
<p><strong>What about scientific explorations of comets?</strong></p>
<p>There have been several space missions to comets. The first one was the Giotto mission of 1985. That was a European Space Agency mission and it went to Halley’s Comet and it flew past the cometary nucleus and took the first picture that we have of a comet’s nucleus. But it just went straight past. But that mission sowed the seeds of the Rosetta Mission.</p>
<p>There have been two other missions to comets: there’s been the Stardust Mission, which was a NASA mission which went through the tail of a comet and collected material from the comet’s tail and brought it back to the Earth.</p>
<p>And then, there was Deep Impact which was a NASA mission where a comet ran into a copper projectile. So, NASA let go this great, big copper thing and the comet ran into it. What Deep Impact did was it excavated a big crater in the side of the comet and we could observe the interior of a comet for the first time. So we could see what actually happened when the impact evaporated the ice and release a lot of the dust and we could see what was deeper down.</p>
<p>The Stardust Mission brought back a bit of Comet Wild 2. But it only brought back solid material. It didn’t bring back any gas and it didn’t bring back any ice. And of the solid material that came back, it’s a bit difficult to disentangle some of the data for the organic compounds because of the way the material was collected.</p>
<p><strong>Why was 67P – and I can never pronounce its full name – chosen as the target comet and not the many billions out there?</strong></p>
<p>Comet 67P is also known as Churyumov–Gerasimenko, which is a bit of a tongue-twister. It’s named after two astronomers Churyumov and Gerasimenko, who observed it first. It’s a comet which is part of the inner solar system so it travels round partly under the influence of Jupiter but, of course, mainly under the influence of the sun. The reason it was chosen is because its orbit is in the plane of the solar system. So all the planets, the Earth, orbit the sun, right? Now some comets have really inclined orbits and that makes it very difficult to track them. So, Comet C-G has got this orbit, which is more or less what we call the plane of the ecliptic so we could track it relatively easily.</p>
<p><strong>People assume that comets come from the outer edges of the solar system. But 67P is different. What about it is different?</strong></p>
<p>There are two big groups or classes of comets: there are the long-period comets and the short-period comets. </p>
<p>The long-period comets are ones which live at the outermost fringes of the solar system. They inhabit a region called the Oort Cloud, which nobody’s ever seen or observed but we believe it’s there because when you observe the paths, the orbits, of some comets, especially the ones that are really steeply inclined, they always go out to this region, which is about 50,000 times as far away from the sun as the Earth is. So, these are the really long-period comets. They only might come in and out of the solar system every three or five thousand years. </p>
<p>The short-period comets are ones that used to be long-period comets but they’ve been grabbed by Jupiter or they’ve been scattered inwards by some events, perhaps the passage of a nearby star or something like that. That is why Halley’s Comet comes round every 76 years. The difference between the two types of comets is the length of their orbits and the length of time they stay within the solar system.</p>
<p><strong>From when the planning began, to the actual comet landing, it has taken 20 years. Why did it take so long?</strong></p>
<p>The Rosetta mission has been a long time in the planning. The roots of its mission was in the success of the Giotto mission from 1985 to 1986. Once the results had come back, it was, hey, we’ve learnt a lot about comets but there’s even more we need to know. So, planning started more or less then. </p>
<p>But there aren’t that many space missions. You’ve got to wait your turn in the queue for one thing. You’ve got to have an excellent science case so that the European Space Agency will accept that there is really interesting work to be done. You’ve got to get the science team together, you’ve got to persuade the politicians of the different countries. So all that took from say 1986 to 1996. </p>
<p>Then you’ve got to build the instruments and when you have built your instruments you have to deliver it to the rocket for it to be launched. Now, usually an instrument has to be delivered, maybe one, maximum of two years, prior to launch, where they’re all integrated because you know, the Brits have built this one and the French have built that one and the Germans have built that one, and the Italians have built that one and you’ve got to make sure that all the plugs and sockets all fit together and that they all communicate with each other and that, you know, if you switch this one on, it doesn’t fuse that one … That sort of thing, so integration takes a lot of time. So, you’re allowed two years for integration and so Rosetta was integrated, it was delivered almost to the rocket. </p>
<p>Unfortunately what then happened was that the launch previous to the one Rosetta was going to go on exploded on takeoff. That was the mission which was going to launch the Cluster mission. And that put everything back another two years because there had to an investigation into the explosion of Cluster so it’s actually taken two years longer than it should have done. </p>
<p>It took all that time to actually get into the launchpad but didn’t mean that we were really to actually start taking any data. The mission had to be launched and it doesn’t just go from Earth to comet, it had to go twice around the Earth and once around Mars. But to build up enough speed and thrust so that it start to get on the right trajectory so that it would catch up with the comet. So that’s what it did, it took nearly ten years to actually catch up with the comet. </p>
<p>For the first eight years, it was doing tests, it passed a couple of asteroids and took some measurements. For the last two of those years, it was asleep. It rested, saved its batteries and it woke up in January of this year. In August of this year, it actually caught up with the comet and between August and November, it has been doing a whole load of manoeuvres to bring it closer and closer into the comet so now it’s only a few kilometres away from the comet’s surface.</p>
<p><strong>The mission’s objectives are to understand more about the origin and the evolution of our solar system. That is a big goal. What have you achieved so far?</strong></p>
<p>The aims of the Rosetta mission are very grand: it’s to understand the origin and evolution of the solar system by looking at primitive material that was formed when the solar system was formed. It’s going to look at the water and the carbon and the organics to see how they relate to the water and the organics on Earth, and to life on Earth.</p>
<p>Now, the main part of that scientific investigation will take place when the Philae lander actually arrives on the comet’s surface. But till now, we’ve been doing a lot of science. Obviously, we’ve had the fantastic images of the comet’s nucleus, we know its temperature, we know its density, we know its angular momentum, we know its spin speed, we’ve got some idea of the differences in composition of the surface of the comet. And so, there’s been a lot of information so far about the comet itself taken remotely from the instruments actually on the Rosetta spacecraft.</p>
<p><strong>If the comet landing succeeds, what are the realistic expectations?</strong></p>
<p>Assuming that Philae lands successfully on the surface of the comet, what the instruments on board will do is drill a small amount of material from the surface and the sub-surface regions of the comet and this will be brought up and placed in the ovens on the comet, where they will be heated up and melted and then eventually burned. The melting will melt the ice, so that we get an idea of what gases are trapped in the ice, we’ll get an idea of the composition of the ice – its hydrogen and its oxygen – and then we’ll get an idea of the composition of the more solid material. How much carbon there is there? How much sulphur?</p>
<p><strong>Can Rosetta give us a definitive answer to whether water of Earth came from the water on comets?</strong></p>
<p>One of the aims of the Rosetta mission is to see what the relationship is between the water in the comet and water on the Earth. Now assuming they all formed in the same place at the same time, they should be the same. But when the Earth formed, it got very, very hot. Its surface was completely molten and it is assumed that it lost practically all of its water. And so when the Earth cooled down and after the moon had formed, the Earth would have been quite a dry planet. What we want to see is how much of its water it managed to retain in the early times when it was molten and how much has been added subsequently by bodies like comets.</p>
<p><strong>The mission is to end in late 2015 when the comet comes close to the sun. Do you think Philae will survive? And what about Rosetta?</strong></p>
<p>The comet keeps going. It’s going to get close to the sun and then it’s going to go round the sun and then it’s going to come back out again. As it goes on that journey, it will develop a huge big tail as more and more of the ice from the surface of the cometary nucleus sublimes.</p>
<p>Now, it’s very unlikely that Philae will actually survive the growth of those tails because these are very strong jets of gas. These will be coming up as geysers and if one comes up just underneath where Philae is then it won’t survive for very long. However the Rosetta mother-craft will be flying alongside the comet, it will watch as the tail develops, it will go with the comet as it swings round the sun and then continue to track Comet C-G as the tail then decays away. So, Rosetta is planned to actually survive the tail formation but sadly Philae isn’t. But it might do, you never know.</p>
<p><strong>What about applications on Earth for the technologies that have been developed to build Rosetta?</strong></p>
<p>One of the really great things about being involved with a space mission is that you do lots of experiments first in the laboratory using huge, great, big pieces of equipment. And then the real challenge is to shrink down those bits of equipment into instruments that don’t weigh very much, and don’t need much power. Colleagues at the Open University have done that successfully. </p>
<p>They’ve taken a piece of equipment, which is the size of a room, they’ve shrunk it down to something which is about the size of a shoe box – and that’s the Ptolemy instrument which is on board of the Philae lander. This is great, it’s going to go and sniff the comet, it’s going to measure the gas and the dust in the comet and we’ll learn about the formation of the early solar system, which is fantastic for planetary scientists.</p>
<p>What the taxpayer does benefit from though is that we can take the know-how that we’ve got from taking something very big and making it very small – we’ve made it portable. And it’s something which can test for volatile compounds and so we can use that it all sorts of applications: you can use it on submarines to test their quality; you can use it out in field hospitals to test for disease; you can put it on an orbiting satellite going round the Earth to look at carbon dioxide emissions from forests and so on. As soon as you’ve built something small and portable then you can do all sorts of things with it. And that is where a lot of the value of space research comes in to.</p>
<p>For the scientist, it’s valuable to do research. But for the taxpayer, we also get that additional spin-off as well.</p>
<p><strong>What next for cometary exploration after Rosetta?</strong></p>
<p>The Rosetta mission has been very ambitious. But it’s limited. It’s sending something to the comet – and making very sophisticated measurements using very sophisticated instruments – but it’s a sort of one-shot. What we really need to do is to be able to repeat these things to much more sophisticated experiments that we can do, that we couldn’t do ten, 15 years ago when the mission was being planned. What we really need to do, what we want to do, is bring some of that comet nucleus back to the Earth. That, I think, would be the next step in the age of cometary exploration: planning a comet nucleus sample return mission.</p>
<p><strong>That would be great, and I hope that happens in my lifetime. Thank you so much for your time today, Monica.</strong></p><img src="https://counter.theconversation.com/content/34116/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Monica Grady receives funding from the STFC and the AHRC</span></em></p>Rosetta is a first-class mission, because it is a mission of firsts. First to fly-by asteroid Steins, a rare metal-poor asteroid. First to travel past asteroid Lutetia, which might be related to a class…Monica Grady, Professor of Planetary and Space Sciences, The Open UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/340312014-11-11T13:46:14Z2014-11-11T13:46:14ZMarriage of ancient and modern makes Rosetta mission a true space Odyssey<figure><img src="https://images.theconversation.com/files/64236/original/s6y8h8v9-1415700652.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The new ancient Egypt.</span> <span class="attribution"><span class="source">ESA/ATG medialab</span></span></figcaption></figure><p>What’s the betting that <a href="https://theconversation.com/historic-comet-landing-site-is-looking-for-a-name-33280">Agilkia</a> makes it into the baby name charts in 2015? This romantic, lyrical word is the name of an island in the Egyptian Nile, but it’s also just been given to the patch of Comet 67P/Churyumov-Gerasimenko where the <a href="http://rosetta.esa.int">Rosetta</a> mission’s Philae lander is due to touch down.</p>
<p>More than 8,000 people from 135 different countries entered the <a href="http://www.esa.int/Our_Activities/Space_Science/Rosetta/Name_Rosetta_mission_s_landing_site">ESA’s competition</a> to name the landing site. More than 150 of these entrants independently suggested Agilkia. Surprised? You shouldn’t be, because this geographical reference fits beautifully with the overarching Egyptian imagery of the Rosetta mission.</p>
<p>It’s well known that the Rosetta spacecraft was named after the famous <a href="http://www.britishmuseum.org/explore/highlights/highlight_objects/aes/t/the_rosetta_stone.aspx">Rosetta stone</a>, whose discovery in 1799 enabled historians to unlock the secrets of hieroglyphics. The <a href="http://blogs.esa.int/rosetta/2014/10/17/naming-rosetta-an-interview-with-eberhard-grun/">choice of that name</a> reflected the spacecraft’s role in deciphering the mysteries of the universe, while poetically linking space with time, language with science, archaeology with cosmology.</p>
<p>The connections continue. The Philae lander was christened in 2004 by an <a href="http://blogs.esa.int/rosetta/2014/10/21/naming-philae-an-interview-with-2004-contest-winner-serena-olga-vismara/">Italian high-school student</a>, who made the connection between the lander and an ancient obelisk found on the island of Philae near Aswan. The obelisk was inscribed in both Greek and Egyptian characters and its discovery represented another landmark in the translation of hieroglyphics and the understanding of distant kingdoms.</p>
<p>Other ancient Egyptian references in the space mission include <a href="http://www.open.ac.uk/science/pssri/research/missions/rosetta/ptolomy.php">Ptolemy</a> (after Ptolemy V, whose name appears on both the Rosetta stone and the Philae obelisk), and the on-board camera <a href="http://sci.esa.int/sre-fi/35973-osiris/">OSIRIS</a> – an acronym for Optical, Spectroscopic, and InfraRed Remote Imaging System but also one of the most intriguing ancient Egyptian deities.</p>
<p>And now we have <a href="http://www.esa.int/Our_Activities/Space_Science/Rosetta/Farewell_J_hello_Agilkia">Agilkia</a> – that enigmatic landscape which silently awaits the arrival of Philae.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/64239/original/ks2kqw35-1415701159.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/64239/original/ks2kqw35-1415701159.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/64239/original/ks2kqw35-1415701159.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/64239/original/ks2kqw35-1415701159.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/64239/original/ks2kqw35-1415701159.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/64239/original/ks2kqw35-1415701159.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/64239/original/ks2kqw35-1415701159.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The reconstruced Philae temple on Agilkia Island.</span>
<span class="attribution"><a class="source" href="http://www.flickr.com/photos/endlisnis/442397499/in/photolist-F6pn6-d2EqGQ-9JYik6-MLR2W-6Gsmcr-F6pMJ-F6pyF-F6pMg-6GskBP-6GrYsK-6Gs1ex-6Gw4wd-6GwbV5-6Gsjj2-6Gs2Xr-6Gwo3s-6GrWxk-6Gs5yx-6Gs2hP-6Gwb3N-6Gw7EG-6Gw1YC-6Gsfht-6Gw8MC-6GsiKR-6GrVZD-6Gs9L4-6GrXVg-6Gskan-6GscwF-6Gsevi-6Gsd8a-6GsgGV-6GsdNx-6GsmEg-6GshYD-6Gs8An-6Gwk1G-6GrZ3i-6Gw5Hb-6GwmFw-6Gsn8p-6Gw8nN-6GwfVy-6GsjKt-6Gsh8Z-6Gsb6F-76zpza-76DiLQ-76Dkay">endlisnis</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Back on earth, Philae and Agilkia aren’t just neighbouring islands. In the 1970s, when Philae was at risk of floods after the building of the Aswan Dam, the ancient temple complex on the island was <a href="http://portal.unesco.org/en/ev.php-URL_ID=26414&URL_DO=DO_TOPIC&URL_SECTION=201.html">dismantled and then re-built</a> on Agilkia.</p>
<p>The journey of the Philae lander to the Agilkia comet site re-enacts this piece of rescue archaeology on a cosmic scale and sets up an almost perfect analogy between ancient Egypt and modern space travel.</p>
<p>Almost perfect, because the inscribed Philae obelisk wasn’t actually among the monuments dispatched to Agilkia. A British aristocrat named William John Bankes had discovered the obelisk in 1815 and taken it back to his stately home in England. Like many other Egyptian obelisks – including those plundered by “Egyptomaniac” Roman emperors – this one has ended up far from its original place of display, and now stands in impressive isolation in the gardens of a <a href="http://www.nationaltrust.org.uk/article-1355864908966/">National Trust property in Dorset</a>.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/64241/original/bpgkpjb6-1415701855.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/64241/original/bpgkpjb6-1415701855.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/64241/original/bpgkpjb6-1415701855.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/64241/original/bpgkpjb6-1415701855.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/64241/original/bpgkpjb6-1415701855.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=500&fit=crop&dpr=1 754w, https://images.theconversation.com/files/64241/original/bpgkpjb6-1415701855.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=500&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/64241/original/bpgkpjb6-1415701855.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=500&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The original Philae obelisk.</span>
<span class="attribution"><a class="source" href="http://www.flickr.com/photos/daubneyphotography/12949869914">daubneyphotography</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<h2>Universal heritage</h2>
<p>But although the Rosetta’s web of symbolism becomes complicated on close inspection, the overall Egyptian theme is still an incredibly powerful one.</p>
<p>Using hieroglyphs to frame the mission presents space as an entity that can – and eventually will – be deciphered. And while most of us have trouble grasping the colossal distances involved in space travel (Rosetta has travelled a cumulative distance of over <a href="http://www.esa.int/Our_Activities/Space_Science/Rosetta/Frequently_asked_questions">6.4 billion km</a>), the names of ancient places, pharaohs and gods can help us to mentally reach the physical remoteness of celestial bodies.</p>
<p>Other symbolic resonances include the <a href="http://abyss.uoregon.edu/%7Ejs/glossary/ptolemy.html">Ptolemaic system of astronomy</a> and the infamous conspiracy theories about the <a href="http://www.outerworlds.com/likeness/aliens/aliens.html">alien origins of the pyramids</a>.</p>
<p>Sending ancient Egypt into space makes our cosmos alive with history and myth. It makes space seem more tangible, yet simultaneously more distant. The analogy can also enhance our perceptions of the past, influencing how we regard our monumental heritage. Philae and Agilkia are currently trending on Google and Twitter – and it’s clear that the world’s attention has been refocused on these sites thanks to their appropriation by space scientists.</p>
<p>And at a time of <a href="http://www.telegraph.co.uk/news/worldnews/europe/greece/11164525/Amal-Clooney-Greece-has-just-cause-to-claim-return-of-Elgin-Marbles.html">increasingly strained debates</a> about cultural patrimony it makes a refreshing change to see ancient monuments used as symbols – not of an individual or nation – but of the whole planet. Rosetta, Philae, Ptolemy and Agilkia now rise far above national or political boundaries. They have become distant representatives of our shared, earthly heritage. And in that cosmic light, they look even more noble.</p><img src="https://counter.theconversation.com/content/34031/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jessica Hughes does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>What’s the betting that Agilkia makes it into the baby name charts in 2015? This romantic, lyrical word is the name of an island in the Egyptian Nile, but it’s also just been given to the patch of Comet…Jessica Hughes, Lecturer in Classical Studies, The Open UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/338632014-11-06T10:33:15Z2014-11-06T10:33:15ZRosetta comet mission: five questions you desperately want answered<figure><img src="https://images.theconversation.com/files/63757/original/qs35crts-1415199535.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Once upon a time preparing for comet landing.</span> <span class="attribution"><span class="source">ESA</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>On November 12, the Rosetta spacecraft’s Philae lander is due to land on the surface of a comet. As a space scientist working with those who have instruments on board, I <a href="https://theconversation.com/why-rosetta-is-the-greatest-space-mission-of-our-lifetime-33763">can’t wait</a>. I met up with some of the Rosetta scientists at the Open University to ask them the top five questions I am always being asked about the Rosetta mission.</p>
<h2>Why bother to go to a comet?</h2>
<p><a href="https://theconversation.com/profiles/ian-wright-114049">Ian Wright</a>, professor of planetary sciences, said: </p>
<p>“We want to go because it’s there. It’s an object in our astronomical backyard and we want to know what it looks like and what it’s made of. We also want to know whether the water in a comet has a relationship with the water on Earth. If it does then we want to study the organics in the comet to know something about the organics that were brought to the surface of the early Earth.”</p>
<h2>Why does the Philae lander have harpoons?</h2>
<p><a href="http://www.open.ac.uk/people/adm6">Andrew Morse</a>, research fellow, said: </p>
<p>“There are two harpoons onboard and this is the first time they’ve been used in space. The gravity on a comet is so low that they’re needed to attach the lander to the comet but they’re not just required for the landing. The harpoons are also needed throughout the mission because as the comet becomes active, gases coming off the comet will act to push the lander away so they keep it firmly attached throughout the whole of the mission.”</p>
<h2>Why is there an oven onboard Rosetta?</h2>
<p><a href="http://science-people.open.ac.uk/s.sheridan">Simon Sheridan</a>, project officer, said:</p>
<p>“There are a number of ovens onboard the instrument, located behind the drill on a carousel. We need ovens because the Open University’s instrument, Ptolemy, is a mass spectrometer and we need to analyse the gases in the comet so we take the solid cometary material, pop it in the oven and heat it up to get the gases off that to analyse. The Ptolemy instrument is located inside the lander and the gases from the oven reach it via a pipe.”</p>
<h2>But what if it crashes on landing?</h2>
<p><a href="http://science-people.open.ac.uk/g.h.morgan">Geraint Morgan</a>, project officer, said:</p>
<p>“The instruments including Ptolemy are already pre-programmed so will sniff the comet whatever happens, whichever way we land. Ptolemy is a miniature version of a lab instrument we have at the Open University and has similar functionality. We’ve been applying the knowledge we’ve developed with Ptolemy to several challenges back here on Earth including healthcare, safety equipment and also even measuring the quality of our drinking water.”</p>
<h2>Could this mission save the world?</h2>
<p><a href="https://theconversation.com/profiles/monica-grady-125306">Monica Grady</a>, professor of planetary and space sciences, said: </p>
<p>“This mission couldn’t directly save the Earth but it could indirectly. Comets travel through the inner Solar System all the time. Some of them travel very near to the Earth and have even hit the Earth in the past. The more we know about comets; their composition, how tough they are, how easily they break up, the better it is so we can understand more about deflecting them away from the Earth. It might sound like science fiction but if the choice is between science fiction and global devastation because a comet hits then what choice do we have?”</p>
<p>All that’s left to say is good luck to all the Rosetta scientists.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/4-Wbb9cDeGY?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
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<p class="fine-print"><em><span>Natalie Starkey receives funding from the Science & Technology Facilities Council. She is affiliated with The Open University.</span></em></p>On November 12, the Rosetta spacecraft’s Philae lander is due to land on the surface of a comet. As a space scientist working with those who have instruments on board, I can’t wait. I met up with some…Natalie Starkey, Research Associate, The Open UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/332802014-10-21T21:47:29Z2014-10-21T21:47:29ZHistoric comet-landing site is looking for a name<figure><img src="https://images.theconversation.com/files/62395/original/xj4pjqh5-1413905763.png?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Rosetta's selfie.</span> <span class="attribution"><a class="source" href="http://www.esa.int/spaceinimages/Images/2014/10/Rosetta_mission_selfie_at_16_km">ESA/Rosetta/Philae/CIVA</a></span></figcaption></figure><p>The Rosetta mission reaches a defining moment on Wednesday November 12, when its lander, Philae, is released. After about seven hours of descent, Philae will arrive on the surface of Comet 67P Churyumov-Gerasimenko. But exactly where will it land?</p>
<p>As the first images of the comet became available back in June, the European Space Agency (ESA) started work on selecting a landing site. This has to be a trade-off between several factors: the topography of the site as well as the number and size of any boulders around it. Thermal properties of the site must also be considered. The site cannot be tucked away from sunlight, which will prevent the lander from charging its batteries (on the other hand, too much sunshine can damage sensitive instruments).</p>
<p>As Rosetta has come closer to its target, details of the comet’s surface features have become clearer. In September, ESA narrowed the list of landing sites to 10 – labelled A to J. In October, after taking all the above factors into consideration, it chose site J as the primary landing site.</p>
<p>This mission is a historical undertaking, and “Site J” is not a name that is likely to resonate through history. ESA officials realise this too, so the agency has decided to hold a <a href="http://www.esa.int/Our_Activities/Space_Science/Rosetta/Name_Rosetta_mission_s_landing_site">competition to name the landing site</a>. Anybody can enter and suggest a name but reasons for proposal of the name are also a necessary part of the competition. You have until 23:59 GMT on October 22 to get your entry in. <em>(Update: the competition is a now over.)</em></p>
<p>So what is the thinking behind the names that have, so far, been given to the mission? Rosetta is <a href="http://www.esa.int/Our_Activities/Space_Science/Rosetta/Why_Rosetta">named</a> for the Rosetta Stone, a one-metre high stone <a href="http://www.britishmuseum.org/collectionimages/AN00016/AN00016456_004_l.jpg?width=304">recovered from Egypt</a> at the beginning of the 19th century. It is renowned because it contains a single text in three separate languages: including Greek and Egyptian hieroglyphs. It was the transliteration between these three texts that finally allowed translation of Egyptian hieroglyphs and thus massively enhanced our understanding of Egyptian civilisation. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/62406/original/fwt3chhb-1413909035.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/62406/original/fwt3chhb-1413909035.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=425&fit=crop&dpr=1 600w, https://images.theconversation.com/files/62406/original/fwt3chhb-1413909035.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=425&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/62406/original/fwt3chhb-1413909035.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=425&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/62406/original/fwt3chhb-1413909035.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=534&fit=crop&dpr=1 754w, https://images.theconversation.com/files/62406/original/fwt3chhb-1413909035.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=534&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/62406/original/fwt3chhb-1413909035.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=534&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Rosetta stone.</span>
<span class="attribution"><a class="source" href="http://www.flickr.com/photos/chanc/333321656">chanc</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
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<p>Planetary scientists hope that the Rosetta mission will provide a similar understanding of the origins of the solar system and its component materials.</p>
<p>Philae is an island in the River Nile, just north of the Aswan Dam, the site of a major temple of Isis. It is one of the places where the Greek god Osiris was alleged to have been buried. The entrance to the temple was marked by two engraved obelisks. The hieroglyphics on one of the obelisks could be interpreted because they were accompanied by text in Greek, and this helped in translation of the Rosetta Stone. Just like the Philae obelisk facilitated understanding of the Rosetta stone and thus opened up understanding of the Egyptian world, the Philae lander will facilitate instruments on Rosetta, to open up understanding of the solar system’s history.</p>
<p>So what should Philae’s landing site be called? I feel that it should be given a name which reflects the historical theme of the Rosetta mission. There have been suggestions that the site might be named after the scholars who translated the Rosetta Stone. But given that there were international tensions surrounding publication of the translation, it may not be a useful event to commemorate.</p>
<p>The name Isis – an ancient Egyptian goddess – currently has unfortunate connotations. <a href="http://sci.esa.int/rosetta/35061-instruments/?fbodylongid=1642">Osiris</a> and <a href="http://sci.esa.int/rosetta/31445-instruments/?fbodylongid=896">Ptolemy</a> are already recognised in the mission as the names of instruments on the spacecraft. Osiris is also the name of a <a href="http://www.asteroidmission.org/">NASA mission</a> which will be launched to asteroid Bennu in 2016, and bring some of the asteroid back to Earth for analysis.</p>
<p>My submitted suggestion to the ESA competition is Agilkia. This is the name of the island to which the temple on Philae was transferred because it was in danger of damage by flooding following completion of the Aswan Dam. Agilkia, therefore, symbolises a place where ancient material is safeguarded for future generations to investigate, which is, I think, what Philae’s landing site also represents.</p><img src="https://counter.theconversation.com/content/33280/count.gif" alt="The Conversation" width="1" height="1" />
The Rosetta mission reaches a defining moment on Wednesday November 12, when its lander, Philae, is released. After about seven hours of descent, Philae will arrive on the surface of Comet 67P Churyumov-Gerasimenko…Monica Grady, Professor of Planetary and Space Sciences, The Open UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/322302014-09-26T11:22:16Z2014-09-26T11:22:16ZBefore the historic comet landing, Philae faces many dangers<figure><img src="https://images.theconversation.com/files/60170/original/4xzz3zr7-1411725685.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Landing in progress.</span> <span class="attribution"><a class="source" href="http://www.esa.int/spaceinimages/Images/2014/09/Rosetta_and_Philae_at_comet2">ESA–J. Huart, 2014</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>“Are we there yet?” is a plaintive query that most parents learn to dread, especially if uttered while halted in a traffic jam in the baking hot sun. At least the <a href="https://theconversation.com/rosetta-will-teach-us-more-about-comets-than-we-have-learned-in-50-years-30295">Rosetta spacecraft</a> has not had to deal with interplanetary traffic on its way to its destination of Comet 67P Churyumov-Gerasimenko. It is also well-protected against solar radiation. But the scientists working on the Philae lander might be forgiven for feeling as if their journey is never going to end, as Rosetta makes increasingly delicate manoeuvres towards its final orbit.</p>
<p>Over the past few weeks we have been <a href="https://theconversation.com/rosetta-lander-will-seek-a-close-encounter-with-comets-primordial-soup-30741">captivated by detailed images</a> of the comet: progressing from an out-of-focus blob that became a poorly focused duck, to the beautiful pictures of craters and rubble-strewn regions distributed across what must be one of the oddest-shaped bodies ever to have been photographed by a spacecraft. </p>
<h2>Riding the duck</h2>
<p>Images of the two unequally sized lobes, joined in the centre by a narrower bridge of material, have already led to a whole series of questions that have to be answered before the mission can progress successfully. Is Comet 67P two bodies that have come together during an impact? Or is it a single body that has been eroded by impacts? Are the two lobes of the same density?</p>
<p>Instruments on board Rosetta are mapping the composition of the surface and scientists now have a good idea of how the composition varies across the cometary nucleus. On September 26, Rosetta <a href="http://blogs.esa.int/rosetta/2014/09/24/rosettas-night-time-excursion-and-a-go-for-20-km/">starts</a> a series of measurements on the “night side” of 67P. This doesn’t mean that Rosetta is operating in the dark, but that its instruments are pointing towards the part of the comet’s surface which isn’t illuminated. This is so that we can learn more about the thermal properties of the surface, which has already been found to be hotter than expected by some 50 degrees. </p>
<p>A safe landing for Philae depends upon very accurate knowledge of the physical and thermal properties of 67P. To carry out such measurements, Rosetta will need drop into an orbit around 20km above the comet’s surface. Eventually however, Rosetta should be orbiting only about 1km above the surface, a position at which the Philae lander will be released from the mother-ship to make its descent to its destination.</p>
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<img alt="" src="https://images.theconversation.com/files/60171/original/tqbwqfyx-1411726537.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/60171/original/tqbwqfyx-1411726537.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=494&fit=crop&dpr=1 600w, https://images.theconversation.com/files/60171/original/tqbwqfyx-1411726537.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=494&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/60171/original/tqbwqfyx-1411726537.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=494&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/60171/original/tqbwqfyx-1411726537.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=621&fit=crop&dpr=1 754w, https://images.theconversation.com/files/60171/original/tqbwqfyx-1411726537.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=621&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/60171/original/tqbwqfyx-1411726537.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=621&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">The comet’s tail starts to appear.</span>
<span class="attribution"><a class="source" href="http://www.esa.int/spaceinimages/Images/2014/09/Comet_on_19_September_2014_NavCam">ESA/Rosetta/NAVCAM</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
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<p>While the detailed images of the comet’s surface have been fascinating, they have also revealed that Philae faces more dangers that we had considered. Much thought has been given to exactly where on the comet Philae will land. The best site will be a trade-off between its flatness, its slope, the amount of boulders scattered across the surface and how the site is illuminated. </p>
<h2>Danger ahead</h2>
<p>These parameters are all important. If the landing site is too bumpy or has too great a slope, it is likely that the lander will fall over rather than stay upright. If that happens, there is no way for it prop itself back up. Similarly, if there are too many boulders on the surface and one of the three legs hits a boulder, then again the lander will be unstable. </p>
<p>Illumination is also important: too much and the instruments will fry, too little and the battery will drain and not recharge. </p>
<p>Considering all those factors, two weeks ago, the European Space Agency (ESA) announced the preferred landing site to be “site J”, on the top of the smaller of the two lobes which make up the comet. So now we know the proposed place on the comet where Philae will land, preparations are moving towards finalising the actual landing date. </p>
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<p>The ESA has now announced that landing is scheduled for November 12, if site J is chosen. The schedule of events on that day, however, will be unclear until mid-October. If site J suddenly becomes active, such that it is no longer safe to land there, then the back-up landing site – “site C” – will be used. Site C is on the other lobe of the comet, so a new set of launch trajectories and site characterisation would be required, which will delay the landing a bit.</p>
<p>Whenever the landing does happen, though, it is going to be nail-biting for the mission operators. The low gravity of 67P means that there is a real possibility that Philae could bounce straight back into space once it hits the surface. To prevent this, as it approaches, Philae will fire a harpoon into the comet, anchoring the spacecraft to its target. As Philae settles, its legs will take hold, and scientists on Earth will be hoping that all systems are now “go” for the next stage of the mission.</p>
<p><em>This article was updated on September 29.</em></p><img src="https://counter.theconversation.com/content/32230/count.gif" alt="The Conversation" width="1" height="1" />
“Are we there yet?” is a plaintive query that most parents learn to dread, especially if uttered while halted in a traffic jam in the baking hot sun. At least the Rosetta spacecraft has not had to deal…Monica Grady, Professor of Planetary and Space Sciences, The Open UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/307412014-08-28T05:33:56Z2014-08-28T05:33:56ZRosetta lander will seek a close encounter with comet’s ‘primordial soup’<figure><img src="https://images.theconversation.com/files/57541/original/hkygqbkx-1409148354.jpg?ixlib=rb-1.1.0&rect=0%2C171%2C1024%2C640&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">More than a broken heart.</span> <span class="attribution"><a class="source" href="http://www.esa.int/spaceinimages/Images/2014/08/Comet_on_20_August_2014_-_NavCam">ESA/Rosetta/NAVCAM</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>There is much excitement about Rosetta <a href="https://theconversation.com/rosetta-will-teach-us-more-about-comets-than-we-have-learned-in-50-years-30295">at the moment</a>. The European Space Agency’s spacecraft has already made a successful rendezvous with a comet and the images that are being transmitted back are simply awe-inspiring. There is much more to come – the spacecraft will ride alongside the comet for at least another year. </p>
<p>Meanwhile, as early as November, there will be an attempt to put a lander, nicknamed Philae, on the surface of the comet, continuing the string of mission-firsts for Rosetta. The images taken by Rosetta have narrowed down the <a href="http://www.esa.int/Our_Activities/Space_Science/Rosetta/Rosetta_Landing_site_search_narrows">potential landing sites</a> to five.</p>
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<a href="https://images.theconversation.com/files/57547/original/g2nvt8j9-1409150892.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/57547/original/g2nvt8j9-1409150892.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/57547/original/g2nvt8j9-1409150892.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=200&fit=crop&dpr=1 600w, https://images.theconversation.com/files/57547/original/g2nvt8j9-1409150892.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=200&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/57547/original/g2nvt8j9-1409150892.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=200&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/57547/original/g2nvt8j9-1409150892.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=252&fit=crop&dpr=1 754w, https://images.theconversation.com/files/57547/original/g2nvt8j9-1409150892.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=252&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/57547/original/g2nvt8j9-1409150892.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=252&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Philae’s candidate landing sites.</span>
<span class="attribution"><a class="source" href="http://www.esa.int/spaceinimages/Images/2014/08/Philae_candidate_landing_sites">ESA/Rosetta/MPS</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
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<p>The 100kg lander has ten delicate instruments on board to record data. Choosing a land site is a complex task for many reasons. First and foremost, the site must be safe enough for landing without any damage. Next, the site must allow for good communication with Rosetta, which will eventually transmit data back to the Earth. Finally, it must also be illuminated by the sun’s faint light so that Philae can charge its batteries.</p>
<h2>Why take the trouble</h2>
<p>None of this is easy or cheap. So why take the trouble? There are two main reasons for humanity to pursue such challenging ventures. First there is the opportunity to develop capability. It seems clear that the era of space tourism and mining asteroids is not that far away. This “wild west” opportunity will require engineering solutions along with the availability of relevant human capital – Rosetta will inspire or supply some of these. And for those of us who share a certain vision for our species, the continued development of a technological civilisation requires that humans will eventually leave the Earth. Robotic space exploration is one of the ways in which we practice for this.</p>
<p>The second reason is to satisfy our natural curiosity about things. We do not just choose to do a mission like Rosetta. Rather, we simply have to. Exploration is embedded in the human DNA. Anyone who has been for a walk along a previously unvisited coastline knows the imperative of wanting to know what is beyond the next headland. But a walk in the countryside is considerably less expensive than the billion-euro price tag of Rosetta (which, of course, is stumped up by European tax-payers).</p>
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<img alt="" src="https://images.theconversation.com/files/57552/original/5swkvbxt-1409151660.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/57552/original/5swkvbxt-1409151660.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=337&fit=crop&dpr=1 600w, https://images.theconversation.com/files/57552/original/5swkvbxt-1409151660.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=337&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/57552/original/5swkvbxt-1409151660.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=337&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/57552/original/5swkvbxt-1409151660.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/57552/original/5swkvbxt-1409151660.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/57552/original/5swkvbxt-1409151660.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Artistic rendering of Rosetta arrival at the comet.</span>
<span class="attribution"><a class="source" href="http://www.esa.int/spaceinimages/Images/2014/08/Rosetta_arrives_at_comet">ESA/ATG/Rosetta/NAVCAM</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>A billion euros is either a lot of money, or next to nothing depending upon your perspective. But in attempt to place it into some kind of context, it is worth pointing out that by 2030 the UK has an ambition to <a href="https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/298362/igs-action-plan.pdf">secure a 10% share</a> of the global space economy. And that will be equivalent to overall annual revenues for the country of £40 billion (or €50 billion). In this light the cost of Rosetta begins to seem incredibly modest.</p>
<h2>Beyond the price tag</h2>
<p>Beyond the costs and at the excitement of discovery. Why would a scientist want to study comets? </p>
<p>We know that five billion years ago the solar system did not exist. A few hundred million years later, in just a relatively short interval of time, a planetary system was brought into existence. And it would very soon have started to look similar to what we see today.</p>
<p>We have no need to ask why the solar system formed – it just did. What we want to know is how. Comets are relevant in this context since they represent the fossilised remnants of this process. Studying them today allows us to look back in time and to interrogate the period when something substantial was produced from mere clouds of gas.</p>
<p>Given that there was no-one around to record and document this process we have to study the fragments of evidence that were left behind and which survive until the present time. The ethos is one of a forensic investigation. And here is exhibit A – a 4.6 billion year old collection of cosmic detritus known as Comet 67P/Churyumov-Gerasimenko.</p>
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<img alt="" src="https://images.theconversation.com/files/57550/original/8c3rmqns-1409151377.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/57550/original/8c3rmqns-1409151377.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/57550/original/8c3rmqns-1409151377.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/57550/original/8c3rmqns-1409151377.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/57550/original/8c3rmqns-1409151377.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=425&fit=crop&dpr=1 754w, https://images.theconversation.com/files/57550/original/8c3rmqns-1409151377.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=425&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/57550/original/8c3rmqns-1409151377.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=425&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Artistic rendering of Philae on the comet.</span>
<span class="attribution"><a class="source" href="http://www.esa.int/spaceinimages/Images/2013/12/Philae_on_the_comet_Front_view">ESA/ATG</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
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<p>By studying bodies such as 67P we have an opportunity to investigate the materials that formed the Earth. It is impossible to do this by studying the planet itself because the process of formation acts not only to homogenise the starting ingredients but also to then redistribute them during melting. </p>
<p>On Earth this has resulted in a core-mantle-crust structure. Simplistically, some chemical elements, such as iron, have become concentrated in the core, while others dominate above the surface, such as nitrogen. And yet, in the comet we fully expect to see the iron and nitrogen sitting right next to each other in their pre-planetary configuration.</p>
<h2>What Philae may find</h2>
<p>At some point during the formation of the Earth, the planet would have begun to approach the size it is today. Beyond this time, any incoming comets ceased to be implicated in the construction process. Any further additions were the dregs that merely coated the surface. This may not sound glamorous, but it was in this outer layer that life originated.</p>
<p>Before the requisite laboratory experiments had been done, the feeling was that comets hitting the surface of the primitive Earth would only have a negative influence on the origin of life. Massive impacts would have been traumatic and are likely to have sterilised the surface, wiping out any life that had already taken hold. </p>
<p>But now we know that in smaller impacts organic compounds could have survived. The events themselves may even have promoted relevant chemical reactions, spurring the creation of life. Thus, in comets maybe we are able to witness what life looked like at the very moment before it came into existence.</p>
<p>It was back at the start of the 20th century that a Russian biochemist, Alexander Oparin, came up with an idea that life on Earth originated at the surface of the planet within a “primordial soup” of carbon-bearing molecules. Perhaps Philae is destined for a close encounter with a frozen lump of primordial soup.</p>
<hr>
<p><em>Next, read this: <a href="https://theconversation.com/we-could-find-alien-life-but-politicians-dont-have-the-will-29304">We could find alien life, but politicians don’t have the will</a></em></p><img src="https://counter.theconversation.com/content/30741/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ian Wright's research is supported by grants from the Science and Technology Facilities Council and the UK Space Agency.</span></em></p>There is much excitement about Rosetta at the moment. The European Space Agency’s spacecraft has already made a successful rendezvous with a comet and the images that are being transmitted back are simply…Ian Wright, Professor of Planetary Sciences, The Open UniversityLicensed as Creative Commons – attribution, no derivatives.