tag:theconversation.com,2011:/au/topics/infrared-2530/articlesInfrared – The Conversation2024-02-14T12:21:07Ztag:theconversation.com,2011:article/2223162024-02-14T12:21:07Z2024-02-14T12:21:07ZFive reasons to heat your home using infrared fabric<figure><img src="https://images.theconversation.com/files/575023/original/file-20240212-20-j6tamt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">New infrared technology could make homes more energy efficient. </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/hand-turning-knob-make-home-more-1009692889">Olivier Le Moal/Shutterstock</a></span></figcaption></figure><p>Imagine heating your home from the ceiling, not from underfloor heating or radiators. Once installed like wallpaper, hi-tech infrared fabric emits heat in a similar way to the sun’s rays. This could be a logical way to add low-carbon heat into existing homes that need retrofitting to improve energy efficiency. </p>
<p>Under the currently proposed legislative changes, no new home will be built with an incoming gas supply <a href="https://www.britishgas.co.uk/the-source/greener-living/gas-boilers-ban-2025.html#">after 2025</a>. If you’re buying a new home that’s been designed and built to the new <a href="https://www.gov.uk/government/consultations/the-future-homes-standard-changes-to-part-l-and-part-f-of-the-building-regulations-for-new-dwellings">Future Homes Standard</a>, you’ve got little to worry about. </p>
<p>But for older properties, retrofitting projects can be complex, inconvenient and expensive. As gas boilers are phased out, heat pumps are usually the preferred alternative for energy-efficient housing. However, infrared fabric technology could be much better suited as a low-carbon heating solution for our existing housing stock, and here’s why.</p>
<h2>1. Instant heat</h2>
<p>Unlike heat pumps, which are a slow response heating system, infrared fabric emits radiant heat that can be felt within minutes. That has multiple advantages. </p>
<p>Gas boilers heat up our rooms quickly so we don’t have to leave the heating on when we’re out, but heat pumps don’t work like that. Instead, they deliver a continuous low level of heat, so homes need to be well-insulated to retain that heat and airtight to stop draughts. But, without draughts, we’ll need a <a href="https://www.eco-home-essentials.co.uk/home-ventilation-systems.html">mechanical ventilation system</a> to circulate fresh air. </p>
<p>Instant radiant heat reduces the need for all these additional interventions by directly heating the people and surfaces in a room rather than the air itself. It can be turned on or boosted to higher temperatures by motion sensors when you enter a room, with instant results. That means you only need to heat the rooms that you’re in, rather than an entire house.</p>
<h2>2. Simple to install</h2>
<p>Infrared fabric looks like a roll of slightly stiff wallpaper. It’s essentially a graphene sandwich, a thin film of carbon between two sheets of paper that conducts low voltage electricity and emits infrared heat, like the sun, but without the light or harmful <a href="https://www.who.int/news-room/fact-sheets/detail/ultraviolet-radiation">ultraviolet</a>. </p>
<p>A room’s ceiling area emits the right amount of heat for a room, making installation very simple in any property, irrespective of its construction, shape or size. It’s little more than a wallpapering job with a click together wiring connection. Your gas boiler could even be left in place for emergencies alongside it. By comparison, <a href="https://www.sciencedirect.com/science/article/abs/pii/S221462962030339X">heat pump installation</a> requires extensive additional works and sometimes a period of relocation.</p>
<h2>3. Affordable heat</h2>
<p>Infrared fabric is affordable to install and maintain due to its simplicity with a total cost of around £100 per sq metre for a full system. And it’s quite indestructible – it can have holes cut out of it and can get wet in floods without any danger to occupants or damage to the material. It’s also affordable to run. </p>
<p>Heat pumps are known to generate more energy than they use, up to three times as much, by taking low grade heat out of the air and <a href="https://www.greenbuildingrenewables.co.uk/a-beginners-guide-to-heat-pumps/">compressing it</a>. Infrared fabric can’t match that, but because radiant heat is instant, it’s only being emitted when needed in the rooms that you’re in, so even allowing for a <a href="https://sunamp.com/en-gb/">hot water system</a> the total energy use can be up to 20% less than from a heat pump.</p>
<h2>4. Radiant heat is healthy and safe</h2>
<p>Once the infrared heat warms the people, objects and surfaces that it touches, they in turn give off secondary heat through the process of <a href="https://www.metoffice.gov.uk/weather/learn-about/weather/how-weather-works/what-is-convection#:%7E:text=Convection%20is%20the%20movement%20of,another%20upon%20contact%2C%20transferring%20heat.">convection</a>. But the overall temperature is perceived to be 3˚C warmer than it actually is because people are being heated, as opposed to the air.</p>
<p>That’s both <a href="https://bmjopen.bmj.com/content/8/5/e021085">healthier</a> and <a href="https://nexgenheating.com/what-is-nextgen/the-benefits">cheaper</a> to sustain. Radiant heat also means the air carries <a href="https://www.sciencedirect.com/science/article/pii/S0954611115001870">fewer allergens</a> due to reduced air movement – it’s the convection currents from traditional heating systems that stir up the dust and allergens.</p>
<p>Infrared panels do the same thing but from a <a href="https://www.theecoexperts.co.uk/infrared-heating/the-basics">90˚C point source</a> in your room and with less consistency. Radiators reach 60 – 70˚C, whereas infrared fabric emits a low-level heat (45˚C) over the <a href="https://nexgenheating.com/what-is-nextgen/the-technology">whole area</a>. Heat absorbed into the fabric of the building is retained for longer than warmed air, resulting in a more consistent room temperature across day and night. </p>
<h2>5. Our homegrown future</h2>
<p>Infrared fabric is a UK invention and it’s UK-manufactured. All we need now is for it to be UK accredited. That’s a long and expensive process, but the all important SAP Appendix Q certification is due in 2025 if not before. It already has BSEN (British Standard) approval as a large area low temperature <a href="https://nexgenheating.com/what-is-nextgen/the-technology">emitter</a> and it’s class A fire rated.</p>
<p>The Welsh government already funds its use in retrofit programmes following extensive trials across <a href="https://governmentbusiness.co.uk/news/31052022/heated-wallpaper-trialled-wales">270 homes</a>. Further research is now needed to evidence the health, safety and carbon benefits that will strengthen the case even more for this form of heating. </p>
<p>So if you’re retrofitting an existing property as a home owner, private landlord, housing association or local authority, infrared fabric could be a low-risk, low-cost, low-carbon solution worth considering.</p>
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<p class="fine-print"><em><span>Michael Siebert 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>New infrared fabric technology is easy to install, cheap to run and affordable so it has huge potential as a future alternative to heat pumps, especially for retrofit projects.Michael Siebert, Lecturer in Architecture, School of Architecture, Design and Built Environment, Nottingham Trent UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2065942023-06-07T20:07:17Z2023-06-07T20:07:17ZWe’ve created a new lens that could take thermal cameras out of spy films and put them into your back pocket<figure><img src="https://images.theconversation.com/files/529508/original/file-20230601-25388-svx1ew.jpeg?ixlib=rb-1.1.0&rect=39%2C45%2C4298%2C3205&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Like something out of a spy movie, thermal cameras make it possible to “see” heat by converting infrared radiation into an image. They can detect infrared light given off by animals, vehicles, electrical equipment and even people – leading to specialised applications in a number of industries.</p>
<p>Despite these applications, thermal imaging technology remains too expensive to be used in many consumer products such as self-driving cars or smartphones. </p>
<p>Our team at Flinders University has been working hard to turn this technology into something we can all use, and not just something we see in spy movies. We’ve developed a low-cost thermal imaging lens that could be scaled up and brought into the lives of everyday people. Our findings <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/adom.202300058">are published</a> in the journal Advanced Optical Materials. </p>
<h2>Thermal imaging across industries</h2>
<p>Thermal imaging has obvious applications in surveillance and security, given its ability to detect the heat signature of people. It’s not surprising defence forces all over the world use this technology – <a href="https://www.dst.defence.gov.au/innovation/heat-imaging-technology-infrared">including in Australia</a>. </p>
<p>In medicine, it can be used to detect tissues of a higher temperature. This means thermal cameras are useful in the <a href="https://www.hindawi.com/journals/misy/2022/8952849/#abstract">non-invasive detection</a> of tumours, which run at a higher metabolism (and temperature) than healthy tissue. </p>
<p>Thermal imaging even plays a crucial role in <a href="https://spinoff.nasa.gov/spinoff1997/ps2.html">space exploration</a>. For instance, it can be used to image distant stars, galaxies and planets, because infrared light can penetrate dust clouds much better than visible light. NASA’s James Webb Space Telescope <a href="https://www.nasa.gov/image-feature/goddard/2022/nasa-s-webb-delivers-deepest-infrared-image-of-universe-yet">also takes</a> infrared images – and its ability to see far “redder” wavelengths is opening up new corners of the universe for us.</p>
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<a href="https://theconversation.com/two-experts-break-down-the-james-webb-space-telescopes-first-images-and-explain-what-weve-already-learnt-186738">Two experts break down the James Webb Space Telescope's first images, and explain what we've already learnt</a>
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<h2>Addressing the high-cost conundrum</h2>
<p>Above are just some examples in a long list of the specialised applications of thermal imaging. Yet this technology could have many more potential uses if it wasn’t so expensive to produce.</p>
<p>The high cost comes, in part, from the materials used to produce the camera lenses. These lenses need to have special properties that allow them to be used with infrared radiation in a way standard lenses can’t.</p>
<p>Most glasses and plastics will absorb infrared radiation, so expensive materials such as germanium or zinc selenide must be used. Both materials can be difficult to manufacture and maintain; <a href="https://www.usgs.gov/data/germanium-deposits-united-states#:%7E:text=Germanium%2C%20which%20is%20currently%20classified,Alaska%2C%20Washington%2C%20and%20Tennessee">germanium</a> is a critical element in short supply, and zinc selenide <a href="https://www.ncbi.nlm.nih.gov/books/NBK216723/">contains toxic elements</a>.</p>
<p>Our team wanted to address the lens challenge head-on. We developed a new polymer made from the low-cost and abundant building blocks of sulfur and cyclopentadiene (an organic compound that takes the form of a colourless liquid). </p>
<p>The cost of the raw materials for the lens we’ve developed is less than one cent per lens. In comparison, some germanium lenses can <a href="https://www.edmundoptics.com.au/search/?criteria=Germanium%20lenses&Tab=Products#ProductFamilies_ii=ProductFamilies_ii%3AMTQxODA1">cost thousands of dollars</a>.</p>
<p>This new sulfur-based lens can also be moulded and cast into a variety of complex shapes through common techniques used in the plastics industry. These techniques are simpler and less energy-intensive than those used to create conventional infrared lenses – further reducing the cost and making the polymer more scalable.</p>
<p>The key to developing this material was figuring out how to use cyclopentadiene as a gas for the reaction with sulfur. By doing this, we could precisely control the composition of the resulting polymer – leading to a lens with enhanced capabilities for thermal imaging.</p>
<p>Despite being completely opaque to visible light, the polymer has the highest long-wave infrared transmission of any plastic that has been reported – which means it can be used with a thermal imaging camera.</p>
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<a href="https://images.theconversation.com/files/529513/original/file-20230601-23163-x54b7c.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/529513/original/file-20230601-23163-x54b7c.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/529513/original/file-20230601-23163-x54b7c.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=1200&fit=crop&dpr=1 600w, https://images.theconversation.com/files/529513/original/file-20230601-23163-x54b7c.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=1200&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/529513/original/file-20230601-23163-x54b7c.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=1200&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/529513/original/file-20230601-23163-x54b7c.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1508&fit=crop&dpr=1 754w, https://images.theconversation.com/files/529513/original/file-20230601-23163-x54b7c.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1508&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/529513/original/file-20230601-23163-x54b7c.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1508&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">The lens is black and opaque.</span>
<span class="attribution"><span class="license">Author provided</span></span>
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<h2>Possible applications</h2>
<p>The development of this material opens doors to many new thermal imaging applications that weren’t possible before.</p>
<p>Self-driving cars could use this technology to detect pedestrians or vehicles – even in low light or fog. Or it could be used in agriculture to monitor irrigation and crop health. Importantly, it would be affordable for farmers. </p>
<p>The new lens is also lightweight, which is helpful for aerial imaging by drone. </p>
<p>Finally, it could be integrated into consumer electronics such as smartphones, computers and home automation systems, to name a few. This would enable users to take thermal images or videos at any time from their phone. It could even be used to create next-generation smoke alarms.</p>
<p>The advances developed in this new study have significantly reduced the barrier to using thermal imaging – and may help revolutionise how it’s used in our everyday lives.</p>
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Read more:
<a href="https://theconversation.com/weve-created-a-device-that-could-allow-instant-disease-diagnosis-while-fitting-inside-your-phone-lens-181342">We've created a device that could allow instant disease diagnosis – while fitting inside your phone lens</a>
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<p class="fine-print"><em><span>Samuel Tonkin studies at Flinders University. He receives funding from Flinders University Impact Seed Funding for Early Career Researchers and the Australian Research Council (DP200100090 and FT220100054) awarded to Future Fellow Prof Justin Chalker. Additional support for quantum mechanical calculations was also provided by the ARC to Prof Michelle Coote (DP210100025). Samuel Tonkin is an inventor on a provisional patent application covering the manufacture and use of thermal imaging materials discussed in this article (AU2022900289).</span></em></p><p class="fine-print"><em><span>Justin M. Chalker receives funding from Flinders University and the Australian Research Council (FT220100054, DP230100587, DP200100090) for this project. Justin Chalker is an inventor on a provisional patent application covering the manufacture and use of the thermal imaging materials discussed in this article (AU2022900289). </span></em></p>The costs of the materials is less than one cent per lens.Samuel Tonkin, PhD Candidate, College of Science and Engineering, Flinders UniversityJustin M. Chalker, Matthew Flinders Professor of Chemistry, Flinders UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2033822023-04-07T15:56:02Z2023-04-07T15:56:02ZOn April 8, 2024, parts of Ontario, Québec, the Maritimes and Newfoundland will see a total eclipse of the sun. Here’s how to get ready for it.<figure><img src="https://images.theconversation.com/files/519687/original/file-20230405-22-8wx57z.jpg?ixlib=rb-1.1.0&rect=25%2C11%2C1862%2C1212&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Watching a solar eclipse is always fascinating. During the phase when the moon completely obstructs the sun, daylight gives way to a deep twilight sky.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>You might not know exactly what you will be doing a year from now, on April 8, 2024. It’s pretty hard to predict a year in advance. However, on that date, <a href="https://solarsystem.nasa.gov/eclipses/2024/apr-8-total/where-when/">a total solar eclipse will occur in parts of Mexico, the United States and Canada — including parts of southern Ontario and Québec, New Brunswick, Nova Scotia, Prince Edward Island and Newfoundland</a> — a rare phenomenon. </p>
<p>The total solar eclipse will be visible in locations including: Niagara Falls and Hamilton, Ont.; Montréal; Fredericton, N.B.; western P.E.I.; the northern tip of Cape Breton, N.S.; and Gander, Nfld.</p>
<p>Cities like Toronto and Ottawa will be just beyond the path of the total solar eclipse. </p>
<p>While partial solar eclipses happen quite frequently, the total disappearance of the sun behind the moon only occurs <a href="https://espacepourlavie.ca/en/total-or-annular-solar-eclipse">when the moon is closer to our planet or the sun is at its furthest point from it</a>. It is a question of the size of the moon compared to the sun. When the two are perfectly aligned, it creates a shadow cone that allows people on Earth who are within this narrow band to enjoy the unique spectacle of a total eclipse. </p>
<p>On average, this alignment only occurs <a href="https://espacepourlavie.ca/en/frequency-solar-eclipses">once every 375 years</a>, but it can vary. For example, the last total eclipse visible in Montréal occurred on Aug. 31, 1932. Other regions in Canada have not been as lucky. In St. John’s, Nfld., the last total eclipse was on Feb. 3, 1440, and locals will have to wait a total of 765 years for the next one, which will happen on July 17, 2205! The record belongs to Regina, Sask., which had a total eclipse in 54 BC, but will not see another one until Oct. 17, 2153 — or a total of 2207 years! </p>
<p>So try not to miss the total eclipse in places like Montréal in 2024. If you do, you’ll have to go to a location like <a href="https://espacepourlavie.ca/en/frequency-solar-eclipses">Calgary for the next one, in 20 years</a>. </p>
<p>Yet the phenomenon does pose significant risks to eye health. As an optometrist, I am very concerned about eye health issues. I certainly wouldn’t want anyone to go blind after watching a solar eclipse without properly protecting their eyes.</p>
<h2>Watch it, but protect yourself</h2>
<p>Watching a total solar eclipse is always fascinating. During the phase when the moon completely obstructs the sun, daylight is transformed into a deep twilight sky. The sun’s outer atmosphere (known as the sun’s corona) gradually appears, <a href="https://solarsystem.nasa.gov/eclipses/2024/apr-8-total/overview/">shining like a halo around the moon</a>. The bright stars and planets become more visible in the sky.</p>
<p>In daylight, the sun usually emits visible light that is so intense we cannot look directly at it for very long. If our eye ever looks directly at the sun, we have the reflex of turning away from it immediately, after <a href="https://ehs.lbl.gov/resource/documents/radiation-protection/non-ionizing-radiation/light-and-infrared-radiation/#:%7E:text=Prolonged%20exposure%20to%20IR%20radiation,eye%2C%20swelling%2C%20or%20hemorrhaging">an average of only 0.25 seconds</a>. This reflex provides natural protection for eyes against the harmful rays of the sun, some of which — notably ultraviolet and infrared radiation — are not visible. </p>
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<span class="caption">During a total solar eclipse, the sun’s outer atmosphere (called the solar corona) gradually appears, shining like a halo around the moon that faces it.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
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<h2>Ultraviolet radiation (UV)</h2>
<p>UVs accounts for <a href="https://ehs.lbl.gov/resource/documents/radiation-protection/non-ionizing-radiation/light-and-infrared-radiation/#:%7E:text=Prolonged%20exposure%20to%20IR%20radiation,eye%2C%20swelling%2C%20or%20hemorrhaging.">seven per cent of solar radiation</a>. They are partly absorbed by the cornea (the clear part at the front of the eye) and the crystalline lens (the natural lens inside the eye), without causing any damage, unless the exposure is too great. </p>
<p>In such cases, depending on the amount of UV radiation it absorbs, the cornea may develop inflammation, known as keratitis. The lens, in turn, loses its transparency — this is called a cataract. Other impacts can be expected, such as the development of <a href="https://www.nei.nih.gov/about/news-and-events/news/protecting-your-eyes-suns-uv-light#:%7E:text=Prolonged%20exposure%20to%20UV%20rays,are%20linked%20to%20UV%20exposure">small cysts (pinguecula) on the conjunctiva (white of the eye) or a membrane invading the cornea (pterygium)</a>.</p>
<p>Eyelids can also develop skin cancers. The upper eyelid, which is usually not exposed on the outside when our eyes are open, is particularly at risk when we lie on the beach with our eyes closed without protection. Finally, UV light predisposes us to <a href="https://theconversation.com/macular-degeneration-is-a-leading-cause-of-blindness-heres-how-to-prevent-it-160683">macular degeneration</a>, which is a damage to our best retinal cells and can result in varying degrees of vision loss.</p>
<p>These <a href="https://www.aao.org/eye-health/tips-prevention/sun">diseases</a> all develop as a result of direct radiation, but can also come about when the sun’s rays are strongly reflected by surfaces such as snow (snow ophthalmia), sand or water. It is therefore recommended to wear protective eyewear that cuts out all UV rays (UV400 protection) when you plan to spend more than a few minutes in the sun. For both <a href="https://theconversation.com/summer-is-here-why-you-need-to-protect-your-childrens-eyes-116498">children</a> and adults, the frame should wrap around the eyes, so that no rays pass through the side or top.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/519354/original/file-20230404-2216-nwlh6e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="child wears sunglasses at the beach" src="https://images.theconversation.com/files/519354/original/file-20230404-2216-nwlh6e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/519354/original/file-20230404-2216-nwlh6e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=390&fit=crop&dpr=1 600w, https://images.theconversation.com/files/519354/original/file-20230404-2216-nwlh6e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=390&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/519354/original/file-20230404-2216-nwlh6e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=390&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/519354/original/file-20230404-2216-nwlh6e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=490&fit=crop&dpr=1 754w, https://images.theconversation.com/files/519354/original/file-20230404-2216-nwlh6e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=490&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/519354/original/file-20230404-2216-nwlh6e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=490&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">For both children and adults, the frame of sunglasses should wrap around the eyes, so that no rays pass through from the side or top.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<h2>Infrared radiation (IR)</h2>
<p>IRs make up the majority of the radiation emitted by the sun — <a href="https://ehs.lbl.gov/resource/documents/radiation-protection/non-ionizing-radiation/light-and-infrared-radiation/#:%7E:text=Prolonged%20exposure%20to%20IR%20radiation,eye%2C%20swelling%2C%20or%20hemorrhaging">54 per cent</a>. We feel the effects because it is thermal radiation, which is accompanied by heat. </p>
<p>While the cornea (burning) and lens (cataract) can also be affected by IR, it is more the retina that can suffer from inappropriate exposure to IR. Again, it is a question of intensity and duration. As with UV radiation, the more intense the radiation, the more permanent damage will occur in a short period of time.</p>
<p>IR damage to the retina destroys the cells that allow us to see and ultimately creates a scotoma, a permanent black spot in our field of vision. This is a cause of blindness. </p>
<h2>Eclipse and radiation</h2>
<p>When the Sun is only partially hidden (partial eclipse), the UV and IR radiation is as important as in full sunlight. However, because of the reduced luminosity, we no longer have the natural reflex of turning our eyes away. So it may seem more comfortable to observe the sun for several seconds or even minutes. Without protection, this type of exposure can lead to the pathologies described above and contribute to blindness if the central retina is affected. <a href="https://www.theguardian.com/us-news/video/2017/aug/21/donald-trump-look-directly-sun-eclipse-video">U.S. President Donald Trump was reminded of this in 2017</a>, when he watched a partial eclipse without protection, putting his vision at risk. </p>
<p>During a total eclipse, however, it is possible, during the short duration of the total obstruction of the sun (one minute 37 seconds), to <a href="https://www.nasa.gov/content/eye-safety-during-a-total-solar-eclipse/#:%7E:text=During%20the%20short%20time%20when,put%20back%20on%20your%20glasses.">look at the solar corona without protection</a>. But you must be very vigilant and remember to put protection back in place as soon as the Moon starts to move and the radiation becomes present again, even though the ambient luminosity is still reduced. </p>
<p>The same precautions should be taken when viewing the eclipse directly through binoculars, a telescope, a camera or other optical means. For example, do not look at your phone screen with the naked eye when trying to take pictures of the eclipse. The rays are not blocked by these instruments and can cause significant eye damage. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/519351/original/file-20230404-988-6obvvo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Trump points at the sun" src="https://images.theconversation.com/files/519351/original/file-20230404-988-6obvvo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/519351/original/file-20230404-988-6obvvo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/519351/original/file-20230404-988-6obvvo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/519351/original/file-20230404-988-6obvvo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/519351/original/file-20230404-988-6obvvo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/519351/original/file-20230404-988-6obvvo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/519351/original/file-20230404-988-6obvvo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">President Donald Trump points at the sun without protective glasses during the partial solar eclipse on Aug. 21, 2017, at the White House in Washington, D.C.</span>
<span class="attribution"><span class="source">(AP Photo/Andrew Harnik)</span></span>
</figcaption>
</figure>
<h2>A question of protection</h2>
<p>So, what kind of eye protection are we talking about exactly? Sunscreens that can be mounted in glasses or in temporary glasses, made of cardboard, but that cover the entire surface of the eye perfectly. Once again, it is important to avoid leaving a gap between the eye and the protective screen through which harmful radiation can enter. Permitted filters <a href="https://www.aao.org/eye-health/tips-prevention/solar-eclipse-eye-safety">must meet ISO-12312-2</a>.</p>
<p>Before wearing such filters, be sure to follow the instructions provided with the equipment. It is very important for parents to ensure that children wear the filters properly and do not play with them. When the observation is over, do not remove the filters while you are still looking at the sun: look away, turn your back to the sun and remove the filters. Then don’t look at the sky anymore. </p>
<h2>If ever…</h2>
<p>Damage to the cornea and retina can occur within hours of exposure, but not always immediately. If you have ever been inadvertently or recklessly exposed, monitor your vision in the hours after the eclipse. If you notice any blurring or changes in your vision, you should consult an optometrist or ophthalmologist as soon as possible. </p>
<p>Many activities will be organized for the arrival of the total eclipse. To make the most of this unique event, watch for announcements from organizations such as <a href="https://espacepourlavie.ca/en">Space for Life</a>, institutions such as the Université de Montréal, or your local astronomy clubs. These organizations will provide information, may provide protective glasses/filters and, most importantly, will help you to better understand the phenomenon. </p>
<p>See you in a year’s time! But in the meantime, whether young and old, let’s all protect our eyes properly.</p><img src="https://counter.theconversation.com/content/203382/count.gif" alt="La Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Langis Michaud ne travaille pas, ne conseille pas, ne possède pas de parts, ne reçoit pas de fonds d'une organisation qui pourrait tirer profit de cet article, et n'a déclaré aucune autre affiliation que son organisme de recherche.</span></em></p>Some parts of North America will witness a total solar eclipse in April 2024. This may seem far away, but you should think about preparing for this rare and fascinating phenomenon.Langis Michaud, Professeur Titulaire. École d'optométrie. Expertise en santé oculaire et usage des lentilles cornéennes spécialisées, Université de MontréalLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1815252022-04-26T13:18:26Z2022-04-26T13:18:26ZHere’s one way to burn less fossil fuel – use human energy to heat buildings instead<figure><img src="https://images.theconversation.com/files/459791/original/file-20220426-18-abbvt9.jpg?ixlib=rb-1.1.0&rect=6%2C0%2C2038%2C1364&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Capturing energy from clubbers could help power homes and buildings.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/exitfestival/28128407771">Exit Festival/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span></figcaption></figure><p>In the cult film <a href="https://www.warnerbros.com/movies/matrix">The Matrix</a>, unwitting humans’ body heat was siphoned off by machines to use as their energy source. Although that might not be the ideal situation to find ourselves in, the basis of the idea – using the warmth we generate to heat our buildings – could help fight climate change by cutting <a href="https://theconversation.com/heres-what-it-would-take-to-end-emissions-from-fossil-fuels-170815">fossil fuel use</a>.</p>
<p>Let’s look at the science. The average human body emits about <a href="https://www.sciencedirect.com/science/article/pii/B9781782420323500132">100 watts of heat</a> at rest. When exercising, that heat can easily exceed <a href="https://pubmed.ncbi.nlm.nih.gov/9694408/#:%7E:text=During%20strenuous%20exercise%20the%20body's,temperature%20by%20a%20few%20degrees.">1,000 watts</a>: energy that could boil one litre of water in six minutes. For comparison, a standard (3 kW) home kettle takes more than two minutes to heat a litre of water.</p>
<p>Where does that energy come from? Mostly, food. The body’s <a href="https://www.britannica.com/science/human-disease/Metabolic-control">internal metabolism</a> uses products of digestion, such as carbohydrates and fatty acids, to produce the energy that drives muscle contraction. However, <a href="https://www.sciencedirect.com/science/article/pii/S1566070216300303">about 70-95%</a> of energy produced is released as heat. This shows that the human body isn’t very efficient at generating mechanical energy from food: in fact, it’s slightly less efficient than a petrol engine.</p>
<p>Much of this heat is removed from the body through convection, infrared radiation and <a href="https://theconversation.com/from-perspiration-to-world-domination-the-extraordinary-science-of-sweat-62753">sweating</a>, which cools skin using evaporation. This explains why in extremely <a href="https://theconversation.com/how-humid-is-it-3-things-to-keep-you-cool-in-a-hot-and-sticky-summer-and-3-things-that-wont-176365">hot and humid</a> conditions, you don’t feel comfortable – your sweat isn’t evaporating as easily into the saturated air. </p>
<p>Using infrared cameras, we’re able to see that heat as it moves from bodies to their surroundings. These cameras depict areas of increased heat (where more heat is being lost) as lighter in colour, and cooler areas as darker – showing us where most heat is being wasted.</p>
<figure class="align-left ">
<img alt="An infrared-colour image of the author" src="https://images.theconversation.com/files/458591/original/file-20220419-13-wpw5hq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/458591/original/file-20220419-13-wpw5hq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=730&fit=crop&dpr=1 600w, https://images.theconversation.com/files/458591/original/file-20220419-13-wpw5hq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=730&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/458591/original/file-20220419-13-wpw5hq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=730&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/458591/original/file-20220419-13-wpw5hq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=918&fit=crop&dpr=1 754w, https://images.theconversation.com/files/458591/original/file-20220419-13-wpw5hq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=918&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/458591/original/file-20220419-13-wpw5hq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=918&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">In infrared, you can see which parts of me are hotter and cooler.</span>
<span class="attribution"><span class="source">Amin Al-habaibeh</span></span>
</figcaption>
</figure>
<p>When people gather indoors, this heat starts to accumulate. Imagine a theatre with a 500-person capacity. Assuming each person is producing 100 watts of thermal energy, this means 50 kW of heat will be emitted overall: equivalent to 25-30 <a href="https://www.tameside.gov.uk/EnergyEfficiency/Top-Tips-%E2%80%93-June-Don%E2%80%99t-Fill-The-Kettle-Too-Full">average</a> kitchen kettles continuously boiling water.</p>
<p>If those people are physically active – for example, dancing – together they could generate 150 kW of heat, or 3600 kWh over 24 hours. The average household in the UK consumes about <a href="https://usave.co.uk/energy/how-much-energy-does-the-average-uk-household-consume/#:%7E:text=According%20to%20Ofgem%2C%20the%20average,kWh%20of%20gas%20each%20year.">1,000 kWh</a> of gas per month. Since an average domestic gas boiler has an approximately 30 kW output, just 500 dancers could produce the energy of five gas boilers.</p>
<p>The next question is how this human heat can best be used to warm buildings. Usually, buildings use ventilation or air conditioning systems to reduce temperatures and enhance air quality. This extracted heat is then lost to the outside environment, wasting energy. Instead, crowd heat could be extracted via <a href="https://www.ipieca.org/resources/energy-efficiency-solutions/efficient-use-of-heat/heat-exchangers/">mechanical heat exchangers</a> – devices that transfer heat from one area to another – and used to heat incoming air in neighbouring buildings. </p>
<figure class="align-center ">
<img alt="An infrared-colour image of people walking and sitting in a room" src="https://images.theconversation.com/files/458592/original/file-20220419-20-1tnfsr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/458592/original/file-20220419-20-1tnfsr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=432&fit=crop&dpr=1 600w, https://images.theconversation.com/files/458592/original/file-20220419-20-1tnfsr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=432&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/458592/original/file-20220419-20-1tnfsr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=432&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/458592/original/file-20220419-20-1tnfsr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=543&fit=crop&dpr=1 754w, https://images.theconversation.com/files/458592/original/file-20220419-20-1tnfsr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=543&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/458592/original/file-20220419-20-1tnfsr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=543&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Infrared images can be used to pinpoint where human body heat is being wasted.</span>
<span class="attribution"><span class="source">Amin Al-habaibeh</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>A more flexible option is to use <a href="https://www.sciencedirect.com/science/article/abs/pii/S0166516216301604?via%3Dihub">heat pumps</a>, which are a bit like reverse air conditioning systems that pump heat in instead of out. That heat can also be stored for later use, for example in water cylinders or modified bricks. Technology like this is already used in <a href="https://www.sciencedirect.com/science/article/abs/pii/S1359431115010388">data centres</a>, where the significant amounts of heat emitted by computer networks need to be extracted to avoid system failure.</p>
<h2>Thermal energy in action</h2>
<p>The concept of body heating systems is already a reality in some parts of the world. In Sweden, the <a href="https://earthbound.report/2012/11/02/building-of-the-week-kungsbrohuset/">Kungsbrohuset</a> office building – located above Stockholm’s central subway station – is already <a href="http://www.diva-portal.se/smash/get/diva2:1114930/FULLTEXT01.pdf">partially heated</a> by the body heat of daily travellers through the station, reducing its heating needs by 5-10%. A heat pump extracts heat from the station, where it’s stored in water that’s used for heating the offices above. </p>
<p>Meanwhile, in Mall of America in Minnesota, energy from sunlight and the heat of over 40 million annual visitors has <a href="http://minnesotaconnected.com/lifestyle/local-businesses/did-you-know-the-mall-of-america-has-no-central-heating_178620/">replaced</a> central heating. And the <a href="https://www.bodyheat.club/">BODYHEAT</a> system, currently undergoing installation at an arts centre in Glasgow, uses heat pumps to capture clubbers’ thermal energy and store it in <a href="https://www.nytimes.com/2021/12/30/arts/dance/geothermal-body-heat-glasgow-nightclub.html">underground boreholes</a> that will provide the building with heat and hot water.</p>
<figure class="align-center ">
<img alt="A large, multicoloured play area inside a glass building" src="https://images.theconversation.com/files/459458/original/file-20220425-22-ad6oc2.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/459458/original/file-20220425-22-ad6oc2.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/459458/original/file-20220425-22-ad6oc2.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/459458/original/file-20220425-22-ad6oc2.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/459458/original/file-20220425-22-ad6oc2.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/459458/original/file-20220425-22-ad6oc2.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/459458/original/file-20220425-22-ad6oc2.jpeg?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">Mall of America has used sunlight and body heat to warm its internal space since 1992.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Mall_of_America-2005-05-29.jpg">Jeremy Noble/Wikimedia</a></span>
</figcaption>
</figure>
<p>I’ve studied the heating system at <a href="https://www.sciencedirect.com/science/article/pii/S2095263521000601?via%3Dihub">Nottingham Playhouse</a>, with an auditorium capacity of 750 people. We found that as audience numbers increase inside the theatre, so does the temperature, meaning that the central heating can be lowered on nights with packed crowds. Using this principle, we can develop “<a href="https://theconversation.com/get-ready-for-the-invasion-of-smart-building-technologies-following-covid-19-168646">smart buildings</a>” able to adjust their heating based on the number of people in a room and the expected resulting increase in temperature. This simple solution can be used in many types of buildings – even those without heat pumps installed.</p>
<p>With the <a href="https://theconversation.com/energy-bills-are-spiking-after-the-russian-invasion-we-should-have-doubled-down-on-renewables-years-ago-179336">recent hike</a> in energy prices and the global push towards reaching <a href="https://theconversation.com/more-companies-pledge-net-zero-emissions-to-fight-climate-change-but-what-does-that-really-mean-166547">net zero</a> carbon emissions, systems like these could provide a simple and revolutionary way to cut fossil fuel use and lower energy bills by making use of the wasted heat that fills busy public spaces.</p><img src="https://counter.theconversation.com/content/181525/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Amin Al-Habaibeh 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>Extracting and storing human body heat we generate could improve building sustainability while cutting bills.Amin Al-Habaibeh, Professor of Intelligent Engineering Systems, Nottingham Trent UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1736192021-12-20T09:24:38Z2021-12-20T09:24:38ZJames Webb Space Telescope: how our launch of world’s most complex observatory will rest on a nail-biting knife edge<figure><img src="https://images.theconversation.com/files/438175/original/file-20211217-15-nhmkwp.jpeg?ixlib=rb-1.1.0&rect=0%2C0%2C2880%2C2845&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Artist's impression of the James Webb telescope after deployment of the mirror and sunshield.</span> <span class="attribution"><a class="source" href="https://www.nasa.gov/sites/default/files/thumbnails/image/jwst_in_space.jpg">Northrup Grumman/Nasa</a></span></figcaption></figure><p>When the immense sound of the <a href="https://www.arianespace.com/vehicle/ariane-5/">Ariane 5 rocket</a> rumbles across Europe’s spaceport in French Guiana, it will signal the end of a journey decades in the making. Perched atop the rocket will be the <a href="https://jwst.nasa.gov/content/about/launch.html">James Webb Space Telescope (JWST)</a>, the most sophisticated and complex observatory ever constructed. An enormous mirror 6.5 metres across, consisting of 18 gold-plated segments, will be delicately folded to fit within the nose cone. </p>
<p>That precious cargo carries the hopes and dreams of thousands of engineers and scientists like us who have worked for so long to make this observatory a reality. We’ll no doubt all be holding our breath.</p>
<p>If all goes well, humanity will have a new eye on the cosmos, with capabilities that far surpass anything that has gone before. The telescope will access realms that have been previously hidden from us, being too distant, too cold or too faint for even the venerable <a href="https://theconversation.com/hubbles-deep-field-images-of-the-early-universe-are-postcards-from-billions-of-years-ago-40519">Hubble Space Telescope</a>. </p>
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Read more:
<a href="https://theconversation.com/james-webb-space-telescope-what-astronomers-hope-it-will-reveal-about-the-beginning-of-the-universe-podcast-173436">James Webb Space Telescope: what astronomers hope it will reveal about the beginning of the universe – podcast</a>
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<p>As light from the earliest stars has been stretched by the expansion of the universe over 13 billion years, we need instruments <a href="https://www.esa.int/About_Us/ESA_Publications/ESA_BR-348_Webb_Seeing_farther">that work in infrared light</a>, which we can feel as heat, to peer into this mysterious epoch of cosmic history. JWST is so sensitive that it could theoretically detect the heat signature of a <a href="https://jwst.nasa.gov/content/about/faqs/tweetChat2.html">bumblebee at the distance of the Moon</a>. </p>
<p>We are poised on the edge of new discoveries about the origins of our universe and our place within it: insights that will fill the pages of the textbooks of tomorrow.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/437283/original/file-20211213-19-1su9d84.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Image of the JWST mirror and sunshield." src="https://images.theconversation.com/files/437283/original/file-20211213-19-1su9d84.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/437283/original/file-20211213-19-1su9d84.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/437283/original/file-20211213-19-1su9d84.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/437283/original/file-20211213-19-1su9d84.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/437283/original/file-20211213-19-1su9d84.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/437283/original/file-20211213-19-1su9d84.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/437283/original/file-20211213-19-1su9d84.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>
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<span class="caption">JWST mirror and sunshield (folded) as they underwent final tests before shipping.</span>
<span class="attribution"><span class="source">Credit: NASA/Chris Gunn</span></span>
</figcaption>
</figure>
<p>But before that can happen, we face an agonising wait. Not only during the intense launch that will carry the US$10 billion JWST beyond the reach of our human hands, but also through the tense months of deployment, testing and transfer to a lonely outpost, preparing for the “first light” of a facility that <a href="https://www.nature.com/articles/d41586-021-03620-1">has been described</a> as the “most expensive astronomical gamble in history”. </p>
<p>No previous space observatory has been subjected to more testing and scrutiny than JWST. It has survived cancellations, design changes and technical mistakes. It has also survived budgetary woes, natural disasters such as Hurricane Harvey, a pandemic and even the threat of <a href="https://www.theatlantic.com/science/archive/2021/03/nasa-james-webb-space-telescope-pirates/618268/">piracy</a> as it journeyed from California to French Guiana through the Panama Canal.</p>
<p>That it weathered these storms is a testament to the international team responsible for the observatory, a worldwide partnership led by Nasa, the European Space Agency (Esa), and the Canadian Space Agency, but encompassing hundreds of institutions around the globe. </p>
<h2>The launch and beyond</h2>
<p>With so many years and careers invested in JWST, all eyes will be on that rocket as it clears the tower at the spaceport. As the world holds its breath, JWST’s perilous journey will just be beginning. Over the ensuing weeks, a breathtaking array of mechanisms and sequential deployments must work perfectly, each step adding risk to the process. </p>
<p>Once the faring that protects the telescope separates, the observatory will deploy its communications devices and solar arrays, and embark on its 29-day journey towards the <a href="https://solarsystem.nasa.gov/resources/754/what-is-a-lagrange-point/">‘Lagrange point’ (L2)</a> – a position where the gravitational forces of the Sun, Earth, and orbital motions of a spacecraft interact to create a stable location – some <a href="https://www.theatlantic.com/science/archive/2021/12/james-webb-space-telescope-lagrange-point/620935/">1.5 million kilometres from our planet</a>. Ariane will send JWST directly to this location without orbiting Earth first, but <a href="https://webb.nasa.gov/content/about/orbit.html">small rockets will fire</a> during the first day to tweak the trajectory, and then a final burn will insert the observatory into orbit around L2 a month later.</p>
<p>As it travels to its destination, it will execute a <a href="https://www.nasa.gov/feature/goddard/2021/the-road-to-launch-and-beyond-for-nasa-s-james-webb-space-telescope">delicate unfolding</a>, dancing to a choreography years in the making. To tease out the faint infrared light from distant stars and galaxies, the whole observatory must be cold so as not to be blinded by its own infrared warmth. It does this by keeping its back to the Sun and using an enormous parasol – a tennis-court-sized sunshield, made of five layers of thin plastic coated in reflective aluminium and doped-silicon, durable to withstand strikes by swarms of tiny meteorites. This sunshield will be the first to deploy, around a week after launch.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/437282/original/file-20211213-15-osb3r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Image of the JWST's primary mirror undergoing testing in 2017." src="https://images.theconversation.com/files/437282/original/file-20211213-15-osb3r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/437282/original/file-20211213-15-osb3r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=393&fit=crop&dpr=1 600w, https://images.theconversation.com/files/437282/original/file-20211213-15-osb3r.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=393&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/437282/original/file-20211213-15-osb3r.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=393&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/437282/original/file-20211213-15-osb3r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=494&fit=crop&dpr=1 754w, https://images.theconversation.com/files/437282/original/file-20211213-15-osb3r.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=494&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/437282/original/file-20211213-15-osb3r.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=494&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">JWST’s primary mirror undergoing testing in 2017.</span>
<span class="attribution"><span class="source">NASA/Desiree Stover</span></span>
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</figure>
<p>This will be followed by the unfurling of the petals of the primary mirror. All eighteen segments have to be aligned in space, adjusting and focusing them so that they work together as one giant mirror. These deployments will involve <a href="https://blogs.nasa.gov/drthomasz/2021/08/02/launching-the-worlds-biggest-space-telescope/">344 individual steps</a>, providing a nail-biting wait for the team on Earth. If something goes wrong, we can’t go and fix it – it’s simply too far away.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/437297/original/file-20211213-27-h59xuf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Schematic picture of the JWST deployment procedure." src="https://images.theconversation.com/files/437297/original/file-20211213-27-h59xuf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/437297/original/file-20211213-27-h59xuf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/437297/original/file-20211213-27-h59xuf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/437297/original/file-20211213-27-h59xuf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/437297/original/file-20211213-27-h59xuf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/437297/original/file-20211213-27-h59xuf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/437297/original/file-20211213-27-h59xuf.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"></a>
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<span class="caption">JWST deployment procedure.</span>
<span class="attribution"><span class="source">Esa.</span></span>
</figcaption>
</figure>
<p>Months of testing, calibrating, aligning and more testing will follow, as the telescope cools to 40K (-233°C). One of the instruments, known as MIRI, has to go colder still, to just 7K (-266°C). This will be made possible by thermally isolating it from the rest of the observatory on long legs, and using a special helium refrigerator. </p>
<h2>Astronomical bounty awaits</h2>
<p>Some six months after launch, JWST will finally open its eyes to the cosmos. It will peer back in time, to just a few million years after the Big Bang to witness the end of the dark ages, when matter first coalesced to form the simplest stars of hydrogen and helium. This unexplored era set the stage for the origins of galaxies, shaping our modern cosmos and seeding the universe with complex elements. </p>
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<p>The telescope will also investigate the atmospheres of planets around other stars to understand their origins and potential habitability. Closer to home, JWST will turn its gaze on the worlds of our Solar System, and explore the rocky and icy remnants left over from the birth of planets.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/437286/original/file-20211213-25-4pnqn6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="MIRI integration into JWST payload module in 2013." src="https://images.theconversation.com/files/437286/original/file-20211213-25-4pnqn6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/437286/original/file-20211213-25-4pnqn6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=378&fit=crop&dpr=1 600w, https://images.theconversation.com/files/437286/original/file-20211213-25-4pnqn6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=378&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/437286/original/file-20211213-25-4pnqn6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=378&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/437286/original/file-20211213-25-4pnqn6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=476&fit=crop&dpr=1 754w, https://images.theconversation.com/files/437286/original/file-20211213-25-4pnqn6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=476&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/437286/original/file-20211213-25-4pnqn6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=476&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">MIRI integration into JWST payload module in 2013.</span>
<span class="attribution"><span class="source">NASA/C. Gunn</span></span>
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</figure>
<p>Crucial to this is the MIRI instrument that we worked on here at the University of Leicester, one of four that will deliver on the scientific promise of JWST. MIRI has been built by a <a href="https://www.ukri.org/blog/james-webb-space-telescope-jwst-final-rehearsals-before-launch/">transatlantic partnership</a> of ten European countries plus the US, jointly led by <a href="https://jwst.nasa.gov/content/meetTheTeam/people/wright.html">Professor Gillian Wright</a> at <a href="https://stfc.ukri.org/about-us/where-we-work/royal-observatory-edinburgh/uk-astronomy-technology-centre/">STFC’s UK Astronomy Technology Centre (ATC)</a> in Edinburgh, and <a href="https://jwst.nasa.gov/content/meetTheTeam/people/riekeGeorge.html">Professor George Rieke</a> at the University of Arizona.</p>
<p>As the only mid-infrared instrument in JWST’s toolkit, <a href="https://sci.esa.int/web/jwst/-/46826-miri-the-mid-infrared-instrument-on-jwst">MIRI</a> will provide images and spectroscopy – a technique that breaks down light into specific wavelengths – allowing it to tease out the chemical signatures of JWST’s astronomical targets.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/437280/original/file-20211213-23-ke2hix.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="image of MIRI on JWST." src="https://images.theconversation.com/files/437280/original/file-20211213-23-ke2hix.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/437280/original/file-20211213-23-ke2hix.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/437280/original/file-20211213-23-ke2hix.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/437280/original/file-20211213-23-ke2hix.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/437280/original/file-20211213-23-ke2hix.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/437280/original/file-20211213-23-ke2hix.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/437280/original/file-20211213-23-ke2hix.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"></a>
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<span class="caption">MIRI on JWST.</span>
<span class="attribution"><span class="source">NASA/ Chris Gunn</span></span>
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</figure>
<p>There is no question JWST will open the scientific floodgates, and may lead to unexpected discoveries that the JWST visionaries haven’t even imagined yet. We’re standing on that threshold, hoping that this complex observatory can finally realise our ambitions.</p><img src="https://counter.theconversation.com/content/173619/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Leigh Fletcher leads a range of JWST Solar System observations during its first year, and receives funding from a European Research Council (ERC) Consolidator Grant, the Royal Society, and the UK Science and Technology Facilities Council (STFC).</span></em></p><p class="fine-print"><em><span>John Pye works for the University of Leicester. He is a member of international teams conducting observations during JWST Cycle 1. He receives funding from grants from the UK Space Agency and the UK's Science & Technology Facilities Council, and has previously received funding from grants from the European Community Horizon 2020 programme. </span></em></p><p class="fine-print"><em><span>Piyal Samara-Ratna works for the University of Leicester where he is a technical member of staff. He receives research funding from a variety sources of grants. For the James Webb Space Telescope Mid-Infrared Instrument he has been funded by the UK Space Agency and the UK's Science & Technology Facility Council. He is affiliated with the Institute of Mechanical Engineers where he is a Chartered member.</span></em></p>It will be a nail-biting wait as scientists launch and deploy the most complex observatory ever built.Leigh Fletcher, Associate Professor in Planetary Sciences, University of LeicesterJohn Pye, Senior research fellow, University of LeicesterPiyal Samara-Ratna, Principal Engineer, University of LeicesterLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1626152021-06-16T07:00:52Z2021-06-16T07:00:52ZSeeing the invisible: tiny crystal films could make night vision an everyday reality<figure><img src="https://images.theconversation.com/files/406613/original/file-20210616-3738-1hg0363.png?ixlib=rb-1.1.0&rect=8%2C2%2C902%2C444&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Artist's impression of the view through future night-vision glasses.</span> <span class="attribution"><span class="source">Lei Xu / NTU</span>, <span class="license">Author provided</span></span></figcaption></figure><p>It’s a familiar vision to anyone who has watched a lot of action movies or played Call of Duty: a ghostly green image that makes invisible objects visible. Since the development of the first night-vision devices in the mid-1960s, the technology has captured the popular imagination.</p>
<p>Night vision goggles, infrared cameras and other similar devices detect infrared light reflected from objects or rather detect infrared light emitted from objects in the form of heat. Today these devices are widely used not only by the military, but also by law enforcement and emergency services, the security and surveillance industries, wildlife hunters, and camping enthusiasts.</p>
<p>But current technology is not without its problems. Commercial infrared cameras block visible light, disrupting normal vision. The gear is bulky and heavy, and requires low temperatures — and, in some cases, even cryogenic cooling — to work.</p>
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<img alt="" src="https://images.theconversation.com/files/406606/original/file-20210616-15-1skecj7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/406606/original/file-20210616-15-1skecj7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/406606/original/file-20210616-15-1skecj7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/406606/original/file-20210616-15-1skecj7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/406606/original/file-20210616-15-1skecj7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/406606/original/file-20210616-15-1skecj7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/406606/original/file-20210616-15-1skecj7.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">
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<span class="caption">Rocio Camacho Morales in the optics lab.</span>
<span class="attribution"><span class="source">Jamie Kidston / ANU</span>, <span class="license">Author provided</span></span>
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<p>We have proposed a new technology that uses ultra-thin layers of nanocrystals to make infrared light visible, addressing many of the longstanding problems with current devices. Our research is published in <a href="https://doi.org/10.1117/1.AP.3.3.036002">Advanced Photonics</a>. </p>
<p>Our eventual goal is to produce a light, film-like layer that can sit on glasses or other lenses, powered by a tiny built-in laser, allowing people to see in the dark.</p>
<h2>Conventional infrared detection</h2>
<p>Commercial infrared cameras convert infrared light to an electric signal, which is then shown on a display screen. They require low temperatures, because of the low energy and frequency of infrared light. This makes conventional infrared detectors bulky and heavy – some security personnel have reported
chronic neck injury due to <a href="https://doi.org/10.3357/AMHP.4027.2015">regular use of night vision goggles</a> . </p>
<p>Another drawback of the current technology is that it blocks the transmission of visible light, thereby disrupting normal vision. In some cases, infrared images could be sent to a display monitor, leaving normal vision intact. However, this solution is not feasible when users are on the move.</p>
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Read more:
<a href="https://theconversation.com/looking-at-the-universe-through-very-different-eyes-86068">Looking at the universe through very different 'eyes'</a>
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</em>
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<h2>All-optical alternatives</h2>
<p>There are also some all-optical <a href="https://doi.org/10.1063/1.1651902">alternatives</a>, which do not involve electrical signals. Instead, they directly convert infrared light into visible light. The visible light can then be captured by the eye or a camera.</p>
<p>These technologies work by combining incoming infrared light with a strong light source – a laser beam – inside a material known as “nonlinear crystal”. The crystal then emits light in the visible spectrum. </p>
<p>However, nonlinear crystals are bulky and expensive, and can only detect light in a narrow band of infrared frequencies.</p>
<h2>Metasurfaces provide the solution</h2>
<p>Our work advances this all-optical approach. Instead of a non-linear crystal, we set out to use carefully designed layers of nanocrystal called “metasurfaces”. Metasurfaces are ultra-thin and ultra-light, and can be tweaked to manipulate the color or frequency of the light that passes through them.</p>
<p>This makes metasurfaces an attractive platform to convert infrared photons to the visible. Importantly, transparent metasurfaces could enable infrared imaging and allow for normal vision at the same time.</p>
<p>Our group set out to demonstrate infrared imaging with metasurfaces. We designed a metasurface composed of hundreds of incredibly tiny crystal antennas made of the semiconductor gallium arsenide. </p>
<p>This metasurface was designed to amplify light by resonance at certain infrared frequencies, as well as the frequency of the laser and the visible light output. We then fabricated the metasurface and transferred it to a transparent glass, forming a layer of nanocrystals on a glass surface.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/406071/original/file-20210614-23-1cjuozk.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/406071/original/file-20210614-23-1cjuozk.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=416&fit=crop&dpr=1 600w, https://images.theconversation.com/files/406071/original/file-20210614-23-1cjuozk.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=416&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/406071/original/file-20210614-23-1cjuozk.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=416&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/406071/original/file-20210614-23-1cjuozk.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=523&fit=crop&dpr=1 754w, https://images.theconversation.com/files/406071/original/file-20210614-23-1cjuozk.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=523&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/406071/original/file-20210614-23-1cjuozk.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=523&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A scanning electron microscope image shows the nanocrystal structures of the metasurface used to make infrared light visible.</span>
<span class="attribution"><span class="source">Mohsen Rahmani/ NTU</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>To test our metasurface, we illuminated it with infrared images of a target and saw that the infrared images were converted to visible green images. We tested this with various positions of the target, and also with no target at all — so we could see the green emission of the metasurface itself. In the images obtained, the dark stripes correspond to the infrared target, surrounded by the green visible emission.</p>
<p>Despite different parts of the infrared images being up-converted by independent nanocrystals composing the metasurface, the images were well reproduced in visible light.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/406072/original/file-20210614-25-1ngrt1e.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/406072/original/file-20210614-25-1ngrt1e.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/406072/original/file-20210614-25-1ngrt1e.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=367&fit=crop&dpr=1 600w, https://images.theconversation.com/files/406072/original/file-20210614-25-1ngrt1e.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=367&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/406072/original/file-20210614-25-1ngrt1e.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=367&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/406072/original/file-20210614-25-1ngrt1e.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=461&fit=crop&dpr=1 754w, https://images.theconversation.com/files/406072/original/file-20210614-25-1ngrt1e.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=461&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/406072/original/file-20210614-25-1ngrt1e.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=461&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">These pairs of images show the shape of the infrared target at left and the visible-light view through the metasurface at right.</span>
<span class="attribution"><span class="source">Rocio Camacho Morales</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>While our experiment is only a proof of concept, this technology can in principle do many things that are not possible with conventional systems, such as a broader angle of view and multi-colour infrared imaging.</p>
<h2>The future of metasurfaces in novel technologies</h2>
<p>The demand for detecting infrared light, invisible to human eyes, is constantly growing, due to a wide variety of applications beyond night vision. The technology could be used in the agricultural industry to help monitor and maintain food quality control, and in remote sensing techniques such as LIDAR – a technology that is helping to map natural and manmade environments. </p>
<p>In a wider context, the use of metasurfaces to detect, generate and manipulate light is booming. Harnessing the power of metasurfaces will bring us closer to technologies such as real-time holographic displays, artificial vision for autonomous systems, and ultra-fast light-based wifi. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/small-and-bright-what-nanophotonics-means-for-you-58747">Small and bright: what nanophotonics means for you</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/162615/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Rocio Camacho Morales would like to acknowledge the support of the ARC Centre of Excellence for Transformative Meta-Optical Systems (TMOS) and the Consejo Nacional de Ciencia y Tecnología (CONACYT),</span></em></p>New ‘nanocrystal metasurfaces’ can convert infrared light into the visible spectrumRocio Camacho Morales, Postdoctoral fellow, ARC Center of Excellence for Transformative Meta-Optical Systems (TMOS), Australian National UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1430782020-07-28T12:17:31Z2020-07-28T12:17:31ZHow to hide from a drone – the subtle art of ‘ghosting’ in the age of surveillance<figure><img src="https://images.theconversation.com/files/349270/original/file-20200723-19-1selkhc.jpg?ixlib=rb-1.1.0&rect=0%2C204%2C4252%2C2346&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The federal government has used military-grade border patrol drones like this one to monitor protests in US cities.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/joncutrer/43252568250/">_ Jonathan Cutrer/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>Drones of all sizes are being used by environmental advocates to monitor deforestation, by conservationists to track poachers, and by journalists and activists to document large protests. As a <a href="https://scholar.google.com/citations?user=MEUtCZYAAAAJ&hl=en">political sociologist</a> who studies social movements and drones, I document a wide range of nonviolent and pro-social drone uses in my new book, “<a href="https://mitpress.mit.edu/books/good-drone">The Good Drone</a>.” I show that these efforts have the potential to democratize surveillance. </p>
<p>But when the Department of Homeland Security redirects large, fixed-wing drones from the U.S.-Mexico border to <a href="https://www.nytimes.com/2020/06/19/us/politics/george-floyd-protests-surveillance.html">monitor protests</a>, and when towns experiment with using drones to <a href="https://www.nbcnews.com/news/us-news/connecticut-town-tests-pandemic-drone-detect-fevers-experts-question-if-n1189546">test people for fevers</a>, it’s time to think about how many eyes are in the sky and how to avoid unwanted aerial surveillance. One way that’s within reach of nearly everyone is learning how to simply disappear from view.</p>
<h2>Crowded skies</h2>
<p>Over the past decade there’s been an explosion in the public’s use of drones – everyday people with everyday tech doing <a href="https://digital.sandiego.edu/gdl2016report/1/">interesting things</a>. As drones enter already-crowded airspace, the Federal Aviation Administration is <a href="https://doi.org/10.15394/ijaaa.2020.1453">struggling to respond</a>. The near future is likely to see even more of these devices in the sky, flown by an ever-growing cast of social, political and economic actors. </p>
<figure class="align-center ">
<img alt="small drone over a city street" src="https://images.theconversation.com/files/349265/original/file-20200723-37-1iy93ky.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/349265/original/file-20200723-37-1iy93ky.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/349265/original/file-20200723-37-1iy93ky.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/349265/original/file-20200723-37-1iy93ky.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/349265/original/file-20200723-37-1iy93ky.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/349265/original/file-20200723-37-1iy93ky.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/349265/original/file-20200723-37-1iy93ky.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A law enforcement drone flew over demonstrators, Friday, June 5, 2020, in Atlanta.</span>
<span class="attribution"><a class="source" href="http://www.apimages.com/metadata/Index/America-Protest-Atlanta/db14ae07df09454398c3fb94439453a4/16/0">AP Photo/Mike Stewart</a></span>
</figcaption>
</figure>
<p>Public opinion about the use and spread of drones is still <a href="https://theconversation.com/dont-shoot-that-drone-overhead-probably-isnt-invading-your-privacy-114701">up in the air</a>, but burgeoning drone use has sparked numerous efforts to curtail drones. These responses range from public policies exerting community control over local airspace, to the development of sophisticated jamming equipment and tactics for knocking drones out of the sky. </p>
<p>From startups to major defense contractors, there is a scramble to deny airspace to drones, to hijack drones digitally, to control drones physically and to shoot drones down. Anti-drone measures range from simple blunt force, <a href="https://www.popularmechanics.com/flight/drones/how-to/a16756/how-to-shoot-down-a-drone/">10-gauge shotguns</a>, to the poetic: <a href="https://www.washingtonpost.com/news/worldviews/wp/2016/02/01/trained-eagle-destroys-drone-in-dutch-police-video/">well-trained hawks</a>. </p>
<p>Many of these anti-drone measures are expensive and complicated. Some are illegal. The most affordable – and legal – way to avoid drone technology is <a href="http://www.dronesurvivalguide.org/">hiding</a>.</p>
<h2>How to disappear</h2>
<p>The first thing you can do to hide from a drone is to take advantage of the natural and built environment. It’s possible to wait for bad weather, since smaller devices like those used by local police have a hard time flying in high winds, dense fogs and heavy rains. </p>
<p>Trees, walls, alcoves and tunnels are more reliable than the weather, and they offer shelter from the high-flying drones used by the Department of Homeland Security.</p>
<figure class="align-center ">
<img alt="Silhouettes of drones" src="https://images.theconversation.com/files/349245/original/file-20200723-33-16zsn27.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/349245/original/file-20200723-33-16zsn27.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=418&fit=crop&dpr=1 600w, https://images.theconversation.com/files/349245/original/file-20200723-33-16zsn27.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=418&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/349245/original/file-20200723-33-16zsn27.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=418&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/349245/original/file-20200723-33-16zsn27.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=525&fit=crop&dpr=1 754w, https://images.theconversation.com/files/349245/original/file-20200723-33-16zsn27.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=525&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/349245/original/file-20200723-33-16zsn27.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=525&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">In some parts of the world, hiding from drones is a matter of life and death.</span>
<span class="attribution"><a class="source" href="http://www.dronesurvivalguide.org/">Drone Survival Guide</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<p>The second thing you can do is minimize your digital footprints. It’s smart to avoid using wireless devices like mobile phones or GPS systems, since they have digital signatures that can reveal your location. This is useful for evading drones, but is also important for avoiding other privacy-invading technologies.</p>
<p>The third thing you can do is confuse a drone. Placing mirrors on the ground, standing over broken glass, and wearing elaborate headgear, <a href="https://www.theguardian.com/technology/2017/jan/04/anti-surveillance-clothing-facial-recognition-hyperface">machine-readable blankets</a> or <a href="https://projectkovr.com/">sensor-jamming jackets</a> can break up and distort the image a drone sees. </p>
<p>Mannequins and other forms of mimicry can confuse both on-board sensors and the analysts charged with monitoring the drone’s video and sensor feeds. </p>
<p>Drones equipped with infrared sensors will see right through the mannequin trick, but are confused by tactics that mask the body’s temperature. For example, a space blanket will mask significant amounts of the body’s heat, as will simply hiding in an area that matches the body’s temperature, like a building or sidewalk exhaust vent.</p>
<p>The fourth, and most practical, thing you can do to protect yourself from drone surveillance is to get a disguise. The growth of mass surveillance has led to an explosion in creative experiments meant to mask one’s identity. But some of the smartest ideas are decidedly old-school and low-tech. Clothing is the first choice, because hats, glasses, masks and scarves go a long way toward scrambling drone-based facial-recognition software. </p>
<figure class="align-center ">
<img alt="Facial makeup chart" src="https://images.theconversation.com/files/349271/original/file-20200723-33-2y6x6e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/349271/original/file-20200723-33-2y6x6e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=518&fit=crop&dpr=1 600w, https://images.theconversation.com/files/349271/original/file-20200723-33-2y6x6e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=518&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/349271/original/file-20200723-33-2y6x6e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=518&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/349271/original/file-20200723-33-2y6x6e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=651&fit=crop&dpr=1 754w, https://images.theconversation.com/files/349271/original/file-20200723-33-2y6x6e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=651&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/349271/original/file-20200723-33-2y6x6e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=651&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Clever use of makeup can thwart facial recognition systems.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/johnbullas/4591293468/">John C Bullas BSc MSc PhD MCIHT MIAT/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<p>Your gait is as unique as your fingerprint. As gait-recognition software evolves, it will be important to also mask the key pivot points used in identifying the walker. It may be that the best response is affecting a limp, using a minor leg brace or wearing extremely loose clothing.</p>
<p>Artists and scientists have taken these approaches a step further, developing a <a href="https://weburbanist.com/2013/04/01/stealth-wear-counter-surveillance-fashion-protects-privacy/">hoodie wrap</a> that’s intended to shield the owner’s heat signature and to scramble facial recognition software, and <a href="https://www.chicagotribune.com/business/ct-biz-facial-recognition-blocking-glasses-privacy-20200417-isy77jwrsncoholhndmyifadr4-story.html">glasses</a> intended to foil facial recognition systems. </p>
<h2>Keep an umbrella handy</h2>
<p>These innovations are alluring, but umbrellas may prove to be the most ubiquitous and robust tactic in this list. They’re affordable, easy to carry, hard to see around and can be disposed of in a hurry. Plus you can build a <a href="http://survival.sentientcity.net/umbrella.html">high-tech one</a>, if you want.</p>
<p>It would be nice to live in a world with fewer impositions on privacy, one in which law enforcement did not use small quadcopters and the Department of Homeland Security did not redeploy large Predator drones to surveil protesters. And, for people in some parts of the world, it would be nice not to associate the sound of a drone with impending missile fire. But given that those eyes are in the sky, it’s good to know how to hide. </p>
<p>
<section class="inline-content">
<img src="https://images.theconversation.com/files/248895/original/file-20181204-133100-t34yqm.png?w=128&h=128">
<div>
<header>Austin Choi-Fitzpatrick is the author of:</header>
<p><a href="https://mitpress.mit.edu/books/good-drone">The Good Drone: How Social Movements Democratize Surveillance</a></p>
<footer>MIT Press provides funding as a member of The Conversation US.</footer>
</div>
</section>
</p><img src="https://counter.theconversation.com/content/143078/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Austin Choi-Fitzpatrick has previously won an industry award from drone manufacturer DJI, and his work has been supported through the National Science Foundation. MIT Press provides funding as a member of The Conversation US.</span></em></p>Avoiding drones’ prying eyes can be as complicated as donning a high-tech hoodie and as simple as ducking under a tree.Austin Choi-Fitzpatrick, Associate Professor of Political Sociology, University of San DiegoLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1332202020-06-25T12:24:34Z2020-06-25T12:24:34ZGene therapy and CRISPR strategies for curing blindness (Yes, you read that right)<figure><img src="https://images.theconversation.com/files/343286/original/file-20200622-54993-o5z60d.jpg?ixlib=rb-1.1.0&rect=15%2C7%2C5106%2C3394&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Researchers are now testing treatments for several kinds of visual impairment. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/blind-10-year-old-boy-reading-a-braille-book-royalty-free-image/523091364?adppopup=true&uiloc=thumbnail_same_series_adp">BRIAN MITCHELL / Getty Images</a></span></figcaption></figure><p>In recent months, even as our attention has been focused on the coronavirus outbreak, there have been a slew of scientific breakthroughs in treating diseases that cause blindness. </p>
<p>Researchers at U.S.-based Editas Medicine and Ireland-based Allergan have administered <a href="https://clinicaltrials.gov/ct2/show/NCT03872479">CRISPR for the first time to a person with a genetic disease</a>. This landmark treatment uses the CRISPR approach to a specific mutation in a gene linked to childhood blindness. The mutation affects the functioning of the light-sensing compartment of the eye, called the retina, and leads to loss of the light-sensing cells.</p>
<p>According to the World Health Organization, <a href="https://www.who.int/news-room/detail/08-10-2019-who-launches-first-world-report-on-vision">at least 2.2 billion people</a> in the world have some form of visual impairment. In the United States, approximately <a href="https://lowvision.preventblindness.org/2013/07/06/numbers-of-people-with-macular-degeneration-and-other-retinal-diseases/">200,000 people suffer from inherited forms of retinal disease</a> for which there is no cure. But things have started to change for good. We can now see light at the end of the tunnel.</p>
<p>I am an ophthalmology and visual sciences researcher, and am particularly interested in these advances because <a href="https://www.umassmed.edu/khannalab/">my laboratory is focusing</a> on designing new and improved gene therapy approaches to treat inherited forms of blindness. </p>
<h2>The eye as a testing ground for CRISPR</h2>
<p>Gene therapy involves inserting the correct copy of a gene into cells that have a mistake in the genetic sequence of that gene, recovering the normal function of the protein in the cell. The eye is an ideal organ for testing new therapeutic approaches, including CRISPR. That is because the eye is the most exposed part of our brain and thus is easily accessible. </p>
<p>The second reason is that retinal tissue in the eye is shielded from the body’s defense mechanism, which would otherwise consider the injected material used in gene therapy as foreign and mount a defensive attack response. Such a response would destroy the benefits associated with the treatment. </p>
<p>In recent years, breakthrough gene therapy studies paved the way to the <a href="https://www.fda.gov/news-events/press-announcements/fda-approves-novel-gene-therapy-treat-patients-rare-form-inherited-vision-loss">first ever Food and Drug Administration-approved gene therapy drug, Luxturna TM</a>, for a devastating childhood blindness disease, <a href="https://ghr.nlm.nih.gov/condition/leber-congenital-amaurosis">Leber congenital amaurosis</a> Type 2. </p>
<p>This form of Leber congenital amaurosis is caused by mutations in a gene that codes for a protein called RPE65. The protein participates in chemical reactions that are needed to detect light. The mutations lessen or eliminate the function of RPE65, which leads to our inability to detect light – blindness. </p>
<p>The treatment method developed simultaneously by groups at University of Pennsylvania and at University College London and Moorefields Eye Hospital involved <a href="https://www.nature.com/news/2008/080428/full/news.2008.786.html">inserting a healthy copy of the mutated gene</a> directly into the space between the retina and the retinal pigmented epithelium, the tissue located behind the retina where the chemical reactions takes place. This gene helped the retinal pigmented epithelium cell produce the missing protein that is dysfunctional in patients. </p>
<p>Although the treated eyes showed vision improvement, as measured by the patient’s ability to navigate an obstacle course at differing light levels, <a href="https://www.aop.org.uk/ot/science-and-vision/research/2015/05/05/lca-gene-therapy-unable-to-stop-long-term-sight-loss">it is not a permanent fix</a>. This is due to the lack of technologies that can fix the mutated genetic code in the DNA of the cells of the patient. </p>
<h2>A new technology to erase the mutation</h2>
<p>Lately, scientists have been developing a powerful new tool that is shifting biology and genetic engineering into the next phase. This breakthrough <a href="http://doi.org/10.1126/science.1225829">gene</a> <a href="http://doi.org/10.1126/science.1231143">editing</a> technology, which is called CRISPR, enables researchers to directly edit the genetic code of cells in the eye and correct the mutation causing the disease. </p>
<p>Children suffering from the disease Leber congenital amaurosis Type 10 endure progressive vision loss beginning as early as one year old. This specific form of Leber congenital amaurosis is caused by a change to the DNA that affects the ability of the gene – called CEP290 – to make the complete protein. The loss of the CEP290 protein affects the survival and function of our light-sensing cells, called photoreceptors. </p>
<p>One treatment strategy is to deliver the full form of the CEP290 gene using a virus as the delivery vehicle. But the CEP290 gene is too big to be cargo for viruses. So another approach was needed. One strategy was to fix the mutation by using CRISPR.</p>
<p>The scientists at Editas Medicine first showed safety and proof of the concept of the CRISPR strategy in cells extracted from patient skin biopsy and in nonhuman primate animals. </p>
<p>These studies led to the formulation of the <a href="https://ir.editasmedicine.com/news-releases/news-release-details/allergan-and-editas-medicine-announce-dosing-first-patient">first ever in human CRISPR gene therapeutic clinical trial</a>. This Phase 1 and Phase 2 trial will eventually assess the safety and efficacy of the CRISPR therapy in 18 Leber congenital amaurosis Type 10 patients. The patients receive a dose of the therapy while under anesthesia when the retina surgeon uses a scope, needle and syringe to inject the CRISPR enzyme and nucleic acids into the back of the eye near the photoreceptors. </p>
<p>To make sure that the experiment is working and safe for the patients, the clinical trial has recruited people with late-stage disease and no hope of recovering their vision. The doctors are also injecting the CRISPR editing tools into only one eye. </p>
<h2>A new CEP290 gene therapy strategy</h2>
<p>An ongoing project in my laboratory focuses on designing a gene therapy approach for the same gene CEP290. Contrary to the CRISPR approach, which can target only a specific mutation at one time, my team is developing an approach that would work for all CEP290 mutations in Leber congenital amaurosis Type 10. </p>
<p>This approach involves using <a href="https://www.umassmed.edu/khannalab/ciliopathies-blog-and-news/channa-lab-in-the-news/2017/September/study-shows-potential-of-cep290-minigenes-as-therapeutics-for-childhood-blindness-disorder/">shorter yet functional forms of the CEP290 protein</a> that can be delivered to the photoreceptors using the viruses approved for clinical use.</p>
<p>Gene therapy that involves CRISPR promises a permanent fix and a significantly reduced recovery period. A downside of the CRISPR approach is the possibility of an off-target effect in which another region of the cell’s DNA is edited, which could cause undesirable side effects, such as cancer. However, new and improved strategies have made such likelihood very low. </p>
<p>Although the CRISPR study is for a specific mutation in CEP290, I believe the use of CRISPR technology in the body to be exciting and a giant leap. I know this treatment is in an early phase, but it shows clear promise. In my mind, as well as the minds of many other scientists, CRISPR-mediated therapeutic innovation absolutely holds immense promise. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/343289/original/file-20200622-54977-16bxxmw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/343289/original/file-20200622-54977-16bxxmw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/343289/original/file-20200622-54977-16bxxmw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/343289/original/file-20200622-54977-16bxxmw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/343289/original/file-20200622-54977-16bxxmw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/343289/original/file-20200622-54977-16bxxmw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/343289/original/file-20200622-54977-16bxxmw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/343289/original/file-20200622-54977-16bxxmw.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">An infrared image of a man and a dog. German and Swiss researchers have shown that they can endow living mice with this type of vision.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/thermal-image-of-man-with-dog-royalty-free-image/758300683?adppopup=true">Joseph Giacomin</a></span>
</figcaption>
</figure>
<h2>More ways to tackle blindness</h2>
<p>In another study just reported in the journal Science, German and Swiss scientists have developed <a href="https://doi.org/10.1126/science.aaz5887">a revolutionary technology</a>, which enables mice and human retinas to detect infrared radiation. This ability could be useful for patients suffering from loss of photoreceptors and sight. </p>
<p>The researchers demonstrated this approach, inspired by the ability of snakes and bats to see heat, by endowing mice and postmortem human retinas with a protein that becomes active in response to heat. Infrared light is light emitted by warm objects that is beyond the visible spectrum. </p>
<p>The heat warms a specially engineered gold particle that the researchers introduced into the retina. This particle binds to the protein and helps it convert the heat signal into electrical signals that are then sent to the brain. </p>
<p>In the future, more research is needed to tweak the ability of the infrared sensitive proteins to different wave lengths of light that will also enhance the remaining vision. </p>
<p>This approach is still being tested in animals and in retinal tissue in the lab. But all approaches suggest that it might be possible to either restore, enhance or provide patients with forms of vision used by other species.</p>
<p>[<em>Get our best science, health and technology stories.</em> <a href="https://theconversation.com/us/newsletters/science-editors-picks-71/?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=science-best">Sign up for The Conversation’s science newsletter</a>.]</p><img src="https://counter.theconversation.com/content/133220/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Hemant Khanna receives funding from National Institutes of Health and Iveric Bio. </span></em></p>Strategies to cure various types of blindness are looking more plausible after a series of recent breakthroughs using gene editing and gene therapy.Hemant Khanna, Associate Professor of Ophthalmology, UMass Chan Medical SchoolLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1338772020-04-24T12:22:19Z2020-04-24T12:22:19ZHow the Hubble Space Telescope opened our eyes to the first galaxies of the universe<figure><img src="https://images.theconversation.com/files/322098/original/file-20200321-22614-1c9vb6z.jpg?ixlib=rb-1.1.0&rect=0%2C57%2C373%2C246&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The launch of Hubble Space Telescope on April 24, 1990. This photo captures the first time that there were shuttles on both pad 39a and 39b.
</span> <span class="attribution"><span class="source">NASA</span></span></figcaption></figure><p>The <a href="http://nasa.gov/hubble">Hubble Space Telescope</a> launched on the 24th of April, 30 years ago. It’s an impressive milestone especially as its expected lifespan was just 10 years.</p>
<p>One of the primary reasons for the Hubble telescope’s longevity is that it can be serviced and improved with new observational instruments through Space Shuttle visits. </p>
<p>When Hubble, or HST, first launched, its instruments could observe ultraviolet light with wavelengths shorter than the eye can see, as well as optical light with wavelengths visible to humans. A maintenance mission in 1997 added an instrument to observe near infrared light, which are longer wavelengths than people can see. Hubble’s new infrared eyes provided two new major capabilities: the ability to see farther into space than before and see deeper into the dusty regions of star formation. </p>
<p><a href="https://www.as.arizona.edu/people/faculty/rodger-i-thompson">I am an astrophysicist at the University of Arizona</a> who has used near infrared observations to better understand how the universe works, from star formation to cosmology. Some 35 years ago, I was given the chance to build a near infrared camera and spectrometer for Hubble. It was the chance of a lifetime. The camera my team designed and developed has changed the way humans see and understand the universe. The instrument was built at Ball Aerospace in Boulder, Colorado, under our direction.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/330225/original/file-20200423-47820-1279cti.gif?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/330225/original/file-20200423-47820-1279cti.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/330225/original/file-20200423-47820-1279cti.gif?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=296&fit=crop&dpr=1 600w, https://images.theconversation.com/files/330225/original/file-20200423-47820-1279cti.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=296&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/330225/original/file-20200423-47820-1279cti.gif?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=296&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/330225/original/file-20200423-47820-1279cti.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=372&fit=crop&dpr=1 754w, https://images.theconversation.com/files/330225/original/file-20200423-47820-1279cti.gif?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=372&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/330225/original/file-20200423-47820-1279cti.gif?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=372&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The light we can see with our eyes is part of a range of radiation known as the electromagnetic spectrum. Shorter wavelengths of light are higher energy, and longer wavelengths of light are lower energy. The Hubble Space Telescope sees primarily visible light (indicated here by the rainbow), as well as some infrared and ultraviolet radiation.</span>
<span class="attribution"><a class="source" href="https://www.nasa.gov/content/explore-light">NASA/JHUAPL/SwRI</a></span>
</figcaption>
</figure>
<h2>Seeing further and earlier</h2>
<p><a href="https://www.biography.com/scientist/edwin-hubble">Edwin Hubble</a>, HST’s namesake, discovered in the early 1900s that the universe is expanding and that the light from distant galaxies was shifted to longer, redder wavelengths, a phenomenon called the redshift. The greater the distance, the larger the shift. This is because the further away an object is, the longer it takes for the light to reach us here on Earth and the more the universe has expanded in that time.</p>
<p>The Hubble ultraviolet and optical instruments had taken images of the most distant galaxies ever seen, known as the Northern Hubble Deep Field, or NHDF, which were released in 1996. These images, however, had reached their distance limit due to the redshift, which had shifted all of the light of the most distant galaxies out of the visible and into the infrared. </p>
<p>One of the new instruments added to Hubble in the second maintenance mission has the awkward name, the <a href="https://spacetelescope.org/about/general/instruments/nicmos/">Near Infrared Camera and Multi-Object Spectrometer</a>, NICMOS, pronounced “Nick Moss.” The near infrared cameras on NICMOS observed regions of the NHDF and discovered even more distant galaxies with all of their light in the near infrared.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/330244/original/file-20200423-47788-dhzzix.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/330244/original/file-20200423-47788-dhzzix.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=606&fit=crop&dpr=1 600w, https://images.theconversation.com/files/330244/original/file-20200423-47788-dhzzix.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=606&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/330244/original/file-20200423-47788-dhzzix.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=606&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/330244/original/file-20200423-47788-dhzzix.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=762&fit=crop&dpr=1 754w, https://images.theconversation.com/files/330244/original/file-20200423-47788-dhzzix.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=762&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/330244/original/file-20200423-47788-dhzzix.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=762&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A typical image taken with NICMOS. It shows a gigantic star cluster in the center of our Milky Way. NICMOS, thanks to its infrared capabilities, is able to look through the heavy clouds of dust and gas in these central regions.</span>
<span class="attribution"><a class="source" href="https://spacetelescope.org/about/general/instruments/nicmos/">NASA/JHUAPL/SwRI</a></span>
</figcaption>
</figure>
<p>Astronomers have the privilege of watching things happen in the past which they call the “lookback time.” Our best measurement of the age of the universe is 13.7 billion years. The distance that light travels in one year is called a light year. The most distant galaxies observed by NICMOS were at a distance of almost 13 billion light years. This meant that the light that NICMOS detected had been traveling for 13 billion years and showed what the galaxies looked like 13 billion years ago, a time when the universe was only about 5% of its current age. These were some of the first galaxies ever created and were forming new stars at rates that were more than a thousand times the rate at which most galaxies form stars in the current universe.</p>
<h2>Hidden by dust</h2>
<p>Although astronomers have studied star formation for decades, many questions remain. Part of the problem is that most stars are formed in clouds of molecules and dust. The dust absorbs the ultraviolet and most of the optical light emitted by forming stars, making it difficult for Hubble’s ultraviolet and optical instruments to study the process. </p>
<p>The longer, or redder, the wavelength of the light, the less is absorbed. That is why sunsets, where the light must pass through long lengths of dusty air, appear red. </p>
<p>The near infrared, however, has an even easier time passing through dust than the red optical light. NICMOS can look into star formation regions with the superior image quality of Hubble to determine the details of where the star formation occurs. A good example is the iconic Hubble image of <a href="https://www.nasa.gov/image-feature/eagle-nebula-s-pillars-of-creation-in-infrared">the Eagle Nebula</a>, also known as the pillars of creation. </p>
<p>The optical image shows majestic pillars which appear to show star formation over a large volume of space. The NICMOS image, however, shows a different picture. In the NICMOS image, most of the pillars are transparent with no star formation. Stars are only being formed at the tip of the pillars. The optical pillars are just empty dust reflecting the light of a group of nearby stars.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/330226/original/file-20200423-47826-1bi0uc4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/330226/original/file-20200423-47826-1bi0uc4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/330226/original/file-20200423-47826-1bi0uc4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=626&fit=crop&dpr=1 600w, https://images.theconversation.com/files/330226/original/file-20200423-47826-1bi0uc4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=626&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/330226/original/file-20200423-47826-1bi0uc4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=626&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/330226/original/file-20200423-47826-1bi0uc4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=787&fit=crop&dpr=1 754w, https://images.theconversation.com/files/330226/original/file-20200423-47826-1bi0uc4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=787&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/330226/original/file-20200423-47826-1bi0uc4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=787&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The Eagle Nebula in visible light.</span>
<span class="attribution"><a class="source" href="https://www.nasa.gov/feature/goddard/2017/messier-16-the-eagle-nebula">NASA, ESA and the Hubble Heritage Team (STScI/AURA)</a></span>
</figcaption>
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<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/330222/original/file-20200423-47788-ux54hw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/330222/original/file-20200423-47788-ux54hw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/330222/original/file-20200423-47788-ux54hw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=563&fit=crop&dpr=1 600w, https://images.theconversation.com/files/330222/original/file-20200423-47788-ux54hw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=563&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/330222/original/file-20200423-47788-ux54hw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=563&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/330222/original/file-20200423-47788-ux54hw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=707&fit=crop&dpr=1 754w, https://images.theconversation.com/files/330222/original/file-20200423-47788-ux54hw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=707&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/330222/original/file-20200423-47788-ux54hw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=707&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">In this Hubble Space Telescope image is the Eagle Nebula’s Pillars of Creation. Here, the pillars are seen in infrared light, which pierces through obscuring dust and gas and unveils a more unfamiliar — but just as amazing — view of the pillars.</span>
<span class="attribution"><a class="source" href="https://www.nasa.gov/image-feature/eagle-nebula-s-pillars-of-creation-in-infrared">NASA, ESA/Hubble and the Hubble Heritage Team</a></span>
</figcaption>
</figure>
<h2>The dawning of the age of infrared</h2>
<p>When NICMOS was added into the HST in 1997 NASA had no plans for a future infrared space mission. That rapidly changed as the results from NICMOS became apparent. Based on the data from NICMOS, scientists learned that fully <a href="https://www.nationalgeographic.com/news/2014/1/140107-hubble-oldest-frontier-science-space-astronomy/">formed galaxies existed in the universe much earlier than expected</a>. The NICMOS images also confirmed that the <a href="https://www.nasa.gov/feature/goddard/2019/mystery-of-the-universe-s-expansion-rate-widens-with-new-hubble-data">expansion of the universe is accelerating</a> rather than slowing down as previously thought. The NHDF infrared images were followed by the Hubble Ultra Deep Field images in 2005, which further showed the power of near infrared imaging of distant young galaxies. So NASA decided to invest in the <a href="http://www.jwst.nasa.gov">James Webb Space Telescope</a>, or JWST, a telescope much larger than HST and completely dedicated to infrared observations. </p>
<p>On Hubble, a near infrared imager was added to the third version of the Wide Field camera which was installed in May of 2009. This camera used an improved version of the NICMOS detector arrays that had more sensitivity and a wider field of view. The James Webb Space Telescope has much larger versions of the NICMOS detector arrays that have more wavelength coverage than the previous versions.</p>
<p>The James Webb Space Telescope, scheduled to be launched in March 2021, followed by the Wide Field Infrared Survey Telescope, form the bulk of future space missions for NASA. These programs were all spawned by the near infrared observations by HST. They were enabled by the original investment for a near infrared camera and spectrometer to give Hubble its infrared eyes. With the James Webb Space Telescope, astronomers expect to see the very first galaxies that formed in the universe.</p>
<p>[<em>Deep knowledge, daily.</em> <a href="https://theconversation.com/us/newsletters?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=deepknowledge">Sign up for The Conversation’s newsletter</a>.]</p><img src="https://counter.theconversation.com/content/133877/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Rodger I. Thompson was the Principal Investigator for the Near Infrared Camera and Multi-Object Spectrometer, NICMOS. He was responsible for the execution of a contract to Arizona Board of Regents from NASA to deliver NICMOS as a Hubble Space Telescope Instrument and carry out a scientific investigation with it. Prof. Thompson received summer salary from this contract at his University pay rate during the execution of the contract which ended in 2004. Prof. Thompson is not currently receiving any external funding.</span></em></p>Thirty years ago the Hubble Space Telescope began snapping photos of distant stars, providing a time machine that has taken astronomers back to when the universe was less than a billion years old.Rodger I. Thompson, Professor of Astronomy, University of ArizonaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1126972019-03-06T19:12:25Z2019-03-06T19:12:25ZWhat pill is that? Cheap and easy pill testing could soon be in your own hands<figure><img src="https://images.theconversation.com/files/262074/original/file-20190305-92280-72n5vs.jpg?ixlib=rb-1.1.0&rect=535%2C294%2C3445%2C2452&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Can you be sure which pill is which? It can be difficult to tell if you've picked the correct medication.</span> <span class="attribution"><span class="source">Shutterstock/perfectla </span></span></figcaption></figure><p>Almost nine out of ten Australians take some form of medication, <a href="http://www.roymorgan.com/findings/7598-health-medications-taken-december-2017-201805201234">according to a recent poll</a>. Much of that will be in tablet form, either prescribed or bought over the counter.</p>
<p>But in the rush of daily life it can be easy to confuse or mix up pills, especially if you or someone you care for is taking several medications. So how can you be sure the pill you’re about to take is the correct one?</p>
<p>We’ve designed some technology that could help with this issue. Also, the tool might one day be suitable for pill testing at music festivals and other events where other pill drugs are available.</p>
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Read more:
<a href="https://theconversation.com/your-period-tracking-app-could-tell-facebook-when-youre-pregnant-an-algorithmic-guardian-could-stop-it-111815">Your period tracking app could tell Facebook when you're pregnant – an 'algorithmic guardian' could stop it</a>
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<p>In our <a href="https://doi.org/10.1145/3214272" title="Assisted Medication Management in Elderly Care Using Miniaturised Near-Infrared Spectroscopy">experiments</a> we have demonstrated how off-the-shelf mobile <a href="http://www.ti.com/tool/DLPNIRNANOEVM">hardware</a> can be used to identify pills. Soon we expect this hardware may be built into most <a href="https://www.forbes.com/sites/paulmonckton/2017/01/11/new-smartphone-can-see-inside-objects/">smartphones</a>.</p>
<h2>How does it work?</h2>
<p>The enabling technology, known as <a href="https://www.nature.com/subjects/near-infrared-spectroscopy">near-infrared spectroscopy</a>, is not new. What is new is that it has been miniaturised.</p>
<p>The technology works by shining infrared light onto the pill. The pill absorbs and reflects some of the light depending on its chemical composition.</p>
<p>By measuring the spectrum of the reflected light, we can obtain a unique signature for this pill. By cross-referencing this signature against a database on known pills or chemicals we can identify the pill.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/262083/original/file-20190305-92310-6tmgcx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/262083/original/file-20190305-92310-6tmgcx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/262083/original/file-20190305-92310-6tmgcx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=442&fit=crop&dpr=1 600w, https://images.theconversation.com/files/262083/original/file-20190305-92310-6tmgcx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=442&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/262083/original/file-20190305-92310-6tmgcx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=442&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/262083/original/file-20190305-92310-6tmgcx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=555&fit=crop&dpr=1 754w, https://images.theconversation.com/files/262083/original/file-20190305-92310-6tmgcx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=555&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/262083/original/file-20190305-92310-6tmgcx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=555&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Our prototype scans pills and displays the results to a paired smartphone.</span>
<span class="attribution"><span class="source">Smart Hospital Living Lab</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>The technology does not damage the pill, since it simply shines infrared light for a couple of seconds.</p>
<p>It does not rely on the visual appearance of the pill at all. In our tests we could accurately differentiate between pills that look virtually identical.</p>
<p>Further accuracy improvements are expected soon. But at this stage we can say this technology allows for pill-testing to be done on the spot, using a mobile device. It’s no longer necessary to ship samples to a dedicated testing facility.</p>
<p>At the moment the technology has been tried on only about 60 pills that can be bought over the counter, such as painkillers, vitamins and other supplements. It could easily be extended to prescription medications.</p>
<p>We actually developed our prototype to be used on prescription and over-the-counter pills, as a way to make sure people are taking the correct medication. This work is being carried out as part of a broader <a href="https://smarthospital.research.unimelb.edu.au/smart-pillbox/">Smart Hospital project</a> to make hospitals safer and more efficient.</p>
<p>For example, medication errors occur when nurses give the incorrect pill to patients in a hospital, or when patients take the wrong pill at home. Our technology has been designed to reduce such errors due to mislabelling or lack of labels.</p>
<p>Which brings us to the <a href="https://www.abc.net.au/news/health/2018-12-21/guide-to-pill-testing-at-australian-music-festivals/10638732">debate on pill testing</a>.</p>
<h2>Checking ‘other’ pills</h2>
<p>It’s become clear that our technology also has the potential to check other types of pills and could be used in scenarios such as people attending music festivals, on-the-spot police checks, or any other situation. </p>
<p>But there are some potential problems here. <a href="http://dx.doi.org/10.1145/3064663.3064738" title="Towards Commoditised Near Infrared Spectroscopy">Our work</a> has shown that environmental factors – such as ambient light – may affect the accuracy of the system, so it’s unlikely to be as accurate as in controlled lab settings.</p>
<p>Also, because our prototype works by cross-referencing to a database of known pills, it can be challenging for the system to identify home-made pills that may not exactly match the chemical composition in our database. </p>
<p>Still, there are a couple of ways to deal with this situation.</p>
<p>First, the system can provide a confidence rating, effectively saying that it has not seen a particular pill before, but it can report which pill it is most similar to. </p>
<p>Second, if we are interested in certain active chemical components in the pill, it can report which of those components are present in the pill, but not necessarily in what amounts.</p>
<h2>The tech’s coming, ready or not</h2>
<p>The technology for pill testing is changing quickly. Soon these changes will have an impact on the arguments used by the <a href="https://www.aph.gov.au/About_Parliament/Parliamentary_Departments/Parliamentary_Library/FlagPost/2018/May/The_pros_and_cons_of_pill_testing">different sides of the pill-testing debate</a> that has gripped Australia. </p>
<p>Our technology demonstrates the potential for making pill-testing a private matter, with no need for any taxpayer-funded testing at events. It is entirely conceivable that soon it will be possible to buy a pill-testing device that you can carry in your pocket and use where and when you choose. </p>
<p>Pill-testing proponents argue that it has the potential in its current form at festivals to be one last safeguard and source of advice before pills are consumed (or not).</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/heres-why-doctors-are-backing-pill-testing-at-music-festivals-across-australia-109430">Here's why doctors are backing pill testing at music festivals across Australia</a>
</strong>
</em>
</p>
<hr>
<p>With the pill-testing technology maturing and being miniaturised even further, we expect within a few years to see widespread prototypes being used. While the hardware is quickly improving, the main challenge remains the analysis that we have developed to differentiate between pills. </p>
<p>We want to raise awareness about this technology and advise all camps in the pill-testing debate that they need to consider how to respond to this technology. </p>
<p>Pill-testing critics might need to consider ways to stop pill-testing given the availability of cheap testing devices – should such devices be banned?</p>
<p>Pill-testing supporters need to consider that pill-testing may soon be possible outside well-staffed festival tents. Therefore, there is a need for new interventions, as well as a consideration of who maintains the pill database: government, industry, NGOs, or perhaps some crowdsourced approach?</p><img src="https://counter.theconversation.com/content/112697/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Vassilis Kostakos receives funding from the Academy of Finland, European Union, Samsung, and the University of Melbourne. </span></em></p>The technology to identify pills is getting cheaper and smaller. That means it could also be used to test the make-up of illegal pills at festivals and other events.Vassilis Kostakos, Professor of Human Computer Interaction, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/944232018-04-04T17:03:33Z2018-04-04T17:03:33ZAstronomers may have just discovered a dozen black holes in the centre of our galaxy<figure><img src="https://images.theconversation.com/files/213157/original/file-20180404-189807-11balvx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The Milky Way seen in infrared.</span> <span class="attribution"><span class="source">NASA/JPL-Caltech/S. Stolovy (SSC/Caltech)</span></span></figcaption></figure><p>Astronomers first noticed an enigmatic object, <a href="https://www.nasa.gov/mission_pages/chandra/multimedia/black-hole-SagittariusA.html">dubbed “Sagittarius A*”</a>, at the very heart of our Milky Way galaxy in the 1960s – the earliest days of radio and infrared astronomy. But just how extraordinary this source was only became clear three decades later, when it was identified as a supermassive black hole with the mass of whopping four million suns. </p>
<p>Theory predicts that such supermassive black holes, which reside at the centre of most large galaxies, should be surrounded by a cluster of smaller black holes and other objects. But decades of searches have revealed nothing – until now. In a new paper, <a href="http://nature.com/articles/doi:10.1038/nature25029">published in Nature</a>, a team of researchers report the discovery of what seems to be about 13 black holes close to Sagittarius A*.</p>
<p>The discovery of Sagittarius A* was only possible thanks to the first generation of <a href="http://www2.keck.hawaii.edu/inst/nirc2/">infrared imagers</a> on the best ground-based observing sites in Hawaii and Chile. These could follow the motion of stars very close to the unseen object as they orbited around it. After a decade of observing, complete orbits of stars were <a href="http://iopscience.iop.org/article/10.1086/592738/meta">mapped out in detail</a> – allowing scientists to calculate the mass of Sagittarius A* with high accuracy. </p>
<p>This work had to be done by looking at infrared light. That’s because, at visual wavelengths, huge clouds of dust and gas obstruct our vision – we can only see about 10% of the distance to the galactic centre in this way (Sagittarius A* is approximately 26,000 light years away). Some infrared light, radio waves and X-rays, however, can penetrate the obstacles in the galaxy to reach our detectors on Earth. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/213159/original/file-20180404-189804-16eg2jh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/213159/original/file-20180404-189804-16eg2jh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/213159/original/file-20180404-189804-16eg2jh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/213159/original/file-20180404-189804-16eg2jh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/213159/original/file-20180404-189804-16eg2jh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/213159/original/file-20180404-189804-16eg2jh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/213159/original/file-20180404-189804-16eg2jh.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">Sagittarius A* seen by Chandra.</span>
<span class="attribution"><span class="source">X-ray: NASA/UMass/D.Wang et al., IR: NASA/STScI</span></span>
</figcaption>
</figure>
<p>How supermassive black holes grow so large is <a href="https://www.space.com/32973-supermassive-black-holes-born-big.html">still controversial</a>. Sagittarius A* is actually fairly small – distant objects of a billion solar masses have been found. One possible explanation is that they are created as galaxies merge or interact – trapping their central supermassive black holes into orbits about each other and eventually merging into an even bigger supermassive black hole. </p>
<p>We know that active star formation <a href="https://arxiv.org/abs/1712.01453">is going on</a> in the region of our galactic centre. This will naturally produce copious neutron stars (very dense stars) and black holes, which can form close “binary systems” in which a normal star and a neutron star or a black hole orbit each other. As the normal star evolves, its matter can get sucked up by the black hole or fall onto the neutron star – reaching extremely high temperatures. This makes the system emit X-rays, which we can detect.</p>
<p>It is not surprising then that the unique and very high resolution of the space-based <a href="http://chandra.harvard.edu/">Chandra X-ray Observatory</a> has detected hundreds of X-ray sources in and around our galactic centre. You can view some superb images of these objects <a href="http://chandra.harvard.edu/photo/2018/gcenter360/">here</a>.</p>
<h2>X-ray puzzle</h2>
<p>The new study has used Chandra data to investigate X-ray sources close to Sagittarius A*. Over the last 12 years, Chandra has observed Sagittarius A* many times – adding up to a huge total of two weeks of exposure time. By combining all these data, and concentrating on the area close to the centre, the team discovered diffuse X-ray emission and about 100 distinct X-ray sources within 13 light years of Sagittarius A*, 26 of which are contained within just three light years of it. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/213149/original/file-20180404-189801-r22zyu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/213149/original/file-20180404-189801-r22zyu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=480&fit=crop&dpr=1 600w, https://images.theconversation.com/files/213149/original/file-20180404-189801-r22zyu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=480&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/213149/original/file-20180404-189801-r22zyu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=480&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/213149/original/file-20180404-189801-r22zyu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=603&fit=crop&dpr=1 754w, https://images.theconversation.com/files/213149/original/file-20180404-189801-r22zyu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=603&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/213149/original/file-20180404-189801-r22zyu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=603&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Artist’s impression of an X-ray binary.</span>
<span class="attribution"><span class="source">wikipedia</span></span>
</figcaption>
</figure>
<p>So what are these mysterious sources? It’s been known for some time that thousands of unresolved binary systems involving a normal star and a magnetised <a href="https://imagine.gsfc.nasa.gov/science/objects/dwarfs1.html">white dwarf</a> (a star that has exhausted its fuel, just like our sun will do in a few billion years) can create diffuse X-ray emission. Unlike the X-rays from binary systems involving neutron stars, these are relatively weak. However, there are millions of white dwarfs in the galaxy. </p>
<p>The team also looked at the ratio of hard to soft X-rays (basically just the higher energy light compared to the lower energy rays) to show that the central X-ray sources closest to Sagittarius A* are likely either from binary systems (involving neutron stars or black holes), or from “millisecond pulsars”, which are highly magnetised rotating neutron stars that emit a beam of electromagnetic radiation. </p>
<p>Both types (binary systems and pulsars) undergo occasional X-ray outbursts, but their properties differ. The neutron stars outburst regularly, but Chandra’s observations show that none of the sources near Sagittarius A* have done so – meaning we can rule these out. Pulsars, however, could account for about half of the sources – they are very steady and quiet. But that means that the remaining half at least must be binary systems involving black holes – a class that have much rarer outbursts (usually many decades between them) and properties generally similar to those seen in the study. The team suggests there could be hundreds of such black hole binaries at the centre of our galaxy and thousands of black holes without a companion star. </p>
<p>Future observations are needed to confirm this finding. It can be particularly tricky to distinguish between binary systems involving quiescent (minimally accreting) black holes and millisecond pulsars. But the better the technology gets, the more accurately will we be able to do this.</p>
<p>If these really are black holes, it is extremely exciting – showing that we are on the right track in understanding how supermassive black holes impact the behaviour of stars around them. It might even be important for future observations using <a href="https://theconversation.com/explainer-what-are-gravitational-waves-53239">gravitational waves</a> (ripples in the fabric of space itself). If one of these new sources merge into Sagittarius A*, this should give rise to gravitational waves that we can detect. </p>
<p>Clearly, we still have a lot to learn about our own galaxy. In a way that’s very exciting – there may be many more black holes in the region left to discover.</p><img src="https://counter.theconversation.com/content/94423/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Phil Charles receives funding from the Leverhulme Trust.</span></em></p>There could be thousands of black holes at the heart of the Milky Way.Phil Charles, Professor of Astrophysics, University of SouthamptonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/860682018-01-21T19:14:40Z2018-01-21T19:14:40ZLooking at the universe through very different ‘eyes’<figure><img src="https://images.theconversation.com/files/199349/original/file-20171215-26009-n5x6px.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The Small Magellanic Cloud galaxy here seen in infrared light, but it looks different when viewed at other wavelengths.</span> <span class="attribution"><a class="source" href="https://www.nasa.gov/multimedia/imagegallery/image_feature_2323.html">ESA/NASA/JPL-Caltech/STScI</a></span></figcaption></figure><p>We are bathed in starlight. During the day we see the Sun, light reflected off the surface of the Earth and blue sunlight <a href="https://theconversation.com/curious-kids-why-is-the-sky-blue-and-where-does-it-start-81165">scattered by the air</a>. At night we see the stars, as well as sunlight reflected off the Moon and the planets.</p>
<p>But there are more ways of seeing the universe. <a href="https://theconversation.com/explainer-what-is-the-electromagnetic-spectrum-8046">Beyond visible light</a> there are gamma rays, X-rays, ultraviolet light, infrared light, and radio waves. They provide us with new ways of appreciating the universe.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/what-to-look-for-when-buying-a-telescope-51466">What to look for when buying a telescope</a>
</strong>
</em>
</p>
<hr>
<h2>X-ray Moon</h2>
<p>Have you looked at the Moon during the daytime? You will see part of the Moon bathed in sunlight and the Earth’s blue sky in front of the Moon.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/196867/original/file-20171129-28849-10ab0ib.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/196867/original/file-20171129-28849-10ab0ib.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/196867/original/file-20171129-28849-10ab0ib.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/196867/original/file-20171129-28849-10ab0ib.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/196867/original/file-20171129-28849-10ab0ib.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/196867/original/file-20171129-28849-10ab0ib.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/196867/original/file-20171129-28849-10ab0ib.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/196867/original/file-20171129-28849-10ab0ib.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">The Moon behind a blue sky.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/blachswan/14990521817/">Flickr/Ed Dunens</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Now put on your X-ray specs, courtesy of the <a href="http://www.dlr.de/dlr/en/desktopdefault.aspx/tabid-10424/">ROSAT satellite</a>, and you will see something intriguing. </p>
<p>The Sun emits X-rays, so you can see the daytime side of the Moon easily enough. But the night time side of the Moon is silhouetted against the X-ray sky. The X-ray sky is <em>behind</em> the Moon!</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/196868/original/file-20171129-28899-t5t4hp.gif?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/196868/original/file-20171129-28899-t5t4hp.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/196868/original/file-20171129-28899-t5t4hp.gif?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=627&fit=crop&dpr=1 600w, https://images.theconversation.com/files/196868/original/file-20171129-28899-t5t4hp.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=627&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/196868/original/file-20171129-28899-t5t4hp.gif?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=627&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/196868/original/file-20171129-28899-t5t4hp.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=788&fit=crop&dpr=1 754w, https://images.theconversation.com/files/196868/original/file-20171129-28899-t5t4hp.gif?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=788&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/196868/original/file-20171129-28899-t5t4hp.gif?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=788&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The Moon seen in X-rays by ROSAT. The night side of the Moon is silhouetted against the X-ray background.</span>
<span class="attribution"><a class="source" href="https://apod.nasa.gov/apod/ap960929.html">DARA, ESA, MPE, NASA, J.H.M.M. Schmitt</a></span>
</figcaption>
</figure>
<p>Just what is the <a href="https://ned.ipac.caltech.edu/level5/Fabian/Fabian1.html">X-ray sky</a>? Well, X-rays are more energetic than visible light photons, so X-rays often come from the hottest and most violent celestial objects. Much of the X-ray sky is produced by active galactic nuclei, which are powered by matter falling towards black holes.</p>
<p>In X-rays, the Moon is silhouetted against many millions of celestial sources, powered by black holes, scattered across billions of <a href="https://theconversation.com/explainer-light-years-and-units-for-the-stars-16995">light years</a> of space. </p>
<h2>Radio skies</h2>
<p>If you’re in the southern sky and away from light pollution (including the Moon), then you can see the <a href="http://www.messier.seds.org/xtra/ngc/smc.html">Small Magellanic Cloud</a>. This is a companion galaxy to our own Milky Way. With the unaided eye it looks like a diffuse cloud, but what we are actually seeing is the combined light of millions of distant stars.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/196904/original/file-20171129-29143-1sctcud.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/196904/original/file-20171129-29143-1sctcud.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/196904/original/file-20171129-29143-1sctcud.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=423&fit=crop&dpr=1 600w, https://images.theconversation.com/files/196904/original/file-20171129-29143-1sctcud.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=423&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/196904/original/file-20171129-29143-1sctcud.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=423&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/196904/original/file-20171129-29143-1sctcud.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=531&fit=crop&dpr=1 754w, https://images.theconversation.com/files/196904/original/file-20171129-29143-1sctcud.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=531&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/196904/original/file-20171129-29143-1sctcud.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=531&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Visible light images of the Small Magellanic Cloud are dominated by starlight.</span>
<span class="attribution"><span class="source">ESA/Hubble and Digitized Sky Survey/Davide De Martin</span></span>
</figcaption>
</figure>
<p>Radio waves provide <a href="http://www.anu.edu.au/news/all-news/astronomers-create-most-detailed-radio-image-of-nearby-dwarf-galaxy">a very different view of the Small Magellanic Cloud</a>. Using the <a href="https://www.csiro.au/en/Research/Facilities/ATNF/ASKAP">Australian Square Kilometre Array Pathfinder</a>, tuned to <a href="http://www.cv.nrao.edu/course/astr534/HILine.html">1,420.4MHz</a>, we no longer see stars but instead see atomic hydrogen gas.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/196905/original/file-20171129-29114-mwy2rw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/196905/original/file-20171129-29114-mwy2rw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/196905/original/file-20171129-29114-mwy2rw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/196905/original/file-20171129-29114-mwy2rw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/196905/original/file-20171129-29114-mwy2rw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/196905/original/file-20171129-29114-mwy2rw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=425&fit=crop&dpr=1 754w, https://images.theconversation.com/files/196905/original/file-20171129-29114-mwy2rw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=425&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/196905/original/file-20171129-29114-mwy2rw.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"></a>
<figcaption>
<span class="caption">Radio waves can trace the hydrogen gas in the Small Magellanic Cloud.</span>
<span class="attribution"><a class="source" href="http://www.anu.edu.au/news/all-news/astronomers-create-most-detailed-radio-image-of-nearby-dwarf-galaxy">ANU and CSIRO</a></span>
</figcaption>
</figure>
<p>The hydrogen gas is cold enough that the atoms hang onto their electrons (unlike ionised hydrogen). It can also cool further and collapse (under the force of gravity) to produce <a href="http://coolcosmos.ipac.caltech.edu/cosmic_classroom/cosmic_reference/molecular_clouds.html">clouds of molecular hydrogen gas</a> and eventually new stars. </p>
<p>Radio waves thus allow us to see the fuel for star formation, and the Small Magellanic Cloud is indeed producing <a href="https://arxiv.org/abs/astro-ph/0312100">new stars right now</a>.</p>
<h2>Feeling the heat in the microwave</h2>
<p>If the universe were infinitely large and infinitely old, then presumably every direction would eventually lead the surface of a star. This would lead to a rather bright night sky. The German astronomer <a href="https://www.britannica.com/biography/Wilhelm-Olbers">Heinrich Olbers</a>, <a href="http://www.hup.harvard.edu/catalog.php?isbn=9780674192713">among others,</a> recognised this “paradox” centuries ago. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/196917/original/file-20171129-29101-d1jh91.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/196917/original/file-20171129-29101-d1jh91.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/196917/original/file-20171129-29101-d1jh91.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=300&fit=crop&dpr=1 600w, https://images.theconversation.com/files/196917/original/file-20171129-29101-d1jh91.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=300&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/196917/original/file-20171129-29101-d1jh91.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=300&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/196917/original/file-20171129-29101-d1jh91.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=377&fit=crop&dpr=1 754w, https://images.theconversation.com/files/196917/original/file-20171129-29101-d1jh91.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=377&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/196917/original/file-20171129-29101-d1jh91.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=377&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A visible light image of the entire night sky is dominated by starlight from the Milky Way.</span>
<span class="attribution"><a class="source" href="https://www.eso.org/public/netherlands/images/eso0932a/">ESO/S. Brunier</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>When we look up at the night sky, we can see the stars, planets and Milky Way. But most of the night sky is black, and this tells us something important. </p>
<p>But lets take a look at the universe in microwave light. The <a href="http://sci.esa.int/planck/">Planck satellite</a> reveals glowing gas and dust in the Milky Way. Beyond that, in every direction, there is light! Where does it come from?</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/196919/original/file-20171129-29114-1av7ju3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/196919/original/file-20171129-29114-1av7ju3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/196919/original/file-20171129-29114-1av7ju3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=323&fit=crop&dpr=1 600w, https://images.theconversation.com/files/196919/original/file-20171129-29114-1av7ju3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=323&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/196919/original/file-20171129-29114-1av7ju3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=323&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/196919/original/file-20171129-29114-1av7ju3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=406&fit=crop&dpr=1 754w, https://images.theconversation.com/files/196919/original/file-20171129-29114-1av7ju3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=406&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/196919/original/file-20171129-29114-1av7ju3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=406&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The microwave sky is glowing in every direction.</span>
<span class="attribution"><a class="source" href="https://jpl.jpl.nasa.gov/spaceimages/details.php?id=PIA13239">ESA, HFI & LFI consortia</a></span>
</figcaption>
</figure>
<p>At microwave wavelengths we can observe the <a href="http://www.esa.int/Our_Activities/Space_Science/Planck/Planck_and_the_cosmic_microwave_background">afterglow of the Big Bang</a>. This afterglow was produced 380,000 years after the Big Bang, when the universe had a temperature of roughly 2,700°C. </p>
<p>But the afterglow we see now doesn’t look like a 2,700°C ball of gas. Instead, we see a glow equivalent to -270°C. Why? Because we live in an <a href="https://theconversation.com/au/topics/universe-expansion-6052">expanding universe</a>. The light we observe now from the Big Bang’s afterglow has been stretched from visible light into lower-energy microwave light, resulting in the colder observed temperature.</p>
<h2>Planetary radio</h2>
<p>Jupiter is one of the most rewarding planets to observe with a <a href="http://www.skyandtelescope.com/observing/jupiter-big-bright-andbeautiful/">small telescope</a> – you can see the cloud bands stretching across the giant planet. Even binoculars can reveal the <a href="https://solarsystem.nasa.gov/news/2009/10/15/the-discovery-of-the-galilean-satellites">four moons discovered by Galileo</a> centuries ago.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/197242/original/file-20171201-30916-bv8l14.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/197242/original/file-20171201-30916-bv8l14.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/197242/original/file-20171201-30916-bv8l14.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=750&fit=crop&dpr=1 600w, https://images.theconversation.com/files/197242/original/file-20171201-30916-bv8l14.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=750&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/197242/original/file-20171201-30916-bv8l14.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=750&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/197242/original/file-20171201-30916-bv8l14.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=943&fit=crop&dpr=1 754w, https://images.theconversation.com/files/197242/original/file-20171201-30916-bv8l14.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=943&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/197242/original/file-20171201-30916-bv8l14.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=943&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A visible light image of Jupiter, taken by the Cassini spacecraft.</span>
<span class="attribution"><a class="source" href="https://photojournal.jpl.nasa.gov/catalog/PIA04866">NASA/JPL/Space Science Institute</a></span>
</figcaption>
</figure>
<p>But you get a less familiar view of Jupiter when you switch to radio waves. A radio telescope reveals the dull warm glow of the planet itself. But what really stands out are radio waves coming from <em>above</em> the planet. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/197243/original/file-20171201-30912-ul361c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/197243/original/file-20171201-30912-ul361c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/197243/original/file-20171201-30912-ul361c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=337&fit=crop&dpr=1 600w, https://images.theconversation.com/files/197243/original/file-20171201-30912-ul361c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=337&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/197243/original/file-20171201-30912-ul361c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=337&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/197243/original/file-20171201-30912-ul361c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=423&fit=crop&dpr=1 754w, https://images.theconversation.com/files/197243/original/file-20171201-30912-ul361c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=423&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/197243/original/file-20171201-30912-ul361c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=423&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Jupiter is a copious emitter of radio waves.</span>
<span class="attribution"><a class="source" href="https://www.atnf.csiro.au/research/solarsys/jupiter/images/index.html">CSIRO</a></span>
</figcaption>
</figure>
<p>Much of the radio emission from Jupiter is produced by <a href="http://www.synchrotron.org.au/synchrotron-science/what-is-synchrotron-light">synchrotron and cyclotron radiation</a>, which results from speeding electrons spiralling in a magnetic field.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/fifty-years-ago-jocelyn-bell-discovered-pulsars-and-changed-our-view-of-the-universe-88083">Fifty years ago Jocelyn Bell discovered pulsars and changed our view of the universe</a>
</strong>
</em>
</p>
<hr>
<p>On Earth we use particle accelerators to produce such radiation. But in Jupiter’s powerful magnetic field it occurs naturally (and copiously).</p>
<p>The synchrotron produced by Jupiter is so powerful that you can detect it on Earth – not just with multimillion-dollar radio telescopes, but with equipment that can be bought for <a href="https://radiojove.gsfc.nasa.gov/">several hundred dollars</a>. You don’t need to be a professional astronomer to expand your view of the universe beyond visible light.</p><img src="https://counter.theconversation.com/content/86068/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michael J. I. Brown receives research funding from the Australian Research Council and Monash University.</span></em></p>The galaxies, stars and planets in our universe can look very different when you view them through equipment that sees beyond the visible light our eyes can see.Michael J. I. Brown, Associate professor, Monash UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/344642014-11-25T13:38:58Z2014-11-25T13:38:58ZFive ways to keep your home warm this winter<figure><img src="https://images.theconversation.com/files/65475/original/image-20141125-4244-1sf5h95.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The cat approves.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/mike9alive/311694061">Michel Filion</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>If you live in a poorly insulated home, and many of us do, you could spend thousands this winter on energy bills. But our ancestors had many ways to keep snug at little or no cost. Now, thanks to modern infrared cameras and advances in environmental physics, we can understand how these methods work and measure how effective they are.</p>
<p>The key to understanding how to keep warm is the fact you lose more heat by radiation to your surroundings than you do by convection to the air. This is why your house feels so cold when you get back from a winter break, even after you’ve turned on the central heating; though the air quickly warms up, the walls take far longer to do so and may continue to make you shiver for up to a day. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/65471/original/image-20141125-4244-17ufcyr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/65471/original/image-20141125-4244-17ufcyr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/65471/original/image-20141125-4244-17ufcyr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/65471/original/image-20141125-4244-17ufcyr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/65471/original/image-20141125-4244-17ufcyr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/65471/original/image-20141125-4244-17ufcyr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/65471/original/image-20141125-4244-17ufcyr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/65471/original/image-20141125-4244-17ufcyr.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">What to do about those warm windows?</span>
<span class="attribution"><span class="source">Roland Ennos</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>In the same way, in poorly insulated houses the inside of the external walls can be several degrees colder than the air and the internal walls, making you feel chilly. </p>
<p>Fortunately, there are five simple ways to overcome this and minimise your energy bills.</p>
<h2>Close your curtains at night</h2>
<p>During the day, your windows let in more radiant energy than gets out; sunlight can enter through the glass, but the window is opaque to the infrared radiation trying to escape. At night, however, single-glazed windows can get extremely cold – in my Victorian house which we try and keep at a <a href="https://theconversation.com/why-room-temperature-needed-to-be-taken-down-a-notch-33798">room temperature</a> of 20°C, an infrared camera showed internal window temperatures of as low as 7°C on a frosty night. </p>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/65473/original/image-20141125-4250-1h3t04f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/65473/original/image-20141125-4250-1h3t04f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/65473/original/image-20141125-4250-1h3t04f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/65473/original/image-20141125-4250-1h3t04f.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/65473/original/image-20141125-4250-1h3t04f.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/65473/original/image-20141125-4250-1h3t04f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/65473/original/image-20141125-4250-1h3t04f.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/65473/original/image-20141125-4250-1h3t04f.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">From inside, you can see the difference a curtain makes.</span>
<span class="attribution"><span class="source">Roland Ennos</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Even double-glazed windows aren’t great insulators and can fall to around 14°C. This results in energy losses of 50-100 watts per square metre, equivalent to running an old-fashioned light bulb. </p>
<p>The best way to prevent this heat loss is to close your curtains and lower your blinds immediately after dusk. They provide an extra barrier to radiant heat loss, add insulation and reduce draughts. My cheap blinds raise the internal surface temperature to 16°C and thick curtains raise it virtually to room temperature, minimising heat loss and making the room feel cosier.</p>
<h2>Cover your walls</h2>
<p>Solid brick or stone walls are better insulators than glass, but they still get cold and let out lots of heat. In my house the external walls fell to 16-17°C, 3-4°C cooler than the air in the room, even though they were made of 50cm thick sandstone. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/65468/original/image-20141125-4258-hwfq8q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/65468/original/image-20141125-4258-hwfq8q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/65468/original/image-20141125-4258-hwfq8q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/65468/original/image-20141125-4258-hwfq8q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/65468/original/image-20141125-4258-hwfq8q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/65468/original/image-20141125-4258-hwfq8q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/65468/original/image-20141125-4258-hwfq8q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/65468/original/image-20141125-4258-hwfq8q.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">A framed picture hung on an external wall is around 1.5°C warmer than the bare wall.</span>
<span class="attribution"><span class="source">Roland Ennos</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Fortunately you can significantly reduce energy losses by covering them with picture or mirrors. Even a simple poster adds an extra layer of insulting air, raising internal surface temperatures by around 1°C and cutting lost energy by a quarter. Framed pictures or mirrors are better, if more expensive. Not being a Russian oligarch or a medieval baron I don’t have any carpets or tapestries to hang on my walls, but these would be even more effective. </p>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/65469/original/image-20141125-4231-1mkskdh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/65469/original/image-20141125-4231-1mkskdh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/65469/original/image-20141125-4231-1mkskdh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/65469/original/image-20141125-4231-1mkskdh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/65469/original/image-20141125-4231-1mkskdh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/65469/original/image-20141125-4231-1mkskdh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/65469/original/image-20141125-4231-1mkskdh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/65469/original/image-20141125-4231-1mkskdh.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">Who needs Kindle when you have warm books?</span>
<span class="attribution"><span class="source">Roland Ennos</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Best of all are bookshelves. My partner is an avid collector and her old books make superb insulators. The spines of the volumes in our book-lined study are raised almost to room temperature, making it snug and warm. Thermally at least, printed books are far superior to their electronic counterparts.</p>
<h2>Cover your front door</h2>
<p>Doors can let in draughts, and being thin and sometimes glazed can be very poor insulators, falling to 10-15°C on cold nights. Covering your door and the surrounding wall with a thick lined door curtain can eliminate pretty much all the heat loss.</p>
<h2>Use screens</h2>
<p>Even if you can’t reduce all the heat loss from your outer walls you can still shield yourself from the cold. Our ancestors used to draw up wooden screens behind themselves and huddle up to the fire. Being at room temperature, the screens kept their backs warm, while radiation from the fire heated up their front. You could do the same, and you could even protect your face from the damaging effects of a roaring fire by using miniature fire screens, just like Georgian ladies.</p>
<h2>Position your furniture in the warm</h2>
<p>How warm you feel in a room depends on where you are, even though air temperature is the same throughout. You will feel warmer if you position yourself closer to the inside of the house because the cold external walls are further away. So try and place your furniture next to an internal wall. </p>
<p>If your desk is up against an external wall so you can look out of the window your legs will tend to get cold, though you can reduce this effect by leaning a cardboard sheet against the wall. If the head of your bed is next to a cold external wall you will be prone to getting a stiff neck, though you can counter this somewhat by using a solid headboard. The best solution, of course, is a four-poster bed, but most bedrooms just aren’t big enough.</p>
<p>So knowing something about how heat moves can help you brave the cold winter. My experience has also shown that investigating the thermal properties of your house with an infrared camera will keep your kids amused for hours.</p><img src="https://counter.theconversation.com/content/34464/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Roland Ennos 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>If you live in a poorly insulated home, and many of us do, you could spend thousands this winter on energy bills. But our ancestors had many ways to keep snug at little or no cost. Now, thanks to modern…Roland Ennos, Professor of Biomechanics, University of HullLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/313492014-09-07T20:38:23Z2014-09-07T20:38:23ZLooking at the future through graphene goggles<figure><img src="https://images.theconversation.com/files/58321/original/ssh2tm4k-1409897403.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">There's definitely room for improvement in night-vision goggle technology – and graphene could make a huge contribution.</span> <span class="attribution"><a class="source" href="http://www.flickr.com/photos/defenceimages/9241716090">UK Ministry of Defence/Flickr</a>, <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/from-pencil-to-high-speed-internet-graphene-is-a-modern-wonder-3146">Graphene</a> – an atom-thick sheet of carbon – has been touted as a new wonder material: it is stronger than steel and conducts electricity better than copper. </p>
<p>In the journal <a href="http://www.nature.com/nnano/index.html">Nature Nanotechnology</a> today, my colleagues and I show how graphene can be used to build a detector of long wavelength (far infrared or <a href="http://en.wikipedia.org/wiki/Terahertz_radiation">terahertz</a>) light that is as sensitive as any existing detector, but far smaller and more than a million times faster. The detector could improve night-vision goggles, chemical analysis tools and airport body scanners.</p>
<p>But before I go into the research, I’d like to talk about how we get from the discovery of a new wonder material such as graphene to new technologies that are useful. </p>
<p>As a researcher working on new materials, I am constantly asked “what is it good for?” To answer this, the first thing we researchers often try is to imagine the new material as a replacement for an existing one in an existing technology. </p>
<p>The problem with that approach is that any existing technology has a lot of momentum. For example, consider computer processors. The electrons in graphene move about 70 times faster than those in silicon (used in most computer processors today) under the same conditions, so graphene could arguably be used to make faster computer chips. </p>
<p>But it’s not that simple. There are many reasons we use silicon besides the speed at which electrons travel – it readily forms a strong oxide coating and it is easy to <a href="http://electronics.howstuffworks.com/diode1.htm">dope</a>, to name a couple. And changing to a radically different material would mean throwing away all the infrastructure used to make silicon chips that was developed at enormous expense over the past several decades.</p>
<p>So a better question — though much more difficult to answer — is to ask what a new material might enable us to do that no other material has before. The answers to that question don’t always come immediately, and sometimes they come serendipitously.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/6cmZ2IGacsQ?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">A walk-through of some of the research in the Fuhrer laboratory: created by Anna Grieve, Big Stories Co.</span></figcaption>
</figure>
<h2>Two layers are better than one</h2>
<p>One property of graphene that interested me was that bilayer graphene (two layers stacked one on another) has a bandgap — the basic property of a semiconductor — that can be tuned by applying an electric field to the material.</p>
<p>I teamed up with researchers at the University of Maryland to try to measure this bandgap using infrared light, since infrared photons have energies which are similar to bilayer graphene’s bandgap. When we measured the conductance of our bilayer graphene under infrared illumination, we found that it changed much more than we expected. </p>
<p>In fact, the change in conductance in our graphene was greater than that of the commercial silicon photodetector we were using to measure the power of our infrared beam! For some reason, our graphene was an excellent photodetector. </p>
<p>We knew enough about graphene to figure out what was happening. When the electrons in graphene absorb light, they heat up. In most materials, the electrons quickly lose energy to vibrations of the atoms, which we sense as heat. </p>
<p>But in graphene this process of heat loss is very inefficient, which gives graphene its extraordinarily high electrical conductivity. What we realised is that bilayer graphene with a bandgap has a conductance that varies strongly with electron temperature, allowing us to read out the change in electron temperature caused by the light heating the electrons. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/58322/original/gr9mcq95-1409897608.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/58322/original/gr9mcq95-1409897608.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/58322/original/gr9mcq95-1409897608.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=210&fit=crop&dpr=1 600w, https://images.theconversation.com/files/58322/original/gr9mcq95-1409897608.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=210&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/58322/original/gr9mcq95-1409897608.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=210&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/58322/original/gr9mcq95-1409897608.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=264&fit=crop&dpr=1 754w, https://images.theconversation.com/files/58322/original/gr9mcq95-1409897608.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=264&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/58322/original/gr9mcq95-1409897608.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=264&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A graphene photothermoelectric detector. The active area of the device is a 0.5 mm by 0.5 mm square which consists of strips of graphene contacted by partially overlapping gold and chromium electrodes.</span>
<span class="attribution"><span class="source">Michael Fuhrer</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Such a device is called a “hot electron bolometer” and bilayer graphene makes a very good one. We <a href="http://www.nature.com/nnano/journal/v7/n7/full/nnano.2012.88.html">published our result</a> in the journal Nature Nanotechnology in 2012, and several research groups are interested in developing graphene bolometers as exquisitely sensitive cryogenic detectors for use in radio astronomy.</p>
<p>Unfortunately, the bolometric effect only works well at low temperature, where bilayer graphene’s resistance changes strongly with temperature. But we knew from our measurements that hot electron effects should be important in graphene at room temperature. </p>
<p>Our team designed a device which could measure the hot electrons at room temperature, using an effect called thermoelectricity. Our first graphene photothermoelectric detectors were comparable in sensitivity to the best available room-temperature detectors of light in the far infrared, or terahertz, regime of the electromagnetic spectrum, and we saw room for orders of magnitude improvements in sensitivity with new designs. </p>
<p>Interestingly, our devices were more than a million times faster than those detectors, and it’s these results we publish today, once again in Nature Nanotechnology.</p>
<h2>Graphene shows us the light</h2>
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<span class="attribution"><a class="source" href="http://www.flickr.com/photos/plushplex/5267461232/in/photostream/">plushplex/Flickr</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>Detection of infrared and terahertz light has numerous uses, from chemical analysis to night-vision goggles to body scanners used in airport security. </p>
<p>But since an ultra-fast, sensitive terahertz detector had never been considered a possibility before, it’s hard to say where our devices might be applied. </p>
<p>Our detector could be used to speed up chemical analysis techniques such as Fourier transform infrared spectroscopy, or <a href="http://chemwiki.ucdavis.edu/Physical_Chemistry/Spectroscopy/Vibrational_Spectroscopy/Infrared_Spectroscopy/How_an_FTIR_Spectrometer_Operates">FTIR</a>. </p>
<p>Because the graphene detector is easily microfabricated, we envision arrays of detector pixels suitable for imaging, which could lead to inexpensive infrared cameras or night-vision goggles.</p>
<p>Our calculations show that the hot electron photothermoelectric effect can be an efficient means of gathering energy from light. Perhaps our devices could be used to gather the infrared light escaping the Earth into the night sky, and turn it into electricity. Maybe they will be used for something that we haven’t even thought of yet. </p>
<p>But had we never set out to investigate a new material simply for the sake of understanding how it works, we never would have discovered these new answers to the question, “what is it good for?”</p><img src="https://counter.theconversation.com/content/31349/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michael Fuhrer receives funding from the Australian Research Council, U.S. National Science Foundation, U.S. Office of Naval Research, and U.S. Intelligence Advanced Research Projects Activity.</span></em></p>Graphene – an atom-thick sheet of carbon – has been touted as a new wonder material: it is stronger than steel and conducts electricity better than copper. In the journal Nature Nanotechnology today, my…Michael Fuhrer, Professor of Physics, Monash UniversityLicensed as Creative Commons – attribution, no derivatives.