Sections

Services

Information

US United States

Why I’m proud to be a crystallographer

This year I have learnt more that it is probably healthy to know about crystal structures. I’ve learnt how you can turn a rabbit green with a protein, read up on French military history and marvelled at how a crystal structure can destroy itself. I’ve even found cement interesting!

When looked at the right way, even cement can be beautiful. This is the crystal structure of tricalcium aluiminate, a vital mineral in cement.

These examples are just the tip of the iceberg, or (to put more appropriately) merely the surface layer of atoms of the science of crystallography and what it has achieved. It’s been a pleasure to discover so much about the field this year.

Why? 2014 was sanctioned by the UN to be the International Year of Crystallography (along with farming and family – or was that family farming?). A definite improvement on last year’s “International year of Quinoa”, but as we loll into December I reckon there’s a few of you out there still scratching your head as to what it’s all about?

Crystallography is the science behind structure, of knowing where your atoms are. There have been some excellent “explainers” already on The Conversation, and a number of videos explaining it.

To date, across the various databases, there’s coming up to 1 million crystal structures that have been determined. That’s nearly a million times a researcher has collected a diffraction pattern (like von Laue did to kick off the whole field in 1911) and interpreted how this could be generated from an arrangement of atoms (like Bragg did in 1912). In an effort to highlight just 365 of them, myself and 40 other researchers, have blogged about one every day. I’d urge you to look over the Crystallography 365 project to see the massive diversity of science that crystallography encompasses.

But why be a crystallographer?

I don’t usually like giving myself a “scientific label” – I have a degree in planetary science, a PhD in physics and my first job was in a chemistry department. I promise you (and my parents) that it did all make some sense at the time. But one thread has run through all of these career twists, and that’s my use of crystallography.

You’ll not find many scientists who call themselves just “crystallographers” and that’s because (as my career to date shows) it’s an inherently interdisciplinary science. Most of us are something else as well, be that geologists, chemists, physicists or biologists. As a scientist starting out, that really appealed to me. I have taken my crystallographic skills, mostly learnt during my PhD in physics, and applied them to problems in fields diverse as forensics, minerals and explosives. I’ve even collected a diffraction pattern of cocoa butter!

My particular crystallographic hero, Kathleen Yardley Lonsdale - who told us that the benzene molecule was flat.

Then there are the role models. In science, as a rule, there are not usually all that many female role models to look up to. But crystallography smashes that out of the park. From Lonsdale to Hodgkin to Megaw to Franklin, women have been front and centre in some of the biggest leaps in crystallography and the community still retains its healthy gender balance.

It’s not just the crystal structure that you can get from these studies, but a very fundamental view of the properties of the material that you are looking at. As a result, crystallography has brought about some of the most famous scientific leaps, 28 Nobels have been awarded through its application. Knowing where the atoms are in materials brings fundamental insights that have revolutionised our world, from the structure of DNA to giant magneto-resistance.

Crystallography is also often at the forefront of “movements” in research. For instance, big data is old news in crystallography, with institutions like the Cambridge Crystallography Database Centre (custodian of a database of over 600,000 crystal structures, mostly of molecular compounds) set up to collate molecular structural information and “mine” that to discover new interactions and even predict how new materials will form.

There’s an argument that much of the success of crystallography has been that it is an inherently “open” science. Most of the software tools that I use day in day out are freeware – developed and maintained by researchers in the field. I’m supremely grateful for their hard work, making tools that are essential to a wide range of scientific projects, with often only citations as reward. Added to this data depositories (such at the Crystallographic Open Database) and standardisation of format have meant that scientists across disciplines can easily communicate their findings to each other.

So every time I collect a diffraction pattern, I enjoy the fact that I’m part of a collective of people (and one robot on Mars) doing the same thing. It’s a fabulous “clan” to belong to, and that’s why I’m proud to be a crystallographer.

US plans to answer the lure of Europa

To planetary scientists Jupiter’s icy moon Europa is a Siren, calling out to them across the solar system. With its youthful surface, abundance of water and the tantalising evidence of a moon-wide ocean – it is one of the best chances for us to find life within our solar system. Last week the Europa Clipper mission won some critical support of US congress representatives, who attended a meeting organised by the Planetary Society called ‘The lure of Europa’.

Can you hear it calling you? The beautiful surface of Europa. NASA/JPL/Ted Stryk

But it hasn’t been ‘plain sailing’ for the Clipper mission. In 2013 the planetary science community gathered and put out a decadal plan, citing the exploration of Europa as one of its highest objectives. However, cuts to funding for ‘outer’ planetary research in favour of Mars and the manned space program left many dispirited. The community have powered on, investing energy in lobbying policy makers, and now traction for the Europa mission is building.

So why go back?

Just in the past year there have been two remarkable insights made about Europa, only making its Siren call louder. The first of these was that the Hubble Space Telescope spotted evidence that geysers were shooting up into space from the moons surface. This immediately put Europa in a rather elite category of planetary bodies, ones that we have observed to be doing things! Now along with the ‘Tiger Stripes’ of Enceladus, sulfur volcanoes of Io and magic islands of Titan – the geysers of Europa show that this moon is more than a passive snowball.

The second insight has been a paper that did a ‘reverse jigsaw puzzle’ study of Europa’s surface. Since the Galileo mission returned it’s startling images of the surface of Europa, the features that were most obvious were extensional. Analogous to the mid-Atlantic ridge, these features were interpreted to be extending the ice crust.

The issue was, though, that nobody could see where the crust had contracted to compensate for this. Putting aside the thought that Europa had just got bigger, a recent paper has picked up on a number of lines of evidence for subduction on Europa. On Earth, subduction is one of the main ways the giant plates of crust are destroyed, with one plate being forced under the other. Among the evidence that was picked up from the Galileo images – was the mismatch of features on the surface, leaving the researchers to identify the missing ‘pieces’ of crust that had been pushed under.

Finding the missing pieces of Europa’s crust, this image shows the tectonic reconstruction of part of the surface. NASA/JPL/S. Kattenhorn

Both of these insights have highlighted the fact that Europa’s surface and interior are linked and there are ways and means that material can be brought to the surface from the interior and vice versa. There’s not proof yet that this would extend to the potential ocean below, but it’s tantalising that maybe it hasn’t been locked away from outside influences.

For me, Europa has currently lured me away from home in Australia to Japan. For the next three months I’ll be based at the University of Tokyo where I’m currently recreating bits of Europa in the lab, using high-pressure and low temperature equipment. Chiefly what I’m interested in, is how possible impurities from Europa’s sister moon Io could effect water-ice under these conditions.

Will Clipper be scooping up the Europan surface to investigate the ice crust and its impurities directly? Sadly not, there are no plans for a lander in the Clipper mission. This is mostly because we don’t have good enough images of the surface to plan this yet. But the fly-bys that are currently being planned for Clipper would add greatly to the potential of this happening, with audacious plans to have a lander that could then burrow through the ice.

The Europa Clipper probe, zipping past the icy moon NASA/JPL

But until about 2020, when the hope is that Clipper will launch towards the Jupiter system, there’s a lot of time for me to do experiments yet!

Who are the two new arrivals at Mars?

As I write this, a team of engineers and scientists will be nervously watching the clock (in fact they are probably in their beds not sleeping). They are waiting for the time when the Mars Orbiter Mission (or MOM) will fire its thrusters and start a gravitational pas-de-deux with Mars.

These engineers and scientists are not sat in Huston, but in Bangalore and represent India’s first attempt at reaching the red planet. If they succeed they will become only the fourth space agency, after NASA, the Soviets and ESA, to achieve such a feat.

Mangalyaan Mars Orbiter Mission MOM Vipal M.B.

Mostly the MOM spacecraft is a technology mission, designed to test the systems and space engineering of the craft as well as the technology the Indians have developed to complete it.

It has, however, carried a few scientific instruments mostly to investigate Mars’s atmosphere. One key scientific target of MOM, is to search for the signal of methane in Mars atmosphere – a potential sign of life hiding somewhere on the planet.

A potential ‘whiff’ of methane in the atmosphere of Mars was first detected in 2004, by the ESA Mars Express mission. But counter to these observation, as MOM took off in November 2013, was the fact that just months before the Curiosity rover had looked for methane and did not find any. So there’s fantastic potential that any observations from MOM will really add to this debate.

The project has not been without controversy, and has sparked debate as to how a country racked with poverty, can afford to send missions to space. Not only is it expensive sending spacecraft to Mars, but also very risky – as the Chinese, Japaneseand NASA space agencies have found to their cost.

Having said that, NASA has learnt from its difficulties with other Mars missions, and made the insertion of MAVEN into the gravitational well of Mars look ‘old hat’.

Arriving at Mars orbit on Sunday, MAVEN’s (which is a rather forced acronym standing for Mars Atmosphere and Volatile EvolutioN) scientific goals will focus almost entirely on the red planet’s atmosphere. One of the questions it is hoping to answer is ‘Has all of Mars’ water escaped to space?’

How MAVEN will go about searching for Mars’s lost water.

Water on Mars is an on-going issue - we now have planet-wide images of Mars showing, what seem to be, water cut features. On top of this the rovers on the ground are picking up evidence for minerals that (from our current understanding), could only have been formed through some interaction with water.

Evidence is mounting that it is not trapped underground, with the results from the ground penetrating radars carried by the Mars Express and NASA’s Mars Global Surveyor. Hence, the next ‘sink’ of the water to be investigated is space itself – and that’s the job MAVEN has turned up to do.

So fingers crossed for a couple of hours’ time, when MOM tries to wriggle into orbit. You can watch the live feed from the Indian Space Agency here http://webcast.isro.gov.in/. I hope that it makes it, and together with MAVEN can find another piece to the puzzle that is Mars’s geological history.