Dr Lewis Dartnell
Lewis Dartnell is an astrobiologist working in the Centre for Planetary Studies searching for the possibility of micro bacterial life on the surface of Mars. He also gives regular talks on the subject at schools and science festivals and has published a number of popular science books.
We’ve found more and more Earth-like planets orbiting other stars in the night sky.
On early inspirations
I genuinely don’t have a good answer for that, I can’t remember a time when I was younger when I didn’t have that curiosity about what was going on in the world around me and I think, to be honest, we’re kind of all scientists when we’re younger, we all wonder about how things work and we’ll be sat in our high chair, throwing things off the edge just to see what happens and, yep, they always fall, there’s always this gravity thing. And I guess scientists are just, kind of, people that in a way never grow up and they take that forward into their adult life and then use some more toys, and some of them are quite expensive and you call it a laboratory rather than a playroom, but it’s still that same process of trying to understand how things work and, you know, what is this world around us.
On moving into astrobiology
So I came from a biological background, I did biological sciences as my first degree, and I’m involved now in a…kind of a new field of science of astrobiology, and the possibility of life on other planets, life beyond the Earth, so a lot of what I do now is taking that biology and mixing it with a lot of planetary science and astrophysics and a lot of computer modelling as well as getting my hands nice and wet and dirty in a lab: it feels natural to me as a biologist to do experiments with real life.
But the kind of transition, if you like, the moment when I was able to make that step from biology into this deeply interdisciplinary field of astrobiology was when I got accepted onto a PhD programme at UCL, at University College London, and the department that they’d just set up was called CoMPLEX – the Centre of Mathematics, Physics and Life Sciences in Experimental Biology – which is a massive mouthful and about the most convoluted acronym I’ve ever come across. But it really gets across the direction that modern science is going in, that no one’s just a biologist or just a chemist any more, it’s all interdisciplinary: you’re applying knowledge from lots of different areas and techniques from different areas to answer these, you know, the hardest questions that are on the coalface of science now.
On day to day work as an astrobiologist
At the moment in my kind of day to day life, if you like, now that I’ve moved to the University of Leicester, I’m working on an instrument called Raman spectroscopy, which sounds a lot like the noodles, but it’s named after an Indian scientist, Raman. And it’s a technique, it’s a laser based technique, where you zap your sample with this laser beam and look at the light that kind of scatters around and comes back at you and has changed and modified the sample you’re looking at. And so you can tell using Raman what kind of minerals are in a rock, what the composition of the rock is, but also, and most importantly for astrobiology, you can see what organic molecules are inside that rock, if there’s any signatures of cells like chlorophyll maybe in this rock.
So it’s a great instrument, it’s a kind of a two for one, cause it tells you about the rock and it tells you what might be living inside that rock. So at the moment I’m using a Raman spectrometer to understand how we might look for signs of life on Mars using the next rover, which is ExoMars.
On the Curioisty mission
Curiosity is NASA’s latest rover, and this thing is a beast: it’s a Jeep-sized, six wheel drive, nuclear powered, laser-wielding exploration robot, it’s incredibly capable, and what we’re trying to understand about Mars with Curiosity is how habitable the planet has been, how warm and wet in Martian history the planet has been, and specifically what conditions there might have been in liquid water and rivers and lakes on primordial Mars and whether there would’ve been the chance for biology, for life to have got started there: whether there was ever a Martian genesis of life on the red planet.
One of the latest discoveries that Curiosity has sent back was to do with the radiation that Curiosity saw in outer space as it flew from Earth across the gulf of space to Mars and was exposed to all this radiation in outer space that we’re protected from here by lovely thick atmosphere above our heads and a global deflector shield, the Earth’s magnetic field protects our planet. And if we want to send humans to Mars, one of the key questions is, what’s the radiation in outer space, what dose does it reach and how might we best protect our astronauts from this, and this is something that Curiosity has just sent back.
What we’re really waiting for now is the measurements from the surface of Mars so we can kind of complete that picture, because we’ve never been able to measure that before.
One of the instruments, or one of the bits of kit, that Curiosity has got on the end of its robotic arm – this kind of Swiss army knife fist with all these different bits of equipment on the end – it’s got a drill and it can kind of poke a little finger drill into the surface of a rock and then pull out some of the material that’s inside that rock and been protected from some of the harsh environment that’s on Mars and in particular get deeper than the kind of windblown red dust layer that’s been covering and smothering absolutely everything. And really, really excitingly, inside one of these drill turnings that’s brought back out, it wasn’t red, it was grey, and the minerals that poured out inside this rock are clays, and the only way we know how to explain Martian clays are if they’ve been laid down in an aqueous environment, so if it’s a water based mineral. And so that’s exactly the right kind of environment for life to have got started and thrive and what we’re hoping for, what we’ve really got our fingers crossed for for Mars, is that when we start looking inside those clay minerals, we’ll find organic molecules, we’ll find the building blocks of all life as we know it.
On life elsewhere in the galaxy
And if we look beyond Mars in our solar system, there are some other places we suspect might have the kind of right combination of conditions to allow life. And Europa, which is one of the icy moons orbiting Jupiter, might actually have a much better chance of, sort of, harbouring active biology today than even Mars. And we know that beneath the frozen face of this moon, beneath an icy shell, there’s an alien ocean of liquid water with more liquid water in it than all the seas and lakes and rivers and oceans of the whole of the Earth put together, so it’s Europa that is the water world of our solar system and not the Earth. So maybe there would be a biosphere, a marine biosphere in this dark ocean, living off the kind of chemical nutrients, maybe leeching out of the sea floor like we find in the deep depths of our own oceans.
Or maybe, even further afield, we’ve found more and more Earth-like planets orbiting other stars in the night sky, these kind of distant suns elsewhere in the galaxy, and so maybe one of these extra solar planets would have a far better chance of having biology on its surface that we could detect remotely by perhaps sensing oxygen in the air of this alien Earth.