As Requested: IAmA(n) Astrobiologist, AMA

Where, in your opinion, are we most likely to find other life in our solar system?

Still living - probably at the bottom of the ocean inside Europa - it's warm enough there for chemistry and biology to do its stuff, and it's shielded from radiation by an icy crust. The only challenge is to get there - it'll involve flying to Europa, drilling/melting through the ice, and then piloting a submersible from millions of miles away - like this awesome picture

Why no love for Enceladus? The geysers seem to be a sure sign of an ocean underneath and even have some interesting chemistry.

I love enceladus! But I was already concious I was making my answer too long, so would only talk about the obvious ones.

You're right, some scientists think they've found amino acids in the geysers, so its a first step towards earth-like life. We're still missing other good bits of evidence though, and even the ocean underneath isn't certain - it could just be fleeting bursts of hot ice...

Something I've always wondered: If we go there and don't find life, would it be ethical to genetically modify Earth-type life and seed habitable worlds with it? They may not be habitable for us but we can stick cool bacteria there...

If nothing else it'd be an excellent way to troll future intelligent species that may come after us.

There are some people who want to terraform Mars - to put genetically modified algae and plants on it and get them to create an atmosphere and liqud water, to make it habitable for animals and humans hundreds of years in the future. Nobody really takes them seriously though - I still think its a cool idea.

2 days ago NASA threw Casini through Enceladus' water jets and it appears to have almost the exact make-up of our oceans! (http://www.clarksvilleonline.com/2012/03/29/nasas-cassini-spacecraft-discovers-water-jets-on-saturns-moon-enceladus/)

Am I just not understanding this correctly or were you not yet aware of it? This to me makes Enceladus the MOST EXCITING place in our solar system to explore for life.

Not exactly, though it is exciting... The results show that the salinity is the same as the Earth's oceans, and its probably this salinity that helps to make the jets liquid in the super cold conditions of the outer solar system.

Just because it's salty doesn't mean it's ideal for life, and we'd also be looking for more than a few amino acids. Still, it's deifinitely up there with the best of 'em.

fleeting bursts of hot ice? could you elaborate?

What I mean is, there probably isn't permanent oceans under the surface, and it is kind of warm slushy ice beneath. When the heated core becomes unstable (maybe due to tidal effects from Saturn or the other moons), extra pressure is put on these slushy reservoirs and they're ejected as geysers. They're hot for a short time, but become ice instantly on meeting the cold of outer space.

What effect would the lack of sunlight have on the chance for life there? Not only is the sun many more miles away than earth, it also has to penetrate through a mile or two of ice. Life as we know it is driven by the sun's energy; obviously, life likely exists outside of the "as we know it" realm, but the lack of the sun's energy has to be a limiting factor, right?

Yup, lots of life forms don't need light to function at all. As long as you have some source of energy - that energy could come from heat, or chemical reactions. You don't even have to be an extremophile to manage without sunlight - think of the bacteria that live inside your gut - they get their food and their energy from the molecules in your food and its breakdown products.

Correct me if I'm wrong, but doesn't Europa's energy come from the fact that it orbits Jupiter in sort of an egg shaped pattern which leads to the stretching and contracting of the moon due to gravity?

Yeah, it's called tidal heating. Because of the gravitational forces of the other Galilean moons, Europa's orbit is slightly elliptical. As it orbits around Jupiter, the difference in gravitational pulls causes Europa to stretch and contract accordingly; the flexure creates friction, subsequently heating the moon's interior - much like the heat you feel on a rubber band after stretching it a bunch of times.

/took Astrobio at uni with Bruce Runnegar. Fascinated the shit out of me.

Bruce Runnegar = mega dude. Any yep, that's all correct :)

Do you believe that the organisms at the bottom of Europa's lake will, within a few billion years, evolve into more biologically complex creatures similar to how we hypothesize Earth's history to be?

Edit: grammar/spelling

If there are microbial organisms down there, and there is enough variation to let them survive the inevitable catastrophes that affect any planetary body, then given enough time, evolution may lead to larger and more complex organisms just like on earth.

But because it's such a different environment, don't go expecting to see anything you recognise!

I think this sounds like the coolest job ever, but how do you respond to people who argue that governmental spending should not be "wasted" on searching for hypothetical microorganisms and should be spent on solving issues here at home?

Basically I'm just looking for a good comeback when people say that to me.

It is the coolest job ever!

Really astrobiology explores blue-sky research which is always a bit hard to defend, except for the natural human curiosity to know whether we are alone, and how we got here...

But an awesome comeback is to mention all of the stuff that we use day to day that were developed as part of an apparently 'pointless' space exploration program. Without NASA we wouldn't have TV satellite dishes, medical imaging like MRI scans, barcodes, firefighter equipment, smoke detectors, anything aerodynamic, space pens, joystick controllers, and most plastics!

1) How do you feel about the comet seeding life theory? Also, would that change, in your mind, the probabilites of life being very similiar all throughout the universe?

2) I have always bee amazed at the RNA / DNA / Protein relationship and its implications in the origin of life here. Can you explain what we know about which molecule came first and the implications for life developing on other worlds? For example, self assembling lipid membranes may not occur the same way under all conditions.... Etc.

3) thank you, and I want to work with you!! What a rad dream job.

1) I think it is possible - comets are thought to have delivered the earth's water, and organic compounds like amino acids have been found associated with comets. This is just one of the ideas for the origin of life by panspermia.

But panspermia as a theory is riddled with problems. If life was delivered by comets, was it as fully formed cells, or as DNA, or just organic molecules (which form on earth just fine). And if they're on the comet, how did they get to be there? Panspermia just shifts the big problem of the origin of life away from our own planet (which we can understand to some extent), to an unspecified place and time in the vast extent of the universe. Not a very good theory then.

The life wouldn't have to solely come from a comet. Meteorites are more then capable of transferring basic life from planet to planet through impacts. We have martian meteorites which may shown existence of life ALH84001, although this is dubious since it was a find rather then a fall. But the fact we have, martian, lunar, HED and some may argue even meteorites from Venus (controversial) shows that there is a system for moving life from planet to planet.

Yes we have the system for moving all kinds of stuff around, but no convincing evidence whatsoever for life (beyond amino acids, which are showing up everywhere these days on their own) on them.

Even the several pieces of evidence on ALH84001 have been systematically undermined. There are lots of physical problems too - how would living things survive the burning up in the atmosphere and the intense pressure on impact?

2) This really isn't my specialist area - but I'll do my best!

Today we have a really complex interaction inside each of our cells, that starts with double stranded DNA, which is transcribed into a single stranded RNA using a protein enzyme. That RNA is taken elsewhere and translated into a protein molecule using another piece of protein machinery - a ribosome. So if proteins are needed to make RNA from DNA, but RNA is needed to make proteins, it's sort of a vicious circle that we can't easily find a starting point from.

But scientists are starting to think that the answer may lie in the versatility of RNA molecules. Because they are single stranded, they can fold themselves into shapes that can resemble the functional shapes of proteins. It may be that the early life molecules were all RNAs in different shapes, that were then adapted through a kind of molecular natural selection to make proteins from the amino acids swimmin freely around in the world, and to make DNA by pairing up strands.

This'll have the implication for life other worlds, of opening up the possibilities of what is possible to identify for life. We may not be looking for DNA-based life forms, but maybe just RNA-based life. It also means that all these amino acids that are floating around won't necessarily mean life unless there's an RNA molecule there to help them along.

Wrong astrobiologist here (just a lowly grad student), but I thought I'd weigh in on 1).

I honestly don't think panspermia is a particularly feasible idea. To the best of our current knowledge, Earth has the best conditions, and has generally had the best conditions throughout time, for supporting the growth and development of life. Saying that life was seeded is, in my view, far more problematic because we still have to explain how that life came to be in the first place. Earth is, in my opinion, a more likely point of origin due to the sheer abundance of surface water present, which is roughly constant over time. We know that life on Earth started in the presence of water, so I'd say that you're more likely to initiate the reactions that lead to the formation of life on Earth than elsewhere.

I agree with you that the chemistry we are familiar with is more likely to occur in water. However, given the vast times, and I do mean vast, that the universe has had to generate life I just feel like it is going to be more common and more varied than we can even comprehend right now.

I agree, but that will explain the kinds of life that you get in those specific environments. The life on Earth is extremely well adapted to ancient and modern conditions on earth. There is absolutely no need to invoke an external source for our own life here (which by extension, invokes a source elsewhere, a safe mode of ejection and delivery), just to explain the one step we haven't yet mastered - the move from prebiotic chemistry to biological reactions.

3) It is awesome! And thanks!

Is there any possibility of inorganic life being found? such as virii or perhaps, silicone silicon based forms that resemble computers?

Yeah maybe - and that's where astrobiologists have to start being a bit creative!

At the moment, we only really have to tools to recognise earth-like life, things with cells and DNA and a solvent to lubricate it all. But even our (many) definitions of life are hazy, and sometimes overlap with the replicating of computers, or the adaptability of viruses. The problem is being able to recognise them!

[deleted]

I suppose it would have to work like that, if it was going to do respiration like us. The other option is a more computational idea where 'respiration' is driven by free electrons travelling around the organism in a way totally 'alien' to what we're familiar with. Then the byproducts might come in the form of light or heat energy...

Why should an organism resemble a computer just because it uses silicone?

Silicon as an element is similar to carbon in that it can form 4 bonds, but is very different in the nature of those bonds. Carbon's bonds are longer and more flexible, allowing it to be mobile and create the changeable structures used in biology. Silicon forms much shorter, stronger bonds that make a much more rigid structure. We haven't found a rigid kind of life like this yet, and as far as we know it's unlikely for biological reactions.

It doesn't need to resemble a computer, and that's not how I read it in Freedmonster's original post. Because life made of silicon can't have the same kind of flexible solvent beased reactions that carbon based life can, the only analogy we have is of computers, which have a kind of life to them, but are rigid, and depend on the exchange of free electrons, rather than the transport of whole molecules.

Make sense?

[deleted]

I'm not a chemist so I've not worked much on the chemistry of it, but as I understood it it's not the C-C, Si-Si energies that matter, but the C-O, Si-O energies, which google tells me is 85.5 vs 110 (in kcal/mol)... so the backbone molecules can change their functional groups more easily if they're made of Carbon than Silicon...

What is your educational background?

I did a bunch of science A-Levels, then went to Oxford to do a Masters Degree in Earth Sciences (that's Geology with a fancy title).

Then I always enjoyed biology, so started focusing on the palaeontology side of things, and started looking at some of the big questions in early life palaeontology. Where did animals come from, how did animals and plants evolve, when did sex start...

I've been doing research for a PhD for the last 4 years, and 3 years of that have had some crossover with astrobiology. I went to a summer school while avoiding doing real work, and fell in love with the subject. A really supportive community, and finding my own niche helped open the doors. I'm now looking at starting work with NASA and then, who knows!

What form would you expect to find life outside of Earth? All of the movies have googley-eyed little Martians, but isn't it just as likely that it's some sort of gelatinous cube that we wouldn't recognize?

I think it's terrific!

With the infinite possibilities of infinite space, life forms could look like literally anything. Even gelatinous cubes, or odd silicon like lifeforms. Our problem is how would we recognise that kind of life? How do we define life?

NASA defines it as a 'self-replicating, self contained organism capable of undergoing Darwinian evolution', and so far we only know of DNA-containing cells that can do that. So maybe we would only be able to objectively identify earth-like life in the beginning, and that's likely to be bacteria and tiny microbes.

If we consider that the universe is based on the same principles everywhere, wouldn't we expect to find similar life forms elsewhere as well?

There are so many factors affecting the evolution of life on earth as we know it, I wouldn't expect to see giraffes and elephants walking around on another planet.

This is right, and it comes down to an understanding of evolution on Earth, which is something I have a lot of background in.

Evolution on earth is both contingent on random events, and convergent on particular environmental optimal. For example, dolphins and the extinct aquatic dinosaur, the ichthyosaur, look very similar because they are/were doing the same thing - hunting fish in the sea. But we don't have ichthyosaurs any more because of the random interruption in dinosaur evolution by the meteor stroke 65Ma ago.

Extraterrestrial creatures can be expected to be the same, but on a smaller scale. To be living, something has to have a compartment, and intructions for replication, and it's likely that life will converge on a cell, with DNA-like stuff inside it. But depending on the random chance of where that life started, and the proportions of different elements and the conditions, the later stages of that alien's evolution could take it in completely different directions. On a planet just like earth, life could be very similar, even with giraffes, or it could be completely different.

what have you thought about the arsen liveform "discovered" from nasa a couple of month ago.

(discovered in quotes, because my last information is a falsification)

I don't really work on the chemistry side of things, but as far as I know, the scientists claimed to have grown some bacteria that used Arsenic in the backbone of DNA, where we usually have phosphorus. If true, it would be a really exciting development, because it would show that we can build 'life' molecules, using elements different to those most commonly used on Earth.

I think there has been a big fight over it because it has such big implications, but the experiments weren't as precise as they could have been. They claimed they grew the bacteria only in arsenic, so no phosphorus could have got in - but then other scientists showed that some small amount of phosphorus was there. Really, more work needs to be done!

As a chemist, lemme step in and say that this paper is sketchy as hell and should not have been published in Nature. It's highly likely that the findings were false.

There's a lot that shouldn't be published in nature, for one reason or another. Sensationalism and human interest, that's all it really is...

1: Is your name really Leila? Cuz I only know of one other Leila and the irony is palpable.

2: (Playing devil's advocate:) What would you say the inherent value to finding microbial life in our solar system is compared to the cost? Don't get me wrong, I'm certainly excited by the prospect, but the cost of a mission to find it would astronomical (ugh) and even if it turned out to exist, I severely doubt it would be a global paradigm shifting discovery.

2b: Because of the huge range of extremophiles (sp?) that we've found on Earth wouldn't it be safe to just assume that there were microbial life in the oceans of Europa and elsewhere and focus on to more practical space science like NEO detection, or even more grandiose goals like finding intelligence?

3: On more of a philosophical level, where, for you, is the line drawn for "life?" Could our terrestrial understanding of what life is be too narrow for what is actually out there in the universe? As an example, the classic conundrum with this is viruses, but lets say that there is a self-adhering gaseous blob somewhere in Jupiter that runs a process on it's surrounding environment that sustains it's structure and maybe even gives it the ability to multiply. Would you call that life?

4: What was your degree in?

5: From your description of yourself, you don't seem to be too much on the intelligent, "little green men" side of astrobiology, but what are your personal thoughts on the Fermi Paradox anyway?

Thanks for doing this AMA. You have a baller profession.

1, Yep, my name is really Leila, and it means 'dark', or 'nighttime'. I was born with black hair but then it fell out and I was bald for 2 years before it grew back blonde :/

2, You're right about it costing a lot of money, but it's hard to estimate how much something is 'worth it' when you're talking about exploration. Was it 'worth it' for astronauts to walk on the moon? Was it 'worth it' for Chris Columbus to risk his life setting out to discover america? I think finding that we're not alone would be paradigm shifting. It may impact major religions, it will give us a new perspective on how life started, and what is possible within our universe.

2b, The first thing that the organised astrobiology program attempted was to look for intelligence by listening in to radio signals. We've been doing it non-stop for 50 years and so far have found nothing. The US government pulled the funding, and it's still going on... It's a much more profitable endeavour to look for things we actually have a chance of finding. If we do find life inside Europa, it will power research in all the sciences for many decades. How does the chemistry work, what are they capable of, how can we get them back here/us out there. It's simply a question of returns!

3, I really like the NASA definition of life, as a usable, and sufficiently open-minded definition that will allow for very unearthly life forms. It says life is 'A self contained, self replicating organism, capable of darwinian evolution'. The self contained bit could mean a membrane-bound cell, or it could be a cloud of gas held together by gravity. Self replicating could mean DNA, or it could mean Van Neumann machines. And Darwinian evolution takes into account all of the things that life will have to do to keep on living, be variable, and adapt.

4, An easy one! Earth Sciences, 4 years.

5, I find the Fermi Paradox, and in particular the weird and wonderful solutions to the eerie silence, fasicnating! But if there are other intelligent civilisations out there, and I do think that there might be (because of the extreme age and size of the universe) I think the reason we don't hear from them is that they're simply too far away!

• If not an astrobiologist, what else would you rather be?
• What did those around you think of your career choice?
• Why "follow the water"? As you said, there may be various life forms that don't depend on water for sustenance...
• What's the next step after actually discovering life beyond our planet? Where does the focus of research shift to afterwards?
• Any advice for those who may be pursuing similar career paths?

If not an astrobiologist - an astronaut! No, a dancer, or an artist?

I get a lot of people who don't know much about it thinking I'm a bit loopy, looking for little green men, but the real science behind it is so appealing - I hope they respect the curiosity that drives me!

Follow the water is a simplification of 'follow the liquid'. Yes it is concievable that life could survive by metabolising methane, and that's why we haven't ruled out Titan. But our only examples of life (on Earth) all use water as the solvent that lubricates biological reactions. We don't know of any other way of doing it, and it is a lot easier to find things we recognise than casting in the dark for something completely 'alien'.

Depending on what it is, and where it is, we'll study it. If it's microbial, steps will be taken to prevent contamination, and we'll go and study it, or bring it back. If intelligent, I guess we'll try to communicate!

If you're interested in investigating astrobiology, find an aspect of it that is being actively researched and that interests you - the broadness of it makes it easy to find something whether you prefer biology, physics or chemistry. The NASA community is huge and admittedly hard to penetrate (especially if you're not American, like me), but once you're in it's like a big alien-hunting family!

Regarding your point on "following the liquid": I've heard (from threads over in r/askscience, I don't have any official sources) that one of the things we're looking for isn't just liquid, but an molecule that can exist as a liquid, solid, and gas on the same planet, like water does on Earth. Is this something that you guys look for, or am I completely out of line and you guys basically just look for water?

Something that can transition between liquid, solid and gas easily within the variable conditions on a planet is a good sign that it will be useful for life, because it's bonding and melting and boiling temperatures will make it flexible enough to be used in energy-saving biological reactions. Any more than that, I'm afraid I don't know.

Liquid is really the thing we're looking for, because life as we know it is cellular, with liquid squishy insides, and you need a solvent that can give the flexibility, as well as contain the necessary molecules and compounds dissolved within it.

Is the way hard to become an Astrobiologist ?

No harder than becoming any kind of scientist. All it takes is a genuine interest, motivation to work hard at investigating a topic, and a bit of creativity to imagine new possibilities.

It doesn't matter what kind of scientist you are, there will be something in astrobiology that will make use of your knowledge.

I want the grisly details of your research on microbial life making inter planetary travel more feasible!

Ok so. When you're in space you aren't under the influence of gravity. Without gravity your bones start to decay. The calcium from your bones leaves your body via urine. The urine on the ISS/Space ships is cleaned and recycled into drinkable water, but the calcium in it blocks up the pipes, making keeping this water recycling going for the time it take to travel between planets really difficult.

So the idea is to use my experience with algae who mineralise themselves in calcite or phosphate (like in stromatolites) to process this urine to remove the calcite before it is 'cleaned'. And maybe even recycle this calcite into edible supplements to keep your bones healthy. While all the time using the carbon dioxide astronauts breath out and recycling it into breathable oxgygen.

These miracle wonderbugs could solve all our problems, and be easier to grow and more reliable than any other kind of plant!

How would you explain that the same type of algae and bacteria can be found on for instance the Kiribati islands and the french Polynesia islands ?

I'm not really familiar with these particular cases, can you tell me what makes them special and I can hopefully give you an answer!

Lots of microenvironments on earth have extreme conditions where specially adapted microbes can survive and thrive. They're called extremophiles, and they are a whole branch of astrobiology.

What is your opinion on the 'nutjobs' searching for life out there? Do you think the prominence of people who believe in little green men in conspiracies is detrimental to the validity of your work or do you see it as a method of driving interest?

To be honest, it doesn't really overlap very much. The people who believe in little green men tend to not be the people who will listen to the nitty gritty science which, while exciting, doesn't support their ideas.

And the scientists who work on real astrobiology, and people like you guys who ask sensible questions about it, don't really pay much attention to the little green men theorists!

What's the deal with the acetylene/hydrogen chemistry on Titan?

So Titan is made up of a landscape of ice (where we have rock), and instead of water, it has methane and ethane lakes on the surface, as part of a methane cycle that includes methane clouds and methane rain. If life existed on the surface of Titan, it would have to use methane as a solvent for its reactions instead of water. This will change the basic equations of meabolism - so Titan creatures will inhale hydrogen instead of oxygen, react it with acetylene instead of glucose, and exhale methane instead of carbon dioxide.

Some scientists think that if there is life on Titan, you'd be able to detect it by measuring the amount of hydrogen in the atmosphere, which would be produced by the Titan-ian version of photosynthesis.

If the methane being produced on Mars comes from a biological source, does the fact it produces methane as a by-product mean it must be very similar to life on earth? Composed of the same types of molecules?

Probably so yes - if, if, if...

We have analogies on earth, bacteria that metabolise chemicals to result in methane as a by-product. They're called methanogens or methanotrophs, and we get them in the bottom of stagnant pools along with bacteria that produce smelly sulphur.

So there could be martian microbes just like our methanogens, but we'd need to find them and study them to be sure. Occams razor says that the easiest explanation - that they're both the same - is probably the right one, but we'll have to wait and see...

When you search for life in space are you explicitly looking for organic life - like plants? or are you looking for sentient beings - like human like creatures, machine life or anything with consciousness? Would you consider something non-organic, but sentient life?

We're really looking for anything out there that we can recognise.

The SETI program started 50 years ago and was listening in for radio signals from sentient, intelligent, and communicating alien civilisations. But so far we've heard nothing. Maybe life isn't so intelligent...

In that case we would be looking for organic life, because it's the kind of life we can recognise. We're looking for the signals it would leave in rocks, in the atmosphere, or in the patterns on planets or moons, and comparing them with things we see on earth, because it's the only example we have.

Non-organic things are possible, but they're even harder to identify , because we've nothing to compare them to on Earth.

I use to run the SETI program on my computer to help look for life. I always wondered if it really did any good.

It made my computer overheat A LOT. I wouldn't recommend it.

How did you become interested in astrobiology?

I went on a summer school organised for students who were doing crossover sciences like cosmology and palaeontology and prebiotic chemistry. At the time I was just going along to things to procrastinate against doing real research, but I enjoyed it so much, and found all the questions that could be explored in astrobiology so fascinating, it completely changed the course of my reserach. That was three years ago, and since then I have done lots of conferences and talks and workshops, and have learnt loads more about the subject by teaching it to undergaduates.

Approximately how many jobs are their in the world for Astrobiologists?

I ask because I once had a secretary that had a PhD in 14th Century French Literature. I asked her why she got a PhD in that (huge education debt) and little job prospects. She told me that there were 3 maybe 4 jobs in the entire world for her education. Talk about getting an "education" the hard way.

When you do a PhD, you're finding out about something that nobody else has ever found out. So you become the world expert on that subject and there is only one job, yours, that will suit you.

But it's about how adaptable your research is, and how adaptable you are. For example, my research actually focuses on microfossils from 1000 million year old rocks from scotland, but I teach and collaborate with other astrobiologists about the habitability of the Jovian and Saturnian moons and, soon, how algae can keep astronauts alive and healthy!

There are about 120 centres in the UK where astrobiology is taught or researched, and in the US, the NASA astrobiology community is really big. It's all about finding a niche that you can occupy.

I've always imagined that the closest thing we to intelligent alien life we can find and study is the octopus, since its complex brain evolved completely independently from mammalian intelligence and in an environment that we find deeply alien.

What are your thoughts?

An interesting idea and probably quite close to the truth.

I find it incredible that in the 60s and 70s we were trying to communicate with alien species through binary messages and pictograms in space, but even today we haven't managed to communicate properly with a single species (intelligent or otherwise) on our own planet! Puts our efforts into perspective a bit eh?

I'm also about to start a project with NASA too that will use algae and bacteria to help make human inter-planetary travel a tiny bit more feasible

Could you explain this?? Thanks!

Ok so. When you're in space you aren't under the influence of gravity. Without gravity your bones start to decay. The calcium from your bones leaves your body via urine. The urine on the ISS/Space ships is cleaned and recycled into drinkable water, but the calcium in it blocks up the pipes, making keeping this water recycling going for the time it take to travel between planets really difficult.

So the idea is to use my experience with algae who mineralise themselves in calcite or phosphate (like in stromatolites) to process this urine to remove the calcite before it is 'cleaned'. And maybe even recycle this calcite into edible supplements to keep your bones healthy. While all the time using the carbon dioxide astronauts breath out and recycling it into breathable oxgygen.

These miracle wonderbugs could solve all our problems, and be easier to grow and more reliable than any other kind of plant!

I'm currently getting my bachelors in biological science, and I plan to go to grad school after that. My dream career has always been to work for NASA. So I was wondering how difficult was it to get work with NASA? Does everyone who works with them come from a college that is highly touted? (MIT for example) Is it possible (or likely) that we will find an alien species so differet from us we won't be able to recognize it? (most likely not carbon based)

I can't really say much for how easy it is to work with NASA if you're from the US. I'm guessing it's difficult, because getting to work with them from the UK is really really really difficult. There are a bunch of courses they offer though, aimed at people at the beginning of grad school, so you should keep an eye out for those. The Planetary Biology Internship is a good one.

Astrobiologists have tried to find a definition for life that will include non-earth like forms, and our success is limited by the extent of our scientific imagination. Hopefully we'd be able to recognise living things, even if they weren't made from carbon, but without something on earth to compare it to, we may not.

How have you not been asked about the NASA project? Could you possibly explain what you'll be looking into?
I'd guess that it's to do with using bacteria to recycle carbon dioxide etc.
Please don't hold back, the grislier the better!

When you're in space you aren't under the influence of gravity, and without gravity your bones start to decay. The calcium from your bones leaves your body via urine. The urine on the ISS/Space ships is cleaned and recycled into drinkable water, but the calcium in it blocks up the pipes, making keeping this water recycling going for the time it take to travel between planets really difficult.

So the idea is to use my experience with algae who mineralise themselves in calcite or phosphate (like in stromatolites) to process this urine to remove the calcite before it is 'cleaned'. And maybe even recycle this calcite into edible supplements to keep your bones healthy. While all the time using the carbon dioxide astronauts breath out and recycling it into breathable oxgygen.

These miracle wonderbugs could solve all our problems, and be easier to grow and more reliable than any other kind of plant!

• Given that you're looking for water as an indicator for life potential - and you already mentioned above that Europa's ocean is for now the best bet to find life close by (relative) - how important will the discoveries in Lake Vostok be to you? How may it affect your research?

• What really happened at Area 51? Have you been called in to investigate farmed samples of extraterrestrial life there under a top secret envoy? Seriously though, you can trust us.

While discoveries in lake Vostok (and any of the other sub-Antarctica drilling projects) won't impact my own research directly (I'm more concerned with finding patterns left by long dead microbes), it will help astrobiologists to understand better what happens to microbes when they are isolated in water without exposure to fresh air for millions of years. It will give us a better idea of what to look for and how to look in Europa. It's already teaching us important lessons about how to engineer ways of getting to distant areas without contaminating them.

Haha, I have no idea. And even if I did, I wouldn't tell you. Seriously though, I have no idea

[deleted]

I would have her tell her professors to stop being so narrow minded, and follow her dreams.

Astrobiology is not unrealistic. No, we've not found anything yet, but some of the most exciting science today is being done by people pursuing essentially astrobiological goals. Whatever you're doing, you can turn it to what you need, and stick two fingers up to your stinky fuddy duddy professors.

Hi there, thanks for the AMA! I have a couple of questions.

1. What are the most likely materials, for lack of a better word, that life existing on other planets or in space could be made from?

2. Does what you do tie in with SETI at all? I would imagine that they are narrowing the scope a little bit by searching for communication.

3. You say in your post that there could be methane-based microbial life. How does a gaseous life-form work?

1, When it comes to life, you want a versatile set of elements - ones that can form bonds easily, but also break them easily enough when needed, and be flexible enough. For this, we've really hit on a winner with carbon, hydrogen and oxygen, so we think that alien life would find it similarly easy to make it's living molecules from these elements.

2, I've never done any research that directly relates to SETI. SETI was the first effort of the astrbiology community to find ET life, but it's been going 50 years with no success. We have now adjusted our goals to look for life in the first instance, before we jump the gun and try to detect intelligent life.

3, I didn't mean that the life forms would be gaseous, although I'm sure there must be some conditions in the infinite variety of space where it's possible, but instead that the life forms would use methane instead of water in its reactions.