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Could There Be Life On Titan?
Posted by
Soulskill
on Sun Aug 24, 2008 08:49 AM
from the reply-hazy-try-again dept.
from the reply-hazy-try-again dept.
Adam Korbitz writes "Astrobiology Magazine reports on new research indicating extremophile microbes may be able to live on Titan, the sixth and largest moon of Saturn — in spite of the fact that the moon is largely ice and covered with lakes of liquid methane. Titan joins Mars, Venus, Europa and Enceladus as a potential home to extremophile life in our solar system."
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Joins? (Score:5, Interesting)
Titan has been a prime candidate for life for as long as I can remember. Since they figured out that it had an atmosphere, it probably had lakes of some kinde and pretro.. possibility for life.
Re:Joins? (Score:5, Insightful)
TFA is not about Titan being a candidate, but some research trying to recreate (some) of the conditions on Titan.
Of course TFA also is a long, long way away from life. But knowing the building blocks can form there is another step forward.
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Re:Joins? (Score:5, Informative)
I don't think anyone is arguing that Titan doesn't have the building blocks (by all accounts its atmosphere is probably pretty damned similar to the reducing atmosphere that the early Earth had). The problem is energy. Titan only receives a fraction of the energy that Earth does, and that's why it's in a deep freeze. It's hard to imagine at any point in the evolution of the solar system when Titan would have had, for any substantial amount of time, that much energy from either the sun or Saturn.
The fact that some highly specialized terrestial organisms might be able to make a go of it doesn't, in my mind, suggest that similar organisms could have ever evolved on Titan. These organisms have had nearly four billion years to slowly march into extreme environments. I simply don't think Titan would have ever have been in a similar situation.
I think our best bets for the moment are still Mars and Europa. Mars, because it does lie close enough to the sun and there is evidence that liquid water was once common. Europa because, while it's significantly farther from the sun, is in a rather special situation where Jovian tidal forces are quite likely keep the interior very warm, meaning liquid oceans, and possibly an active core.
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Re:Joins? (Score:4, Insightful)
Thing is, life on Titan doesn't need to evolve on Titan . . . it just needs to survive the journey to Titan from where it evolved. Endospores are quite durable.
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Re: (Score:3)
Being sucked into Saturn's gravity well doesn't make it impossible to land on Titan. Titan just might happen to be in the way ;) ;)
Likely? Slightly more than a snowball in hell. Impossible? In theory atleast
Re: (Score:3, Informative)
Assuming the reasonable (if not proven) ideas that life on Earth began before the Late Heavy Bombardment, and that the Late Heavy Bombardment happened, there should have been lots of bacteria-infested ejecta from the Earth spreading throughout the solar system. Enough that some landing on Titan is perhaps not probable, but is much more likely than "essentially impossible". (One hundred miles per hour average speed, and you get from Earth to Titan in a mere 1,000 years; the distance, at least, is not a pro
Re: (Score:3, Insightful)
Titan is only about five percent farther away from Saturn than Europa is from Jupiter. Europa has a special resonance setup with Io and Ganymede but Titan also has some fair sized moons and a big planet to pull on it.
There's a quite reasonable theory that life on Earth could have originated with organic molecules brought into close contact in ice. The article describes research that shows some of the probable constituents of Titan's atmosphere undergo promising chemical processes even around the freezing
Re:Joins? (Score:5, Interesting)
Considering the vast variety of conditions where life exists on earth I would consider it likely that there is life elsewhere too.
And with life - it may be completely different from the life we know about, but if there is life it is single-cell organisms that we should expect.
Even here on earth we have bacteria that actually thrives in environments that would kill most other forms of life. All the way from extremely acid environment that easily would tear through human flesh to high temperatures well above the boiling point and radiation so hard that it cracks the DNA in the cells - which the bacteria resolves by joining it together again with processes still unknown. And freezing bacteria will just suspend them or make them behave in slow motion.
In any atmosphere where there is complex molecules - especially amino acids - there is a potential for life remotely similar to us on a cellular level. But of course - there may be life in completely different forms with completely different timespans, maybe so long that we wouldn't recognize it as life.
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Re: (Score:3, Insightful)
We know there are certain types of bacteria that can exist in extreme conditions on earth, but to my (untrained) mind that doesn't imply it is possible for abiogenesis to occur in the same conditions.
What does it take for life to come about from non-life. Do we have an idea?
Re:Joins? (Score:5, Insightful)
What does it take for life to come about from non-life. Do we have an idea?
The error - and even most scientists have not understood this - is, to make a spearation between the two.
There is no single moment, where something became "alive".
It's a veeery gradual process, starting with the simples physical/chemical reactions, and evolving to more complex systems.
Even we ourselves are such very complex systems.
See... I do not even have to mention the word "life".
It's just another one of those egocentric concepts, like seeing humans as separate from animals, thinking we were the center of the universe... and so on....
So the problem is purely psychological.
This is the only reason, such an obvious concept is still mostly repressed.
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Re: (Score:2)
Sorry for my typos. I meant "separation". Obviously scientists and geeks do not "spear" life or non-life. Conan does!
And "simplest" instead of "simples". Obviously I do not know a funny line for this one. Conan does! (The other one.)
(No, I won't point out every punctuation error. You know who to ask... Stars with C...)
Re:Joins? (Score:5, Insightful)
Egocentric mankind (generally speaking, science community excluded) thinks life means Youtube, Social Networking, Church, and High End Tennis shoes.
I really wish children were taught an early age about the Universe and the life breeding ground that it is. Different conditions produce different forms, it is now up to mankind to acknowledge and accept this.
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Re:Joins? (Score:4, Interesting)
Abiogensis is fascinating. I hope to live one day to see life created from scratch. Right now, the best we have is interesting speculation.
One workable hypothesis for the natural origin of life is the RNA World Hypothesis [wikipedia.org]. Another is the Iron-Sulfer World Theory [wikipedia.org].
Parent
Re: (Score:3, Interesting)
Not really, no. Aside from having the necessary ingredients, we don't know how abiogenesis happened, or even that it happened here on Earth. The first microbes might've formed or partially formed in comets that later impacted the Earth and "came to life" down here, or maybe it happened entirely in warm little puddles and tidepools. Regardless, the conditions in which it did happen, or even CAN happen are largely unknown. There ve
Re:Joins? (Score:4, Interesting)
Some of the "building blocks" that may be in comets could even be remnants of life that surrounded sol's parent star that went supernova and gave us all of the elements in the periodic table above iron. Although it's hard to believe any actual life surviving those conditions for those periods of time, it can't be proven to be impossible. Who knows?
Parent
Re:Joins? (Score:4, Interesting)
What many scientists look for in remote planets is chemical imbalance, from an energetic point of view. Chemical imbalance may not be the only result of the existence of life, or even a guaranteed result, it is very reasonable to look for that as both core aspects of life would cause such a chemical imbalance.
A typical aspect of life (at least life as we know it, and what we commonly consider "living") is a mechanism that is doing something with energy: usually storing energy using chemical reactions. As a result there is a lot of matter on earth that is not in a very low energy level, e.g. oil and coal. The ultimate source of this energy could be light (most lifeforms on earth use this energy source - directly or indirectly), but other sources are also possible, think of sulfur-reducing bacteria near hot wells, using sulfur and maybe also heat as energy source. The sulfur getting in that high-energy form thanks to the heat in the core of the earth reducing the sulfur to it's elemental form, later oxidations by the bacteria release energy.
A second typical aspect of life is self-replication. This is a necessity of survival: even if an individual would not age, there are always accidents and diseases that will put an end to an individual. So self-replication is also a requirement. And I suspect that most, if not all self-replication reactions take energy, for the simple reason that self-replication means a decrease in entropy in the matter used to create this copy. Again energy is stored: releasing the molecules and restoring the entropy will result in the release of energy as well.
So for non-life to become life, I'd say a system should be able to replicate itself, and to collect energy from it's surroundings. That I think is the most basic requirement for what one could call "life".
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Re: (Score:3, Interesting)
To expand a little, a better sign of life is an atmosphere that's not statically stable. Our own oxy-nitrogen mix wouldn't stay the way it is without life; there are too many processes that would take the oxygen out. The only thing keeping it in the balance it is is the fact that plants are generating more oxygen at the same rate it's used up, both by animals and by inorganic routes. Any species capa
Re: (Score:3, Insightful)
Considering the vast variety of conditions where life exists on earth I would consider it likely that there is life elsewhere too.
The catch is that although life can exist in extreme conditions as we observe here on earth in places, the likelyhood of genesis in such conditions is much lower than the odds of genesis in more gentle environments. So it makes sense to look for either existing conditions, or previously existing conditions, that are "gentle" and are statistically much more likely to experience g
Re: (Score:3, Informative)
I'd be happy to be proved wrong, but as anyone following the wrangling over the next outer-planets flagship mission knows, we could easily not get a dedicated Titan mission for until the end of the decade after next.
Re: (Score:3, Insightful)
There's not enough energy for complex reactions to happen quickly, but they can still happen. And there's nothing that says life has to be able to form there today. Assuming it has a large, rocky core, it must've gone through a long cooling phase after forming, so there would have be
Re: (Score:2)
What about the subsurface ocean? (Score:5, Interesting)
Arthur C. Clarke all the way... (Score:5, Funny)
Book or Movie? (Score:4, Informative)
Parent
Book: 2010. (Score:2)
Re:Book or Movie? (Score:5, Informative)
Parent
On Titan, water ice is a rock (Score:5, Interesting)
Titan is a very different place from Earth. Water ice is a rock (surface temperatures never come close to the melting point) and, critically, temperature / entropy gradients are much smaller than on Earth. (It's not just cold, the flow of energy is slow.) So, if there is life, i would anticipate not something like terrestrial extremophiles, but an entirely new form of life, which doesn't use water as a medium and which would be very slow from our viewpoint. I asbolutely think that such life could evolve, if it is possible at all, but who knows if it is possible. Going there would be one way to find out, but that will neither be easy, simple, cheap or quick.
I think that the article is misleading in one respect - a body of liquid water might survive for a while (in the same way that a pool of lava - molten rock - can survive for decades or longer on the Earth, and presumably on Mars), but, just like the pool of lava, it would be quickly encased in a layer of frozen water ice. You might have water at the surface, but you would not have water on the surface for any length of time (think polar ice caps in the middle of winter, and you are still way too warm). It is hard to see how extremophiles could evolve in those circumstances, and it is very hard to see how biological material from the Earth or Mars, blasted out by meteor impacts, could reach Titan intact.
Re: (Score:2)
We don't yet know if Titan was always frozen.
There are lakes of liquid methane there. I imagine some microbes could adapt to living in methane.
Though, I bet there will probably be taun tauns there.
According to TFA... (Score:2)
Re: (Score:2, Informative)
This is especially relevant, since Geisler found [wikipedia.org] some (rather indirect) evidence that life was present on Earth just a few hundred million years after the planet solidified. This suggests that life can form relatively quickly in a water-rich environment. However, the lateness of the Cambrian explosion suggests that oxygenation of the biosphere presents a hard metabolic requirement to forming complex multicellular organisms, like us.
Re: (Score:3, Informative)
I once tried freezing a complete 2 litre of bottle of water in -20C temperatures. All but a central core of 1.5 inches froze - This gave me a solid ice tube which actually split the bottle itself. There was water in the middle - the pressure from the surrounding ice must have been enough to keep it liquid.
We should send the modern day Malachi Constant (Score:2)
an awful lot of words to say "maybe" (Score:2)
Of course cutting the article down to it's basics "we don't know, but it's possible" wouldn't fill much magazine space or sell many adverts.
What about Venus and Mercury? (Score:2, Interesting)
No... there couldn't. solar radiation was probably important for creating life as we know it, providing that critical energy input to build the first organic molecules. Titan is tooooo far away to get much radiation. Life could evolve there, but if it were a random event it would be MUCH slower than here on earth because it is so much colder over there. So we might have to wait a few more billion years.
And so by that rationale, we should be looking for remnants or indications of life on venus and mercury...
Not necessarily (Score:2)
Re: (Score:2, Interesting)
Precisely. So there's little to no chance of finding anything on the *surface* of Titan, which is the only place we have a remote capability to look.
We would need deep sea autonomous vehicles or autonomous digging machines, none of which are within NASA's budget (because we've never built them successfully here on Earth). We've never looked near Earth's core for life either.
It's too cold where we're looking, and we don't have the capabilities to look deeper into the crust.
Moreover, we only ever look for "Ea
Re: (Score:2)
I often wonder what we could find if hypothetical carbon planets [wikipedia.org] turn to exist.
Re: (Score:3, Insightful)
These statements are all true... on Earth. Plenty of reactive silanes are possible. All known biochemistry is based on carbon, so of course silicon is not going to catalyze many biochemical reactions. But carbon-based reactions do not go so efficiently in the cold... Iron chemistries might have gone wild on Ma
Re: (Score:3, Interesting)
Yes (Score:2)
It could.
Extremeophile (Score:3, Insightful)
That is basically the Rare Earth theory (Score:2)
Disappointed! (Score:2)
It's a MOON! (Score:3, Funny)
One's extreme is the other's comfort zone (Score:2)
We're talking about life here after all... we know on earth that life can be found virtually anywhere. And after all, an environment what we call "extreme", some microbes may call "nice and comfortable".
Those microbes may well consider us to be an extremophile!
entire solar system "infection" is possible (Score:3, Insightful)
Earth life is very hardy. It lives six miles undergound, at the boiling point of water, high in clouds, etc. It survived on a moon lander for a decade. Some could be likely to survive centuries if would take meteors to travere the solar system.
Re: (Score:2)
This claim has recently been challenged [wikipedia.org]. However I'd love to search for Earth rocks on Mars and look at the surroundings -but it is probably a prohibitively time-consuming, complex search.
If we're talking about extremophiles (Score:2, Interesting)
Re:Don't worry. (Score:5, Interesting)
ah, yes, I suspect if you wanted to burn it the suspected water/ammonia mix found in the ice could be a source of oxygen if needed, I also suspect methane would work really well in a fuel cell designed for it.
http://www.nature.com/nature/journal/v400/n6745/abs/400649a0.html [nature.com]
when I said fuel, I didn't say burn.
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Re: (Score:2)