Could There Be Life On Titan?

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."

Comments

Joins?

[Henriok]

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?

[Rob Kaper]

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.

Re:Joins?

[Z00L00K]

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.

Re:Joins?

[Anonymous Coward]

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?

[Hurricane78]

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.

Re:Joins?

[Neuropol]

IAWTP 100%

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.

Re:Joins?

[wvmarle]

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".

Re:Joins?

[MightyMartian]

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.

Re:Joins?

[symbolset]

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.

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?

Re:Joins?

[QuoteMstr]

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. Another is the Iron-Sulfer World Theory.

Re:Joins?

[SEE]

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.

What about the subsurface ocean?

[localroger]

One of the recent blips on the Cassini-Huygens website (since scrolled off) is that Titan's crust seems to be decoupled from the moon's core, indicting that its "mantle" may be liquid -- an ocean of water hundreds of kilometers deep. Combined with all the organic crap sitting on top and the ice volcanoes I am starting to think it would be surprising if there weren't life on Titan.

Arthur C. Clarke all the way...

[kale77in]

It's Europa. And the Chinese will get there first.

Book or Movie?

[localroger]

In the original 2001 book they went to Saturn, where Titan and Enceladus are. It would have been a long walk to get to Europa. In the movie and sequels they go to Jupiter, where Europa is. It would be a long walk from there to Titan.

Re:Book or Movie?

[FooAtWFU]

More specifically, in the 2010 book, they send people back to the vicinity of Jupiter, only they're racing the Chinese, who overcome the American head start and get their first by blasting through all their fuel: they land on Europa to get more, find some sort of life, and perish... then the monoliths turn Jupiter into a small star (presumably in order to foster said life) and send out a message about how "all these worlds are yours - except Europa: attempt no landings there".

On Titan, water ice is a rock

[mbone]

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:Don't worry.

[Roskolnikov]

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

when I said fuel, I didn't say burn.

Re:Not necessarily

[jmil]

There is a problem with silicon-based life. Silicon is not as nearly versatile chemically as carbon is. It is highly doubtful silicon can sustain any meaningful biochemistry -at least, not by itself

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 Mars. Why not metal-based life (lots of metals form strong alloys)?

Carbon itself is highly unreactive. This is why pencils and diamond rings are allowed on airplanes. It needs bonded groups such as amines, hydroxyls, thiols, etc. to get any meaningful work done. Carbon is just the backbone.

We simply haven't tried every possible chemical reaction in all possible environmental conditions to know which reactions might be "spontaneous" on other planets. We can sure try and guess. However, chemists are surprised every day by reaction kinetics, behaviors, and mechanisms here on Earth. We still don't understand chemistry that well. So why do we need to stifle ideas of how things might evolve on other planets with vastly different experimental conditions?

We should be looking closer at Venus instead... it's nearby, lots of strong chemicals and lots of heat make for an intriguing place for reactions to take place. Moving far away from the Sun is misguided if we're looking for interesting chemistry...