Tropical Lakes On Saturn Moon Could Expand Options For Life

ananyo writes "Nestling among the dunes in the dry equatorial region of Saturn's moon Titan is what appears to be a hydrocarbon lake. The observation, by NASA's Cassini spacecraft, suggests that oases of liquid methane — which might be a crucible for life — lie beneath the moon's surface. Besides Earth, Titan is the only object in the Solar System to circulate liquids in a cycle of rain and evaporation, although on Titan the process is driven by methane rather than water. This cycle is expected to form liquid bodies near the moon's poles, but not at its dune-covered equator. Now scientists think they have found a tropical lake — some 60 kilometers long and 40 kilometers wide, and at least 1 meter deep — in Cassini observations made between 2004 and 2008. Because tropical lakes on Titan should evaporate over a period of just a few thousand years, the researchers argue that these ponds and lakes are being replenished by subsurface oases of liquid methane. That would expand the number of places on the moon where life could potentially originate."

Comments

Re:Any pics of lake?

[CSMoran]

Was it discovered using something besides imaging and spread radar, such as point radar?

Imaging of data gathered in a chronosynclastic infundibulum, AFAIK.

CHON is where it's at

[Pfhorrest]

AFAIK there's nothing to say that methane-based life couldn't also use DNA. Methane is still carbon and hydrogen. All living organisms on Earth are composed primarily of carbon, hydrogen, oxygen, and nitrogen (CHON), and the general presumption looking for life elsewhere in the universe is that places with high concentrations of those elements is a good place to look, because we know life can be built out of them. Hydrogen and carbon dioxide are interconvertible with methane and water very much like carbohydrates (such as methane) and oxygen are interconvertible with carbon dioxide and water; all these processes involve the, C, H, and O of CHON equally, and the former was actually quite common early in the history of life on Earth. It wasn't until photosynthetic organisms started using light to convert CO2 and H20 into O2 and various CH's that the now-free O2 and CH4 reacted to become more of the H2O and CO2 that now cover our planet. (And then the O2 kept piling up and almost killed it all until some enterprising organisms started combusting it with those other CH's into more H20 and CO2).

TL:DR; methane really isn't all that weird an environment to find life much like we know it. Molten silicon and iron, on the other hand, or liquid helium, that would require some as-yet-unknown chemistry).

Re:CHON is where it's at

[codewarren]

Extreme cold, on the other hand, does reduce the odds of finding life. Not because things can't live in cold climate, but because evolution is ultimately a chemical process, and all chemical processes are retarded by cold. It took life on earth billions of years to evolve in a temperate climate. In a gigantic freezer, it could be expected to take much much longer.

Re:CHON is where it's at

[grep_rocks]

It takes more than just having the right elements to create life - water has some interesting chemical properties that methane lacks - such as it is one of the only chemicals which expands when it freezes, water is a polar molecule being slightly positive on one side and negative on the other, can form a large number of hydrogen bonds for its size, and especially relevant is that it is a fantastic solvent - all these properties are favorable for life, for example being a good solvent allows other molecules and ions to dissolve into water, allowing for lots of different types of chance chemical reactions to occur between different dissolved molecules - Methane is not as good a solvent as water, as it lacks polarity, however some people have proposed life working using poly-lipids as a substitute for proteins in non-polar liquids but because it is a poor solvent the chances of life working in a methane ocean seem less likely than water...

Helium rain

[arisvega]

Besides Earth, Titan is the only object in the Solar System to circulate liquids in a cycle of rain and evaporation

No, it is not.

Re:Helium rain

[arth1]

What about Venus ? I thought it rained on Venus, hot sulphuric acid, but still..

Yes and no. It rains sulphuric acid in the upper athmosphere (which is almost all carbon dioxide and so dense you can almost swim in it), but the rain never hits the ground.

Still, Venus is - by far - the planet that resembles Earth the most. Much more so than Mars.
Yes, it's more inhospitable too.

Re:Since the boiling point of methane is...

[Rogerborg]

I'd love to think that right now on Titan some right-minded blob is telepathically ranting "But the melting point of dihydrogen monoxide is 273K! Nothing could live in such a hostile environment!"