Nucleotides in Titan’s atmosphere?

Paul Raven @ 06-01-2011

I’m somewhat surprised that I haven’t seen this story all over the place. Perhaps everyone’s taking a while to get back up to speed after the holidays… or perhaps no one wants to get burned the same way they were by the last story about life chemistry that came out of NASA’s press department.

Nonetheless, complete with obligatory “maybe real life is stranger than science fiction after all OMGZ!!” closer, here’s NASA Science News talking about an experiment that demonstrates the possibility of basic life chemistry building blocks in the atmosphere of the Saturnian moon, Titan:

Hörst and her colleagues mixed up a brew of molecules (carbon monoxide(1), molecular nitrogen and methane) found in Titan’s atmosphere. Then they zapped the concoction with radio waves – a proxy for the sun’s radiation.

What happened next didn’t make the scientists shout “it’s alive!” but it was intriguing.

[ There’s good reason to make science journalism accessible, but do we really need shitty little asides like that, NASA? This isn’t Sesame Street, for goodness’ sake… ]

A rich array of complex molecules emerged, including amino acids and nucleotides.

“Our experiment is the first proof that you can make the precursors for life up in an atmosphere, without any liquid water(2). This means life’s building blocks could form in the air and then rain down from the skies!”

[ The metal-head in me now really wants to use Slayer’s “Reign In Blood” as a voice-over bed for this article. Sing along at home! ]

“We didn’t start out to prove we could make ‘life’ in Titan’s skies,” explains Hörst. “We were trying to solve a mystery. The Cassini spacecraft detected large molecules(3) in Titan’s atmosphere, and we wanted to find out what they could be.”

In hopes of obtaining clues to the mystery molecules, Hörst used computer codes to search the lab results for matches to known molecular formulas. She decided, on a whim, to look for nucleotides and amino acids.

[…]

“We had about 5000 molecules containing the right stuff: carbon, nitrogen, hydrogen, and oxygen. We knew we had the elements for organic molecules, but we couldn’t tell how they were arranged. It’s kind of like legos – the more there are, the more possible structures can be made. And they can be put together in many different ways.”

Among the structures identified in the lab experiment so far are five nucleotides found in DNA and RNA, and two amino acids. But she says there could be more amino acids in the mix.

How could those molecules have gotten there? The ice geysers of Enceladus are a possible answer, apparently, though this is all strictly speculative stuff at this point.

Search-for-alien-life bonus material! Antarctica’s massive Lake Vostok may finally give up its secrets (presuming it has any, natch) now that a Russian team has come up with a way to sample the lake’s water without contaminating its effectively closed ecosystem with dirty surface-monkey germs. What mysterious things might we discover lurking miles beneath the ice? Whatever’s down there, it might give us some more clues to what’s going on on Enceladus…