Saturday, May 31, 2008

Saturn's Titan has Implications for Understanding of Life Throughout the Galaxy

NASA's Cassini spacecraft buzzed Titan last month, coming close enough to taste the Saturnian moon's atmosphere. The data acquired has implications for our understanding of life throughout the galaxy, as well as Earth's own past.

Titan_ir_2The second largest moon in the solar system, Titan has long been of interest for hopeful exobioligists. As the only other body we know of with surface bodies of liquid, complete with nitrogen, methane and complete seasonal weather weather patterns (similar to Earth's). It even has beaches, though you'll need a little more than a swimsuit to visit. Vast bodies of chemicals constantly stirred by wind and wave, heated over a gentle sunlight heat with the occasional dash of articles from Saturn's magnetosphere for spice - a perfect recipe for life. Just like a certain planet you might be familiar with (look down if you forget).

Of course there a few minor differences from our own blue-green globe. There's no oxygen for one thing, but if you think that's a problem then you're guilty of "aerobic respiration prejudice" (don't worry, most multicellular organisms are). It's also really quite amazingly cold - so cold that it has awesomely-named "cryovolcanoes", where boiled (or even just melted) water is enough to set off seismic-level explosions. Again, that's a barrier that's been overcome by homegrown Earth bacteria, so there's no reason it couldn't be managed elsewhere.

Cassini's onboard instruments have detected hydrocarbons containing up to seven carbon atoms. How important is that for life? Here's a hint: molecules with carbon in them are called organic, and those without are inorganic. Carbon is kind of a big deal, and the more (and more complicated) carbon compounds present the further towards the great cosmic chemical cocktail that is "life" you are. Some scientists believe that the Titanian interior, with its greater temperature, could already host microbial life - but it'll be a while before we can check that (unless we get real lucky, and some alien cells get real unlucky, with a cryovolcano eruption). One thing's for sure - the craft is only on the sixth of forty-five planned flybys so we can expect to hear a lot more about this real soon.

PS Yes, it is ironic that we're expecting Titanic lifeforms to be single celled.

Posted by Luke McKinney. Photo Credit: James Estrin/New York Times.

Original here

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