flickering pictures

We’ve known for a long time that there’s an awful lot of water in space. Comets send huge amounts of the stuff hurtling every which way, and just last Thursday NASA extracted water from Martian soil for the very first time. But because the universe is, for the most part, really really cold, nearly all of its water seems to be frozen solid, which dramatically decreases the chances of evolving life — at least as we know it.

Recently though, NASA discovered hundreds of liquid lakes on Titan, one of Saturn’s moons, prompting all kinds of speculation about what they might be like — and, inevitably, whether there may be some living creatures wriggling around down there. What we do know is that the lakes aren’t filled with water, but rather with liquid ethane and other hydrocarbons that would be unpleasant for us, but might be downright cozy for something else. We also know that Titan’s atmosphere is 95 per cent nitrogen — only about 18 per cent more than ours — and that the moon has an ethane cycle much like our water cycle: liquid ethane rains down, fills the lakes and rivers, and then evaporates to be rained down again. It has wind, experiences seasons, and may be our best shot at finding extraterrestrial life for a good long time. Then again, of course, it might not.

From a prescient Christian Science Monitor article on the odds of Titan sustaining life, published a remarkable six years ago:

For starters, Titan’s atmosphere is packed full of complex organic molecules. When sunlight (even as faint as the sun is all the way out around Saturn) travels through Titan’s atmosphere, it creates all kinds of interesting chemicals from the methane and ethane already there. We know that there’s acetylene, ethylene, and hydrogen cyanide in Titan’s air, the last of which was a very important molecule (we think) for getting life started on Earth. And there’s plenty of other gook floating around Titan’s atmosphere, including brownish, smoggy hydrocarbons that may actually precipitate and rain down on the surface into viscous, oily puddles. In short, the chemistry on Titan is a lot like what we think the early Earth was like.

One of the key requirements for creating life, it seems, is the presence of a liquid. In order for life to begin, large, complex molecules have to be given the chance to mix around and interact with each other. If everything is frozen solid in ice, there’s not much mixing to be had. If there’s nothing but gas around, the molecules don’t have much time to hang on to each other as they blow past each other in the air.

But liquid is just right for those kinds of interactions. In a liquid, molecules can mix, interact with each other, maybe even form longer, more complicated chains. With enough time and the right circumstances, the molecules may even learn to replicate themselves from smaller bits and pieces floating around in the muck. Let sit for a few million years, and lo and behold, you get DNA, or something similar. Life has begun.

Story via Slashdot.
Image via NASA.

• plug this post
  
  • Digg
  • del.icio.us
  • Facebook
  • NewsVine
  • Reddit
  • StumbleUpon
  • Technorati