Monday, September 23, 2013

Saturn's Moon Titan Might Explain How Life Started on Earth


A fisheye view of Titan from about 3 miles above the surface.

Titan is an intriguing world. The largest moon orbiting the ringed planet Saturn, its rich nitrogen and methane atmosphere produce hydrocarbons that rain down on the dunes and fields that lie over an underlying bedrock of water ice. It has, in short, the building blocks for life. But for all its intriguing potential, we’ve only visited this moon once in 2005 with the Huygens probe. But there may soon be a stronger reason to return. In a talk last week at the 246th National Meeting & Exposition of the American Chemical Society, Jonathan Lunine form Cornell and his team presented an interesting idea: Titan might be the laboratory scientists need to understand and explain how life arose on our planet. 

Exactly how life sprung up on Earth is a bit of a mystery, but scientists generally agree the story goes something like this: the early Earth had the right kind and amount of simple organic chemicals. As energy was added to this so-called primordial soup, in the form of either sunlight or lightning,  these simple chemicals underwent a series of reactions that yielded increasingly complex chemicals. At some point, this chemically complex soup crossed a threshold and the compounds within developed the ability to reproduce themselves. Over many generations, these self-replicating compounds eventually developed into the first DNA strands, forming the first simple organisms. Life had begun. 

The main problem with this theory is that it’s really hard to test. Running a billion-year experiment is just plain impractical. And there’s the problem of getting the right primordial matter. All organic matter on Earth have been cycled through living things for billions of years, so we don’t really have the right pre-life matter to study.
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