Friday, October 22, 2010

More on Titan

So, we've been getting a ton of information on Titan--for good reason--since it gives strong evidence of Earth's burgeoning atmosphere in the throes of planetary formation several billion years ago, in the Hadean eon, named for how ruthlessly chaotic it was.

Titan: not so much.

A few facts we know right off the bat about Titan we've learned, tying it closer to our own planet:

Largest moon of Saturn.
It is the only moon we know of with a fully developed atmosphere.
When it comes to atmospheric pressure, Titan is the Earth's closest relative, just one and a half times thicker (1).
It was the site of the first ever, up close picture of extra-terrestrial liquid (whaat?)
It's still really cold (-178 celsius?!) (2)

So let's get to the heart of astronomy: what could it be?

Already, many astronomers are itching to find out how similar the atmosphere is to Earth and what it can tell us about our early Earth's atmosphere.

We've figured out that its atmosphere is "controlled by five major processes: CH4 photolysis and photosensitized dissociation, H-to-H2 conversion and hydrogen escape, higher hydrocarbon synthesis, nitrogen and hydrocarbon coupling, and oxygen and hydrocarbon coupling" (3). We've learned about photolysis/photosensitized dissociation--the process by which compounds are broken up by photons, as well as the basics of escape due to thin atmospheric conditions and low-gravity--and the combinations here contribute to its familiar atmospheric composition.

However, there's also something to look for in Titan's haze. Many point to it as the lifeblood of the planet--a haze that could have very easily influenced our own planet's life-origin. In fact, scientists have begun working on trying to imitate the haze of Titan through analogous lab-produced aerosol (4). They explain that when sunlight hits a methane/nitrogen atmosphere, this type of aerosol is produced--so this could be the start of an experiment much like the aforementioned Miller-Urey experiment.

With all of the similarities seen, including Galia's recent post mentioning the possible similarities between a methane weather cycle and our own Earth's water cycle as well as last week's discussions of Mars, it seems that we could afford to spend more money looking at Mars and Titan to understand our own origins.

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