Wednesday, July 26, 2006
The Lakes of Titan
Waaayyyy back when, before Cassinin arrived at Saturn and Huygens landed on Titan, astronomers wondered about the high level of methane in Titans atmosphere. Methane doesn't last very long, in geological terms, before it is broken down by UV (incidentally creating lots of interestion organic compounds that might contribute to the origin of life). So where was the methane coming from? One idea was that Titan was covered in seas of Methane.
Then Cassini arrived, and while tantalising dark patches were found, no methane seas were evident. Huygens laned in a spot where it looks like methane rivers occasionally ran, and there was lots of evidence for fluid erosion, but no evidence of standing bodies of methane.
Now the radar imager of Cassini has sent back the best evidence of liquid methane. To quote the press release
Some of the dark patches and connecting channels are completely black, that is, they reflect back essentially no radar signal, and hence must be extremely smooth. In some cases rims can be seen around the dark patches, suggesting deposits that might form as liquid evaporates.This is seriously cool (pun intended). Maybe future missions will investigarte these patches in greater detail.
See also The Bad Astronomers take.