Thursday, March 09, 2006
Who could have conceived of this? A Cassini press release gives the story, possibly the biggest of the Cassini mission thus far: "Our search for liquid water has taken a new turn. The type of evidence for liquid water on Enceladus is very different from what we've seen at Jupiter's moon Europa. On Europa the evidence from surface geological features points to an internal ocean. On Enceladus the evidence is direct observation of water vapor venting from sources close to the surface," said Dr. Peter Thomas, Cassini imaging scientist, Cornell University, Ithaca, N.Y. Remember that Enceladus is not just an over-sized ice cube. This is about 325 degrees below zero--on the surface. They're talking about reservoirs of water just a few dozen feet under the surface. Here's a proposed model for the geyser: This water could be easily accessed by 22nd century explorers. Of course, there's so much water ice in the outer solar system, there would never be any lack of drinking water. (So much for those silly ice pirate science fiction notions.) Drinking water, assuming, of course, one had purification equipment and a reliable heater. I wouldn't want to drink the unfiltered tap water on Titan. Nothing like a little acetylene and cyanide to give your drink a bit of a kick.
Cassini also found an interesting temperature profile across one of the "tiger stripes." Those temperature readings are on the Kelvin scale, or degrees above absolute zero. Your living room is about 292K, just as a reference.
James Oberg from MSNBC is pretty excited about this. He's talking about a sample return mission already. I'm not as optimistic about finding life on Enceladus. Those northern hemisphere craters look pretty old--billions of years. Whatever is serving as the heat engine on Enceladus isn't touching the northern hemisphere at all. The geyser process on Enceladus might be very intermittent. If those pools have ever frozen for a few million years, you can probably kiss goodbye the chance of finding life.