Friday, May 27, 2005
At Saturn: Things Worth Watching
For any science geeks out there, the Cassini web site has a few new items worth checking out. Watch the movie of the small moon making waves in the rings if you haven't done so already. A "hot spot" on Titan is pondered. ("Hot" being relative; it would still chill your frosty beer mug quite effectively.) Is it a weather system? Is it molten water gushing from Titan's subsurface?
I'm suspicious of a weather system staying in one place for a long time; that only happened in fairy tales. There's speculation that a warm weather system is trapped by mountains, but there's a problem with that hypothesis. On other outer solar system moons with cryovulcanism (volcanic activity based on liquid water, not liquid rock) tides from other moons are most often responsible for producing the internal heat that leads to volcanos and geysers. (Triton, moon of Neptune, being one exception: it has black nitrogen geysers, but on a fairly small scale.) Titan is the only moon of substantial size in the Saturn system. It's one thing for a moon the size of a city to make ripples in rings: these moons within tens of miles of the scallopped waves they produce. Is Titan large enough to hold residual heat? Earth volcanoes are powered by radioactivity. (Did you know that?) Mars' volcanoes have nearly died out because the planet is only about one tenth the heft of earth. Titan, though big, has only a fraction of the bulk of Mars. What is its heat source?
Pretty pictures, too. Check out the various shots of Saturn and rings. The archives are full of them. Nice color reproductions here and there, too.
