| Page 2 of 2 < |
Lakefront Property on a Saturn Moon?
Cassini's mission, which is overseen by NASA, is the work of 17 nations. The European Space Agency built and contributed a mechanical explorer called the Huygens Probe, which parachuted onto Titan's surface on Jan. 14, 2005. Data from the probe revealed the methane drizzle reported last week.
Despite the dramatic, ringed appearance of Saturn, the environs of that huge gas planet are pretty gloomy. Saturn and its moons get one-tenth the solar radiation Earth does.
  The first detailed photographs of high latitudes of Titan, which is a moon of Saturn, showed what appear to be dunes, hills, valleys and rivers running into lakes. If the dark, ovoid features on the landscape are indeed lakes, Titan would be the only body in the solar system besides Earth to have that geological feature. But the liquid that runs into the lakes from the sky isn't water -- it's probably a form of liquid hydrocarbon. (Nasa Jet Propulsion Laboratory) |
Titan's atmosphere is four times as dense as Earth's at sea level, further blocking sunlight. To top things off, it has a serious smog problem.
Hydrocarbons evaporate off Titan's surface and recondense in clouds. During that process, some molecules react with sunlight, just as happens in Earth's smoggy cities. Because there is little oxygen on Titan, the compounds are different and even more unappealing.
"They are ethane, acetylene, benzene, hydrogen cyanide -- things that go out the fume hood of an organic chemistry lab so that people don't drop dead," Lunine said.
The area with the lakes and streams, which is about the size of Australia, was first seen by the Hubble Space Telescope in 1994 through infrared imaging. It was named Xanadu.
The images gathered by Cassini this month were made with radar waves, not with visible light. The scientists are not positive the smooth, black areas in the images are liquid. But they have the same appearance that smooth bodies of water have on Earth when photographed with radar-frequency waves.
The spacecraft has time to confirm this impression with further studies. It will orbit Saturn at least until late 2008 and, perhaps, a few years longer if all goes well.
-- David Brown
