Saturn's Moon Enceladus Has an Atmosphere

Dimentox writes "The Mercury News reports that the international Cassini spacecraft has discovered that Saturn's moon Enceladus has a significant atmosphere, NASA said Wednesday. The icy moon's atmosphere may be created by volcanism, geysers or gases escaping from the surface or the interior, the space agency's Jet Propulsion Laboratory said. Excluding Saturn's giant moon Titan, which was already known to have an atmosphere, it's the first discovery of an atmosphere on one of the more than 30 moons that orbit the ringed planet."

Comments

Re:Well, for one thing

[Rei]

The link says that it's made of water vapor, but doesn't give a density. It's interesting, because Europa (a seemingly similar moon - it has the same sort of wrinkled surface) has a *very* tenative (about 1/100,000,000,000th of 1 atmosphere) water vapor and oxygen atmosphere from the sublimation of ice and the breakdown of water from interaction with the solar wind.

I'd imagine that this atmosphere is notably more significant than Europa's, or they wouldn't have described it as they did. And, with less solar energy at these distances, they're speculating that the source is from internal heating causing water geysers. That's really rather fascinating, when you think of it - now we know of another moon with a likely subsurface sea. The moon is a lot smaller than Europa, but it probably has more significant internal heating for its size.

Plus, the saturnian system has a lot of interesting organics - Titan is virtually a drifting mobile organic chemistry lab in its upper atmosphere. Even neglecting Titan, there's the unknown dark organics on Iapetus, Phoebe, and in the rings, among other places.