Saturn's tiny icy moon Enceladus boasts at least 101 geysers, NASA scientists say. Researchers have spent more than seven years plotting the moon's eruptions, and now they think they've spotted and charted them all. The new research has also offered some clarity as to what they are and where they come from.
The research into Enceladus's geysers was carried out by Cassini, NASA's hard-working, Saturn-centric space probe -- which has been studying the ringed giant and its many moons for more than ten years.
Since they were first spotted in 2005, scientists have understood the geysers to be some sort of eruption, but they've been at odds over whether the spewed material is solid surface matter exploded as the result of friction or liquid sprayed through surface cracks from the moon's subsurface ocean.
The new infrared analysis technique that allowed scientists to locate and map Enceladus geysers has also offered clues as to their origin. Using Cassini's heat-sensing instruments, scientists were able to correlate the moon's individual geysers with small-scale hot spots -- hot spots too small to be the byproduct of frictional heating, but just the right size to be cause by warm vapor escaping through surface vents.
"Once we had these results in hand, we knew right away heat was not causing the geysers, but vice versa," explained Carolyn Porco, a researcher at the Space Science Institute in Boulder, Colorado, and leader of NASA's Cassini imaging team. "It also told us the geysers are not a near-surface phenomenon, but have much deeper roots."
Porco is the lead author of one of two papers on Enceladus's geysers, both published recently in the current online edition of the Astronomical Journal.
If the geysers really are ocean vapors shot through small cracks in the surface, it suggests a probe could one day collect these vapors without having to touch down on the moon's surface. That's an exciting possibility for astronomers who've long suggested Enceladus offers the best chance at locating alien life within the solar system.