The mysteries of Saturn’s moon Enceladus just get more puzzling… it’s been known for a while now that the water vapour/ice geysers at the south pole emanate from fissures where heat is continuously leaking, more than was thought possible for such a tiny world. Now, new data from the Cassini spacecraft shows that much more heat than that even is coming out of Enceladus’ interior.
The expected heat energy output from tidal heating, based on a 2007 study, was about 1.1 gigawatts (averaged out over time). Plus maybe another 0.3 gigawatts from natural radioactive heating. But the new results indicate an energy output of 15.8 gigawatts, about 2.6 times the energy from all of the hotsprings in Yellowstone, or 20 coal-fueled power stations. For a tiny, icy body like Enceladus, that’s amazing, and also makes it even more likely that the geysers originate from a subsurface sea or ocean. A salty one at that, as salts have already been found in the vapour/ice plumes, as well as organic molecules. What else might be lurking below?
Highlighted by, among other things, the next exoplanet update from Kepler in February and the launch of Curiosity, the next bigger and better Mars rover, in November, 2011 should also be an interesting year…
“Matson and his colleagues came up with a computer model that accommodates much of what is known about the geysers of Enceladus. Their findings support the supposition that a salty sea flows under the moon’s surface.
This ocean has gases dissolved in it, the theory goes. As the seawater flows up to and through the tiger stripe fissures, its pressure drops and the gases bubble up, Matson said — making the ocean fizzy, like Perrier. The relatively warm water and expanding gas feed the jets.
When the bubbles pop, they throw off a fine spray that contains salt and other materials, which Cassini spotted in Enceladus’ plumes. Then the seawater, having dumped much of its warmth on the moon’s surface ice, cools and sinks back through cracks, rejoining the ocean and its heat-transferring circulation system.”