JasonColeman.com: Meet Enceladus. . .

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March 9, 2006

Meet Enceladus. . .

I would like to introduce you all to Enceladus, a small icy moon of Saturn and, apart from the Sun, one of the "brightest" objects in our solar system (Enceladus has an albedo of >0.9, in contrast the Earth has an albedo of about 0.3.)

Enceladus is making news today because NASA's Cassini spacecraft is making it's closest approach yet to Saturn's satellite, and Cassini has made some remarkable discoveries in the small (approx. 500 km across) moon. Volcanic forces are present on Enceladus, forces which are warming the interior of the small moon and in turn warming the liquid under the sheet of ice which encapsulates the moon. Further, all the evidence indicates that this liquid is actually water. That's right kiddies, liquid water, not ice, not liquid methane, not liquid sulphur, but actual liquid water is believed to have been found and confirmed, not just theorized, on another body in our very own solar system.

Astronomically speaking, this is the equivalent of man's discovery of fire. This is the big one, a discovery that may forever change how we look at the night sky and a discovery which brings the possibility of life exterestrial life out of the realm of science fiction and closer to the realm of science fact.

Since it's discovery by Herschel in 1789, it was tought that Enceladus was just another rocky, icy orb out in the "middle part" of our solar system. Enceladus was too small for radioactive decay to heat the little planet's core and it was though to be just another rock with an icy crust.

Enter Dione, another of Saturn's moons and one which is locked in resonance with Enceladus. Dione's close proximity to Enceladus has caused perturbations in it's partners orbit and gravitational forces have been tugging away at the moons inards and in turn producing heat, heat which causes volcanism, volcanism which keeps the subsurface sea of Enceladus warm enough to keep liquid water stable.

This is truely a remarkable event, and I'll be updating more today as this story develops.

--Jason

UPDATE: The story of Enceladus has all the earmarks of a great detective thriller. Late last year, scientists began to notice that Enceladus was geologically active. As mentioned above, this was curious because of Enceladus' small size, but it was the interference of Dione which turned out to be the culprit.

Next we find that there's fresh snow on Encelaus' surface, as the liquid beneath the ice caps escapes as vapor only to be frozen solid in the cold of space and fall back onto the tiny world. When scientists turned their attention to this bizarre little world, more and more startling discoveries awaited.

The Saturn system was awash in Oxygen molecules, a very strange occurance to find so far out into the solar system. Turns out, Enceladus was outgassing water vapor which breaks down into, of course, hydrogen (very common out in the ether) and oxygen (very unusual to find out in the inky black). Following the oxygen back to it's source led to the discovery of liquid water on Enceladus.

Images: Enceladus via Voyager - "false-color" enhance image from Cassini

Solarviews.com page on Enceladus.

NASA's Cassini-Huygens page on Enceladus.

In Janurary 2002, Enceladus hit the APOD with the headline "Ski Enceladus".

-JC

Posted by JasonColeman at March 9, 2006 12:52 PM