NASA-funded Study Says Saturn's Moon Enceladus Rolled Over (JPL)

[eppur_se_muova]

NEWS - News Releases - 2006
NASA-funded Study Says Saturn's Moon Enceladus Rolled Over
May 31, 2006
(Source: Jet Propulsion Laboratory / University of Santa Cruz, Calif. / University of Colorado, Boulder)

Saturn's moon Enceladus -- an active, icy world with an unusually warm south pole -- may have performed an unusual trick for a planetary body. New research shows Enceladus rolled over, literally, explaining why the moon's hottest spot is at the south pole.
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"The mystery we set out to explain was how the hot spot could end up at the pole if it didn't start there," said Francis Nimmo, assistant professor of Earth sciences, University of California, Santa Cruz.

The researchers propose the reorientation of the moon was driven by warm, low-density material rising to the surface from within Enceladus. A similar process may have happened on Uranus' moon Miranda, they said. Their findings are in this week's journal Nature.

"It's astounding that Cassini found a region of current geological activity on an icy moon that we would expect to be frigidly cold, especially down at this moon's equivalent of Antarctica," said Robert Pappalardo, co-author and planetary scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "We think the moon rolled over to put a deeply seated warm, active area there." Pappalardo worked on the study while at the University of Colorado.

Rotating bodies, including planets and moons, are stable if more of their mass is close to the equator. "Any redistribution of mass within the object can cause instability with respect to the axis of rotation. A reorientation will tend to position excess mass at the equator and areas of low density at the poles," Nimmo said. This is precisely what happened to Enceladus.
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more: http://saturn.jpl.nasa.gov/news/press-release-details.cfm?newsID=662

[jeff30997]

1. Thanks for posting eppur_se_muova!

I love science and in particular astronomy!

[MikeNearMcChord]

2. Do you ever go to the NASA site

Astronomy Picture of the day?
http://antwrp.gsfc.nasa.gov/apod/astropix.html
Great pictures on that site!

[eppur_se_muova]

5. Direct link to NASA site, lots of links to graphics:

http://www.nasa.gov/multimedia/imagegallery/index.html

and Space.com has their own image of the day:
http://www.space.com/imageoftheday/image_of_day_060602.html

[MikeNearMcChord]

7. Thanks, I got them bookmarked

I see the National Geographic is going to do a special on the Space Race, which I will be sure to see.

[havocmom]

3. Hasn't earth flipped a time or two? Poles in different places than now?

Really cool that they are discerning this about other planetary bodies.

I saw a really cool site with funny sayings attributed to God. One of my favorites:

Want to know my ways? READ A SCIENCE BOOK! ~ God

[htuttle]

4. The Magnetic poles move all over the place

IIRC, the actual rotational axis has only ever moved a few degrees from what we know.

The continents themselves have cruised all over the planet over the last few billions years, so Antarctica was much closer to the equator at one point -- but not because the axis flipped.

[mike_c]

6. one can only imagine what stresses must have roiled the surface...

...during the flip. I mean, the momentum of surface rotation was wrenched to a new angle!