Starship Asterisk*

[url=http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA12569]This mosaic[/url] of Saturn's moon Mimas was created from images taken by NASA's Cassini spacecraft during its closest flyby of the moon on Feb. 13, 2010. [b][i]Image credit: NASA/JPL-Caltech/Space Science Institute[/i][/b]

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A new study focused on the interior of Saturn's icy moon Mimas suggests its cratered surface hides one of two intriguing possibilities: Either the moon's frozen core is shaped something like a football, or the satellite contains a liquid water ocean.

Researchers used numerous images of Mimas taken by NASA's Cassini mission to determine how much the moon wobbles as it orbits Saturn. They then evaluated several possible models for how its interior might be arranged, finding two possibilities that fit their data.The study is published in the Oct. 17 issue of the journal Science.

"The data suggest that something is not right, so to speak, inside Mimas," said Radwan Tajeddine, a Cassini research associate at Cornell University, Ithaca, New York, and lead author on the paper. "The amount of wobble we measured is double what was predicted."

Either possiblity for the interior of Mimas would be interesting, according to Tajeddine, as the moon's heavily cratered outward appearance does not suggest anything unusual lies beneath its surface. Because Mimas formed more than four billion years ago, scientists would expect its core to have relaxed into a more or less spherical shape by now. So if Mimas' core is oblong in shape, it likely represents a record of the moon's formation, frozen in time.

If Mimas possesses an ocean, it would join an exclusive club of "ocean worlds" that includes several moons of Jupiter and two other Saturn moons, Enceladus and Titan. A global ocean would be surprising, said Tajeddine, as the surface of Mimas does not display signs of geologic activity. ...

• Science 346(6207) 322 (17 Oct 2014) DOI: 10.1126/science.1255299

geckzilla wrote:Haha, I forgot all about the football thing until you brought it back up just now. That's surely falling into so-bad-it's-good territory by this point.