JPL: Mimas May Hide a "Fossil" Core or an Ocean

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JPL: Mimas May Hide a "Fossil" Core or an Ocean

Post by bystander » Fri Oct 17, 2014 4:38 am

Saturn's Moon Mimas May Hide a "Fossil" Core or an Ocean
NASA | JPL-Caltech |Cassini | 2014 Oct 16
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. ...

Wobbling of a Saturn moon hints at what lies beneath
Cornell University | 2014 Oct 16

Constraints on Mimas’ interior from Cassini ISS libration measurements - R. Tajeddine et al
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Re: JPL: Mimas May Hide a "Fossil" Core or an Ocean

Post by geckzilla » Fri Oct 17, 2014 6:14 am

2014 is the year of subsurface oceans or something.
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Re: JPL: Mimas May Hide a "Fossil" Core or an Ocean

Post by Nitpicker » Fri Oct 17, 2014 6:26 am

... and things shaped something like a football ...

Interesting that the otherwise unexplained wobble is referred to as libration and not non-spherical perturbation.

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Re: JPL: Mimas May Hide a "Fossil" Core or an Ocean

Post by geckzilla » Fri Oct 17, 2014 6:37 am

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.
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Re: JPL: Mimas May Hide a "Fossil" Core or an Ocean

Post by Nitpicker » Fri Oct 17, 2014 6:51 am

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.
It was always a good discussion from my point of view, which as I recall, was pointier than some and not as pointy as others. :ssmile:

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Re: JPL: Mimas May Hide a "Fossil" Core or an Ocean

Post by geckzilla » Fri Oct 17, 2014 7:01 am

Sharper than round but blunter than sharp? (I totally stole this quote from Bones.)
Just call me "geck" because "zilla" is like a last name.

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