APOD: Saturns Hyperion: A Moon with Odd... (2013 Jun 30)

Comments and questions about the APOD on the main view screen.
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Re: APOD: Saturns Hyperion: A Moon with Odd... (2013 Jun 30)

Post by geckzilla » Mon Jul 01, 2013 1:00 am

swimmerscott1956 wrote:I think it is a comet that was captured by Saturn's gravity, and has reached a thermodynamic state of equilibrium where no more outgassing is possible at this time. It looks just like pictures of the other comets from the last ten years or so.
What comet would you say it looks just like?
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Re: APOD: Saturns Hyperion: A Moon with Odd... (2013 Jun 30)

Post by chmonori » Mon Jul 01, 2013 4:25 am

Personally I don't see any dark material in the craters, just very deep funnel like craters with ordinary shadows.

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Re: APOD: Saturns Hyperion: A Moon with Odd... (2013 Jun 30)

Post by zoomer » Mon Jul 01, 2013 5:49 am

swimmerscott1956 wrote:I think it is a comet that was captured by Saturn's gravity, and has reached a thermodynamic state of equilibrium where no more outgassing is possible at this time. It looks just like pictures of the other comets from the last ten years or so.
Full agreement on captured comet. Additionally most of the 'craters' look to me shaped more like rocket nozzles, as you might expect pressurized outflow gasses to create. Further, I cannot think of craters forming this pattern or these angles of impact.

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Re: APOD: Saturns Hyperion: A Moon with Odd... (2013 Jun 30)

Post by Chris Peterson » Mon Jul 01, 2013 2:34 pm

zoomer wrote:Full agreement on captured comet. Additionally most of the 'craters' look to me shaped more like rocket nozzles, as you might expect pressurized outflow gasses to create. Further, I cannot think of craters forming this pattern or these angles of impact.
It's very large for a comet, and it's location and low inclination argue against a capture. It seems more likely to me that we're looking at an original moon, altered by a collision. A body need not be a comet to show evidence of venting; many of Saturn's moons are icy bodies, similar in some respects to comets.
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Re: APOD: Saturns Hyperion: A Moon with Odd... (2013 Jun 30)

Post by ta152h0 » Mon Jul 01, 2013 3:56 pm

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Re: APOD: Saturns Hyperion: A Moon with Odd... (2013 Jun 30)

Post by neufer » Mon Jul 01, 2013 10:16 pm

Chris Peterson wrote:
zoomer wrote:
Full agreement on captured comet. Additionally most of the 'craters' look to me shaped more like rocket nozzles, as you might expect pressurized outflow gasses to create. Further, I cannot think of craters forming this pattern or these angles of impact.
It's very large for a comet, and it's location and low inclination argue against a capture. It seems more likely to me that we're looking at an original moon, altered by a collision. A body need not be a comet to show evidence of venting; many of Saturn's moons are icy bodies, similar in some respects to comets.
Also note that with chaotic rotation Hyperion currently undergoes considerable tidal stretching as compared with tidally locked/low eccentricity moons. This produces strong internal heating as compared with the external heating of a comet.
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Re: APOD: Saturns Hyperion: A Moon with Odd... (2013 Jun 30)

Post by Chris Peterson » Mon Jul 01, 2013 10:22 pm

neufer wrote:
Chris Peterson wrote:
zoomer wrote:
Full agreement on captured comet. Additionally most of the 'craters' look to me shaped more like rocket nozzles, as you might expect pressurized outflow gasses to create. Further, I cannot think of craters forming this pattern or these angles of impact.
It's very large for a comet, and it's location and low inclination argue against a capture. It seems more likely to me that we're looking at an original moon, altered by a collision. A body need not be a comet to show evidence of venting; many of Saturn's moons are icy bodies, similar in some respects to comets.
Also note that with chaotic rotation Hyperion currently undergoes considerable tidal stretching as compared with tidally locked/low eccentricity moons. This produces strong internal heating as compared with the external heating of a comet.
Exactly. I'm not sure if the total heat generated is more or less with a rubble pile or a rigid body, but in either case there will be heating. And that's after any heat generated by a collision. I think there are plenty of opportunities for an icy moon to outgas similar to a comet under the right conditions.
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Re: APOD: Saturns Hyperion: A Moon with Odd... (2013 Jun 30)

Post by Steen Thomsen » Sat Sep 14, 2013 6:30 pm

Those craters ceartainly look like cryoconite holes.
http://www.danbbs.dk/~stst/glaciologi/s ... oniteHoles

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