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

[geckzilla]

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?

[chmonori]

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

[zoomer]

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.

[Chris Peterson]

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.

[ta152h0]

driving a windshield thru a sandstorm.

[neufer]

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.

[Chris Peterson]

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.

[Steen Thomsen]

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