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Cassini at Hyperion
Take a look at the false-color image of Hyperion at http://saturn.jpl.nasa.gov/multimedi...m?imageID=1762 Note the bright, obliquely-angled surfaces forming a tilted, elongated 'C' shape. Does this look like an artifact of the image processing? A partial rim of a degraded old super-crater? The longer I look at it, the more puzzling it is. |
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"Monte Davis" wrote in message
... Take a look at the false-color image of Hyperion at http://saturn.jpl.nasa.gov/multimedi...m?imageID=1762 Note the bright, obliquely-angled surfaces forming a tilted, elongated 'C' shape. Does this look like an artifact of the image processing? A partial rim of a degraded old super-crater? The longer I look at it, the more puzzling it is. The fact that there are few impacts visible on the walls of the "crater" is really, really strange. That implies that the walls are young, but the central portion has an appearance similar to the rest of the surface. If it's a crater, how could the floor be old? If it's a degraded crater, what is the mechanism of degradation that allows walls with such a young appearance? It looks something like a slump structure of some kind -- but Hyperion is so small that I'm hard put to imagine the gravitational mechanics of any slump. I'll look for images of the other side of the moon. It's remotely possible that this is a "contrecoup" feature, generated by a impact on the far side that blew out a ring on the side we are viewing here. But it's profoundly unlikely that the "floor" would have settled back into the ring with so little disturbance. Interesting mystery. Jim McCauley |
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"Jim McCauley" wrote:
Hyperion is so small that I'm hard put to imagine the gravitational mechanics of any slump. Yup. When you don't have the, uhh, global simplification of gravity strong enough to pull things into a sphere, all sorts of one-of-a-kind weirdness are likely to ensue. |
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Jim McCauley wrote:
"Monte Davis" wrote in message ... Take a look at the false-color image of Hyperion at http://saturn.jpl.nasa.gov/multimedi...m?imageID=1762 Note the bright, obliquely-angled surfaces forming a tilted, elongated 'C' shape. Does this look like an artifact of the image processing? A partial rim of a degraded old super-crater? The longer I look at it, the more puzzling it is. The fact that there are few impacts visible on the walls of the "crater" is really, really strange. That implies that the walls are young, but the central portion has an appearance similar to the rest of the surface. If it's a crater, how could the floor be old? If it's a degraded crater, what is the mechanism of degradation that allows walls with such a young appearance? It looks something like a slump structure of some kind -- but Hyperion is so small that I'm hard put to imagine the gravitational mechanics of any slump. I'll look for images of the other side of the moon. It's remotely possible that this is a "contrecoup" feature, generated by a impact on the far side that blew out a ring on the side we are viewing here. But it's profoundly unlikely that the "floor" would have settled back into the ring with so little disturbance. Interesting mystery. For some reason, my previous reply did not get posted. The Feature you are talking about is the left side of what appears in the Voyager pics as a heart(valentine)-shaped ridge (scarp?). The right side is beyond the terminator and continues over the limb as seen in the recent Cassini pics. Just below the "V" of the valentine is a group of 4 large craters that are visible in the Voyager pics, too. The more I look at the new pics, the odder Hyperion seems. Part of it is that we're not used to the physics of this size-range of bodies. Gravity does still work here, don't worry (look closely at that scarp/ridge, and you can see in several places the fan-shaped signitures of landslides). It's getting pretty obvious that something catastrophic has occured in the Saturian system in the relatively recent past. My feeling is that a large moon was struck by another large body, perhaps in the final stage of the Formation Era. Hyperion was left as the largest chunk with a hell of a lot of debris scattered all through Saturnian orbit. Still leaves a lot of questions, though. |
#5
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