Dawn's Survey Orbit at Ceres |
Dawn's Survey Orbit at Ceres |
Jun 15 2015, 05:47 PM
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Senior Member Group: Members Posts: 1729 Joined: 3-August 06 From: 43° 35' 53" N 1° 26' 35" E Member No.: 1004 |
daily Ceres picture from the survey orbit
http://dawn.jpl.nasa.gov/multimedia/images...tml?id=PIA19572 I started a new topic, as we are no longer in the first orbit phase |
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Jun 22 2015, 02:42 AM
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#2
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Member Group: Members Posts: 890 Joined: 18-November 08 Member No.: 4489 |
QUOTE Perhaps at a large enough kinetic energy an impact breaks through the crust into the subsurface ocean and allows the floors to be filled for a very short period of time. Over time the crust has become thicker and so more kinetic energy is needed to break on through to the other side - the subsurface ocean and allow flows to occur. The deeper the ocean, the shorter the time before the opening freezes again. this thing is way too small and there is no "jupiter" to tug at it it has been a solid bit of ice and rock for a VERY long time and has been DEEP COLD for a very long time impacts on "high ice " content are VERY different than on a rock or on nickel /iron you get very FLAT floors on the impacts in ices |
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Jun 22 2015, 06:49 PM
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#3
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Member Group: Members Posts: 112 Joined: 31-January 15 From: Houston, TX USA Member No.: 7390 |
this thing is way too small and there is no "jupiter" to tug at it it has been a solid bit of ice and rock for a VERY long time and has been DEEP COLD for a very long time impacts on "high ice " content are VERY different than on a rock or on nickel /iron you get very FLAT floors on the impacts in ices Yes, I agree that at those temperatures ice is harder than rock. Ceres surface today looks old to me, so I don't believe there are any active flows going on right now. However, subsurface there are other factors that *could* be working to make water slush (or water), which could then get exposed by high kinetic energy impacts. As Gerald said long lived radioactive isotopes can provide some heat. While tidal heating isn't possible, the pressures under the crust can provide pockets of heating. Throw in some speculated salts and now the freezing point of the liquid is a little lower. Then add in heat transfer from a high energy object impacting and there could be enough heat for a water flow to occur with a large high velocity impact. As for how the flow would look, I would expect a wave-like feature that freezes rather quickly. Maybe something like the southern rim of this crater? (Provided by user eliBonora) https://www.flickr.com/photos/lunexit/18344202083/ All that said, I'm willing to wait for the detailed gravity measurements to see if there is a possibility that Ceres still has anything liquid in its interior. Andy |
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