Europan Impact Structures Options

[algorimancer]

Mannann'an really intrigues me, there's some interesting stuff going on there (as seen in the post by ExploitCorporations http://conamera.byethost6.com/Exploitcorpo...ATER01_02w.jpg), That small feature in the center of the broader crater basin, with the radial cracks and more distal circumferential cracks ... I'm not sure whether to treat this as a crater within the larger crater basin, or perhaps the result of some subsequent internal activity, possibly a gas bubble discharge; I find it hard to believe that the small feature generated the larger crater basin. Oddly, I can find no papers referencing the high resolution images of Mannann'an crater, so this seems ripe for publication.

[volcanopele]

Mannann'an really intrigues me, there's some interesting stuff going on there (as seen in the post by ExploitCorporations http://conamera.byethost6.com/Exploitcorpo...ATER01_02w.jpg), That small feature in the center of the broader crater basin, with the radial cracks and more distal circumferential cracks ... I'm not sure whether to treat this as a crater within the larger crater basin, or perhaps the result of some subsequent internal activity, possibly a gas bubble discharge; I find it hard to believe that the small feature generated the larger crater basin.  Oddly, I can find no papers referencing the high resolution images of Mannann'an crater, so this seems ripe for publication.

Whew, I'm not the only puzzled by that part of Mannann'an. I'm not sure what to make of it other than perhaps a collapse pit (like the central pits in some Ganymedan craters).

[Decepticon]

It looks like the the object that impacted the surface did not punch threw!

[JRehling]

Whew, I'm not the only puzzled by that part of Mannann'an.  I'm not sure what to make of it other than perhaps a collapse pit (like the central pits in some Ganymedan craters).

Just a stab in the dark, but supposing that crustal thickness varied over various epochs in Europa's history as orbital evolution changed the tidal heat input. A crater with a central peak could be formed at T1, with the rim and peak supported by the crust at that time. Later, the crust thins out until very suddenly the peak collapses downwards.

Or, maybe Moe was trying to hit Larry with a lead pipe, and Larry ducked so that Moe hit Europa.

[vexgizmo]

Oddly, I can find no papers referencing the high resolution images of Mannann'an crater, so this seems ripe for publication.

Moore, J. M., E. Asphaug, M. J. S. Belton, B. Bierhaus, H. Herbert Breneman, C. R. Chapman, F. Chuang, G. C. Collins, B. Giese, R. Greeley, J. W. Head III, S. Kadel, K. P. Klaasen, J. E. Klemaszewski, K. P. McGee, J. Moreau, D. Morrison, G. Neukum, R. T. Pappalardo, C. B. Phillips, P. M. Schenk, D. A. Senske, R. J. Sullivan, E. P. Turtle, and K. K. Williams, Impact features on Europa: Results of the Galileo Europa Mission, Icarus, 151, 93-111, 2001.

See pages 99-103 for initial results, but there is certainly more to do!

[algorimancer]

Moore, J. M., E. Asphaug, M. J. S. Belton, B. Bierhaus, H. Herbert Breneman, C. R. Chapman, F. Chuang, G. C. Collins, B. Giese, R. Greeley, J. W. Head III, S. Kadel, K. P. Klaasen, J. E. Klemaszewski, K. P. McGee, J. Moreau, D. Morrison, G. Neukum, R. T. Pappalardo, C. B. Phillips, P. M. Schenk, D. A. Senske, R. J. Sullivan, E. P. Turtle, and  K. K. Williams, Impact features on Europa: Results of the Galileo Europa Mission, Icarus, 151, 93-111, 2001.

See pages 99-103 for initial results, but there is certainly more to do!

I stand corrected I don't agree 100% with their conclusions, but overall they've done a good job of analysis.

[JRehling]

I stand corrected   I don't agree 100% with their conclusions, but overall they've done a good job of analysis.

So you know, vexgizmo is one of the "they"

[Exploitcorporati...]

The high-resolution mosaic of Tyre is one of my favorite Galileo images (minus the ugly gap right in the middle of the basin). Although this was a rare example of a mosaic released in its entirety by NASA/JPL, I'm posting my take on it anyway, along with a new colorized version from the G7 data.

14ESTYREHR01

Tyre in color

[Decepticon]

That white fault line seems to be the youngest feature in this image.

[ljk4-1]

That white fault line seems to be the youngest feature in this image.

Have exogeologists been able to judge the age of Europa's ice crust by figuring out how long it would take an impact crater such as this latest one presented to deform into the shape it has, taking into effect the moon's average surface temperatures, the amount of pull it gets from Jupiter and the other Galilean moons, and how that type of ice is affected out there?

Can they also tell how thick the crust is from such formations?

[algorimancer]

Have exogeologists been able to judge the age of Europa's ice crust by figuring out how long it would take an impact crater such as this latest one presented to deform into the shape it has, taking into effect the moon's average surface temperatures, the amount of pull it gets from Jupiter and the other Galilean moons, and how that type of ice is affected out there? 

Can they also tell how thick the crust is from such formations?

I've certainly seen modeling in that direction, however it turns out that there are a lot of unknowns which get in the way of that sort of detail. The viscosity of the ice is going to vary with the ice shell thickness as a function of latitude and possibly longitude, as well as the weakly constrained internal heat from radioactive decay and tidal dissipation. Add-in the mobility of the ice shell, and I think it would be very difficult to get a good time frame based upon topography. Now if we could get an orbiter for global hires imaging plus radar sounding, plus drop a few landers to directly measure some surface properties, we may eventually be in a position to unravel the history in quite a lot of detail. Tell your congressman

[vexgizmo]

The high-resolution mosaic of Tyre is one of my favorite Galileo images (minus the ugly gap right in the middle of the basin).

Beautiful! Are you able to do a reprojection that retains the true near-circular shape of Tyre? BTW, the ugly gaps (here, and also in the E14 Wedges mosaic) were related to degradation of the Galileo gyros, which led to poor scan platform pointing.

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-Bob P.