Crater Questions

[Tom128]

Continuing on my walk about at the South Pole perimeter of the ACT-REACT map, I came across Jabba the Hutt from Star Wars.  He must have escaped to the Moon.  Jabba is about 10 miles wide and 16 miles long.



Can't even guess how this crater formation was formed but I did find a scarp-like object near Jabba's tail.



http://target.lroc.asu.edu/da/qmap.html?mv=orthosp&mcx=-84272.25&mcy=-829724&mz=7&ml=FTFB00TT    -174.31103, -61.01529



 

[placidstorm]

Hey Tom128 ,
  Walk around the south pole ? Hope ya packed a lunch .

  Do you know the name of this crater ?

ACT -164.28666 lon 21.87893 lat

  I'm lookin for the moon realtor , I wana buy it .

[jules]

Jackson Crater! Really clear terracing. Classic!

[Tom128]

Interesting bench crater with white ray.



ACT-REACT http://target.lroc.asu.edu/da/qmap.html?mv=eqc&mcx=713899.25&mcy=458452.25&mz=16&ml=FFFB00TT

NAC photo strip http://wms.lroc.asu.edu/lroc/view_lroc/LRO-L-LROC-3-CDR-V1.0/M106726654RC

[Tom128]

Check this out.  An ejecta ray blocking boulder 



ACT-REACT http://target.lroc.asu.edu/da/qmap.html?mv=eqc&mcx=617574&mcy=432424.25&mz=16&ml=FFFB00TT

NAC photo strip http://wms.lroc.asu.edu/lroc/view_lroc/LRO-L-LROC-3-CDR-V1.0/M139775235LC

[jules]

Nice find!

[placidstorm]

Was this a volcano ?

lon -163.04123 lat 22.04023 @ 8 m/p

A lil n/e of crater

lon -163.01900 lat 22.06397 @ 2 m/p
 
And a lil n/e of that

lon -163.01481 lat 22.06864 @ 0.5 m/p

[Tom128]

Some incredible examples of impact melt and flow at Weiner F crater.





ACT-REACT http://target.lroc.asu.edu/da/qmap.html?mv=eqc&mcx=4547539.57635&mcy=1260609&mz=10&ml=FFFB00TT

http://target.lroc.asu.edu/da/qmap.html?mv=eqc&mcx=4558571.57635&mcy=1258161&mz=12&ml=FFFB00TT

http://target.lroc.asu.edu/da/qmap.html?mv=eqc&mcx=4553481.57635&mcy=1264353&mz=13&ml=FFFB00TT


I had to add this last photograph of a dark flow moving down into the lower crater.



ACT-REACT http://target.lroc.asu.edu/da/qmap.html?mv=eqc&mcx=4555290.57635&mcy=1255465&mz=12&ml=FFFB00TT

It does not look like a debris/rock slide when viewed up close on NAC photo strip http://wms.lroc.asu.edu/lroc/view_lroc/LRO-L-LROC-3-CDR-V1.0/M143641913LC  Maybe some type of secondary flow.  Could be shadow as well but seems odd to be the only one like that in the area. 

[placidstorm]

 ok this is fun .
blue is possible impact sights roman numereled in order of hitting . With red arrows and lines indicating direction of flow .

 
Now more than likely i have this wrong but hey , Begginer ...
Looks to me #1 hit then , #2 , possibly a double splat on the side of the big crater throwing the melt over the rim to make your shadow .
Then #3 comes in and cap's of the norther edge's .


                                                      I'm with the guy who said we learn more from our mistakes    were workin on a phd.rongness

[IreneAnt]

Hi Jules,
I think what we are seeing is not an ejecta ray but a linear impact melt flow or splash.

Hey Tom,

Sorry for the long delay. I was away camping with the family (no internet).

Anyway, this is exactly what we are seeing. These wedge shaped melt flows that happen after the ejecta is emplaced and landing on top of the ejecta deposit. That's the interesting thing. Some of these wedge shapes aren't an absence of ejecta, but an extra layer of melt on top!!

[IreneAnt]

Some incredible examples of impact melt and flow at Weiner F crater.

I love this image Tom128. It reminds me of the surface of Ganymede (moon of Jupiter), which looks a lot like this in places.

[IreneAnt]

 ok this is fun .
blue is possible impact sights roman numereled in order of hitting . With red arrows and lines indicating direction of flow .

 
Now more than likely i have this wrong but hey , Begginer ...
Looks to me #1 hit then , #2 , possibly a double splat on the side of the big crater throwing the melt over the rim to make your shadow .
Then #3 comes in and cap's of the norther edge's .


                                                      I'm with the guy who said we learn more from our mistakes    were workin on a phd.rongness

Hi Placidstorm,

I'm a bit confused. I don't see craters at any of the "impact sites" you have marked here. What I am seeing is a lot of impact melt, all coming from this one large crater. Any later, smaller craters would not have created as much impact melt as we see here.

However, your mapping of the linear features on the melt is really spot on. Though you should keep in mind that not all of these are flow features. Some of them are cooling cracks or underlying topography (in the ejecta) showing through. And I think the flow direction here is always away from the crater rim. You can get some minor flow back towards the rim if the melt is splashed onto a local topographic rise of some kind, but I don't see any evidence of that here.

Keep up the good work. The only way to learn (for me too) is to look at this stuff, a lot!

[IreneAnt]

Check this out.  An ejecta ray blocking boulder 



ACT-REACT http://target.lroc.asu.edu/da/qmap.html?mv=eqc&mcx=617574&mcy=432424.25&mz=16&ml=FFFB00TT

NAC photo strip http://wms.lroc.asu.edu/lroc/view_lroc/LRO-L-LROC-3-CDR-V1.0/M139775235LC

This is really interesting Tom 128, because the boulder really shouldn't affect the placement of the ejecta all that much. When the crater is being formed, ejecta is being thrown out from closer to the centre, so the boulder would be too far away to affect the ejection of material. And, when the material lands, it is thought to land from above (not sideways), so again, the boulder shouldn't affect the emplacement of ejecta material.

Very interesting. I need to think about this more.

By the way, for a better understanding of the impact process, with regards to ejecta formation and emplacement, check out the first half of this video:
http://www.youtube.com/watch?v=GmKWYPWTo9o

[Tom128]

Hi Irene,

Maybe there are two waves of ejecta one that rises up and out and one that moves out horizontally closer to the surface similar to the debris wave of a collapsing building.  I was thinking that perhaps this surface wave is following the contour of the crater up the wall at an angle hitting the boulder and forming the pattern. There may be  split second delay between the two waves- impact up and out from the center like you shared and the other following a surface trajectory. May account for the ejecta sculpting we see so close to these craters with fresh white craters, etc.  Pretty strange that the area devoid of ejecta looks like a ray.

That is one cool video of the simulated impacts 

This is really interesting Tom 128, because the boulder really shouldn't affect the placement of the ejecta all that much. When the crater is being formed, ejecta is being thrown out from closer to the centre, so the boulder would be too far away to affect the ejection of material. And, when the material lands, it is thought to land from above (not sideways), so again, the boulder shouldn't affect the emplacement of ejecta material.

Very interesting. I need to think about this more.

By the way, for a better understanding of the impact process, with regards to ejecta formation and emplacement, check out the first half of this video:
http://www.youtube.com/watch?v=GmKWYPWTo9o

[jules]

Could the boulder have fallen back after the main ejecta event throwing up fresher darker material? I suppose it could have even been thrown there by a completely different impact elsewhere at a much later time.