Starship Asterisk*

GiacomoFalcucci wrote:Dear All,

Good morning!
What stunning images!!

Who casts the shadows in Norgay region?
Is it the Sun or Charon?

Thanks and best

G

all the Light in the image comes from the sun and the shadows are cast by the mountains blocking that sunlight

OK Tombaugh region has to be an impact crater on the left with ejecta moving out to the right up and down. I've a feeling this was some large slow moving object that made a splash but also a slump/wave of ice that formed the mountain ranges as well.
The polygonal patterns in the flat plain area are just convection cells from the cooling and freezing of the lake left after the impact.

madtom1999 wrote:OK Tombaugh region has to be an impact crater on the left with ejecta moving out to the right up and down. I've a feeling this was some large slow moving object that made a splash but also a slump/wave of ice that formed the mountain ranges as well.
The polygonal patterns in the flat plain area are just convection cells from the cooling and freezing of the lake left after the impact.

An impact on solid ice or an ice/rock mixture doesn't leave a lake. That scenario is only plausible if the crust is very thin and there's a liquid sea underneath. Possible, but still not known.

Perhaps not a lake but I can imagine the shocked ice forming a slush that would take a while to solidify.

madtom1999 wrote:Perhaps not a lake but I can imagine the shocked ice forming a slush that would take a while to solidify.

I doubt it. If the impact is in solid material, most of it will be ejected. Even if there's slush in the bottom, we're going to be left with a crater, not a plain.

I would bow to Chris' wisdom on this. I would ask him one quick thing, if he has a moment to reply. It may not be possible so far out and in such coldness but I wonder if the friction of impact could potentially cause any amount of temperature increase leading to liquefaction or, at least, a lessening of the hard nature of the ices that could be permit an impact area to developing a mare type of appearance? Or is it just too, plain cold out there for such things?

Pianosorplanets wrote:I would bow to Chris' wisdom on this. I would ask him one quick thing, if he has a moment to reply. It may not be possible so far out and in such coldness but I wonder if the friction of impact could potentially cause any amount of temperature increase leading to liquefaction or, at least, a lessening of the hard nature of the ices that could be permit an impact area to developing a mare type of appearance? Or is it just too, plain cold out there for such things?

I'm sure that an impact produces melting, and even in the near vacuum some liquid will persist for a bit. But what I'd expect would be a fairly typical crater, with some evidence of that melt on the walls and bottom. But we don't see craters at all. So the options are that there hasn't been cratering (which seems unlikely), or the surface has been remodeled fairly recently.

Have you seen the latest image? Craters are plentiful in the dark region of the new picture.
http://www.nasa.gov/press-release/nasa- ... or-july-24

geckzilla wrote:Have you seen the latest image? Craters are plentiful in the dark region of the new picture.
http://www.nasa.gov/press-release/nasa- ... or-july-24

Yes, and even in some of the earlier pictures. But I wouldn't say "plentiful". Nevertheless, this supports the idea of resurfacing rather than a lack of impacts. It's just that the resurfacing process isn't uniform over the entire surface.

I think a lot of details have been lost during compression. It seems especially bad where the craters are. Only the ones with high contrast light material seem to be outlined. It will be nice to look at the uncompressed imagery when it comes in to see if there are any low-contrast craters in there.

This image of Enceladus shows a fairly well cratered region near the southern pole Tiger Striped region. On an icy body with a probable ocean below

geckzilla wrote:Have you seen the latest image? Craters are plentiful in the dark region of the new picture.
http://www.nasa.gov/press-release/nasa- ... or-july-24

This would be the area that has been dubbed "The Whale" at the area where the Whales Head meets the Heart
This area also reminds me of Iapetus