[X] My Assistant

[Decepticon]

Note: Most of the Dione-specific discussion is in a different thread - moderator



Just before closets approach http://space.jpl.nasa.gov/cgi-bin/wspace?t...s=1&brite=1
An hour later.. http://space.jpl.nasa.gov/cgi-bin/wspace?t...s=1&brite=1

And the night side (I really hope we get some night side mapping. Make mapping of the moons much quicker!) http://space.jpl.nasa.gov/cgi-bin/wspace?t...s=1&brite=1



And Enceladus
http://space.jpl.nasa.gov/cgi-bin/wspace?t...s=1&brite=1

[Phil Stooke]

A thought or two on Telesto...

First those 'creases' noted by edstrick... frost polygons? I can't quite get my mind around that. You get the freezing but how would you get any thawing? I am more inclined to think they are merely the places where talus aprons (for want of a better term... debris shaken downslope by successive impacts) meet. Start with an irregular surface shedding debris, and it moves outwards from the high points until it meets another apron coming from another direction. If you draw expanding boundaries around a set of points they meet and form linear troughs... called thiessen polygons, if I recall correctly, in geometry.

Second... where's the debris coming from? Telesto looks more like Deimos, to me, than any other object we've seen. The best explanation for Deimos's thick debris layer is that it's ejecta from a VERY large crater, either just deposited directly from the impact or reaccreted after a period spent orbiting Mars. Remember the last phase of ejecta dispersal is slow, low energy, forming high rims on lunar craters... it doesn't have to get blown off even a small object, but it can also get reaccreted.

Deimos doesn't have a very large crater? Yes, it does, the big saddle at the south pole, nearly the same diameter as Deimos itself.

These ideas about Deimos are from Peter Thomas, not me, but I agree with him.

Phil