[X] My Assistant

[ugordan]

To wrap up the year, Cassini took a few Tethys low phase images from about 400 000 km.
A stretched color (IR/G/UV) composite:

[nprev]

One thing that strikes me is that Tethys, Dione & Iapetus all have a number of relatively large craters (co-orbital small moon impacts?), and Rhea doesn't. However, Rhea looks considerably more battered at lower scales.

Sure would like to know the complete, unabridged story of the Saturn system...many tantalizing clues, but no grand unified theory seems evident.

[As old as Voyage...]

One thing that strikes me is that Tethys, Dione & Iapetus all have a number of relatively large craters (co-orbital small moon impacts?), and Rhea doesn't. However, Rhea looks considerably more battered at lower scales.

Sure would like to know the complete, unabridged story of the Saturn system...many tantalizing clues, but no grand unified theory seems evident.

Rhea does have two fine impact basins; the 375 km Tirawa and a 500km basin alongside it. This second basin was identified by Phil Stooke in re-processed Voyager 1 images:

http://www.lpi.usra.edu/meetings/lpsc2001/pdf/1074.pdf

Here's some nice pics of Tethys' stripe:

http://www.lpi.usra.edu/meetings/lpsc2002/pdf/1553.pdf

[nprev]

Rhea does have two fine impact basins; the 375 km Tirawa and a 500km basin alongside it. This second basin was identified by Phil Stooke in re-processed Voyager 1 images:

Thanks for the enlightenment, AOAV, and belated congrats to Phil!

So, Rhea falls more nearly in line with the rest of the icy moons in general character as far as a history of major impactors. Does this imply that the Saturn system was riddled with large objects above the normal background level, and if so does this say something about the age of the ring system given the apparent antiquity of the craters?