Phobos Options

[Guest_Sunspot_*]

http://www.esa.int/SPECIALS/Mars_Express/

These images, taken by the High Resolution Stereo Camera (HRSC) on board ESA’s Mars Express spacecraft, are Europe’s highest-resolution pictures so far of the Martian moon Phobos.

http://www.esa.int/SPECIALS/Mars_Express/SEM21TVJD1E_0.html

[Ian R]

Good catch on the splatter pattern Ed. That certainly does look more like a crater chain from a debris or cometary impact.

[tty]

Good catch on the splatter pattern Ed. That certainly does look more like a crater chain from a debris or cometary impact.

Now that is interesting. How do you get a splatter pattern/crater chain on a body with essentially zero gravity? It certainly can't be by stuff just falling back to the surface. Anything moving slowly enough to fall back on Phobos probably wouldn't be able to crater a marshmallow.
I suppose a string of debris might stay together well enough to hit Phobos on a subsequent orbit but it seems rather unlikely. It seems at least as likely to be debris coming from an impact on Mars itself.