Cool, can you make them orbit? Hmm, Think... No gravity, no air, springs, motion... Orbit? I shalt try.
I also just downloaded the Algodoo demo. Are there any things in Phun that would make that worth downloading too?
Edit: Lol, springs and... Of course there was a gravity setting for bodies. Found.
Edit: I made two simulations of a planetary surface you can bombard, if you want to try it (for Algodoo). The big one might require a fast computer, while the small version is faster (but probably less exciting).