Enormous asteroid Vesta is the second-largest body in the asteroid belt. It’s so big, in fact, that many consider it to be more of a planet than just another rocky lump. There are good reasons to consider it planet-like: But for two massive impacts that nearly blew the thing apart (we’ll come back to that later), Vesta would be roughly spherical; and among other things, its innards are differentiated – it has a core, mantle, and crust. Just like Earth and Mars and Venus.

If Jupiter hadn’t formed, and its massive gravity hadn’t stirred the asteroid belt into perpetual crumbliness, it’s possible Vesta may have grown up and become a real planet of its own. But Jupiter did come along, and