Why Is There a Huge Mountain on Ceres?

The Dawn spacecraft has dropped itself into its lowest and final mapping orbit around the protoplanet Ceres, and the images it's now returning are both beautiful and baffling. We're still waiting for close-up shots of Occator crater with its bizarre bright spots in it, but in the meantime there's no lack of weirdness coming from Ceres. The shot above shows Ahuna Mons, a mountain on Ceres 5 kilometers high and 20 kilometers long. But what the heck is it? There's nothing else quite like it on Cere...