NASA's Dawn probe, now orbiting Vesta in the asteroid belt, has found some surprising things on the giant asteroid--things that have prompted one researcher to declare Vesta "the smallest terrestrial planet."
FULL STORY at http://science.nasa.gov/science-news/science-at-nasa/2011/09dec_vestaplanet/
A video version of this story is available at http://www.youtube.com/watch?v=_JBNkts5YXA
