September 4, 1997: Astronomers have used the Hubble Space telescope to discover a giant impact crater on the asteroid Vesta. The crater is a link in a chain of events thought responsible for forming a distinctive class of tiny asteroids as well as some meteorites that have reached the Earth.
The giant crater is 285 miles across, which is nearly equal to Vesta's 330-mile diameter. If Earth had a crater of proportional size, it would fill the Pacific Ocean basin. Astronomers had predicted the existence of one or more large craters, reasoning that if Vesta is the true "parent body" of some smaller asteroids then it should have the wound of a major impact that was catastrophic enough to knock off big chunks. In this Hubble picture of Vesta, a "nub" at the bottom of the asteroid is suggestive of a catastrophic impact.See the rest:
Credit: Ben Zellner (Georgia Southern University), Peter Thomas (Cornell University) and NASA