Vesta is geologically different from the other large asteroids. Images taken by the Hubble Space Telescope show a basaltic surface indicative of ancient lava flows originating from a molten interior and a giant crater, about 285 mi (460 km) across and 8 mi (13 km) deep, that may go all the way through the crust to expose the mantle. The crater is thought to have resulted from a collision with another celestial body, the impact tearing out large chunks of Vesta that formed a distinctive class of small asteroids, some of which have reached earth as meteorites. Alternatively, they all may have originated from the breakup of a large parent body early in the history of the solar system. These hypotheses were made more credible in 1999 when the space probe Deep Space 1 spectroscopically analyzed the small asteroid Braille and found it to be akin in composition to Vesta.