A series of 24 images taken by the HST between November 28 and December 1, 1994, are arranged here in order to illustrate one 5.34-hour rotation of the asteroid Vesta. Though only 525 kilometers (325 miles) across, Vesta is a true mini-planet which has survived almost intact since our solar system formed. This contrasts with many other asteroids which are chunks broken off larger objects when they were involved in collisions early in the history of the solar system.
Vesta's battered surface has been cratered by impacts and shows evidence of ancient lava flows dating from an era more than 4,000 million years ago when its interior was hot and molten. Since that time, Vesta has changed very little, apart from the effects of occasional meteorite impacts. The HST images reveal details down to 80 kilometers (50 miles) in size and provide a glimpse of some of the oldest terrain ever seen in the solar system. One large impact crater is so deep it seems to have torn away Vesta's outer crust completely, exposing the rocks of the mantle below.
Astronomers believe that fragments gouged out of Vesta during ancient collisions have fallen to Earth as meteorites, making Vesta only the fourth solar system object, after Earth, the Moon and Mars, from which scientists have a confirmed laboratory sample.
Vesta is the brightest known asteroid and the third largest. It was discovered 1802 by H. W. M. Olbers and orbits the Sun in the main asteroid belt between Mars and Jupiter. When these images were taken, Vesta was 250 million kilometers (156million miles) away from Earth.
Camera: WFPC2
Credit: B. Zellner (Georgia Southern University),
and NASA
