Web page excerpt from Window's to the Universe:
Our Solar System - Asteroids
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Galileo image of Gaspra
(29 October 1991) courtesy of NASA/JPL
"Asteroids are small bodies that are believed to be left over from
the beginning of the solar system 4,600 million years ago. They are rocky
objects with strange shapes up to several hundred km across, but most are
much smaller.
Many thousands of asteroids lie in a belt between Mars and Jupiter. Scientists
think that this debris may be the remains of an early planet, which broke
up early in the solar system. Several thousand of the largest asteroids
in this belt have been given names. "
Windows to the Universe - Asteroids:
http://www.windows.umich.edu/cgi-bin/tour.cgi?link=/our_solar_system/asteroids.html&br=graphic&sw=
false&sn=4477&d=/our_solar_system&tour=&edu=elem
NASA IITA Project. 9/96