ASTEROIDS
Small rock bodies, most orbiting the Sun, between Mars and Jupiter
(Asteroid Belt, 2-4 AU). Also called minor planets.The
largest asteroids - Ceres (1020 km diameter, discovered 1801), Vesta (550 km) and Pallas (538 km) are spherical and probably have undergone some geological activity.16 Asteroids with greater than 240km.
Estimated total mass of all asteroids would be less one body 1,500 km across -- less than half the diameter of our Moon.
Asteroids are material that never coalesced into a planet.
Compositional variation within the Asteroid Belt reflect early temperature variations within the solar system (more volatile in outer part of Belt).
Kirkwood gaps are asteroid "free" regions
in the Belt in which an object's orbital period would be a simple fraction of that of Jupiter. Jupiter would over time accelerate objects in these regions into a different orbit.The Galileo spacecraft flew past
Gaspra in October 1991 and Ida in August 1993.In December 1992,
Toutatis came to within about 4 million kilometers from Earth.Near and Eros
Eros
is one of the largest near-Earth asteroids (33x13x13km)Eros Gravity:200lb persons weighs 2 ounces. 22mph escape velocity.
Eros is a primitive, undifferentiated asteroid that was never subjected to melting.
Eros is a consolidated body as opposed to a rubble pile.
On Monday, 12 February 2001, the NEAR spacecraft touched down on asteroid Eros