Seven Wonders of Asteroids, Comets, and Meteors

Seven Wonders of Asteroids, Comets, and Meteors — page 7
The Dawn space probe is seen near the asteroid Vesta left and the dwarf planet Ceres right in this illustration Dawn was launched in 2007 On September 27 2007 the National Aeronautics and Space Administration NASA launched the Dawn spacecraft Its mission is to explore the asteroid belt It is scheduled to visit the asteroid Vesta in 2011 and Ceres in February 2015 As the spacecraft swings close to Ceres it will take photos and scan the surface of the asteroid This will help scientists learn what Ceres is made of and how it was formed Seven Wonders of Asteroids Comets and Meteors THE ASTEROID ZOO Asteroids come in all sizes and shapes They range from rocks only a few hundred feet across to flying mountains 500 miles 800 km wide The very biggest are round But smaller objects have weaker gravity A large body such as Earth tends to be round Every point on the surface of Earth is just about the same distance from the center This is because its gravity is strong enough to flatten out any large lumps But with much less gravity to pull at an asteroid's surface it can be any shape at all The first asteroid to be explored by a spacecraft was 433 Eros The Near Earth Asteroid Rendezvous NEAR Shoemaker spacecraft launched in 1996 10 The asteroid belt is a great grinding mill producing smaller and smaller pieces down to motes of dust Carl Sagan American astronomer Cosmos 1980