View of the solar system showing the locations of all the asteroids starting in 1980, as asteroids are discovered they are added to the map and highlighted white so you can pick out the new ones.
The final colour of an asteroids indicates how closely it comes to the inner solar system.
– Earth crossers are red
– Earth approachers (perihelion less than 1.3AU) are yellow
– All others are green
Link (via Tim)