Asteroids in the Distance . ... Credit Copyright: R. Evans K. Stapelfeldt ( JPL ), WFPC2 , HST , NASA Explanation: Rocks from space hit Earth every day. The larger the rock, though, the less often Earth is struck. Many kilograms of space dust pitter to Earth daily. ... Many asteroids remain undiscovered . ... In 2002 June, the small 100-meter asteroid 2002 MN was discovered only after it whizzed by the Earth, passing well within the orbit of the Moon. ... NASA Official: Jay Norris. ...