What are Near Earth Asteroids?
Near Earth asteroids are asteroids that travel to within 1.3AU (195 million kilometers/121 million miles) of the Sun. There are over 250 near Earth asteroids known and they are classified into three groups: Classes of Near Earth Asteroids Amor crosses the orbit of Mars, does not cross orbit of Earth. (representative example = 433 Eros – visited by the NEAR Shoemaker spacecraft) Apollo crosses Earth’s orbit, orbital period greater than one year. (example=1620 Geographos) Aten crosses Earth’s orbit, orbital period less than one year. (example=2340 Hathor) Most near Earth asteroids are believed to be main belt asteroids that were knocked out of the belt by collisions with other asteroids and/or by the gravitational forces of Jupiter. Some NEAs may actually be remnants of dead comets. The orbits of near Earth asteroids are thought to be influenced by gravitational interactions with the Sun or terrestrial planets or by collisions with other bodies. How Big? The largest known near Earth aste
