Meteoroids are small rocky bodies that travel through space. When they enter Earth's atmosphere, they are called meteors and if they survive entry and hit the ground, they are called meteorites. Meteoroids come from asteroids and comets. Meteors are commonly called shooting stars. Meteor showers occur when Earth passes through streams of debris left by comets. Comets originate from the Kuiper Belt beyond Neptune or farther out in the Oort Cloud, and are composed of ice and dust. When comets approach the sun, their tails always point away from the sun due to the pressure of the solar wind.