Comets and Meteors | Introduction
Introduction
Earth is part of a solar system that is filled with celestial objects moving about. Scientists theorize that many of these objects are materials left over from when the solar system formed—about 4.6 billion years ago. CometsAn icy body orbiting in the solar system, which partially vaporizes when it nears the Sun and develops a diffuse envelope of dust and gas as well as one or more tails. and meteorsAn object from space that becomes glowing hot when it passes into Earth's atmosphere; also called shooting star. are two such chunks of materials in the solar system. Every so often these objects are visible to the naked eye as brilliant streaks of light across the sky. Meteors appear regularly and are sometimes called "shooting stars"; comets show themselves with far less frequency. Astronomers look to these objects to learn more about the universe around Earth and the early history of the solar system.