A meteoroid is a sand- to boulder-sized particle of debris in the Solar System.Actually meteorides are the debris left by comets.
Each time a comet passes close to the Sun, a bit of its mass is boiled away—about 1⁄1,000 of its mass with each pass. After some 100 passages, a comet typically fragments and continues to orbit as a collection of debris or coalesces with the Sun. As Earth passes through the orbital paths of such debris, we experience meteor showers. Whenever a comet makes its nearest approach to the Sun, some pieces break off from its nucleus. The larger fragments take up orbits near the parent comet, but some fall behind, so that the comet’s path is eventually filled with these tiny micrometeoroids.Periodically, Earth’s orbit intersects with a cluster of such micrometeoroids, resulting in a meteor shower as the fragments burn up in our upper atmosphere. Meteors are often called shooting stars, although they have nothing at all to do with stars. A meteor is a streak of light in the sky resulting from the intense heating of a narrow channel in Earth’s upper atmosphere. The heat generated by friction with air molecules as the meteoroid hurtles through Earth’s atmosphere ionizes—strips electrons away from atoms along—a pathway behind this piece of space debris. The ionized path in Earth’s atmosphere glows for a brief time, producing the meteor. The meteor streaks across a part of the sky, whereas a comet does not streak rapidly and may, in fact, be visible for many months because of its great distance from Earth. A meteor is an event occurring in Earth’s upper atmosphere, whereas a comet is typically many A.U. distant from Earth. Meteor is the term for the sight of the streak of light caused by a meteoroid—which is the term for the actual rocky object that enters the atmosphere. Most meteoroids are completely burned up in our atmosphere, but a few do get through to strike Earth. Any fragments that reaches the earth surface without burning up in atmosphere and then recovered are called meteorites. Millions of meteors occur in the Earth’s atmosphere every day.