
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.
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