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Meteors may occur in [http://en.wikipedia.org/wiki/Meteor_shower showers], which arise when the [[Earth]] passes through a trail of debris left by a [[comet]], or as "[[random]]" or "sporadic" meteors, not [[associated]] with a specific single [[cause]]. A [[number]] of specific meteors have been [[observed]], largely by members of the [[public]] and largely by [[accident]], but with enough detail that [[orbits]] of the incoming meteors or meteorites have been [[calculated]]. All of them came from orbits from the vicinity of the [http://en.wikipedia.org/wiki/Asteroid_belt asteroid belt].[http://en.wikipedia.org/wiki/Meteor#Meteor]
Meteors may occur in [http://en.wikipedia.org/wiki/Meteor_shower showers], which arise when the [[Earth]] passes through a trail of debris left by a [[comet]], or as "[[random]]" or "sporadic" meteors, not [[associated]] with a specific single [[cause]]. A [[number]] of specific meteors have been [[observed]], largely by members of the [[public]] and largely by [[accident]], but with enough detail that [[orbits]] of the incoming meteors or meteorites have been [[calculated]]. All of them came from orbits from the vicinity of the [http://en.wikipedia.org/wiki/Asteroid_belt asteroid belt].[http://en.wikipedia.org/wiki/Meteor#Meteor]
==Meteorite==
A '''meteorite''' is a ''meteoroid'' (a solid piece of debris from such sources as asteroids or [[comets]]) originating in outer [[space]] that [[survives]] impact with the Earth's [[surface]]. A meteorite's size can range from small to extremely large. When a meteoroid enters the [[atmosphere]], frictional pressure, and chemical [[interactions]] with the atmospheric gases cause the body to heat up and emit [[light]], thus forming a fireball, also known as a meteor or shooting/falling star. The term ''bolide'' refers to either an [[extraterrestrial]] body that collides with the Earth, or to an exceptionally bright, fireball-like meteor regardless of whether it ultimately impacts the surface.
More generally, a meteorite on the [[surface]] of any [[celestial]] body is a natural object that has come from elsewhere in [[space]]. Meteorites have been found on the [[Moon]] and [http://en.wikipedia.org/wiki/Mars Mars]. Meteorites that are recovered after being [[observed]] as they transited the [[atmosphere]] or impacted the Earth are called falls. All other meteorites are known as finds. As of February 2010, there are approximately 1,086 witnessed falls having specimens in the world's collections. In [[contrast]], there are more than 38,660 well-documented meteorite finds.
Meteorites have traditionally been divided into three broad categories: stony meteorites are rocks, mainly composed of silicate [[minerals]]; iron meteorites are largely composed of metallic iron-nickel; and, stony-iron meteorites contain large amounts of both metallic and rocky material. Modern [[classification]] schemes divide meteorites into [[groups]] according to their [[structure]], [[chemical]] and isotopic [[composition]] and mineralogy. Meteorites smaller than 2mm are classified as ''micrometeorites''.
[[Category: Astronomy]]
[[Category: Astronomy]]
