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A bolide (French from the Greek βολίς ''bolis'', "missile" or "to flash"〔http://www.merriam-webster.com/dictionary/bolide〕) is an extremely bright meteor that explodes in the atmosphere. In astronomy, it refers to a fireball approximately as bright as the full moon, and it is generally considered a synonym of a fireball. In geology a bolide is a very large impactor. One definition describes a bolide as a fireball reaching an apparent magnitude of −14 or brighter, which is more than twice as bright as the full moon.〔 :156〕 Another definition describes a bolide as any generic large crater-forming impacting body whose composition (for example, whether it is a rocky or metallic asteroid, or an icy comet) is unknown.〔 〕 A superbolide is a bolide which reaches an apparent magnitude of −17 or brighter.〔〔 :133〕 Recent examples of superbolides are the Sutter's Mill meteorite and the Chelyabinsk meteor. == Astronomy == The IAU has no official definition of "bolide", and generally considers the term synonymous with fireball, a brighter-than-usual meteor. However, the term generally applies to fireballs reaching an apparent magnitude −14 or brighter.〔 Astronomers tend to use ''bolide'' to identify an exceptionally bright fireball, particularly one that explodes (sometimes called a detonating fireball). It may also be used to mean a fireball that is audible. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「bolide」の詳細全文を読む スポンサード リンク
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