The most frequent hypervelocity cratering events on the Earth are caused by iron meteoroids, which are most easily able to transit the atmosphere intact. The force of such collisions has the potential to cause widespread destruction. The kind of crater will depend on the size, composition, degree of fragmentation, and incoming angle of the impactor. Large meteoroids may strike the earth with a significant fraction of their escape velocity (second cosmic velocity), leaving behind a hypervelocity impact crater. The impact pit made by a 61.9-gram Novato meteorite when it hit the roof of a house on 17 October 2012. Extraterrestrial meteorites have been found on the Moon and on Mars. "Meteorites" less than ~1 mm in diameter are classified as micrometeorites, however micrometeorites differ from meteorites in that they typically melt completely in the atmosphere and fall to Earth as quenched droplets. Modern classification schemes divide meteorites into groups according to their structure, chemical and isotopic composition and mineralogy. Meteorites have traditionally been divided into three broad categories: stony meteorites that are rocks, mainly composed of silicate minerals iron meteorites that are largely composed of ferronickel and stony-iron meteorites that contain large amounts of both metallic and rocky material. Meteorites that are recovered after being observed as they transit the atmosphere and impact the Earth are called meteorite falls. For geologists, a bolide is a meteorite large enough to create an impact crater. ![]() Once it settles on the larger body's surface, the meteor becomes a meteorite. ![]() It then becomes a meteor and forms a fireball, also known as a shooting star astronomers call the brightest examples " bolides". When the original object enters the atmosphere, various factors such as friction, pressure, and chemical interactions with the atmospheric gases cause it to heat up and radiate energy. Ī meteorite is a solid piece of debris from an object, such as a comet, asteroid, or meteoroid, that originates in outer space and survives its passage through the atmosphere to reach the surface of a planet or moon. The 60- tonne, 2.7 m-long (8.9 ft) long Hoba meteorite in Namibia is the largest known intact meteorite.
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