meteor

meteor, appearance of a small particle flying through space that interacts with the earth's upper atmosphere. While still outside the atmosphere, the particle is known as a meteoroid. Countless meteoroids of varying sizes are moving about the solar system at any time. Perhaps a billion meteoroids a day enter the atmosphere, their speeds ranging from 10 to 45 mi (16–72 km) per sec. They experience friction due to collisions with the atmosphere; by the time they reach 50 to 75 mi (80–120 km) from the earth's surface, they have been heated to incandescence through friction and are visible as "shooting stars," or "falling stars." Most disintegrate completely before they reach the earth; those large enough to reach the ground are called meteorites. A meteor of considerable duration and brightness is known as a fireball; a fireball that breaks apart with an explosion is a bolide. The brightest fireball ever recorded fell in the Tunguska Basin, Siberia, in 1908, causing the destruction of forest over an area of about 770 sq mi (2,000 sq km). Meteoroids are composed of stone, iron, or a mixture of stone and iron, with other metals present in very small proportions. Other meteoroids, the carbonaceous chondrites, are stony with a large amount of carbon. Although most meteoroids are quite small, and even though only a very small fraction of them reach the earth's surface, their large quantity accounts for several tons of matter falling on the earth each day. A single observer under a dark sky can see an average of 5 to 10 meteors per hour; more during a meteor shower. More meteors are visible after midnight because the earth's rotation has then positioned the observer's part of the earth in the direction of the earth's motion about the sun. The frequency of meteors also increases when the earth passes through certain swarms of particles that intersect the earth's orbit. Such meteor showers are named for the constellation from which they appear to originate.

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meteor

 or shooting star or falling star

Streak of light in the sky that results when a particle or small chunk of stony or metallic matter from space enters Earth's atmosphere and is vapourized by friction. The term is sometimes applied to the falling object itself, properly called a meteoroid. Most meteoroids, traveling at five times the speed of sound or more, burn up in the upper atmosphere, but a large one may survive its fiery plunge and reach the surface as a solid body (meteorite). See also meteor shower.

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METEOR - A version of COMIT with Lisp-like syntax, written in MIT Lisp 1.5 for the IBM 7090. "METEOR - A List Interpreter for String Transformation", D.G. Bobrow in The Programming Language LISP and its Interpretation, E.D. and D.G. Bobrow eds, 1964.