meteoroid(redirected from Ionization trail)
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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.
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meteoroid(mee -tee-ŏ-roid) The collective term applied to meteoritic material in the Solar System, usually replaced by the terms micrometeorite for particles with mass less than 10–6 gram and meteorite for bodies with mass greater than about 105 grams. The majority of the mass of the meteoroid cloud around the Sun is made up of particles with individual masses between 10–7 and 10–3 gram. Meteoroids are usually produced by the decay of short-period comets and the collisional fragmentation of asteroids. In the main they move around the Sun in low-inclination direct orbits. The space density of meteoroids maximizes near the orbit of Mars and then falls off as 1/r 1.5, where r is the distance from the Sun. Individual meteoroids in the mass range 10–6 to 104 grams are fragile crumbly rocky dust particles with a composition similar to carbonaceous chondrite meteorites. See also meteor.
a relatively small solid body that moves in outer space. The aggregate of meteoroids revolving around the sun forms the meteoric material in interplanetary space. Meteoroids are cometary debris or fragments of asteroids and in their motion occasionally encounter the earth and other planets.