<P> Meteoroids are significantly smaller than asteroids, and range in size from small grains to one - meter - wide objects . Objects smaller than this are classified as micrometeoroids or space dust . Most are fragments from comets or asteroids, whereas others are collision impact debris ejected from bodies such as the Moon or Mars . </P> <P> When a meteoroid, comet, or asteroid enters Earth's atmosphere at a speed typically in excess of 20 km / s (72,000 km / h; 45,000 mph), aerodynamic heating of that object produces a streak of light, both from the glowing object and the trail of glowing particles that it leaves in its wake . This phenomenon is called a meteor or "shooting star". A series of many meteors appearing seconds or minutes apart and appearing to originate from the same fixed point in the sky is called a meteor shower . If that object withstands ablation from its passage through the atmosphere as a meteor and impacts with the ground, it is then called a meteorite . </P> <P> An estimated 15,000 tonnes of meteoroids, micrometeoroids and different forms of space dust enter Earth's atmosphere each year . </P> <P> In 1961, the International Astronomical Union (IAU) defined a meteoroid as "a solid object moving in interplanetary space, of a size considerably smaller than an asteroid and considerably larger than an atom". In 1995, Beech and Steel, writing in the Quarterly Journal of the Royal Astronomical Society, proposed a new definition where a meteoroid would be between 100 μm and 10 meters across . In 2010, following the discovery of asteroids below 10 m in size, Rubin and Grossman proposed a revision of the previous definition of meteoroid to objects between 10 μm and 1 m in diameter in order to maintain the distinction . According to Rubin and Grossman, the minimum size of an asteroid is given by what can be discovered from Earth - bound telescopes, so the distinction between meteoroid and asteroid is fuzzy . Some of the smallest asteroids discovered (based on absolute magnitude H) are 2008 TS with H = 33.2 and 2011 CQ 1 with H = 32.1 both with an estimated size of 1 meter . In April 2017, the IAU adopted an official revision of its definition, limiting size to between 30 μm and 1 m in diameter, but allowing for a deviation for any object causing a meteor . </P>

How many meteoroids enter the earth’s atmosphere
find me the text answering this question