Meteoroid

A meteoroid is a small rocky or metallic body travelling through outer space. Meteoroids are significantly smaller than asteroids, and range in size from small grains to 1 meter-wide objects.^[1] Objects smaller than this are classified as micrometeoroids orspace dust.^[1][2][3] Most are fragments from comets or asteroids, whereas others are collision impact debris ejected from bodies such as the Moon or Mars.

When a comet, asteroid, or meteoroid enters the 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 ameteorite.