Meteoroid

A meteoroid (/ˈmiːtiərɔɪd/ MEE-tee-ə-royd)^[1] is a small rocky or metallic body in outer space. Meteoroids are distinguished as objects significantly smaller than asteroids, ranging in size from grains to objects up to a meter wide.^[2] Objects smaller than meteoroids are classified as micrometeoroids or space dust.^[2][3][4] Many are fragments from comets or asteroids, whereas others are collision impact debris ejected from bodies such as the Moon or Mars.^[5][6][7]

The visible passage of a meteoroid, comet, or asteroid entering Earth's atmosphere is called a meteor, and 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.

An estimated 25 million meteoroids, micrometeoroids and other space debris enter Earth's atmosphere each day,^[8] which results in an estimated 15,000 tonnes of that material entering the atmosphere each year.^[9] A meteorite is the remains of a meteoroid that has survived the ablation of its surface material during its passage through the atmosphere as a meteor and has impacted the ground.