Description: A meteoroid is a fragment of an asteroid or comet with a size ranging from a few millimeters to several tens of meters. Meteoroids can fall towards any celestial object, with or without an atmosphere, at very high speed. If the celestial body has an atmosphere the meteoroid is slowed down by collisions with atmospheric molecules. We observe meteoroids in Earth's atmosphere as meteors. If the meteoroid is not completely destroyed in the atmosphere (or if the celestial body has no atmosphere) it falls to the surface of that body, and then it is called a meteorite.

Related Terms:

• Meteorite
• Shooting Star

Term and definition status: This term and its definition have been approved by a research astronomer and a teacher

The OAE Multilingual Glossary is a project of the IAU Office of Astronomy for Education (OAE) in collaboration with the IAU Office of Astronomy Outreach (OAO). The terms and definitions were chosen, written and reviewed by a collective effort from the OAE, the OAE Centers and Nodes, the OAE National Astronomy Education Coordinators (NAECs) and other volunteers. You can find a full list of credits here. All glossary terms and their definitions are released under a Creative Commons CC BY-4.0 license and should be credited to "IAU OAE".