The following definitions for meteorite, meteoroid, micrometeorite, micrometeoroid, and interplanetary dust particle (IDP) have been proposed by Alan Rubin (UCLA) and Jeffrey Grossman (U.S. Geological Survey); excerpted from Meteoritics and Planetary Science 45, #1, 114–122 (2010).


A natural solid object larger than 10 µm in size, derived from a celestial body that was transported by natural means from the body on which it formed to a region outside the dominant gravitational influence of that body, and that later collided with a natural or artificial body larger than itself (even if it is the same body from which it was launched). Weathering processes do not affect an object's status as a meteorite as long as something recognizable remains of its original minerals or structure. An object loses its status as a meteorite if it is incorporated into a larger rock that becomes a meteorite itself.


A 10 µm to 1-m-sized natural solid object moving in interplanetary space. Meteoroids might be primary objects or derived by the fragmentation of larger celestial bodies, not limited to asteroids.


A meteorite between 10 µm and 2 mm in size.


A meteoroid between 10 µm and 2 mm in size.

Interplanetary Dust Particle (IDP)

A particle smaller than 10 µm in size moving in interplanetary space. If such particles susequently accrete to larger natural or artificial bodies, they are still called IDPs.