Article
Meteors, Meteorites and Impact Craters
The solar system contains many objects smaller than the planets (or their satellites) travelling in individual orbits about the SUN; space between the planets also contains myriad dust grains in the micron size range. Near Earth, dust concentrations are only a few hundred particles per cubic kilometre, but 35 000 to 100 000 t of extraterrestrial material enters the atmosphere annually, swept up by our planet from debris that is in its path or crosses its path.