that are consistent with many micrometeorites. Nonetheless, some parent bodies of micrometeorites appear to be asteroids with chondrule-bearing carbonaceous chondrites. Extraterrestrial micrometeorites The influx of micrometeoroids also contributes to the composition of regolith (planetary/lunar soil) on other bodies in the Solar System. Mars has an estimated annual micrometeoroid influx of between 2,700 and 59,000 t/yr. This contributes to about 1 m of micrometeoritic content to the depth of the Martian regolith every billion years. Measurements from the Viking program indicate that the Martian regolith is composed of 60% basaltic rock and 40% rock of meteoritic origin. The lower-density Martian atmosphere allows much larger particles than on Earth to survive the passage through to the surface, largely unaltered until impact. While on Earth particles that survive entry typically have undergone significant transformation, a significant fraction of particles entering the Martian atmosphere throughout the 60 to 1200-μm diameter range probably survive unmelted. See also Carbonaceous chondrite, a class of chondritic meteorites comprising at least seven known groups and many ungrouped Center for Meteorite Studies at Arizona State University Cosmic dust Glossary of meteoritics List of Martian meteorites List of meteorite minerals List of meteorites on Mars Meteorite classification Meteoritical Society Solar System The British and Irish Meteorite Society References Further reading John Larsen: In Search of Stardust: Amazing Micrometeorites and Their Terrestrial Imposters. Voyageur Press, Minneapolis 2017, . External links Meteoroids Page at NASA's Solar System exploration Current meteorite news articles International Meteorite Collectors Association News and information about meteorite collecting and authentication ethics Planetary Science Research Discoveries: meteorite articles and photographs The British and Irish Meteorite Society Types of extraterrestrial material available for study The Natural History Museum's meteorite catalogue database Meteoritical Society Earth Impact Database Meteoroids Meteorites Geophysics Planetary science Geochemistry Articles containing video clips