Planetary geology, alternatively known as astrogeology or exogeology, is a planetary science discipline concerned with the geology of celestial bodies such as planets and their moons, asteroids, comets, and meteorites.[1][2] Although the geo- prefix typically indicates topics of or relating to Earth, planetary geology is named as such for historical and convenience reasons; due to the types of investigations involved, it is closely linked with Earth-based geology. These investigations are centered around the composition, structure, processes, and history of a celestial body.[3]
Planetary geology includes such topics as determining the properties and processes of the internal structure of the terrestrial planets, and also looks at planetary volcanism and surface processes such as impact craters, fluvial and aeolian processes. The structures and compositions of the giant planets and their moons are also examined, as is the make-up of the minor bodies of the Solar System, such as asteroids, the Kuiper belt, and comets. Planetary geology largely applies concepts within the geosciences to planetary bodies in the broadest sense, and includes applications derived from fields in the geological sciences, such as geophysics and geochemistry.
Today, many institutions are concerned with the study and communication of planetary sciences and planetary geology. The Visitor Center at Barringer Meteor Crater near Winslow, Arizona includes a museum of planetary geology.[citation needed] The Geological Society of America's Planetary Geology Division has been growing and thriving since May 1981 and has two mottos: "One planet just isn't enough!" and "The GSA Division with the biggest field area!"[citation needed]
Simulated interplanetary missions performed on Earth have studied procedures and tools for planetary geology. Various tools, including common archaeological tools such as hammers, shovels, brushes, were evaluated for use by planetary geologists.[5] Along with these common tools, new advanced technologies have become available. These include spectroscopic databases, and data (such as mission logs, images and mapping) from previous unmanned interplanetary missions.[6] Scientists use maps, images, telescopes on Earth, and orbiting telescopes (such as the Hubble Space Telescope).[7] The maps and images are stored in the NASA Planetary Data System where tools such as the Planetary Image Atlas help to search for certain items such as geological features including mountains, ravines, and craters.[8]
Planetary geology uses a wide variety of standardized descriptor names for features.[9] All planetary feature names recognized by the International Astronomical Union (IAU) combine one of these names with a possibly unique identifying name. The conventions which decide the more precise name are dependent on which planetary body the feature is on, but the standard descriptors are in general common to all astronomical planetary bodies. Some names have a long history of historical usage, but new must be recognized by the IAU Working Group for Planetary System Nomenclature as features are mapped and described by new planetary missions.[10] This means that in some cases, names may change as new imagery becomes available,[10] or in other cases widely adopted informal names changed in line with the rules.[11] The standard names are chosen to consciously avoid interpreting the underlying cause of the feature, but rather to describe only its appearance.[9]
Island (islands), an isolated land area (or group of such areas) surrounded by, or nearly surrounded by, a liquid area (sea or lake). Used only on Titan.
A "sea" or large circular plain on Moon and Mars, e.g. Mare Erythraeum; on Titan, large expanses of dark materials thought to be liquid hydrocarbons, e.g. Ligeia Mare.
^Young, Kelsey; Hurtado, José M.; Bleacher, Jacob E.; Brent Garry, W.; Bleisath, Scott; Buffington, Jesse; Rice, James W. (2013-10-01). "Tools and technologies needed for conducting planetary field geology while on EVA: Insights from the 2010 Desert RATS geologist crewmembers". Acta Astronautica. NASA's 2010 Desert Research and Technology Studies Mission Objectives and Results. 90 (2): 332–343. Bibcode:2013AcAau..90..332Y. doi:10.1016/j.actaastro.2011.10.016. hdl:2060/20120012887. ISSN0094-5765. S2CID85509925.
^Listed pronunciations are conventional or follow the traditional English pronunciation of Latin words. However, some speakers use different (often variable) pronunciations that are closer to the Latin or Greek.
Rossi, Angelo Pio; Gasselt, Stephan van, eds. (2018). Planetary Geology. Astronomy and Planetary Sciences. Springer International Publishing. ISBN978-3-319-65177-4.
