Planetary geology, alternatively known as astrogeology or exogeology, is a
planetary science
Planetary science (or more rarely, planetology) is the scientific study of planets (including Earth), celestial bodies (such as moons, asteroids, comets) and planetary systems (in particular those of the Solar System) and the processes of their f ...
discipline concerned with the
geology
Geology () is a branch of natural science concerned with Earth and other astronomical objects, the features or rocks of which it is composed, and the processes by which they change over time. Modern geology significantly overlaps all other Ear ...
of the
celestial bodies
An astronomical object, celestial object, stellar object or heavenly body is a naturally occurring physical entity, association, or structure that exists in the observable universe. In astronomy, the terms ''object'' and ''body'' are often us ...
such as the
planet
A planet is a large, rounded astronomical body that is neither a star nor its remnant. The best available theory of planet formation is the nebular hypothesis, which posits that an interstellar cloud collapses out of a nebula to create a you ...
s and their
moons
A natural satellite is, in the most common usage, an astronomical body that orbits a planet, dwarf planet, or small Solar System body (or sometimes another natural satellite). Natural satellites are often colloquially referred to as ''moons'' ...
,
asteroid
An asteroid is a minor planet of the inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic or icy bodies with no atmosphere.
...
s,
comet
A comet is an icy, small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process that is called outgassing. This produces a visible atmosphere or coma, and sometimes also a tail. These phenomena ar ...
s, and
meteorite
A meteorite is a solid piece of debris from an object, such as a comet, asteroid, or meteoroid, that originates in outer space and survives its passage through the atmosphere to reach the surface of a planet or Natural satellite, moon. When the ...
s. Although the geo- prefix typically indicates topics of or relating to
Earth
Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...
, 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 planet.
Planetary geology includes such topics as determining the properties and processes of the internal structure of the
terrestrial planets
A terrestrial planet, telluric planet, or rocky planet, is a planet that is composed primarily of silicate rocks or metals. Within the Solar System, the terrestrial planets accepted by the IAU are the inner planets closest to the Sun: Mercury, Ven ...
, and also looks at planetary
volcanism
Volcanism, vulcanism or volcanicity is the phenomenon of eruption of molten rock (magma) onto the surface of the Earth or a solid-surface planet or moon, where lava, pyroclastics, and volcanic gases erupt through a break in the surface called ...
and surface processes such as
impact crater
An impact crater is a circular depression in the surface of a solid astronomical object formed by the hypervelocity impact of a smaller object. In contrast to volcanic craters, which result from explosion or internal collapse, impact craters ...
s,
fluvial
In geography and geology, fluvial processes are associated with rivers and streams and the deposits and landforms created by them. When the stream or rivers are associated with glaciers, ice sheets, or ice caps, the term glaciofluvial or fluviog ...
and
aeolian processes
Aeolian processes, also spelled eolian, pertain to wind activity in the study of geology and weather and specifically to the wind's ability to shape the surface of the Earth (or other planets). Winds may erode, transport, and deposit materials ...
. 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
asteroid
An asteroid is a minor planet of the inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic or icy bodies with no atmosphere.
...
s, the
Kuiper Belt
The Kuiper belt () is a circumstellar disc in the outer Solar System, extending from the orbit of Neptune at 30 astronomical units (AU) to approximately 50 AU from the Sun. It is similar to the asteroid belt, but is far larger—20 times ...
, and
comet
A comet is an icy, small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process that is called outgassing. This produces a visible atmosphere or coma, and sometimes also a tail. These phenomena ar ...
s. Planetary geology largely applies concepts within the
geosciences
Earth science or geoscience includes all fields of natural science related to the planet Earth. This is a branch of science dealing with the physical, chemical, and biological complex constitutions and synergistic linkages of Earth's four spheres ...
to planetary bodies in the broadest sense, includes applications derived from other closely related fields within in the geological sciences, such as
geophysics
Geophysics () is a subject of natural science concerned with the physical processes and physical properties of the Earth and its surrounding space environment, and the use of quantitative methods for their analysis. The term ''geophysics'' som ...
and
geochemistry
Geochemistry is the science that uses the tools and principles of chemistry to explain the mechanisms behind major geological systems such as the Earth's crust and its oceans. The realm of geochemistry extends beyond the Earth, encompassing the e ...
.
History of planetary geology
Eugene Shoemaker
Eugene Merle Shoemaker (April 28, 1928 – July 18, 1997) was an American geologist. He co-discovered Comet Shoemaker–Levy 9 with his wife Carolyn S. Shoemaker and David H. Levy. This comet hit Jupiter in July 1994: the impact was televise ...
is credited with bringing geologic principles to planetary mapping and creating the branch of planetary science in the early 1960s, the
Astrogeology Research Program
The Astrogeology Science Center is the entity within the United States Geological Survey concerned with the study of planetary geology and planetary cartography. It is housed in the Shoemaker Building in Flagstaff, Arizona. The Center was establ ...
, within the
United States Geological Survey
The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, ...
. He made important contributions to the field and the study of
impact crater
An impact crater is a circular depression in the surface of a solid astronomical object formed by the hypervelocity impact of a smaller object. In contrast to volcanic craters, which result from explosion or internal collapse, impact craters ...
s,
Selenography
Selenography is the study of the surface and physical features of the Moon (also known as geography of the Moon, or selenodesy). Like geography and areography, selenography is a subdiscipline within the field of planetary science. Historical ...
(study of the Moon), asteroids, and comets.
Today many institutions are concerned with the study and communication of planetary sciences and planetary geology. The Visitor Center at
Barringer Meteor Crater
Meteor Crater, or Barringer Crater, is a meteorite impact crater about east of Flagstaff and west of Winslow in the desert of northern Arizona, United States. The site had several earlier names, and fragments of the meteorite are official ...
near
Winslow Winslow may refer to:
Places United Kingdom
* Winslow, Buckinghamshire, England, a market town and civil parish
* Winslow Rural District, Buckinghamshire, a rural district from 1894 to 1974
United States and Canada
* Rural Municipality of Winslo ...
,
Arizona
Arizona ( ; nv, Hoozdo Hahoodzo ; ood, Alĭ ṣonak ) is a state in the Southwestern United States. It is the 6th largest and the 14th most populous of the 50 states. Its capital and largest city is Phoenix. Arizona is part of the Fou ...
includes a museum of planetary geology. 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!"
Major centers for planetary science research include the
Lunar and Planetary Institute
The Lunar and Planetary Institute (LPI) is a scientific research institute dedicated to study of the Solar System, its formation, evolution, and current state. The Institute is part of the Universities Space Research Association (USRA) and is supp ...
, the
Applied Physics Laboratory
The Johns Hopkins University Applied Physics Laboratory (Applied Physics Laboratory, or APL) is a not-for-profit University Affiliated Research Center, university-affiliated research center (UARC) in Howard County, Maryland. It is affiliated w ...
, the
Planetary Science Institute
The Planetary Science Institute (PSI) is a 501(c)(3) non-profit research institute based in Tucson, Arizona, focusing on planetary science. , its director is Dr. Mark V. Sykes. PSI, along with Space Science Institute (SSI) Southwest Researc ...
, the
Jet Propulsion Laboratory
The Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center in the City of La Cañada Flintridge, California, United States.
Founded in the 1930s by Caltech researchers, JPL is owned by NASA an ...
,
Southwest Research Institute
Southwest Research Institute (SwRI), headquartered in San Antonio, Texas, is an independent and nonprofit applied research and development (R&D) organization. Founded in 1947 by oil businessman Tom Slick, it provides contract research and develop ...
, and
Johnson Space Center
The Lyndon B. Johnson Space Center (JSC) is NASA's center for human spaceflight (originally named the Manned Spacecraft Center), where human spaceflight training, research, and flight control are conducted. It was renamed in honor of the late U ...
. Additionally, several universities conduct extensive planetary science research, including
Montana State University
Montana State University (MSU) is a Public university, public land-grant university, land-grant research university in Bozeman, Montana. It is the state's largest university. MSU offers baccalaureate degrees in 60 fields, master's degrees in 6 ...
,
Brown University
Brown University is a private research university in Providence, Rhode Island. Brown is the seventh-oldest institution of higher education in the United States, founded in 1764 as the College in the English Colony of Rhode Island and Providenc ...
, the
University of Arizona
The University of Arizona (Arizona, U of A, UArizona, or UA) is a public land-grant research university in Tucson, Arizona. Founded in 1885 by the 13th Arizona Territorial Legislature, it was the first university in the Arizona Territory.
T ...
,
Caltech
The California Institute of Technology (branded as Caltech or CIT)The university itself only spells its short form as "Caltech"; the institution considers other spellings such a"Cal Tech" and "CalTech" incorrect. The institute is also occasional ...
, the
University of Colorado
The University of Colorado (CU) is a system of public universities in Colorado. It consists of four institutions: University of Colorado Boulder, University of Colorado Colorado Springs, University of Colorado Denver, and the University of Co ...
,
Western Michigan University
Western Michigan University (Western Michigan, Western or WMU) is a public research university in Kalamazoo, Michigan. It was initially established as Western State Normal School in 1903 by Governor Aaron T. Bliss for the training of teachers ...
,
MIT
The Massachusetts Institute of Technology (MIT) is a private land-grant research university in Cambridge, Massachusetts. Established in 1861, MIT has played a key role in the development of modern technology and science, and is one of the m ...
, and
Washington University in St. Louis
Washington University in St. Louis (WashU or WUSTL) is a private research university with its main campus in St. Louis County, and Clayton, Missouri. Founded in 1853, the university is named after George Washington. Washington University is r ...
.
Tools
Several tools been used in planetary geology, including common archaeological tools such as hammers, shovels, brushes, etc. are often used by planetary geologists. Along with these common tools, new advanced technologies are used by planetary geologists Scientists also with these tools, use maps and images that telescopes on Earth (thirty meter telescope) and orbiting telescopes (Hubble) have taken different planetary bodies. 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.
Features and terms
Planetary geology uses a wide variety of standardized descriptor names for features.
All planetary feature names recognized by the
International Astronomical Union
The International Astronomical Union (IAU; french: link=yes, Union astronomique internationale, UAI) is a nongovernmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreac ...
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.
[Morton, Oliver. Mapping Mars: science, imagination, and the birth of a world. Farrar, Straus, and Giroux, 2002.] This means that in some cases names may change as new imagery becomes available,
or in other cases
widely adopted informal names changed in line with the rules.
The standard names are chosen to consciously avoid interpreting the underlying cause of the feature, but rather to describe only its appearance.
By planet
See also
*
Astrobiology
Astrobiology, and the related field of exobiology, is an interdisciplinary scientific field that studies the origins, early evolution, distribution, and future of life in the universe. Astrobiology is the multidisciplinary field that investig ...
*
Exoplanet
An exoplanet or extrasolar planet is a planet outside the Solar System. The first possible evidence of an exoplanet was noted in 1917 but was not recognized as such. The first confirmation of detection occurred in 1992. A different planet, init ...
*
Exoplanetology
*
Planetary habitability
Planetary habitability is the measure of a planet's or a natural satellite's potential to develop and maintain environments hospitable to life. Life may be generated directly on a planet or satellite endogenously or be transferred to it from ...
References
Further reading
*
*
*Hauber E et al. (2019) Planetary geologic mapping. In: Hargitai H (e
) Planetary Cartography and GIS Springer.
*Hargitai H et al. (2015
Classification and Characterization of Planetary Landforms.In: Hargitai H, Kerszturi Á (eds) Encyclopedia of Planetary Landforms. Springer.
*Page D (2015
The Geology of Planetary Landforms In: Hargitai H, Kereszturi Á (eds) Encyclopedia of Planetary Landforms. Springer.
*
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