Theoretical planetology, also known as theoretical planetary science [3] is a branch of planetary sciences that developed in the 20th century. [4] Scientific models supported by laboratory experiments are used to understand the formation, evolution, and internal structure of planets.
Theoretical planetologists, also known as theoretical planetary scientists, use modelling techniques to develop an understanding of the internal structure of planets by making assumptions about their chemical composition and the state of their materials, then calculating the radial distribution of various properties such as temperature, pressure, or density of material across the planet's internals. [4]
Theoretical planetologists also use numerical models to understand how the Solar System planets were formed and develop in the future, their thermal evolution, their tectonics, how magnetic fields are formed in planetary interiors, how convection processes work in the cores and mantles of terrestrial planets and in the interiors of gas giants, how their lithospheres deform, the orbital dynamics of planetary satellites, how dust and ice are transported on the surface of some planets (such as Mars), and how the atmospheric circulation takes place over a planet. [5]
Theoretical planetologists may use laboratory experiments to understand various phenomena analogous to planetary processes, such as convection in rotating fluids. [5]
Theoretical planetologists make extensive use of basic physics, particularly fluid dynamics and condensed matter physics, and much of their work involves interpretation of data returned by space missions, although they rarely get actively involved in them. [7]
Typically a theoretical planetologist will have to have had higher education in physics, astronomy, geophysics, or planetary science, at PhD doctorate level. [9] [10]
Because of the use of scientific visualisation animation, theoretical planetology has a relationship with computer graphics. Example movies exhibiting this relation are the 4-minute "The Origin of the Moon" [8]
One of the major successes of theoretical planetology is the prediction and subsequent confirmation of volcanism on Io. [1] [2]
The prediction was made by Stanton J. Peale who wrote a scientific paper claiming that Io must be volcanically active that was published one week before Voyager 1 encountered Jupiter. When Voyager 1 photographed Io in 1979, his theory was confirmed. [2] Later photographs of Io by the Hubble Space Telescope and from the ground also showed volcanoes on Io's surface, and they were extensively studied and photographed by the Galileo orbiter of Jupiter from 1995-2003.
D. C. Tozer of University of Newcastle upon Tyne, [11] writing in 1974, expressed the opinion that "it could and will be said that theoretical planetary science is a waste of time" until problems related to "sampling and scaling" are resolved, even though these problems cannot be solved by simply collecting further laboratory data. [12]
Researchers working on theoretical planetology include:
Voyager 2 is a space probe launched by NASA on August 20, 1977, as a part of the Voyager program. It was launched on a trajectory towards the gas giants Jupiter and Saturn and enabled further encounters with the ice giants Uranus and Neptune. It remains the only spacecraft to have visited either of the ice giant planets, and was the third of five spacecraft to achieve Solar escape velocity, which will allow it to leave the Solar System. It has been sending scientific data to Earth for 47 years, 22 days, making it the oldest active space probe. Launched 16 days before its twin Voyager 1, the primary mission of the spacecraft was to study the outer planets and its extended mission is to study interstellar space beyond the Sun's heliosphere.
Ganymede, or Jupiter III, is the largest and most massive natural satellite of Jupiter and in the Solar System. It is the largest Solar System object without a substantial atmosphere, despite being the only moon in the Solar System with a substantial magnetic field. Like Titan, Saturn's largest moon, it is larger than the planet Mercury, but has somewhat less surface gravity than Mercury, Io, or the Moon due to its lower density compared to the three.
David John Stevenson is a professor of planetary science at Caltech. Originally from New Zealand, he received his Ph.D. from Cornell University in physics, where he proposed a model for the interior of Jupiter. He is well known for applying fluid mechanics and magnetohydrodynamics to understand the internal structure and evolution of planets and moons.
Carolyn C. Porco is an American planetary scientist who explores the outer Solar System, beginning with her imaging work on the Voyager missions to Jupiter, Saturn, Uranus and Neptune in the 1980s. She led the imaging science team on the Cassini mission in orbit around Saturn. She is an expert on planetary rings and the Saturnian moon, Enceladus.
The Physical Research Laboratory is a National Research Institute for space and allied sciences, supported mainly by Department of Space, Government of India. This research laboratory has ongoing research programmes in astronomy and astrophysics, atmospheric sciences and aeronomy, planetary and geosciences, Earth sciences, Solar System studies and theoretical physics. It also manages the Udaipur Solar Observatory and Mount Abu InfraRed Observatory. The PRL is located in Ahmedabad.
Albert Roach Hibbs was an American mathematician and physicist affiliated with the Jet Propulsion Laboratory (JPL). He was known as "The Voice of JPL" due to his gift for explaining advanced science in simple terms. He helped establish JPL's Space Science Division in 1960 and later served as its first chief. He was the systems designer for Explorer 1, the USA's first satellite, and helped establish the framework for exploration of the Solar System through the 1960s. Hibbs qualified as an astronaut in 1967 and was slated to be a crew member of Apollo 25, but he ultimately did not go to the Moon due to the Apollo program ending after the Apollo 17 mission in 1972.
Peter Goldreich is an American astrophysicist whose research focuses on celestial mechanics, planetary rings, helioseismology and neutron stars. He is the Lee DuBridge Professor of Astrophysics and Planetary Physics at California Institute of Technology. Since 2005 he has also been a professor at the Institute for Advanced Study in Princeton, New Jersey. Asteroid 3805 Goldreich is named after him.
The Lunar and Planetary Laboratory (LPL) is a research center for planetary science located in Tucson, Arizona. It is also a graduate school, constituting the Department of Planetary Sciences at the University of Arizona. LPL is one of the world's largest programs dedicated exclusively to planetary science in a university setting. The Lunar and Planetary Lab collection is held at the University of Arizona Special Collections Library.
The exploration of Jupiter has been conducted via close observations by automated spacecraft. It began with the arrival of Pioneer 10 into the Jovian system in 1973, and, as of 2023, has continued with eight further spacecraft missions in the vicinity of Jupiter. All of these missions were undertaken by the National Aeronautics and Space Administration (NASA), and all but two were flybys taking detailed observations without landing or entering orbit. These probes make Jupiter the most visited of the Solar System's outer planets as all missions to the outer Solar System have used Jupiter flybys. On 5 July 2016, spacecraft Juno arrived and entered the planet's orbit—the second craft ever to do so. Sending a craft to Jupiter is difficult, mostly due to large fuel requirements and the effects of the planet's harsh radiation environment.
The exploration of Uranus has, to date, been through telescopes and a lone probe by NASA's Voyager 2 spacecraft, which made its closest approach to Uranus on January 24, 1986. Voyager 2 discovered 10 moons, studied the planet's cold atmosphere, and examined its ring system, discovering two new rings. It also imaged Uranus' five large moons, revealing that their surfaces are covered with impact craters and canyons.
The exploration of Saturn has been solely performed by crewless probes. Three missions were flybys, which formed an extended foundation of knowledge about the system. The Cassini–Huygens spacecraft, launched in 1997, was in orbit from 2004 to 2017.
Jonathan I. Lunine is an American planetary scientist and physicist. Lunine teaches at Cornell University, where he is the David C. Duncan Professor in the Physical Sciences and chair of the Department of Astronomy. Having published more than 380 research papers, Lunine is at the forefront of research into planet formation, evolution, and habitability. His work includes analysis of brown dwarfs, gas giants, and planetary satellites. Within the Solar System, bodies with potential organic chemistry and prebiotic conditions, particularly Saturn's moon Titan, have been the focus of Lunine's research.
The Carnegie Institution for Science, also known as Carnegie Science and the Carnegie Institution of Washington, is an organization in the United States established to fund and perform scientific research. The institution is headquartered in Washington, D.C. As of June 30, 2020, the Institution's endowment was valued at $926.9 million. In 2018 the expenses for scientific programs and administration were $96.6 million. Eric Isaacs is president of the institution.
Space research is scientific study carried out in outer space, and by studying outer space. From the use of space technology to the observable universe, space research is a wide research field. Earth science, materials science, biology, medicine, and physics all apply to the space research environment. The term includes scientific payloads at any altitude from deep space to low Earth orbit, extended to include sounding rocket research in the upper atmosphere, and high-altitude balloons.
Io Volcano Observer (IVO) is a proposed low-cost mission to explore Jupiter's moon Io to understand tidal heating as a fundamental planetary process. The main science goals are to understand (A) how and where tidal heat is generated inside Io, (B) how tidal heat is transported to the surface, and (C) how Io is evolving. These results are expected to have direct implications for the thermal history of Europa and Ganymede as well as provide insights into other tidally heated worlds such as Titan and Enceladus. The IVO data may also improve our understanding of magma oceans and thus the early evolution of the Earth and Moon.
Planetary science is the scientific study of planets, celestial bodies and planetary systems and the processes of their formation. It studies objects ranging in size from micrometeoroids to gas giants, aiming to determine their composition, dynamics, formation, interrelations and history. It is a strongly interdisciplinary field, which originally grew from astronomy and Earth science, and now incorporates many disciplines, including planetary geology, cosmochemistry, atmospheric science, physics, oceanography, hydrology, theoretical planetary science, glaciology, and exoplanetology. Allied disciplines include space physics, when concerned with the effects of the Sun on the bodies of the Solar System, and astrobiology.
Candice Joy Hansen-Koharcheck is a planetary scientist. She is responsible for the development and operation of the JunoCam, for which she received the NASA's Outstanding Public Leadership Medal in 2018.
Theodore Neil Divine (1939–1994) was an American stellar astrophysicist and planetary scientist whose work centered on the understanding of star formation.
Sushil K. Atreya is a planetary scientist, educator, and researcher. Atreya is a professor of Climate and Space Sciences and Engineering at the University of Michigan, Ann Arbor.
Cynthia B. Phillips is an American planetary geologist who works for NASA at the Jet Propulsion Laboratory. A focus of her research has been Europa, one of the moons of Jupiter, and she is project staff scientist and project science communications lead for the Europa Clipper spacecraft mission. An expert on processing images from space missions to the planets and their moons, and on the geological processes operating within moons, she has studied the effects of asteroid impacts on the surface of Europa, and definitions of non-earth-based life that could apply on places like Europa that are outside the circumstellar habitable zone.