158 relations: Absolute magnitude, Acetylene, Alastair G. W. Cameron, Albedo, American Geosciences Institute, Ammonia, Apparent magnitude, Applied Physics Laboratory, Apsis, Armin Otto Leuschner, Asteroid, Asteroid belt, Asteroid capture, Astronomer, Astronomical naming conventions, Astronomical unit, Astronomy Cast, Blink comparator, Brian G. Marsden, Carbon monoxide, Centaur (minor planet), Ceres (dwarf planet), Cerro Tololo Inter-American Observatory, Charge-coupled device, Charles T. Kowal, Charon (moon), Chemical compound, Chemical element, Circumstellar disc, Classical Kuiper belt object, Clearing the neighbourhood, Clyde Tombaugh, Comet, Comet Hale–Bopp, Cosmic ray, Dark Matter and the Dinosaurs, David C. Jewitt, Debris disk, Definition of planet, Discover (magazine), Dwarf planet, Earth mass, Ecliptic, Eris (dwarf planet), Ethane, Ethylene, Expected value, Five-planet Nice model, Formation and evolution of the Solar System, Fred Lawrence Whipple, ..., Frederick C. Leonard, Gerard Kuiper, Halley's Comet, Haumea, Hills cloud, Hubble Space Telescope, Hydrate, Hydrocarbon, Hydrogen sulfide, Icarus (journal), Ice giant, Infrared excess, International Astronomical Union, Jan Oort, Jane Luu, Julio Ángel Fernández, Jupiter, Kelvin, Kenneth Edgeworth, Kirkwood gap, Kitt Peak National Observatory, Kobe University, Lagrangian point, Large Synoptic Survey Telescope, List of periodic comets, List of possible dwarf planets, List of trans-Neptunian objects, Makemake, Mars, Mass, Massachusetts Institute of Technology, Mauna Kea, Methane, Minor planet, Minor Planet Center, Monthly Notices of the Royal Astronomical Society, Moons of Jupiter, Moons of Pluto, Moons of Saturn, Moons of Uranus, NASA, Natural satellite, Nature (journal), Neptune, Neptune trojan, New Horizons, Nice model, Observation, Occultation, Oort cloud, Orbit, Orbital eccentricity, Orbital inclination, Orbital period, Orbital resonance, Outgassing, Pan-STARRS, PDF, Phoebe (moon), Planetary migration, Planetesimal, Planets beyond Neptune, Plutino, Pluto, Primordial nuclide, Protoplanetary disk, Resonant trans-Neptunian object, Retrograde and prograde motion, Rock (geology), Saturn, Scattered disc, Scientific theory, Scott Tremaine, Semi-major and semi-minor axes, Small Solar System body, Solar System, Solid nitrogen, Space Telescope Science Institute, Spectral line, Spectroscopy, Spectrum, Streaming instability, Sun, Surface gravity, Synonym, The Astronomical Journal, The Astrophysical Journal, The Planetary Society, Tholin, Torus, Trans-Neptunian object, Triton (moon), University of Hawaii, Uranus, Volatiles, Volatility (chemistry), Vox (website), Water, (181708) 1993 FW, (486958) 2014 MU69, 15760 Albion, 20000 Varuna, 2060 Chiron, 28978 Ixion, 38628 Huya, 50000 Quaoar, 5145 Pholus, 90482 Orcus. Expand index (108 more) » « Shrink index
Absolute magnitude is a measure of the luminosity of a celestial object, on a logarithmic astronomical magnitude scale.
Acetylene (systematic name: ethyne) is the chemical compound with the formula C2H2.
Alastair G. W. (Graham Walter) Cameron (21 June 1925 in Winnipeg, Manitoba, Canada – 3 October 2005 in Tucson, Arizona, USA) was a Canadian astrophysicist and space scientist who was an eminent staff member of the Astronomy department of Harvard University.
Albedo (albedo, meaning "whiteness") is the measure of the diffuse reflection of solar radiation out of the total solar radiation received by an astronomical body (e.g. a planet like Earth).
The American Geosciences Institute (AGI) is a nonprofit federation of 51 geoscientific and professional organizations that represents geologists, geophysicists, and other earth scientists.
Ammonia is a compound of nitrogen and hydrogen with the formula NH3.
The apparent magnitude of a celestial object is a number that is a measure of its brightness as seen by an observer on Earth.
The Johns Hopkins University Applied Physics Laboratory, commonly known as simply the Applied Physics Laboratory, or APL, located in Howard County, Maryland, near Laurel and Columbia, is a not-for-profit, university-affiliated research center (or UARC) employing 6,000 people.
An apsis (ἁψίς; plural apsides, Greek: ἁψῖδες) is an extreme point in the orbit of an object.
Armin Otto Leuschner (January 16, 1868 – April 22, 1953) was an American astronomer and educator.
Asteroids are minor planets, especially those of the inner Solar System.
The asteroid belt is the circumstellar disc in the Solar System located roughly between the orbits of the planets Mars and Jupiter.
Asteroid capture is the entering by an asteroid into an orbit around a larger planetary body.
An astronomer is a scientist in the field of astronomy who concentrates their studies on a specific question or field outside the scope of Earth.
In ancient times, only the Sun and Moon, a few hundred stars and the most easily visible planets had names.
The astronomical unit (symbol: au, ua, or AU) is a unit of length, roughly the distance from Earth to the Sun.
Astronomy Cast is an educational nonprofit podcast discussing various topics in the field of astronomy.
A blink comparator was a viewing apparatus used by astronomers to find differences between two photographs of the night sky.
Brian Geoffrey Marsden (5 August 1937 – 18 November 2010) was an English astronomer and the longtime director of the Minor Planet Center (MPC) at the Harvard-Smithsonian Center for Astrophysics (director emeritus from 2006 to 2010).
Carbon monoxide (CO) is a colorless, odorless, and tasteless gas that is slightly less dense than air.
Centaurs are small solar system bodies with a semi-major axis between those of the outer planets.
Ceres (minor-planet designation: 1 Ceres) is the largest object in the asteroid belt that lies between the orbits of Mars and Jupiter, slightly closer to Mars' orbit.
The Cerro Tololo Inter-American Observatory (CTIO) is an astronomical observatory located on Cerro Tololo in the Coquimbo Region of northern Chile, with additional facilities located on Cerro Pachón about to the southeast.
A charge-coupled device (CCD) is a device for the movement of electrical charge, usually from within the device to an area where the charge can be manipulated, for example conversion into a digital value.
Charles Thomas Kowal (November 8, 1940 – November 28, 2011) was an American astronomer known for his observations and discoveries in the Solar System.
Charon, also known as (134340) Pluto I, is the largest of the five known natural satellites of the dwarf planet Pluto.
A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) composed of atoms from more than one element held together by chemical bonds.
A chemical element is a species of atoms having the same number of protons in their atomic nuclei (that is, the same atomic number, or Z).
A circumstellar disc (or circumstellar disk) is a torus, pancake or ring-shaped accumulation of matter composed of gas, dust, planetesimals, asteroids or collision fragments in orbit around a star.
A classical Kuiper belt object, also called a cubewano ("QB1-o"), is a low-eccentricity Kuiper belt object (KBO) that orbits beyond Neptune and is not controlled by an orbital resonance with Neptune.
"Clearing the neighbourhood around its orbit" is a criterion for a celestial body to be considered a planet in the Solar System.
Clyde William Tombaugh (February 4, 1906January 17, 1997) was an American astronomer.
A comet is an icy small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process called outgassing.
Comet Hale–Bopp (formally designated C/1995 O1) is a comet that was perhaps the most widely observed of the 20th century, and one of the brightest seen for many decades.
Cosmic rays are high-energy radiation, mainly originating outside the Solar System and even from distant galaxies.
Dark Matter and the Dinosaurs: The Astounding Interconnectedness of the Universe is a 2015 non-fiction book by Harvard astrophysicist Lisa Randall.
David C. Jewitt (born 1958) is an English astronomer and professor of astronomy at UCLA's Earth, Planetary, and Space Science Department in California.
A debris disk is a circumstellar disk of dust and debris in orbit around a star.
The definition of planet, since the word was coined by the ancient Greeks, has included within its scope a wide range of celestial bodies.
Discover is an American general audience science magazine launched in October 1980 by Time Inc.
A dwarf planet is a planetary-mass object that is neither a planet nor a natural satellite.
Earth mass (where ⊕ is the standard astronomical symbol for planet Earth) is the unit of mass equal to that of Earth.
The ecliptic is the circular path on the celestial sphere that the Sun follows over the course of a year; it is the basis of the ecliptic coordinate system.
Eris (minor-planet designation 136199 Eris) is the most massive and second-largest (by volume) dwarf planet in the known Solar System.
Ethane is an organic chemical compound with chemical formula.
Ethylene (IUPAC name: ethene) is a hydrocarbon which has the formula or H2C.
In probability theory, the expected value of a random variable, intuitively, is the long-run average value of repetitions of the experiment it represents.
The five-planet Nice model is a recent variation of the Nice model that begins with five giant planets, the current four plus an additional ice giant, in a chain of mean-motion resonances.
The formation and evolution of the Solar System began 4.6 billion years ago with the gravitational collapse of a small part of a giant molecular cloud.
Fred Lawrence Whipple (November 5, 1906 – August 30, 2004) was an American astronomer, who worked at the Harvard College Observatory for over 70 years.
Frederick Charles Leonard (March 12, 1896 – June 23, 1960) was an American astronomer.
Gerard Peter Kuiper (born Gerrit Pieter Kuiper; December 7, 1905 – December 23, 1973) was a Dutch–American astronomer, planetary scientist, selenographer, author and professor.
Halley's Comet or Comet Halley, officially designated 1P/Halley, is a short-period comet visible from Earth every 74–79 years.
Haumea, minor-planet designation 136108 Haumea, is a dwarf planet located beyond Neptune's orbit.
In astronomy, the Hills cloud (also called the inner Oort cloud and inner cloud) is a vast theoretical circumstellar disc, interior to the Oort cloud, whose outer border would be located at around 20,000 to 30,000 astronomical units (AU) from the Sun, and whose inner border, less well-defined, is hypothetically located at, well beyond planetary and Kuiper Belt object orbits - but distances might be much greater.
The Hubble Space Telescope (HST) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation.
In chemistry, a hydrate is a substance that contains water or its constituent elements.
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon.
Hydrogen sulfide is the chemical compound with the chemical formula H2S.
Icarus is a scientific journal dedicated to the field of planetary science.
An ice giant is a giant planet composed mainly of elements heavier than hydrogen and helium, such as oxygen, carbon, nitrogen, and sulfur.
An infrared excess is a measurement of an astronomical source, typically a star, that in their spectral energy distribution has a greater measured infrared flux than expected by assuming the star is a blackbody radiator.
The International Astronomical Union (IAU; Union astronomique internationale, UAI) is an international association of professional astronomers, at the PhD level and beyond, active in professional research and education in astronomy.
Jan Hendrik Oort (or; 28 April 1900 – 5 November 1992) was a Dutch astronomer who made significant contributions to the understanding of the Milky Way and who was a pioneer in the field of radio astronomy.
Julio Ángel Fernández Alves (born Montevideo, 5 April 1946) is a Uruguayan astronomer and teacher, member of the department of astronomy at the Universidad de la República in Montevideo.
Jupiter is the fifth planet from the Sun and the largest in the Solar System.
The Kelvin scale is an absolute thermodynamic temperature scale using as its null point absolute zero, the temperature at which all thermal motion ceases in the classical description of thermodynamics.
Kenneth Essex Edgeworth, DSO, MC (26 February 1880 – 10 October 1972) was an Irish astronomer, economist and engineer.
A Kirkwood gap is a gap or dip in the distribution of the semi-major axes (or equivalently of the orbital periods) of the orbits of main-belt asteroids.
The Kitt Peak National Observatory (KPNO) is a United States astronomical observatory located on Kitt Peak of the Quinlan Mountains in the Arizona-Sonoran Desert on the Tohono O'odham Nation, west-southwest of Tucson, Arizona.
, also known in the Kansai region as, is a leading Japanese national university located in the city of Kobe, in Hyōgo.
In celestial mechanics, the Lagrangian points (also Lagrange points, L-points, or libration points) are positions in an orbital configuration of two large bodies, wherein a small object, affected only by the gravitational forces from the two larger objects, will maintain its position relative to them.
The Large Synoptic Survey Telescope (LSST) is a wide-field survey reflecting telescope with an 8.4-meter primary mirror, currently under construction, that will photograph the entire available sky every few nights.
Periodic comets (also known as short-period comets) are comets having orbital periods of less than 200 years or that have been observed during more than a single perihelion passage (e.g. 153P/Ikeya–Zhang).
It is estimated that there may be 200 dwarf planets in the Kuiper belt of the outer Solar System and possibly more than 10,000 in the region beyond.
This is a list of trans-Neptunian objects (TNOs), which are minor planets in the Solar System that orbit the Sun at a greater distance on average than Neptune, that is, their orbit has a semi-major axis greater than 30.1 astronomical units (AU).
Makemake (minor-planet designation 136472 Makemake) is a dwarf planet and perhaps the largest Kuiper belt object in the classical population, with a diameter approximately two thirds that of Pluto.
Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System after Mercury.
Mass is both a property of a physical body and a measure of its resistance to acceleration (a change in its state of motion) when a net force is applied.
The Massachusetts Institute of Technology (MIT) is a private research university located in Cambridge, Massachusetts, United States.
Mauna Kea is a dormant volcano on the island of Hawaii.
Methane is a chemical compound with the chemical formula (one atom of carbon and four atoms of hydrogen).
A minor planet is an astronomical object in direct orbit around the Sun (or more broadly, any star with a planetary system) that is neither a planet nor exclusively classified as a comet.
The Minor Planet Center (MPC) is the official worldwide organization in charge of collecting observational data for minor planets (such as asteroids and comets), calculating their orbits and publishing this information via the Minor Planet Circulars.
Monthly Notices of the Royal Astronomical Society (MNRAS) is a peer-reviewed scientific journal covering research in astronomy and astrophysics.
There are 69 known moons of Jupiter.
The dwarf planet Pluto has five moons down to a detection limit of about 1 km in diameter.
The moons of Saturn are numerous and diverse, ranging from tiny moonlets less than 1 kilometer across to the enormous Titan, which is larger than the planet Mercury.
Uranus is the seventh planet of the Solar System; it has 27 known moons, all of which are named after characters from the works of William Shakespeare and Alexander Pope.
The National Aeronautics and Space Administration (NASA) is an independent agency of the executive branch of the United States federal government responsible for the civilian space program, as well as aeronautics and aerospace research.
A natural satellite or moon is, in the most common usage, an astronomical body that orbits a planet or minor planet (or sometimes another small Solar System body).
Nature is a British multidisciplinary scientific journal, first published on 4 November 1869.
Neptune is the eighth and farthest known planet from the Sun in the Solar System.
Neptune trojans are bodies that orbit the Sun near one of the stable Lagrangian points of Neptune, similar to the trojans of other planets.
New Horizons is an interplanetary space probe that was launched as a part of NASA's New Frontiers program.
The Nice model is a scenario for the dynamical evolution of the Solar System.
Observation is the active acquisition of information from a primary source.
An occultation is an event that occurs when one object is hidden by another object that passes between it and the observer.
The Oort cloud, named after the Dutch astronomer Jan Oort, sometimes called the Öpik–Oort cloud, is a theoretical cloud of predominantly icy planetesimals proposed to surround the Sun at distances ranging from.
In physics, an orbit is the gravitationally curved trajectory of an object, such as the trajectory of a planet around a star or a natural satellite around a planet.
The orbital eccentricity of an astronomical object is a parameter that determines the amount by which its orbit around another body deviates from a perfect circle.
Orbital inclination measures the tilt of an object's orbit around a celestial body.
The orbital period is the time a given astronomical object takes to complete one orbit around another object, and applies in astronomy usually to planets or asteroids orbiting the Sun, moons orbiting planets, exoplanets orbiting other stars, or binary stars.
In celestial mechanics, an orbital resonance occurs when orbiting bodies exert a regular, periodic gravitational influence on each other, usually because their orbital periods are related by a ratio of small integers.
Outgassing (sometimes called offgassing, particularly when in reference to indoor air quality) is the release of a gas that was dissolved, trapped, frozen or absorbed in some material.
The Panoramic Survey Telescope and Rapid Response System (Pan-STARRS 1; obs. code: F51 and Pan-STARRS 2 obs. code: F52) located at Haleakala Observatory, Hawaii, USA, consists of astronomical cameras, telescopes and a computing facility that is surveying the sky for moving or variable objects on a continual basis, and also producing accurate astrometry and photometry of already detected objects.
The Portable Document Format (PDF) is a file format developed in the 1990s to present documents, including text formatting and images, in a manner independent of application software, hardware, and operating systems.
Phoebe (Greek: Φοίβη Phoíbē) is an irregular satellite of Saturn with a mean diameter of 213 km.
Planetary migration occurs when a planet or other stellar satellite interacts with a disk of gas or planetesimals, resulting in the alteration of the satellite's orbital parameters, especially its semi-major axis.
Planetesimals are solid objects thought to exist in protoplanetary disks and in debris disks.
Following the discovery of the planet Neptune in 1846, there was considerable speculation that another planet might exist beyond its orbit.
In astronomy, the plutinos are a dynamical group of trans-Neptunian objects in the outermost region of the Solar System that orbit in 2:3 mean-motion resonance with Neptune.
Pluto (minor planet designation: 134340 Pluto) is a dwarf planet in the Kuiper belt, a ring of bodies beyond Neptune.
In geochemistry, geophysics and geonuclear physics, primordial nuclides, also known as primordial isotopes, are nuclides found on Earth that have existed in their current form since before Earth was formed.
A protoplanetary disk is a rotating circumstellar disk of dense gas and dust surrounding a young newly formed star, a T Tauri star, or Herbig Ae/Be star.
In astronomy, a resonant trans-Neptunian object is a trans-Neptunian object (TNO) in mean-motion orbital resonance with Neptune.
Retrograde motion in astronomy is, in general, orbital or rotational motion of an object in the direction opposite the rotation of its primary, that is the central object (right figure).
Rock or stone is a natural substance, a solid aggregate of one or more minerals or mineraloids.
Saturn is the sixth planet from the Sun and the second-largest in the Solar System, after Jupiter.
The scattered disc (or scattered disk) is a distant circumstellar disc in the Solar System that is sparsely populated by icy small solar system bodies, and are a subset of the broader family of trans-Neptunian objects.
A scientific theory is an explanation of an aspect of the natural world that can be repeatedly tested, in accordance with the scientific method, using a predefined protocol of observation and experiment.
Scott Duncan Tremaine (born 1950) is a Canadian-born astrophysicist.
In geometry, the major axis of an ellipse is its longest diameter: a line segment that runs through the center and both foci, with ends at the widest points of the perimeter.
A small Solar System body (SSSB) is an object in the Solar System that is neither a planet, nor a dwarf planet, nor a natural satellite.
The Solar SystemCapitalization of the name varies.
Solid nitrogen is the solid form of the element nitrogen.
The Space Telescope Science Institute (STScI) is the science operations center for the Hubble Space Telescope (HST; in orbit since 1990) and for the James Webb Space Telescope (JWST; scheduled to be launched in March 2021).
A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from emission or absorption of light in a narrow frequency range, compared with the nearby frequencies.
Spectroscopy is the study of the interaction between matter and electromagnetic radiation.
A spectrum (plural spectra or spectrums) is a condition that is not limited to a specific set of values but can vary, without steps, across a continuum.
In planetary science a streaming instability is a hypothetical mechanism for the formation of planetesimals in which the drag felt by solid particles orbiting in a gas disk leads to their spontaneous concentration into clumps which can gravitationally collapse.
The Sun is the star at the center of the Solar System.
The surface gravity, g, of an astronomical or other object is the gravitational acceleration experienced at its surface.
A synonym is a word or phrase that means exactly or nearly the same as another word or phrase in the same language.
The Astronomical Journal (often abbreviated AJ in scientific papers and references) is a peer-reviewed monthly scientific journal owned by the American Astronomical Society and currently published by IOP Publishing.
The Astrophysical Journal, often abbreviated ApJ (pronounced "ap jay") in references and speech, is a peer-reviewed scientific journal of astrophysics and astronomy, established in 1895 by American astronomers George Ellery Hale and James Edward Keeler.
The Planetary Society is an American internationally active, non-governmental, nonprofit foundation.
Tholins (after the Greek θολός (tholós) "hazy" or "muddy"; from the ancient Greek word meaning "sepia ink") are a wide variety of organic compounds formed by solar ultraviolet irradiation or cosmic rays from simple carbon-containing compounds such as carbon dioxide, methane or ethane, often in combination with nitrogen.
In geometry, a torus (plural tori) is a surface of revolution generated by revolving a circle in three-dimensional space about an axis coplanar with the circle.
A trans-Neptunian object (TNO, also written transneptunian object) is any minor planet in the Solar System that orbits the Sun at a greater average distance (semi-major axis) than Neptune, 30 astronomical units (AU).
Triton is the largest natural satellite of the planet Neptune, and the first Neptunian moon to be discovered.
The University of Hawaiʻi system (formally the University of Hawaiʻi and popularly known as UH) is a public, co-educational college and university system that confers associate, bachelor's, master's, and doctoral degrees through three university campuses, seven community college campuses, an employment training center, three university centers, four education centers and various other research facilities distributed across six islands throughout the State of Hawaii in the United States.
Uranus is the seventh planet from the Sun.
In planetary science, volatiles are the group of chemical elements and chemical compounds with low boiling points that are associated with a planet's or moon's crust or atmosphere.
In chemistry and physics, volatility is quantified by the tendency of a substance to vaporize.
Vox is an American news and opinion website owned by Vox Media.
Water is a transparent, tasteless, odorless, and nearly colorless chemical substance that is the main constituent of Earth's streams, lakes, and oceans, and the fluids of most living organisms.
(181708) 1993 FW was the second trans-Neptunian object to be discovered after Pluto and Charon, the first having been.
, previously designated and, and nicknamed Ultima Thule by the New Horizons team, is a trans-Neptunian object from the Kuiper belt located in the outermost regions of the Solar System.
15760 Albion, provisional designation, was the first trans-Neptunian object to be discovered after Pluto and Charon.
20000 Varuna, provisional designation, is a large classical Kuiper belt object.
2060 Chiron, provisional designation, and also known as 95P/Chiron, is a minor planet in the outer Solar System, orbiting the Sun between Saturn and Uranus.
28978 Ixion, provisional designation, is a plutino (an object that has a 2:3 orbital resonance with Neptune).
38628 Huya, provisional designation, is a trans-Neptunian object and binary system from the Kuiper belt in the outermost region of the Solar System.
50000 Quaoar, provisional designation, is a non-resonant trans-Neptunian object (cubewano) and possibly a dwarf planet in the Kuiper belt, located in the outermost region of the Solar System.
5145 Pholus (from Φόλος) provisional designation, is an eccentric centaur in the outer Solar System, approximately 180 kilometers in diameter, that crosses the orbit of both Saturn and Neptune.
90482 Orcus, provisional designation, is a trans-Neptunian object from the Kuiper belt with a large moon, Vanth.
Comet belt, Cooper belt, Cuiper Belt, Edgeworth-Kuiper Belt, Edgeworth-Kuiper belt, Edgeworth–Kuiper Belt, Edgeworth–Kuiper belt, KBOs, Kaiper belt, Keiber belt, Keiper Belt, Kepler belt, Kuiper Belt, Kuiper Belt Object, Kuiper Belt Objects, Kuiper Belt object, Kuiper Belt objects, Kuiper Cliff, Kuiper Cloud, Kuiper belt object, Kuiper belt objects, Kuiper cliff, Kuiper gap, Kuiper-belt, Kuiper-belt object, Kuiperoid, Kupier belt, Kupiter belt, Kuyper Belt, Kuyper belt, Kyper belt, Similar objects.