231 relations: Academy of the Hebrew Language, Acceleration, Accretion (astrophysics), Acetylene, Adaptive optics, Albedo, Alexis Bouvard, Ammonia, Ammonium hydrosulfide, Ammonium sulfide, Angular diameter, Anticyclone, Apparent magnitude, Apparent retrograde motion, Apsis, Argo (spacecraft), Asteroid, Asteroid belt, Astronomer Royal, Astronomical symbols, Astronomical unit, Astronomy Cast, Atmospheric methane, Atmospheric pressure, Axial tilt, Bar (unit), Barycenter, Berlin Observatory, Bond albedo, Bow shocks in astrophysics, Brady Haran, Bureau des Longitudes, Cambridge Observatory, Carbon dioxide, Carbon monoxide, Cassini–Huygens, Ceres (dwarf planet), Clabon Allen, Columbia University Press, Conjunction (astronomy), Convection, CRC Press, Cyan, Degree (angle), Dennis Rawlins, Despina (moon), Differential rotation, Doc (computing), Dwarf planet, Dynamo, ..., Earth, Ecliptic, Edward Guinan, Electrical conductor, Empirical research, Epoch (astronomy), Equator, Ethane, European Southern Observatory, Exoplanet, Exosphere, Fixed stars, François Arago, Friedrich Georg Wilhelm von Struve, G-force, Galatea (moon), Galilean moons, Galileo Galilei, Gas giant, Gauss (unit), Geometric albedo, George Biddell Airy, Giant planet, Gravity, Gravity wave, Great Dark Spot, Great Red Spot, Greek language, Greek mythology, Gustav Holst, Hebrew language, Heinrich Louis d'Arrest, Heliocentrism, Helium, Hindu astrology, Hot Neptune, Hubble Space Telescope, Hydrocarbon, Hydrogen, Hydrogen cyanide, Hydrogen deuteride, Hydrogen ion, Hydrogen sulfide, IAU definition of planet, Ice giant, Infrared, Internal heating, International Astronomical Union, Invariable plane, James Challis, Janus, Johann Gottfried Galle, John Couch Adams, JPL Horizons On-Line Ephemeris System, Julian year (astronomy), Jupiter, Ketu (mythology), Korean language, Kuiper belt, Lagrangian point, Large Strategic Science Missions, Larissa (moon), Lawrence Livermore National Laboratory, List of telescope types, Lunar node, Magnetic field, Magnetic moment, Magnetopause, Magnetosphere, Māori language, Meteorite, Methane, Methane clathrate, Metonymy, Minute and second of arc, Mongolian language, Monthly Notices of the Royal Astronomical Society, Moons of Neptune, Nahuatl, Naiad (moon), Naked eye, NASA, Natural satellite, Neptune (mythology), Neptune Orbiter, Neptune trojan, Neptunium, Nereid (moon), New Horizons 2, Nice model, Night sky, Nitrogen, OB star, Occultation, Oceanus, Opposition (planets), Orbit, Orbital resonance, Osculating orbit, Outline of Neptune, Oxygen, Pascal (unit), PBS, Perturbation (astronomy), Photodissociation, Planet, Planetary core, Planetary flyby, Planetary migration, Planets beyond Neptune, Plutino, Pluto, Poseidon, Properties of water, Proteus (moon), Protoplanetary disk, Psalms, Quadrupole, Quasi-satellite, Refracting telescope, Retrograde and prograde motion, Ring system, Rings of Saturn, Roche limit, Roman mythology, Rotation, Royal Observatory, Greenwich, Russian Academy of Sciences, S/2004 N 1, Saturn, Science (journal), SETI Institute, Silicate, Small Dark Spot, Solar System, Solar time, Solar wind, Spheroid, Stratosphere, Sun, Superionic water, Supersonic speed, Surface gravity, Tangaroa, Telescope, Tesla (unit), Thai language, Thalassa (moon), The New York Times, The Planets, The Washington Post, Thermosphere, Tidal acceleration, Tidal locking, Timeline of the far future, Titan (moon), Tlaloc, Trident, Triton (moon), Trojan (astronomy), Tropopause, Troposphere, Ultraviolet, University of Arizona Press, University of Melbourne, University of Nottingham, Uranus, Urbain Le Verrier, Visible spectrum, Volatiles, Vortex, Voyager 1, Voyager 2, W. M. Keck Observatory, William Herschel, William Lassell, 2 Pallas, 3 Juno, 4 Vesta, 6 Hebe, 7 Iris. Expand index (181 more) » « Shrink index
The Academy of the Hebrew Language (הָאָקָדֶמְיָה לַלָּשׁוֹן הָעִבְרִית, Ha-Akademya la-Lashon ha-Ivrit) was established by the Israeli government in 1953 as the "supreme institution for scholarship on the Hebrew language in the Hebrew University of Jerusalem of Givat Ram campus." It is an educational institution with the mission of creating new Hebrew words to ensure that the language does not die out.
In physics, acceleration is the rate of change of velocity of an object with respect to time.
In astrophysics, accretion is the accumulation of particles into a massive object by gravitationally attracting more matter, typically gaseous matter, in an accretion disk.
Acetylene (systematic name: ethyne) is the chemical compound with the formula C2H2.
Adaptive optics (AO) is a technology used to improve the performance of optical systems by reducing the effect of incoming wavefront distortions by deforming a mirror in order to compensate for the distortion.
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).
Alexis Bouvard (27 June 1767 – 7 June 1843) was a French astronomer.
Ammonia is a compound of nitrogen and hydrogen with the formula NH3.
Ammonium hydrosulfide is the chemical compound with the formula (NH4)SH.
Ammonium sulfide, also known as diammonium sulfide, is an unstable salt with the formula (NH4)2S.
The angular diameter, angular size, apparent diameter, or apparent size is an angular measurement describing how large a sphere or circle appears from a given point of view.
An anticyclone (that is, opposite to a cyclone) is a weather phenomenon defined by the United States National Weather Service's glossary as "a large-scale circulation of winds around a central region of high atmospheric pressure, clockwise in the Northern Hemisphere, counterclockwise in the Southern Hemisphere".
The apparent magnitude of a celestial object is a number that is a measure of its brightness as seen by an observer on Earth.
Apparent retrograde motion is the apparent motion of a planet in a direction opposite to that of other bodies within its system, as observed from a particular vantage point.
An apsis (ἁψίς; plural apsides, Greek: ἁψῖδες) is an extreme point in the orbit of an object.
Argo was a 2009 spacecraft mission concept by NASA to the outer planets and beyond.
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.
Astronomer Royal is a senior post in the Royal Households of the United Kingdom.
Astronomical symbols are symbols used to represent astronomical objects, theoretical constructs and observational events in astronomy.
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.
Atmospheric methane is the methane present in earth's atmosphere.
Atmospheric pressure, sometimes also called barometric pressure, is the pressure within the atmosphere of Earth (or that of another planet).
In astronomy, axial tilt, also known as obliquity, is the angle between an object's rotational axis and its orbital axis, or, equivalently, the angle between its equatorial plane and orbital plane.
The bar is a metric unit of pressure, but is not approved as part of the International System of Units (SI).
The barycenter (or barycentre; from the Ancient Greek βαρύς heavy + κέντρον centre) is the center of mass of two or more bodies that are orbiting each other, which is the point around which they both orbit.
The Berlin Observatory (Berliner Sternwarte) is a German astronomical institution with a series of observatories and related organizations in and around the city of Berlin in Germany, starting from the 18th century.
The Bond albedo, named after the American astronomer George Phillips Bond (1825–1865), who originally proposed it, is the fraction of power in the total electromagnetic radiation incident on an astronomical body that is scattered back out into space.
Bow shocks form the boundary between a magnetosphere and an ambient magnetized medium.
Brady John Haran (born 18 June 1976) is an Australian-born British independent filmmaker and video journalist who is known for his educational videos and documentary films produced for BBC News and his YouTube channels, the most notable being Periodic Videos and Numberphile.
The Bureau des Longitudes is a French scientific institution, founded by decree of 25 June 1795 and charged with the improvement of nautical navigation, standardisation of time-keeping, geodesy and astronomical observation.
Cambridge Observatory is an astronomical observatory at the University of Cambridge in the East of England.
Carbon dioxide (chemical formula) is a colorless gas with a density about 60% higher than that of dry air.
Carbon monoxide (CO) is a colorless, odorless, and tasteless gas that is slightly less dense than air.
The Cassini–Huygens mission, commonly called Cassini, was a collaboration between NASA, the European Space Agency (ESA), and the Italian Space Agency (ASI) to send a probe to study the planet Saturn and its system, including its rings and natural satellites.
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.
Clabon Walter (Cla) Allen FRAS, (28 December 1904 – 11 December 1987) was an Australian astronomer, director of the University of London Observatory and author of Astrophysical Quantities.
Columbia University Press is a university press based in New York City, and affiliated with Columbia University.
In astronomy, a conjunction occurs when two astronomical objects or spacecraft have either the same right ascension or the same ecliptic longitude, usually as observed from Earth.
Convection is the heat transfer due to bulk movement of molecules within fluids such as gases and liquids, including molten rock (rheid).
The CRC Press, LLC is a publishing group based in the United States that specializes in producing technical books.
Cyan is a greenish-blue color.
A degree (in full, a degree of arc, arc degree, or arcdegree), usually denoted by ° (the degree symbol), is a measurement of a plane angle, defined so that a full rotation is 360 degrees.
Dennis Rawlins (born 1937) is an American astronomer and historian who has acquired the reputation of skeptic primarily with respect to historical claims connected to astronomical considerations.
Despina (or; Latin: Despœna; Greek: Δέσποινα), also known as Neptune V, is the third-closest inner satellite of Neptune.
Differential rotation is seen when different parts of a rotating object move with different angular velocities (rates of rotation) at different latitudes and/or depths of the body and/or in time.
In computing, DOC or doc (an abbreviation of "document") is a filename extension for word processing documents, most commonly in the proprietary Microsoft Word Binary File Format.
A dwarf planet is a planetary-mass object that is neither a planet nor a natural satellite.
A dynamo is an electrical generator that creates direct current using a commutator.
Earth is the third planet from the Sun and the only astronomical object known to harbor life.
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.
Edward F. Guinan is a professor in Villanova University's Department of Astronomy and Astrophysics.
In physics and electrical engineering, a conductor is an object or type of material that allows the flow of an electrical current in one or more directions.
Empirical research is research using empirical evidence.
In astronomy, an epoch is a moment in time used as a reference point for some time-varying astronomical quantity, such as the celestial coordinates or elliptical orbital elements of a celestial body, because these are subject to perturbations and vary with time.
An equator of a rotating spheroid (such as a planet) is its zeroth circle of latitude (parallel).
Ethane is an organic chemical compound with chemical formula.
The European Southern Observatory (ESO) is a 15-nation intergovernmental research organization for ground-based astronomy.
An exoplanet or extrasolar planet is a planet outside our solar system.
The exosphere (ἔξω éxō "outside, external, beyond", σφαῖρα sphaĩra "sphere") is a thin, atmosphere-like volume surrounding a planet or natural satellite where molecules are gravitationally bound to that body, but where the density is too low for them to behave as a gas by colliding with each other.
The fixed stars (stellae fixae) comprise the background of astronomical objects that appear to not move relative to each other in the night sky compared to the foreground of Solar System objects that do.
Dominique François Jean Arago (Domènec Francesc Joan Aragó), known simply as François Arago (Catalan: Francesc Aragó) (26 February 17862 October 1853), was a French mathematician, physicist, astronomer, freemason, supporter of the carbonari and politician.
Friedrich Georg Wilhelm von Struve (Василий Яковлевич Струве, trans. Vasily Yakovlevich Struve; 15 April 1793 –) was a German-Russian astronomer and geodesist from the famous Struve family.
The gravitational force, or more commonly, g-force, is a measurement of the type of acceleration that causes a perception of weight.
Galatea (Greek: Γαλάτεια), also known as Neptune VI, is the fourth-closest inner satellite of Neptune.
The Galilean moons are the four largest moons of Jupiter—Io, Europa, Ganymede, and Callisto.
Galileo Galilei (15 February 1564Drake (1978, p. 1). The date of Galileo's birth is given according to the Julian calendar, which was then in force throughout Christendom. In 1582 it was replaced in Italy and several other Catholic countries with the Gregorian calendar. Unless otherwise indicated, dates in this article are given according to the Gregorian calendar. – 8 January 1642) was an Italian polymath.
A gas giant is a giant planet composed mainly of hydrogen and helium.
The gauss, abbreviated as G or Gs, is the cgs unit of measurement of magnetic flux density (or "magnetic induction") (B).
In astronomy, the geometric albedo of a celestial body is the ratio of its actual brightness as seen from the light source (i.e. at zero phase angle) to that of an idealized flat, fully reflecting, diffusively scattering (Lambertian) disk with the same cross-section.
Sir George Biddell Airy (27 July 18012 January 1892) was an English mathematician and astronomer, Astronomer Royal from 1835 to 1881.
A giant planet is any massive planet.
Gravity, or gravitation, is a natural phenomenon by which all things with mass or energy—including planets, stars, galaxies, and even light—are brought toward (or gravitate toward) one another.
In fluid dynamics, gravity waves are waves generated in a fluid medium or at the interface between two media when the force of gravity or buoyancy tries to restore equilibrium.
The Great Dark Spot (also known as GDS-89) was one of a series of dark spots on Neptune similar in appearance to Jupiter's Great Red Spot.
The Great Red Spot is a persistent high-pressure region in the atmosphere of Jupiter, producing an anticyclonic storm 22° south of the planet's equator.
Greek (Modern Greek: ελληνικά, elliniká, "Greek", ελληνική γλώσσα, ellinikí glóssa, "Greek language") is an independent branch of the Indo-European family of languages, native to Greece and other parts of the Eastern Mediterranean and the Black Sea.
Greek mythology is the body of myths and teachings that belong to the ancient Greeks, concerning their gods and heroes, the nature of the world, and the origins and significance of their own cult and ritual practices.
Gustav Theodore Holst (born Gustavus Theodore von Holst; 21 September 1874 – 25 May 1934) was an English composer, arranger and teacher.
Heinrich Louis d'Arrest (13 August 1822 – 14 June 1875) was a German astronomer, born in Berlin.
Heliocentrism is the astronomical model in which the Earth and planets revolve around the Sun at the center of the Solar System.
Helium (from lit) is a chemical element with symbol He and atomic number 2.
Jyotisha (or Jyotishyam from Sanskrit, from "light, heavenly body") is the traditional Hindu system of astrology, also known as Hindu astrology, Nepalese Shastra, Indian astrology, and more recently Vedic astrology.
A hot Neptune or Hoptune is a type of giant planet with a mass similar to that of Uranus or Neptune orbiting close to its star, normally within less than 1 AU.
The Hubble Space Telescope (HST) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation.
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon.
Hydrogen is a chemical element with symbol H and atomic number 1.
Hydrogen cyanide (HCN), sometimes called prussic acid, is a chemical compound with the chemical formula HCN.
Hydrogen deuteride is a diatomic molecule substance or compound of the two isotopes of hydrogen: the majority isotope 1H protium and 2H deuterium.
A hydrogen ion is created when a hydrogen atom loses or gains an electron.
Hydrogen sulfide is the chemical compound with the chemical formula H2S.
The International Astronomical Union (IAU) defined in August 2006 that, in the Solar System, a planet is a celestial body which.
An ice giant is a giant planet composed mainly of elements heavier than hydrogen and helium, such as oxygen, carbon, nitrogen, and sulfur.
Infrared radiation (IR) is electromagnetic radiation (EMR) with longer wavelengths than those of visible light, and is therefore generally invisible to the human eye (although IR at wavelengths up to 1050 nm from specially pulsed lasers can be seen by humans under certain conditions). It is sometimes called infrared light.
Internal heat is the heat source from the interior of celestial objects, such as stars, brown dwarfs, planets, moons, dwarf planets, and (in the early history of the Solar System) even asteroids such as Vesta, resulting from contraction caused by gravity (the Kelvin–Helmholtz mechanism), nuclear fusion, tidal heating, core solidification (heat of fusion released as molten core material solidifies), and radioactive decay.
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.
The invariable plane of a planetary system, also called Laplace's invariable plane, is the plane passing through its barycenter (center of mass) perpendicular to its angular momentum vector.
James Challis FRS (12 December 1803 – 3 December 1882) was an English clergyman, physicist and astronomer.
In ancient Roman religion and myth, Janus (IANVS (Iānus)) is the god of beginnings, gates, transitions, time, duality, doorways, passages, and endings.
Johann Gottfried Galle, 1880 Galle's signature Memorial plaque in Wittenberg Johann Gottfried Galle (9 June 1812 – 10 July 1910) was a German astronomer from Radis, Germany, at the Berlin Observatory who, on 23 September 1846, with the assistance of student Heinrich Louis d'Arrest, was the first person to view the planet Neptune and know what he was looking at.
John Couch Adams (5 June 1819 – 21 January 1892) was a British mathematician and astronomer.
JPL Horizons On-Line Ephemeris System provides easy access to key Solar System data and flexible production of highly accurate ephemerides for Solar System objects.
In astronomy, a Julian year (symbol: a) is a unit of measurement of time defined as exactly 365.25 days of SI seconds each.
Jupiter is the fifth planet from the Sun and the largest in the Solar System.
Ketu (Sanskrit: केतु, IAST) is the descending (i.e 'south') lunar node in Vedic, or Hindu astrology.
The Korean language (Chosŏn'gŭl/Hangul: 조선말/한국어; Hanja: 朝鮮말/韓國語) is an East Asian language spoken by about 80 million people.
The Kuiper belt, occasionally called the Edgeworth–Kuiper belt, is a circumstellar disc in the outer Solar System, extending from the orbit of Neptune (at 30 AU) to approximately 50 AU from the Sun.
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.
NASA's Large Strategic Science Missions, formerly known as Flagship missions or Flagship-class missions, are the costliest and most capable NASA science spacecraft.
Larissa (Greek: Λάρισσα), also known as Neptune VII, is the fifth-closest inner satellite of Neptune.
Lawrence Livermore National Laboratory (LLNL) is an American federal research facility in Livermore, California, United States, founded by the University of California, Berkeley in 1952.
The following are lists of devices categorized as types of telescopes or devices associated with telescopes.
The lunar nodes are the orbital nodes of the Moon, that is, the two points at which the orbit of the Moon crosses the ecliptic.
A magnetic field is a vector field that describes the magnetic influence of electrical currents and magnetized materials.
The magnetic moment is a quantity that represents the magnetic strength and orientation of a magnet or other object that produces a magnetic field.
The magnetopause is the abrupt boundary between a magnetosphere and the surrounding plasma.
A magnetosphere is the region of space surrounding an astronomical object in which charged particles are manipulated or affected by that object's magnetic field.
Māori, also known as te reo ("the language"), is an Eastern Polynesian language spoken by the Māori people, the indigenous population of New Zealand.
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 moon.
Methane is a chemical compound with the chemical formula (one atom of carbon and four atoms of hydrogen).
Methane clathrate (CH4·5.75H2O) or (4CH4·23H2O), also called methane hydrate, hydromethane, methane ice, fire ice, natural gas hydrate, or gas hydrate, is a solid clathrate compound (more specifically, a clathrate hydrate) in which a large amount of methane is trapped within a crystal structure of water, forming a solid similar to ice.
Metonymy is a figure of speech in which a thing or concept is referred to by the name of something closely associated with that thing or concept.
A minute of arc, arcminute (arcmin), arc minute, or minute arc is a unit of angular measurement equal to of one degree.
The Mongolian language (in Mongolian script: Moŋɣol kele; in Mongolian Cyrillic: монгол хэл, mongol khel.) is the official language of Mongolia and both the most widely-spoken and best-known member of the Mongolic language family.
Monthly Notices of the Royal Astronomical Society (MNRAS) is a peer-reviewed scientific journal covering research in astronomy and astrophysics.
Neptune has 14 known moons, which are named for minor water deities in Greek mythology.
Nahuatl (The Classical Nahuatl word nāhuatl (noun stem nāhua, + absolutive -tl) is thought to mean "a good, clear sound" This language name has several spellings, among them náhuatl (the standard spelling in the Spanish language),() Naoatl, Nauatl, Nahuatl, Nawatl. In a back formation from the name of the language, the ethnic group of Nahuatl speakers are called Nahua.), known historically as Aztec, is a language or group of languages of the Uto-Aztecan language family.
Naiad (or; Ναϊάδ-ες), also known as Neptune III, is the innermost satellite of Neptune, named after the Naiads of Greek legend.
Naked eye, also called bare eye or unaided eye, is the practice of engaging in visual perception unaided by a magnifying or light-collecting optical instrument, such as a telescope or microscope.
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).
Neptune (Neptūnus) was the god of freshwater and the sea in Roman religion.
Neptune Orbiter was a proposed NASA unmanned planetary spacecraft to explore the planet Neptune.
Neptune trojans are bodies that orbit the Sun near one of the stable Lagrangian points of Neptune, similar to the trojans of other planets.
Neptunium is a chemical element with symbol Np and atomic number 93.
Nereid is the third-largest moon of Neptune.
New Horizons 2 (also New Horizons II, NHII, or NH2) was a proposed mission to the trans-Neptunian objects by NASA.
The Nice model is a scenario for the dynamical evolution of the Solar System.
The term night sky, usually associated with astronomy from Earth, refers to the nighttime appearance of celestial objects like stars, planets, and the Moon, which are visible in a clear sky between sunset and sunrise, when the Sun is below the horizon.
Nitrogen is a chemical element with symbol N and atomic number 7.
OB stars are hot, massive stars of spectral types O or early-type B that form in loosely organized groups called OB associations.
An occultation is an event that occurs when one object is hidden by another object that passes between it and the observer.
Oceanus (Ὠκεανός Ōkeanós), also known as Ogenus (Ὤγενος Ōgenos or Ὠγηνός Ōgēnos) or Ogen (Ὠγήν Ōgēn), was a divine figure in classical antiquity, believed by the ancient Greeks and Romans to be the divine personification of the sea, an enormous river encircling the world.
In positional astronomy, two astronomical objects are said to be in opposition when they are on opposite sides of the celestial sphere, as observed from a given body (usually Earth).
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.
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.
In astronomy, and in particular in astrodynamics, the osculating orbit of an object in space at a given moment in time is the gravitational Kepler orbit (i.e. ellipse or other conic) that it would have about its central body if perturbations were not present.
The following outline is provided as an overview of and topical guide to Neptune: Neptune – eighth and farthest known planet from the Sun in the Solar System.
Oxygen is a chemical element with symbol O and atomic number 8.
The pascal (symbol: Pa) is the SI derived unit of pressure used to quantify internal pressure, stress, Young's modulus and ultimate tensile strength.
The Public Broadcasting Service (PBS) is an American public broadcaster and television program distributor.
In astronomy, perturbation is the complex motion of a massive body subject to forces other than the gravitational attraction of a single other massive body.
Photodissociation, photolysis, or photodecomposition is a chemical reaction in which a chemical compound is broken down by photons.
A planet is an astronomical body orbiting a star or stellar remnant that is massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion, and has cleared its neighbouring region of planetesimals.
The planetary core consists of the innermost layer(s) of a planet; which may be composed of solid and liquid layers.
A planetary flyby is the act of sending a space probe past a planet or a dwarf planet close enough to record scientific data.
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.
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.
Poseidon (Ποσειδῶν) was one of the Twelve Olympians in ancient Greek religion and myth.
Water is a polar inorganic compound that is at room temperature a tasteless and odorless liquid, which is nearly colorless apart from an inherent hint of blue. It is by far the most studied chemical compound and is described as the "universal solvent" and the "solvent of life". It is the most abundant substance on Earth and the only common substance to exist as a solid, liquid, and gas on Earth's surface. It is also the third most abundant molecule in the universe. Water molecules form hydrogen bonds with each other and are strongly polar. This polarity allows it to separate ions in salts and strongly bond to other polar substances such as alcohols and acids, thus dissolving them. Its hydrogen bonding causes its many unique properties, such as having a solid form less dense than its liquid form, a relatively high boiling point of 100 °C for its molar mass, and a high heat capacity. Water is amphoteric, meaning that it is both an acid and a base—it produces + and - ions by self-ionization.
Proteus (Greek: Πρωτεύς), also known as Neptune VIII, is the second-largest Neptunian moon, and Neptune's largest inner satellite.
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.
The Book of Psalms (תְּהִלִּים or, Tehillim, "praises"), commonly referred to simply as Psalms or "the Psalms", is the first book of the Ketuvim ("Writings"), the third section of the Hebrew Bible, and a book of the Christian Old Testament.
A quadrupole or quadrapole is one of a sequence of configurations of things like electric charge or current, or gravitational mass that can exist in ideal form, but it is usually just part of a multipole expansion of a more complex structure reflecting various orders of complexity.
A quasi-satellite is an object in a specific type of co-orbital configuration (1:1 orbital resonance) with a planet where the object stays close to that planet over many orbital periods.
A refracting telescope (also called a refractor) is a type of optical telescope that uses a lens as its objective to form an image (also referred to a dioptric telescope).
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).
A ring system is a disc or ring orbiting an astronomical object that is composed of solid material such as dust and moonlets, and is a common component of satellite systems around giant planets.
The rings of Saturn are the most extensive ring system of any planet in the Solar System.
In celestial mechanics, the Roche limit, also called Roche radius, is the distance in which a celestial body, held together only by its own gravity, will disintegrate due to a second celestial body's tidal forces exceeding the first body's gravitational self-attraction.
Roman mythology is the body of traditional stories pertaining to ancient Rome's legendary origins and religious system, as represented in the literature and visual arts of the Romans.
A rotation is a circular movement of an object around a center (or point) of rotation.
The Royal Observatory, Greenwich (ROG; known as the Old Royal Observatory from 1957 to 1998, when the working Royal Greenwich Observatory, RGO, moved from Greenwich to Herstmonceux) is an observatory situated on a hill in Greenwich Park, overlooking the River Thames.
The Russian Academy of Sciences (RAS; Росси́йская акаде́мия нау́к (РАН) Rossíiskaya akadémiya naúk) consists of the national academy of Russia; a network of scientific research institutes from across the Russian Federation; and additional scientific and social units such as libraries, publishing units, and hospitals.
S/2004 N 1 is a small moon of Neptune, about in diameter, which orbits the planet in just under one Earth day.
Saturn is the sixth planet from the Sun and the second-largest in the Solar System, after Jupiter.
Science, also widely referred to as Science Magazine, is the peer-reviewed academic journal of the American Association for the Advancement of Science (AAAS) and one of the world's top academic journals.
The SETI Institute is a not-for-profit research organization whose mission is to explore, understand, and explain the origin and nature of life in the universe, and to apply the knowledge gained to inspire and guide present and future generations.
In chemistry, a silicate is any member of a family of anions consisting of silicon and oxygen, usually with the general formula, where 0 ≤ x Silicate anions are often large polymeric molecules with an extense variety of structures, including chains and rings (as in polymeric metasilicate), double chains (as in, and sheets (as in. In geology and astronomy, the term silicate is used to mean silicate minerals, ionic solids with silicate anions; as well as rock types that consist predominantly of such minerals. In that context, the term also includes the non-ionic compound silicon dioxide (silica, quartz), which would correspond to x.
The Small Dark Spot, sometimes also called Dark Spot 2 or The Wizard's Eye, was a southern cyclonic storm on the planet Neptune.
The Solar SystemCapitalization of the name varies.
Solar time is a calculation of the passage of time based on the position of the Sun in the sky.
The solar wind is a stream of charged particles released from the upper atmosphere of the Sun, called the corona.
A spheroid, or ellipsoid of revolution, is a quadric surface obtained by rotating an ellipse about one of its principal axes; in other words, an ellipsoid with two equal semi-diameters.
The stratosphere is the second major layer of Earth's atmosphere, just above the troposphere, and below the mesosphere.
The Sun is the star at the center of the Solar System.
Superionic water is a phase of water under extreme heat and pressure which has properties of both a solid and a liquid, which is supported by some experimental evidence.
Supersonic travel is a rate of travel of an object that exceeds the speed of sound (Mach 1).
The surface gravity, g, of an astronomical or other object is the gravitational acceleration experienced at its surface.
In Māori mythology, Tangaroa (also Takaroa) is one of the great gods, the god of the sea.
A telescope is an optical instrument that aids in the observation of remote objects by collecting electromagnetic radiation (such as visible light).
The tesla (symbol T) is a derived unit of magnetic flux density (informally, magnetic field strength) in the International System of Units.
Thai, Central Thai, or Siamese, is the national and official language of Thailand and the first language of the Central Thai people and vast majority Thai of Chinese origin.
Thalassa (Greek: Θάλασσα), also known as Neptune IV, is the second-innermost satellite of Neptune.
The New York Times (sometimes abbreviated as The NYT or The Times) is an American newspaper based in New York City with worldwide influence and readership.
The Planets, Op.
The Washington Post is a major American daily newspaper founded on December 6, 1877.
The thermosphere is the layer of the Earth's atmosphere directly above the mesosphere and below the exosphere.
Tidal acceleration is an effect of the tidal forces between an orbiting natural satellite (e.g. the Moon), and the primary planet that it orbits (e.g. Earth).
Tidal locking (also called gravitational locking or captured rotation) occurs when the long-term interaction between a pair of co-orbiting astronomical bodies drives the rotation rate of at least one of them into the state where there is no more net transfer of angular momentum between this body (e.g. a planet) and its orbit around the second body (e.g. a star); this condition of "no net transfer" must be satisfied over the course of one orbit around the second body.
While predictions of the future can never be absolutely certain, present understanding in various scientific fields allows for the prediction of far-future events, if only in the broadest outline.
Titan is the largest moon of Saturn.
Tlaloc (ˈtɬaːlok) was a member of the pantheon of gods in Aztec religion.
A trident is a three-pronged spear.
Triton is the largest natural satellite of the planet Neptune, and the first Neptunian moon to be discovered.
In astronomy, a trojan is a minor planet or moon that shares the orbit of a planet or larger moon, wherein the trojan remains in the same, stable position relative to the larger object.
The tropopause is the boundary in the Earth's atmosphere between the troposphere and the stratosphere.
The troposphere is the lowest layer of Earth's atmosphere, and is also where nearly all weather conditions take place.
Ultraviolet (UV) is electromagnetic radiation with a wavelength from 10 nm to 400 nm, shorter than that of visible light but longer than X-rays.
The University of Arizona Press, a publishing house founded in 1959 as a department of the University of Arizona, is a nonprofit publisher of scholarly and regional books.
The University of Melbourne is a public research university located in Melbourne, Australia.
The University of Nottingham is a public research university in Nottingham, United Kingdom.
Uranus is the seventh planet from the Sun.
Urbain Jean Joseph Le Verrier (11 March 1811 – 23 September 1877) was a French mathematician who specialized in celestial mechanics and is best known for predicting the existence and position of Neptune using only mathematics.
The visible spectrum is the portion of the electromagnetic spectrum that is visible to the human eye.
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 fluid dynamics, a vortex (plural vortices/vortexes) is a region in a fluid in which the flow revolves around an axis line, which may be straight or curved.
Voyager 1 is a space probe launched by NASA on September 5, 1977.
Voyager 2 is a space probe launched by NASA on August 20, 1977, to study the outer planets.
The W. M. Keck Observatory is a two-telescope astronomical observatory at an elevation of 4,145 meters (13,600 ft) near the summit of Mauna Kea in the U.S. state of Hawaii.
Frederick William Herschel, (Friedrich Wilhelm Herschel; 15 November 1738 – 25 August 1822) was a German-born British astronomer, composer and brother of fellow astronomer Caroline Herschel, with whom he worked.
William Lassell, (18 June 1799 – 5 October 1880) was an English merchant and astronomer.
Pallas, minor-planet designation 2 Pallas, is the second asteroid to have been discovered (after Ceres), and is one of the largest asteroids in the Solar System.
Juno, minor-planet designation 3 Juno in the Minor Planet Center catalogue system, is an asteroid in the asteroid belt.
Vesta, minor-planet designation 4 Vesta, is one of the largest objects in the asteroid belt, with a mean diameter of.
6 Hebe is a large main-belt asteroid, containing around half a percent of the mass of the belt.
7 Iris is a large main-belt asteroid orbiting the Sun between Mars and Jupiter.
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