query: where are most asteroids located in our solar system

pos: Asteroid belt Asteroid belt The asteroid belt is the circumstellar disc in the Solar System located roughly between the orbits of the planets Mars and Jupiter. It is occupied by numerous irregularly shaped bodies called asteroids or minor planets. The asteroid belt is also termed the main asteroid belt or main belt to distinguish it from other asteroid populations in the Solar System such as near-Earth asteroids and trojan asteroids. About half the mass of the belt is contained in the four largest asteroids: Ceres, Vesta, Pallas, and Hygiea. The total mass of the asteroid belt is approximately 4% that of the

pos: Near-Earth object accepted origin of these asteroids is that main-belt asteroids are moved into the inner Solar System through orbital resonances with Jupiter. The interaction with Jupiter through the resonance perturbs the asteroid's orbit and it comes into the inner Solar System. The asteroid belt has gaps, known as Kirkwood gaps, where these resonances occur as the asteroids in these resonances have been moved onto other orbits. New asteroids migrate into these resonances, due to the Yarkovsky effect that provides a continuing supply of near-Earth asteroids. Compared to the entire mass of the asteroid belt, the mass loss necessary to sustain the

pos: Hungaria asteroid Kirkwood gap except for those far enough from Mars's orbital plane where that planet exerts much smaller forces. This has left a situation where the only remaining concentration of asteroids inward of the 4:1 resonance lies at high inclination orbits, although they have fairly low eccentricities. However, even at the present time in Solar System history some Hungaria asteroids cross the orbit of Mars and are still in the process of being ejected from the Solar System due to Mars's influence (unlike asteroids in the "core" of the asteroid belt, where Jupiter's influence predominates). Long-term changes in the orbit of

pos: Geology of solar terrestrial planets approaching Ceres at aphelion, which may constrain Dawn's ability to observe this phenomenon. Note: This info was taken directly from the main article, sources for the material are included there. Asteroids, comets, and meteoroids are all debris remaining from the nebula in which the Solar System formed 4.6 billion years ago. The asteroid belt is located between Mars and Jupiter. It is made of thousands of rocky planetesimals from to a few meters across. These are thought to be debris of the formation of the Solar System that could not form a planet due to Jupiter's gravity. When asteroids collide

pos: Asteroid in the outer asteroid belt, at distances greater than 2.6 AU. Most were later ejected by Jupiter, but those that remained may be the D-type asteroids, and possibly include Ceres. Various dynamical groups of asteroids have been discovered orbiting in the inner Solar System. Their orbits are perturbed by the gravity of other bodies in the Solar System and by the Yarkovsky effect. Significant populations include: The majority of known asteroids orbit within the asteroid belt between the orbits of Mars and Jupiter, generally in relatively low-eccentricity (i.e. not very elongated) orbits. This belt is now estimated to contain between

pos: Stability of the Solar System "n"-body problem. Orbital resonance happens when any two periods have a simple numerical ratio. The most fundamental period for an object in the Solar System is its orbital period, and orbital resonances pervade the Solar System. In 1867, the American astronomer Daniel Kirkwood noticed that asteroids in the asteroid belt are not randomly distributed. There were distinct gaps in the belt at locations that corresponded to resonances with Jupiter. For example, there were no asteroids at the 3:1 resonance – a distance of 2.5 AU – or at the 2:1 resonance at 3.3 AU (AU is the astronomical unit, or

pos: Asteroid belt period in orbit and at the surface. Asteroid belt The asteroid belt is the circumstellar disc in the Solar System located roughly between the orbits of the planets Mars and Jupiter. It is occupied by numerous irregularly shaped bodies called asteroids or minor planets. The asteroid belt is also termed the main asteroid belt or main belt to distinguish it from other asteroid populations in the Solar System such as near-Earth asteroids and trojan asteroids. About half the mass of the belt is contained in the four largest asteroids: Ceres, Vesta, Pallas, and Hygiea. The total mass of the asteroid

pos: Asteroid belt Asteroid belt The asteroid belt is the circumstellar disc in the Solar System located roughly between the orbits of the planets Mars and Jupiter. It is occupied by numerous irregularly shaped bodies called asteroids or minor planets. The asteroid belt is also termed the main asteroid belt or main belt to distinguish it from other asteroid populations in the Solar System such as near-Earth asteroids and trojan asteroids. About half the mass of the belt is contained in the four largest asteroids: Ceres, Vesta, Pallas, and Hygiea. The total mass of the asteroid belt is approximately 4% that of the

pos: Asteroid of the inner Solar System including those co-orbital with Jupiter. There exist millions of asteroids, many thought to be the shattered remnants of planetesimals, bodies within the young Sun's solar nebula that never grew large enough to become planets. The vast majority of known asteroids orbit within the main asteroid belt located between the orbits of Mars and Jupiter, or are co-orbital with Jupiter (the Jupiter trojans). However, other orbital families exist with significant populations, including the near-Earth objects. Individual asteroids are classified by their characteristic spectra, with the majority falling into three main groups: C-type, M-type, and S-type. These

pos: Carbon dioxide contains carbon-14. Carbon-rich asteroids are relatively preponderant in the outer parts of the asteroid belt in our solar system. These asteroids have not yet been directly sampled by scientists. The asteroids can be used in hypothetical space-based carbon mining, which may be possible in the future, but is currently technologically impossible. Isotopes of carbon are atomic nuclei that contain six protons plus a number of neutrons (varying from 2 to 16). Carbon has two stable, naturally occurring isotopes. The isotope carbon-12 (C) forms 98.93% of the carbon on Earth, while carbon-13 (C) forms the remaining 1.07%. The concentration of

pos: Solar System icy objects. Astronomers sometimes informally divide this structure into separate regions. The inner Solar System includes the four terrestrial planets and the asteroid belt. The outer Solar System is beyond the asteroids, including the four giant planets. Since the discovery of the Kuiper belt, the outermost parts of the Solar System are considered a distinct region consisting of the objects beyond Neptune. Most of the planets in the Solar System have secondary systems of their own, being orbited by planetary objects called natural satellites, or moons (two of which, Titan and Ganymede, are larger than the planet Mercury), and, in

pos: Asteroid Location of Ceres (within asteroid belt) compared to other bodies of the Solar System Asteroids and the asteroid belt are a staple of science fiction stories. Asteroids play several potential roles in science fiction: as places human beings might colonize, resources for extracting minerals, hazards encountered by spacecraft traveling between two other points, and as a threat to life on Earth or other inhabited planets, dwarf planets and natural satellites by potential impact. "Further information about asteroids" Asteroid Asteroids are minor planets, especially of the inner Solar System. Larger asteroids have also been called planetoids. These terms have historically been

pos: Hungaria asteroid by the outwards migration of the giant planets of the Solar System according to simulations done under the Nice model—and these dispersed E-belt asteroids might in turn have been the impactors of the Late Heavy Bombardment. Hungaria asteroid The Hungaria group is a dynamical group of asteroids in the asteroid belt. The Hungaria asteroids orbit the Sun with a semi-major axis (longest radius of an ellipse) between 1.78 and 2.00 astronomical units (AU). They are the innermost dense concentration of asteroids in the Solar System—the near-Earth asteroids are much more sparse—and derive their name from their largest member 434 Hungaria.

pos: Asteroid recent observations, such as the analysis of the cometary dust collected by the "Stardust" probe, are increasingly blurring the distinction between comets and asteroids, suggesting "a continuum between asteroids and comets" rather than a sharp dividing line. The minor planets beyond Jupiter's orbit are sometimes also called "asteroids", especially in popular presentations. However, it is becoming increasingly common for the term "asteroid" to be restricted to minor planets of the inner Solar System. Therefore, this article will restrict itself for the most part to the classical asteroids: objects of the asteroid belt, Jupiter trojans, and near-Earth objects. When the IAU

pos: Phaeton (hypothetical planet) Only in 1949 did the well-known Soviet astronomer Sergej Vladirimovich Orlov give it the name Phaeton... This name has become established." Theories regarding the formation of the asteroid belt from the destruction of a hypothetical fifth planet are today collectively referred to as the "disruption theory". This theory states that there was once a major planetary member of our solar system circulating in the present gap between Mars and Jupiter, which was variously destroyed when: Today, the Phaeton hypothesis has been superseded by the accretion model. Most astronomers today believe that the asteroids in the main belt are remnants of

pos: Hilda asteroid to 2.5 magnitudes as compared to the apexes. The Hildas traverse regions of the Solar system from approximately 2 AU up to Jupiter's orbit. This entails a variety of physical conditions and the neighborhood of various groups of asteroids. On further observation some theories on the Hildas may have to be revised. Hilda asteroid The Hilda asteroids (adj. "Hildian") are a dynamical group of more than 4000 asteroids located beyond the asteroid belt in a 3:2 orbital resonance with Jupiter. The namesake is the asteroid 153 Hilda. Hildas move in their elliptical orbits so that their aphelia put them opposite

pos: Interplanetary medium our planet as a solitary sphere traveling in a cold, dark vacuum of space around the Sun". Interplanetary medium The interplanetary medium (IPM) is the material which fills the Solar System, and through which all the larger Solar System bodies, such as planets, dwarf planets, asteroids, and comets, move. The interplanetary medium includes interplanetary dust, cosmic rays and hot plasma from the solar wind. The temperature of the interplanetary medium varies. For dust particles within the asteroid belt, typical temperatures range from 200 K (−73 °C) at 2.2 AU down to 165 K (−108 °C) at 3.2 AU. The density

pos: Desert Fireball Network time, the DFN expanded into an automated digital fireball observatory, which is now expanding further to new regions of Australia and overseas. So far, four meteorites have been recovered with a high-accuracy trajectory and orbit defined. Meteorites are metallic or stony objects that fall to the Earth's surface from space. Scientists believe that most meteorites originate from asteroids within the asteroid belt of our solar system, but there is an increasing amount of evidence to suggest some may come from comets. Some meteorites also come from larger planetary bodies, such as the moon and Mars. Meteorites typically preserve their histories

pos: Frost line (astrophysics) the Solar System was located within this region. The outer asteroids are icy C-class objects (e.g. Abe et al. 2000; Morbidelli et al. 2000) whereas the inner asteroid belt is largely devoid of water. This implies that when planetesimal formation occurred the snow line was located at around 2.7 AU from the Sun. For example, the dwarf planet Ceres with semi-major axis of 2.77 AU lies almost exactly on the lower estimation for water snow line during the formation of the Solar System. Ceres appears to have an icy mantle and may even have a water ocean below the surface.

pos: Lexell's Comet system and be undiscovered. Most new asteroids discovered even in the asteroid belt (as of 2018) are only 1–4 kilometers across. If Lexell's comet remains in the inner Solar System, it would most likely be an unidentified asteroid. The paper identified 4 potential asteroids which could be related: (99.2% chance), (74% chance), (0.2% chance), and (~0% chance). They find that is very likely to be a remnant of Lexell's comet, although due to a number of close approaches with Jupiter as well as uncertain non-gravitational parameters, a definite link cannot be made. Lexell's Comet D/1770 L1, popularly known as Lexell's

pos: Nice model faster traverse of the secular resonances across the asteroid belt limits the loss of asteroids from its core. Most of the rocky impactors of the Late Heavy Bombardment instead originate from an inner extension that is disrupted when the giant planets reach their current positions, with a remnant remaining as the Hungaria asteroids. Some D-type asteroids are embedded in inner asteroid belt, within 2.5 AU, during encounters with the ice giant when it is crossing the asteroid belt. The frequent ejection of the ice giant encountering Jupiter has led David Nesvorný and others to hypothesize an early Solar System with

pos: Asteroid belt asteroids, S-type or silicate asteroids, and M-type or metallic asteroids. Carbonaceous asteroids, as their name suggests, are carbon-rich. They dominate the asteroid belt's outer regions. Together they comprise over 75% of the visible asteroids. They are redder in hue than the other asteroids and have a very low albedo. Their surface composition is similar to carbonaceous chondrite meteorites. Chemically, their spectra match the primordial composition of the early Solar System, with only the lighter elements and volatiles removed. S-type (silicate-rich) asteroids are more common toward the inner region of the belt, within 2.5 AU of the Sun. The spectra of

pos: Kuiper belt Kuiper belt 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. It is similar to the asteroid belt, but is far larger—20 times as wide and 20 to 200 times as massive. Like the asteroid belt, it consists mainly of small bodies or remnants from when the Solar System formed. While many asteroids are composed primarily of rock and metal, most Kuiper belt objects are composed largely of frozen volatiles (termed "ices"), such as methane,

pos: (15692) 1984 RA (15692) 1984 RA , provisional designation , is a Hungaria asteroid from the innermost regions of the asteroid belt, approximately in diameter. It was discovered on 1 September 1984, by Italian astronomer Maria Barucci at the Palomar Observatory in California, United States. The presumed E-type asteroid has a longer-than average rotation period of 37.4 hours and possibly an elongated shape. is a bright core member of the Hungaria family (), a large family of three thousand asteroids located within the dynamical group with the same name. Hungarias form the innermost dense concentration of asteroids in the Solar System; they are

pos: Asteroid dwarf planets as well as an alternative for asteroids since they are not star-like. The word "planetesimal" has a similar meaning, but refers specifically to the small building blocks of the planets that existed when the Solar System was forming. The term "planetule" was coined by the geologist William Daniel Conybeare to describe minor planets, but is not in common use. The three largest objects in the asteroid belt, Ceres, Pallas, and Vesta, grew to the stage of protoplanets. Ceres is a dwarf planet, the only one in the inner Solar System. When found, asteroids were seen as a class

pos: Asteroid Asteroid Asteroids are minor planets, especially of the inner Solar System. Larger asteroids have also been called planetoids. These terms have historically been applied to any astronomical object orbiting the Sun that did not resemble a planet-like disc and was not observed to have characteristics of an active comet such as a tail. As minor planets in the outer Solar System were discovered they were typically found to have volatile-rich surfaces similar to comets. As a result, they were often distinguished from objects found in the main asteroid belt. In this article, the term "asteroid" refers to the minor planets

pos: Nice model sweep through the inner Solar System. In the asteroid belt these excite the eccentricities of the asteroids driving them onto orbits that intersect those of the terrestrial planets causing a more extended period of impacts by stony objects and removing roughly 90% of its mass. The number of planetesimals that would reach the Moon is consistent with the crater record from the LHB. However, the orbital distribution of the remaining asteroids does not match observations. In the outer Solar System the impacts onto Jupiter's moons are sufficient to trigger Ganymede's differentiation but not Callisto's. The impacts of icy planetesimals onto

pos: 2010 GZ60 would be unstable unless it was a Jupiter trojan. Jupiter trojans have (4.6 AU < semi-major axis < 5.5 AU; eccentricity < 0.3). The nominal semi-major axis of "" is just outside of the asteroid belt. As more observations come in, it is expected the orbit determination will be that of a main belt asteroid as they are by far the most numerous discovered objects in the solar system and account for 94% of all known Small Solar System bodies. Outer main belt asteroids have a semi-major axis less than 4.6 AU. The orbital inclination is the easiest part of

pos: Hungaria asteroid Hungaria asteroid The Hungaria group is a dynamical group of asteroids in the asteroid belt. The Hungaria asteroids orbit the Sun with a semi-major axis (longest radius of an ellipse) between 1.78 and 2.00 astronomical units (AU). They are the innermost dense concentration of asteroids in the Solar System—the near-Earth asteroids are much more sparse—and derive their name from their largest member 434 Hungaria. The Hungaria group includes the Hungaria family (), a collisional asteroid family which dominates its population. The Hungaria asteroids typically share the following orbital parameters: The 4:1 resonance Kirkwood gap (at 2.06 AU) marks the outer

pos: E-belt asteroids from 1.7 to 2.1 astronomical units (AU). In the current Solar System most orbits in this region are unstable due to the presence of the ν secular resonance. However, prior to the giant planet migration described in the Nice model the outer planets would have been in a more compact configuration with nearly circular orbits. With the planets in this configuration the ν secular resonance would be located outside the asteroid belt. Stable orbits would have existed inside 2.1 AU and the inner edge of the primordial asteroid belt would have been defined by Mars-crossing orbits. During the migration of

pos: Main-belt comet three identified main-belt comets all orbit within the outer part of the asteroid belt. It is not known how an outer Solar System body like the other comets could have made its way into a low-eccentricity orbit typical of the asteroid belt, which is only weakly perturbed by the planets. Hence it is assumed that unlike other comets, the main-belt comets are simply icy asteroids, which formed in an inner Solar System orbit close to their present positions, and that many outer asteroids may be icy. Some main-belt comets display a cometary dust tail only for a part of their

pos: Chicxulub impactor which caused the death of most of the planet's non-avian dinosaurs and many other species. The impactor's crater is over in diameter making it the second largest known impact crater on Earth. There are several competing models for the impactor's origin and its relationship to other asteroids that still exist in the Solar System. In September 2007, William F. Bottke, David Vokrouhlický, and David Nesvorný proposed an origin for the impactor in an article published in "Nature". This argued that a collision in the asteroid belt 160 million years ago resulted in the Baptistina family of asteroids, the largest surviving

neg: Akaa Solar System Scale Model Model was built in 2017 by amateur astronomer Kari-Pekka Arola. A walking tour of Akaa Solar System Scale Model starts from the Sun and all the planets are located northbound from the Sun. The walking route goes through the center of Toijala and towards the port of Toijala, where the furthest dwarf planet in the scale model, Eris is located. All the planets and most notable dwarf planets are included in the scale model. The current location (140 AU) of Voyager 1 -spacecraft in relation to our solar system is also presented in the scale model (as the most distant

neg: Stability of the Solar System essentially the distance from sun to earth). These are now known as the Kirkwood gaps. Some asteroids were later discovered to orbit in these gaps, but their orbits are unstable and they will eventually break out of the resonance due to close encounters with a major planet. Another common form of resonance in the Solar System is spin–orbit resonance, where the period of spin (the time it takes the planet or moon to rotate once about its axis) has a simple numerical relationship with its orbital period. An example is our own Moon, which is in a 1:1 spin–orbit resonance

neg: Gaia (spacecraft) target. The spacecraft has enough consumables to operate for approximately nine years, if its detectors are not degrading as fast as initially expected. The mission could therefore be extended. The "Gaia" targets represent approximately 1% of the Milky Way population with all stars brighter than magnitude 20 in a broad photometric band that covers most of the visual range. Additionally, "Gaia" is expected to detect thousands to tens of thousands of Jupiter-sized exoplanets beyond the Solar System, 500,000 quasars outside our galaxy and tens of thousands of new asteroids and comets within the Solar System. "Gaia" will create a precise

neg: Near-Earth object Near-Earth object A near-Earth object (NEO) is any small Solar System body whose orbit brings it to proximity with Earth. By convention, a Solar System body is a NEO if its closest approach to the Sun (perihelion) is less than 1.3 astronomical units (AU). If a NEO's orbit crosses the Earth's and the object is larger than across, it is considered a potentially hazardous object (PHO). Most known PHOs and NEOs are asteroids, but a small fraction are comets. There are over 19,000 known near-Earth asteroids (NEAs), over a hundred short-period near-Earth comets (NECs), and a number of solar-orbiting spacecraft

neg: Heliocentric orbit Orbiter Mission. Heliocentric orbit A heliocentric orbit (also called circumsolar orbit) is an orbit around the barycenter of the Solar System, which is usually located within or very near the surface of the Sun. All planets, comets, and asteroids in the Solar System, and the Sun itself are in such orbits, as are many artificial probes and pieces of debris. The moons of planets in the Solar System, by contrast, are not in heliocentric orbits, as they orbit their respective planet (although the Moon has a convex orbit around the Sun). The barycenter of the Solar System, while always very

neg: Heliocentric orbit Heliocentric orbit A heliocentric orbit (also called circumsolar orbit) is an orbit around the barycenter of the Solar System, which is usually located within or very near the surface of the Sun. All planets, comets, and asteroids in the Solar System, and the Sun itself are in such orbits, as are many artificial probes and pieces of debris. The moons of planets in the Solar System, by contrast, are not in heliocentric orbits, as they orbit their respective planet (although the Moon has a convex orbit around the Sun). The barycenter of the Solar System, while always very near the

neg: Goldstone Solar System Radar Goldstone Solar System Radar The Goldstone Solar System Radar, or GSSR, is a large radar system used for investigating objects in the Solar system. Located in the desert near Barstow, California, it comprises a 500-kW X-band (8500 MHz) transmitter and a low-noise receiver on the 70-m DSS 14 antenna at the Goldstone Deep Space Communications Complex. It has been used to investigate Mercury, Venus, Mars, the asteroids, and moons of Jupiter and Saturn. The most comparable facility is the radar at Arecibo Observatory. GSSR can work in two different modes. In the monostatic radar mode, GSSR both transmits and receives.

neg: Contact binary (small Solar System body) Contact binary (small Solar System body) A contact binary is a small Solar System body that is composed of two bodies that have gravitated toward each other until they touch. This means contact binaries have odd shapes. Comet Churyumov–Gerasimenko and Comet Tuttle are most likely contact binaries. Asteroids suspected of being contact binaries include the unusually elongated 624 Hektor and the bilobated 216 Kleopatra and 4769 Castalia. 25143 Itokawa, which was photographed by the "Hayabusa" probe, also appears to be a contact binary which has resulted in an elongated, bent body. About 10–15% of near-Earth asteroids larger than 200 meters

neg: 773 Irmintraud of the Tagish Lake meteorite which landed in Canada on January 18, 2000. In 1992, Larry Lebofsky and colleagues published an article in which they noted that "unaltered asteroids are thought to represent the raw materials available for terrestrial planet formation and so are important to our understanding of the origin and evolution of the Solar System." Since at least 1980, it was believed that D-type asteroids were unaltered asteroids, ultraprimitive in composition and composed largely of hydrated silicates and organic material. However, in analyzing the spectra of 773 Irmintraud for the water of hydration band (the 3-µm absorption feature

neg: Wesley Huntress Discoveries" with Soviet space scientist Mikhail Ya Marov. Wesley Huntress Wesley T. Huntress, Jr. is an American space scientist. An astrochemist and space scientist, Huntress worked for about twenty years at NASA's Jet Propulsion Laboratory. During the 1980s he was also a videogame designer, producing games for Apple computers. In 1988 Huntress moved to NASA headquarters, where he would serve in several positions, including Director of NASA's Solar System Exploration Division and Associate Administrator for Space Science. As a part of these positions, Huntress oversaw all NASA research missions to the planets and asteroids of our solar system, including missions

neg: Wesley Huntress Wesley Huntress Wesley T. Huntress, Jr. is an American space scientist. An astrochemist and space scientist, Huntress worked for about twenty years at NASA's Jet Propulsion Laboratory. During the 1980s he was also a videogame designer, producing games for Apple computers. In 1988 Huntress moved to NASA headquarters, where he would serve in several positions, including Director of NASA's Solar System Exploration Division and Associate Administrator for Space Science. As a part of these positions, Huntress oversaw all NASA research missions to the planets and asteroids of our solar system, including missions to Mars, Venus, Jupiter, and Saturn. Following his

neg: Near-Earth object its mission, Rosetta was crashed into the comet′s surface in 2016. Near-Earth object A near-Earth object (NEO) is any small Solar System body whose orbit brings it to proximity with Earth. By convention, a Solar System body is a NEO if its closest approach to the Sun (perihelion) is less than 1.3 astronomical units (AU). If a NEO's orbit crosses the Earth's and the object is larger than across, it is considered a potentially hazardous object (PHO). Most known PHOs and NEOs are asteroids, but a small fraction are comets. There are over 19,000 known near-Earth asteroids (NEAs), over a

neg: Desert Fireball Network core of large asteroids that may no longer exist in the solar system. They may once have been surrounded by a silicate shell on the parent body, implying that other silicate-rich meteorites originated from the same parent body too, despite the clear compositional differences. This means we can learn about the processes occurring deep within asteroids fairly easily, and we know the composition of the inner core of Earth based on these rocks. Highly primitive meteorites contain some of the first solids to have formed in our solar system. These materials have been used to date a more precise age

neg: Asteroid family all the members have closely matching compositions for most families. Notable exceptions are those families (such as the Vesta family) which formed from a large differentiated parent body. Asteroid families are thought to have lifetimes of the order of a billion years, depending on various factors (e.g. smaller asteroids are lost faster). This is significantly shorter than the Solar System's age, so few if any are relics of the early Solar System. Decay of families occurs both because of slow dissipation of the orbits due to perturbations from Jupiter or other large bodies, and because of collisions between asteroids which

neg: Meteoritical Society Meteoritical Society The Meteoritical Society is a non-profit scholarly organization founded in 1933 to promote research and education in planetary science with emphasis on studies of meteorites and other extraterrestrial materials that further our understanding of the origin and history of the solar system. The membership of the society comprises over 1,000 scientists and amateur enthusiasts from over 52 countries who are interested in a wide range of planetary science topics. Members interests include meteorites, cosmic dust, asteroids and comets, natural satellites, planets, impact events, and the origins of the Solar System. The Meteoritical Society is the organization that records

neg: Name conflicts with minor planets Name conflicts with minor planets There are several real or apparent name conflicts between different Solar System bodies, in spite of efforts to give every named body a distinct name. Most of these conflicts are between asteroids and natural satellites of planets, which are named according to different but partially overlapping schemes. Most satellites are named after people and divinities in Greek and Roman mythology; this is rarely true of asteroids currently, with the exception of centaurs and Jupiter trojans, but formerly many asteroids had mythological names, which consequently came into conflict with the names of natural satellites. Some of

neg: Captain Future The series contains a number of assumptions about the solar system which are outlandish by modern standards but which still seemed plausible, at least to the general public, in the time the stories were written. All of the planets of the solar system, and many of the moons and asteroids, are suitable for life, and most are already occupied by humanoid extraterrestrial races. The initial adventures take place in the planets of the solar system but later stories (after the character invents the "vibration drive") take the hero to other stars, other dimensions and even the distant past and almost

neg: Near-Earth object which means that when viewing closer to the axis of the direction of incoming light, more light is returned. These are objects in a near-Earth orbit without the tail or coma of a comet. , 18,730 near-Earth asteroids are known. NEAs survive in their orbits for just a few million years. They are eventually eliminated by planetary perturbations, causing ejection from the Solar System or a collision with the Sun or a planet. With orbital lifetimes short compared to the age of the Solar System, new asteroids must be constantly moved into near-Earth orbits to explain the observed asteroids. The

neg: HD 149026 b has been described as a "super-Neptune", in analogy to the core-dominated outer ice giants of our solar system, though whether the core of HD 149026 b is mainly icy or rocky is not currently known. Robert Naeye in "Sky & Telescope" claimed "it contains as much or more heavy elements (elements heavier than hydrogen and helium) than all the planets and asteroids in our solar system combined". In addition to uncertainties of radius, its tidal heating over its history needs be taken into account; if its current orbit is circular and if that had evolved from a more eccentric one,

neg: Contact binary (small Solar System body) are expected to be contact binaries with two lobes in mutual contact. Contact binary (small Solar System body) A contact binary is a small Solar System body that is composed of two bodies that have gravitated toward each other until they touch. This means contact binaries have odd shapes. Comet Churyumov–Gerasimenko and Comet Tuttle are most likely contact binaries. Asteroids suspected of being contact binaries include the unusually elongated 624 Hektor and the bilobated 216 Kleopatra and 4769 Castalia. 25143 Itokawa, which was photographed by the "Hayabusa" probe, also appears to be a contact binary which has resulted in an

neg: P-type asteroid into the C and S-type asteroid classifications. In 1976, some of these U-type asteroids with unusual moderate albedo levels were labeled as M-type. Around 1981, an offshoot of the M-type asteroid branch appeared for minor planets that have spectra that are indistinguishable from M-type, but that also have low albedo not consistent with the M type. These were initially labeled X-type asteroids, then type DM (dark M) or PM (pseudo-M), before acquiring their own unique classification as P-type asteroids (where the P indicates "pseudo-M"). The P-type asteroids are some of the darkest objects in the Solar System with very low

neg: Solar System the naked eye. Short-period comets have orbits lasting less than two hundred years. Long-period comets have orbits lasting thousands of years. Short-period comets are thought to originate in the Kuiper belt, whereas long-period comets, such as Hale–Bopp, are thought to originate in the Oort cloud. Many comet groups, such as the Kreutz Sungrazers, formed from the breakup of a single parent. Some comets with hyperbolic orbits may originate outside the Solar System, but determining their precise orbits is difficult. Old comets that have had most of their volatiles driven out by solar warming are often categorised as asteroids. Beyond the

neg: Northolt Branch Observatories Northolt Branch Observatories The Northolt Branch Observatories (NBO; Observatory codes: Z80, Z48 and Z37) is an astronomical observatory located in London, England. NBO collects follow-up astrometry of Near-Earth asteroids and other small Solar System objects. It focuses on public outreach, sharing images, videos and information about asteroids on social media. The two main belt asteroids 72834 Guywells and 128345 Danielbamberger are named after members of the Northolt Branch Observatories team. Northolt Branch Observatories was founded in 2015, as an extension of the London-based "Northolt Branch Astro" group of local amateur astrophotographers. It is a British-German collaboration: Data is collected on-site

neg: Solar System course of its year. A body's closest approach to the Sun is called its "perihelion", whereas its most distant point from the Sun is called its "aphelion". The orbits of the planets are nearly circular, but many comets, asteroids, and Kuiper belt objects follow highly elliptical orbits. The positions of the bodies in the Solar System can be predicted using numerical models. Although the Sun dominates the system by mass, it accounts for only about 2% of the angular momentum. The planets, dominated by Jupiter, account for most of the rest of the angular momentum due to the combination of

neg: New Technology Telescope of star formation in massive stars, and its observations were crucial to determine how asteroids are modified by solar wind. Perhaps most significantly, NTT observations of stars orbiting the centre of our Milky Way helped determine the mass and the radius of its supermassive black hole, effectively helping confirming the existence of such a massive and compact object. New Technology Telescope The New Technology Telescope or NTT is an Alt-Az, 3.58-metre Ritchey–Chrétien telescope part of the European Southern Observatory and began operations in 1989. It is located in Chile at the La Silla Observatory and was an early pioneer in

neg: Sample-return mission their compositions with the data gathered through telescopes and astronomical spectroscopy. One further focus of such investigation—besides the basic composition and geologic history of the various Solar System bodies—is the presence of the building blocks of life on comets, asteroids, Mars or the moons of the gas giants. Several sample-return missions to asteroids and comets are currently in the works. More samples from asteroids and comets will help determine whether life formed in space and was carried to Earth by meteorites. Another question under investigation is whether extraterrestrial life formed on other Solar System bodies like Mars or on the

neg: Northolt Branch Observatories as part of PACA observing campaigns. Examples of PACA campaigns with contributions from NBO include Rosetta's comet 67P/Churyumov–Gerasimenko, and the comets 41P/Tuttle–Giacobini–Kresák and 45P/Honda–Mrkos–Pajdušáková. Northolt Branch Observatories The Northolt Branch Observatories (NBO; Observatory codes: Z80, Z48 and Z37) is an astronomical observatory located in London, England. NBO collects follow-up astrometry of Near-Earth asteroids and other small Solar System objects. It focuses on public outreach, sharing images, videos and information about asteroids on social media. The two main belt asteroids 72834 Guywells and 128345 Danielbamberger are named after members of the Northolt Branch Observatories team. Northolt Branch Observatories was founded in

neg: Solar System all have impact craters and tectonic surface features, such as rift valleys and volcanoes. The term "inner planet" should not be confused with "inferior planet", which designates those planets that are closer to the Sun than Earth is (i.e. Mercury and Venus). Asteroids except for the largest, Ceres, are classified as small Solar System bodies and are composed mainly of refractory rocky and metallic minerals, with some ice. They range from a few metres to hundreds of kilometres in size. Asteroids smaller than one meter are usually called meteoroids and micrometeoroids (grain-sized), depending on different, somewhat arbitrary definitions. The asteroid

neg: Cosmic dust in the Solar System is highly processed dust, recycled from the material out of which the Solar System formed and subsequently collected in the planetesimals, and leftover solid material such as comets and asteroids, and reformed in each of those bodies' collisional lifetimes. During the Solar System's formation history, the most abundant element was (and still is) H. The metallic elements: magnesium, silicon, and iron, which are the principal ingredients of rocky planets, condensed into solids at the highest temperatures of the planetary disk. Some molecules such as CO, N, NH, and free oxygen, existed in a gas phase. Some

neg: Impact crater features on many solid Solar System objects including the Moon, Mercury, Callisto, Ganymede and most small moons and asteroids. On other planets and moons that experience more active surface geological processes, such as Earth, Venus, Mars, Europa, Io and Titan, visible impact craters are less common because they become eroded, buried or transformed by tectonics over time. Where such processes have destroyed most of the original crater topography, the terms impact structure or astrobleme are more commonly used. In early literature, before the significance of impact cratering was widely recognised, the terms cryptoexplosion or cryptovolcanic structure were often used to

neg: Interstellar object Interstellar object An interstellar object is a body, other than a star or substar, that is located in interstellar space and is not gravitationally bound to a star. The term can also be applied to objects that are on an interstellar trajectory but are temporarily passing close to a star, such as certain asteroids and comets (including exocomets). Due to present observational difficulties, an interstellar object can usually only be detected if it passes through the Solar System, where it can be distinguished by its strongly hyperbolic trajectory, indicating that it is not gravitationally bound to the Sun. In contrast,

neg: The 50 Most Extreme Places in Our Solar System The 50 Most Extreme Places in Our Solar System The 50 Most Extreme Places in Our Solar System is the title of a science book by David Baker, professor of physics at Austin College and Todd Ratcliff, a planetary geophysicist at the Jet Propulsion Laboratory. The book is divided into nine sections with a few chapters in each section. The divisions are roughly phenomenological. The book is currently available in two translations with a third in progress. Reviews have been positive including being awarded Honorable Mention in Cosmology and Astronomy in the 2010 PROSE Awards and named an Outstanding University

neg: The 50 Most Extreme Places in Our Solar System Press Book for Public and Secondary School Libraries by the Association of American University Presses. The 50 Most Extreme Places in Our Solar System The 50 Most Extreme Places in Our Solar System is the title of a science book by David Baker, professor of physics at Austin College and Todd Ratcliff, a planetary geophysicist at the Jet Propulsion Laboratory. The book is divided into nine sections with a few chapters in each section. The divisions are roughly phenomenological. The book is currently available in two translations with a third in progress. Reviews have been positive including being awarded Honorable

neg: Solar System orbit, known as the ecliptic. The planets are very close to the ecliptic, whereas comets and Kuiper belt objects are frequently at significantly greater angles to it. All the planets, and most other objects, orbit the Sun in the same direction that the Sun is rotating (counter-clockwise, as viewed from above Earth's north pole). There are exceptions, such as Halley's Comet. The overall structure of the charted regions of the Solar System consists of the Sun, four relatively small inner planets surrounded by a belt of mostly rocky asteroids, and four giant planets surrounded by the Kuiper belt of mostly

neg: Chondrite could have had an extraterrestrial origin. Chondrite Chondrites are stony (non-metallic) meteorites that have not been modified due to melting or differentiation of the parent body. They are formed when various types of dust and small grains that were present in the early solar system accreted to form primitive asteroids. They are the most common type of meteorite that falls to Earth with estimates for the proportion of the total fall that they represent varying between 85.7% and 86.2%. Their study provides important clues for understanding the origin and age of the Solar System, the synthesis of organic compounds, the

neg: Chondrite Chondrite Chondrites are stony (non-metallic) meteorites that have not been modified due to melting or differentiation of the parent body. They are formed when various types of dust and small grains that were present in the early solar system accreted to form primitive asteroids. They are the most common type of meteorite that falls to Earth with estimates for the proportion of the total fall that they represent varying between 85.7% and 86.2%. Their study provides important clues for understanding the origin and age of the Solar System, the synthesis of organic compounds, the origin of life and the presence

neg: Small Solar System body Small Solar System body A small Solar System body (SSSB) is an object in the Solar System that is neither a planet, a dwarf planet, nor a natural satellite. The term was first defined in 2006 by the International Astronomical Union (IAU) as follows: "All other objects, except satellites, orbiting the Sun shall be referred to collectively as 'Small Solar System Bodies' ". This encompasses all comets and all minor planets other than those that are dwarf planets. Thus SSSBs are: the classical asteroids, with the exception of the dwarf planet Ceres; the trojans; and the centaurs and trans-Neptunian objects,

neg: E-type asteroid of the hypothetical E-belt asteroid population. The dispersal of most of that hypothetical E-Belt might have been caused by the outwards migration of the gas giants of the Solar System according to simulations done under the Nice model – and these dispersed E-Belt asteroids might in turn have been the impactors of the Late Heavy Bombardment. On September 5, 2008, unmanned ESA spaceprobe Rosetta visited the E-type asteroid 2867 Šteins. Spectral data from the spacecraft confirmed the asteroid was composed mainly of iron-poor minerals such as enstatite (magnesium-rich pyroxene), forsterite (magnesium-rich olivine) and feldspar. E-type asteroid E-type asteroids are asteroids

neg: Colonization of the outer Solar System elsewhere in the Solar System, perhaps via the proposed Interplanetary Transport Network, may be feasible in the not-so-distant future. This could make colonization of the Moon, Mercury and main-belt asteroids more practical. Robert Zubrin identified Saturn, Uranus and Neptune as "the Persian Gulf of the Solar System", as the largest sources of deuterium and helium-3 to drive a fusion economy, with Saturn the most important and most valuable of the three, because of its relative proximity, low radiation, and excellent system of moons. Zubrin identified Titan as possessing an abundance of all the elements necessary to support life, making Titan

neg: Douglas Vakoch recently discovered asteroids. He proposes targeting stars located within 25 parsecs of Earth, and he advocates transmitting repeatedly to "a set of nearby stars over the course of several months or years.” Vakoch participated in radar studies of the near-Earth asteroid 2015 HM10 using the Green Bank Telescope in West Virginia in conjunction with the NASA Deep Space Network. When astronomers announced in August 2016 the discovery of a potentially Earth-like planet in the habitable zone of the star nearest our solar system, Proxima Centauri, Vakoch emphasized that if inhabited, the star's close proximity to Earth would allow a round

neg: LARLE crater ring dikes. Impact craters are the dominant geographic features on many solid Solar System objects including the Moon, Mercury, Callisto, Ganymede and most small moons and asteroids. On other planets and moons that experience more active surface geological processes, such as Earth, Venus, Mars, Europa, Io and Titan, visible impact craters are less common because they become eroded, buried or transformed by tectonics over time. The cratering records of very old surfaces, such as Mercury, the Moon, and the southern highlands of Mars, record a period of intense early bombardment in the inner Solar System around 3.9 billion years ago.

neg: Asteroids in fiction asteroids. For a list of "fifth planets" in fiction, see "Fictional planets of the Solar System" The prospects of colonizing the Solar System planets became more dim with increasing discoveries about conditions on them. Conversely, the potential value of the asteroids increased, as a vast accumulation of mineral wealth, accessible in conditions of minimal gravity, and supplementing Earth's dwindling resources. Stories of asteroid mining became more and more numerous since the late 1940s, with the next logical step being depictions of a society on terraformed asteroids — in some cases dug under the surface, in others having dome colonies and

neg: Solar 2 with asteroids, planets, stars and solar systems. Life forms are also present in the game. They appear on planets sufficiently big to store life, and are represented by a variety of ships of different size and attack power. Spaceships are coloured green if they belong to the player's planet, or to a planet that belongs to the player's solar system; red if they belong to an enemy planet or solar system; and white if they don't belong to any planet or system. All the spaceships in the map are controlled by the game's artificial intelligence (AI), and they will constantly

neg: Formation and evolution of the Solar System Formation and evolution of the Solar System 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. Most of the collapsing mass collected in the center, forming the Sun, while the rest flattened into a protoplanetary disk out of which the planets, moons, asteroids, and other small Solar System bodies formed. This model, known as the nebular hypothesis was first developed in the 18th century by Emanuel Swedenborg, Immanuel Kant, and Pierre-Simon Laplace. Its subsequent development has interwoven a variety of scientific disciplines including

neg: Discovery and exploration of the Solar System Discovery and exploration of the Solar System Discovery and exploration of the Solar System is observation, visitation, and increase in knowledge and understanding of Earth's "cosmic neighborhood". This includes the Sun, Earth and the Moon, the major planets including Mercury, Venus, Mars, Jupiter, Saturn, Uranus, and Neptune, their satellites, as well as smaller bodies including comets, asteroids, and dust. For many thousands of years, astronomers maintained a geocentric world view and did not recognize the existence of a Solar System. Most believed Earth was stationary at the center of the Universe and categorically different from the divine or ethereal objects

neg: Comet and the tail (a typically linear section consisting of dust or gas blown out from the coma by the Sun's light pressure or outstreaming solar wind plasma). However, extinct comets that have passed close to the Sun many times have lost nearly all of their volatile ices and dust and may come to resemble small asteroids. Asteroids are thought to have a different origin from comets, having formed inside the orbit of Jupiter rather than in the outer Solar System. The discovery of main-belt comets and active centaur minor planets has blurred the distinction between asteroids and comets. Recent years,

neg: Solar System other bodies orbiting the Sun. The principal component of the Solar System is the Sun, a G2 main-sequence star that contains 99.86% of the system's known mass and dominates it gravitationally. The Sun's four largest orbiting bodies, the giant planets, account for 99% of the remaining mass, with Jupiter and Saturn together comprising more than 90%. The remaining objects of the Solar System (including the four terrestrial planets, the dwarf planets, moons, asteroids, and comets) together comprise less than 0.002% of the Solar System's total mass. Most large objects in orbit around the Sun lie near the plane of Earth's

neg: Deep Space 1 technology development and validation for future missions; 12 technologies were tested: The Autonav system, developed by NASA's Jet Propulsion Laboratory, takes images of known bright asteroids. The asteroids in the inner Solar System move in relation to other bodies at a noticeable, predictable speed. Thus a spacecraft can determine its relative position by tracking such asteroids across the star background, which appears fixed over such timescales. Two or more asteroids let the spacecraft triangulate its position; two or more positions in time let the spacecraft determine its trajectory. Existing spacecraft are tracked by their interactions with the transmitters of the

neg: NASA Advanced Space Transportation Program new markets to open up. This includes space-based adventure tourism and travel, along with space-based business parks. Other types of benefits to commerce and the global population includes solar electric power beamed from space to Earth, space-based hospitals for treatment of chronic pain and disabilities, mining asteroids for high-value minerals, and a worldwide, two-hour express package delivery system. The ASTP is developing technologies to decrease the trip times and reduce the weight of the propulsion systems required for planetary missions - including riskier missions to the edge of our solar system and beyond. Some of the technologies under development to

neg: Asteroid 1.1 and 1.9 million asteroids larger than in diameter, and millions of smaller ones. These asteroids may be remnants of the protoplanetary disk, and in this region the accretion of planetesimals into planets during the formative period of the Solar System was prevented by large gravitational perturbations by Jupiter. Trojans are populations that share an orbit with a larger planet or moon, but do not collide with it because they orbit in one of the two Lagrangian points of stability, L4 and L5, which lie 60° ahead of and behind the larger body. The most significant population of trojans are

neg: Hecuba-gap asteroid have been proposed. These are the marginally unstable Griqua asteroids, with an estimated lifetime of more than 100 million years, the stable Zhongguo asteroids (more than 500 million or even 1 billion years), and an unnamed, strongly unstable population of asteroids with a dynamical lifetime of less than 70 million years. Moving further out the Solar System, the asteroids in the Hecuba gap are followed by the resonant Cybeles (7:4), Hildas (3:2), Thules (4:3) and Jupiter trojans (1:1). Both the Zhongguo (stable) and Griqua asteroids (marginally stable) are also described as the "long-lived" group with lifetimes over 70 million years

neg: Mass-independent fractionation almost twice as large as the difference between O and O. Originally this was interpreted as evidence of incomplete mixing of O-rich material (created and distributed by a large star in a supernova) into the Solar nebula. However, recent measurement of the oxygen-isotope composition of the Solar wind, using samples collected by the Genesis spacecraft, shows that the most O-rich inclusions are close to the bulk composition of the solar system. This implies that Earth, the Moon, Mars and asteroids all formed from O- and O-enriched material. Photochemical dissociation of carbon monoxide in the Solar nebula has been proposed to

neg: Enstatite minerals that have been observed in crystalline form outside the Solar System, particularly around evolved stars and planetary nebulae such as NGC 6302. Enstatite is thought to be one of the early stages for the formation of crystalline silicates in space and many correlations have been noted between the occurrence of the mineral and the structure of the object around which it has been observed. Enstatite is thought to be a main component of the E-type asteroids; in the Solar System, the main example are Hungaria asteroids. Enstatite Enstatite is a mineral; the magnesium endmember of the pyroxene silicate mineral

neg: Comparative planetary science itself, on a smaller scale. The planets are considered to have formed by accretion of larger and larger particles, into asteroids and planetesimals, and into today's bodies. Vesta and Ceres are hypothesized to be the only surviving examples of planetesimals, and thus samples of the formative period of the Solar System. Transits of Mercury and Venus have been observed as analogues of extrasolar transits. As Mercury and Venus transits are far closer and thus appear "deeper," they can be studied in far finer detail. Similarly, analogues to our asteroid and Kuiper belts have been observed around other star systems, though

neg: Planetary and Space Science and ionospheres with the sun, solar wind, and their natural satellites. Research that involves the small bodies of the solar system is also published. Small bodies describes dust, objects of rings, asteroids, comets, zodiacal light. This research also describes their interaction with solar radiation and the solar wind. Beyond the solar system, extrasolar system studies are also considered a field of interest for this journal. This includes detection of exoplanets, as well as determining whether or not given exoplanets or exosystems can be detected. Also the formation and evolution of these planets and systems are of interest. History of planetary

neg: Solar System in fiction Solar System in fiction The Solar System and its various bodies (planets, asteroids, moons, etc.) were the earliest objects to be treated as fictional locations in works of science fiction. Among these, imaginary voyages to and explorations of Earth's Moon are found in seventeenth century literature. By the early twentieth century, following the increase in scientific and technological development spurred by the Industrial Revolution, fictional journeys to (or from) the Solar System's other planets had become common in fiction. Early literature regarding the Solar System, following scientific speculations dating back to the 17th century, assumed that every planet hosted its

neg: Enstatite chondrite metal and sulfide minerals. Dusty matrix material is uncommon and refractory inclusions are very rare. Chemically, enstatite chondrites are very low in refractory lithophile elements. Their oxygen isotopic compositions are intermediate between ordinary and carbonaceous chondrites, and are similar to rocks found on the Earth and Moon. Their lack of oxygen content may mean that they were originally formed near the center of the solar nebula that created the solar system, possibly within the orbit of Mercury. Most enstatite chondrites have experienced thermal metamorphism on the parent asteroids. They are divided into two groups: The largest known recorded E-type chondrite

neg: Chondrite fact that the abundance of non-volatile elements in chondrites is similar to that found in the atmosphere of the Sun and other stars in our galaxy. Although chondritic asteroids never became hot enough to melt based upon internal temperatures, many of them reached high enough temperatures that they experienced significant thermal metamorphism in their interiors. The source of the heat was most likely energy coming from the decay of short-lived radioisotopes (half-lives less than a few million years) that were present in the newly formed solar system, especially Al and Fe, although heating may have been caused by impacts onto

neg: Accretion (astrophysics) gas from the solar nebula. Differentiation between these two classes of planetesimals arise due to the frost line of the solar nebula. Meteorites contain a record of accretion and impacts during all stages of asteroid origin and evolution; however, the mechanism of asteroid accretion and growth is not well understood. Evidence suggests the main growth of asteroids can result from gas-assisted accretion of chondrules, which are millimeter-sized spherules that form as molten (or partially molten) droplets in space before being accreted to their parent asteroids. In the inner Solar System, chondrules appear to have been crucial for initiating accretion. The

neg: Five-planet Nice model to its small asteroids being the result of collisions between a small number of large asteroids, to match this constraint. While the Nice model predicts a bombardment by both asteroids and comets, most evidence (although not all) points toward a bombardment dominated by asteroids. This may reflect the reduced cometary bombardment in the five-planet Nice model and the significant mass loss or the break-up of comets after entering the inner Solar System, potentially allowing the evidence of cometary bombardment to have been lost. However, two recent estimates of the asteroid bombardment find it is also insufficient to explain the Late

neg: History of Solar System formation and evolution hypotheses equals c. 2000 trillion trillion kg; Earth is at about 6 trillion trillion kg). T Tauri (see T Tauri type stars) eruptions of the Sun stripped the gases away from the inner planets. Mercury was incompletely condensed and a portion of its gases were stripped away and transported to the region between Mars and Jupiter, where it fused with in-falling oxidized condensate from the outer reaches of the Solar System and formed the parent material for ordinary chondrite meteorites, the Main-Belt asteroids, and veneer for the inner planets, especially Mars. The differences between the inner planets are primarily the consequence

neg: Asteroid and Grossman's 2010 paper revised the previous definition of meteoroid to objects between 10 µm and 1 meter in size in order to maintain the distinction between asteroids and meteoroids. The smallest asteroids discovered (based on absolute magnitude "H") are with "H" = 33.2 and with "H" = 32.1 both with an estimated size of about 1 meter. In 2006, the term "small Solar System body" was also introduced to cover both most minor planets and comets. Other languages prefer "planetoid" (Greek for "planet-like"), and this term is occasionally used in English especially for larger minor planets such as the

neg: Astronomical spectroscopy moving in the horizontal plane. Planets, asteroids, and comets all reflect light from their parent stars and emit their own light. For cooler objects, including solar-system planets and asteroids, most of the emission is at infrared wavelengths we cannot see, but that are routinely measured with spectrometers. For objects surrounded by gas, such as comets and planets with atmospheres, further emission and absorption happens at specific wavelengths in the gas, imprinting the spectrum of the gas on that of the solid object. In the case of worlds with thick atmospheres or complete cloud cover (such as the gas giants, Venus,

neg: Chondrite individual stones, as occurred in the Holbrook fall of 1912, where an estimated 14,000 stones rained down on northern Arizona. Chondrites were formed by the accretion of particles of dust and grit present in the primitive Solar System which gave rise to asteroids over 4.55 billion years ago. These asteroid parent bodies of chondrites are (or were) small to medium-sized asteroids that were never part of any body large enough to undergo melting and planetary differentiation. Dating using Pb/Pb gives an estimated age of 4,566.6 ± 1.0 Ma, matching ages for other chronometers. Another indication of their age is the

neg: Meteoroid number of objects larger than a diameter of "D" meters to hit Earth in a year. This is based on observations of bright meteors seen from the ground and space, combined with surveys of near-Earth asteroids. Above in diameter, the predicted rate is somewhat higher, with a asteroid (one million-megaton TNT equivalent) every couple of million years — about 10 times as often as the power-law extrapolation would predict. Meteoroid collisions with solid Solar System objects, including the Moon, Mercury, Callisto, Ganymede, and most small moons and asteroids, create impact craters, which are the dominant geographic features of many of

neg: 15 Eunomia under the influence of internal heating in the early period of the Solar System. The range of compositions of the remaining Eunomian asteroids, formed by a collision of the common parent body, is large enough to encompass all the surface variations on Eunomia itself. The majority of smaller Eunomian asteroids are more pyroxene rich than Eunomia's surface, and contain very few metallic (M-type) bodies. Altogether, these lines of evidence suggest that Eunomia is the central remnant of the parent body of the Eunomia family, which was stripped of most of its crustal material by the disrupting impact, but was perhaps

neg: Heliophysics NASA science the Sun with the solar system. According to NASA, understanding these connections is especially critical as we contemplate our destiny in the third millennium. Heliophysics is needed to facilitate the accelerated expansion of human experience beyond the confines of our earthly home. Recent advances in technology allow us, for the first time, to realistically contemplate voyages beyond the solar system. There are three primary objectives that define the multi-decadal studies needed: Earth is located within the extended atmosphere of a magnetic variable star that drives the local solar system and sustains life on Earth. The Sun is observed to vary

neg: Micrometeorite 50 times higher than that estimated for meteorites, which represent approximately 50 t/yr, and the huge number of particles entering the atmosphere each year (~10 > 10 µm) suggests that large MM collections contain particles from all dust producing objects in the Solar System including asteroids, comets, and fragments from our Moon and Mars. Large MM collections provide information on the size, composition, atmospheric heating effects and types of materials accreting on Earth while detailed studies of individual MMs give insights into their origin, the nature of the carbon, amino acids and pre-solar grains they contain. Micrometeorites have been collected

neg: Pan-STARRS over longer periods of time by Pan-STARRS. In 2017, Pan-STARRS detected the first known interstellar object, 1I/2017 U1 ‘Oumuamua, passing through the Solar System. During the formation of a planetary system, it is thought that a very large number of objects are ejected due to gravitational interactions with planets (as many as 10 such objects in the case of the Solar System). Objects ejected from planetary systems of other stars might plausibly be throughout the Milky Way and some may pass through the Solar System. Pan-STARRS may detect collisions involving small asteroids. These are quite rare and none have yet