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Encyclopedia > Kuiper Belt
The Kuiper belt, derived from data from the Minor Planet Center. Objects in the main belt are coloured green, while scattered objects are coloured orange. The four outer planets are blue. Neptune's few Trojan asteroids are yellow, while Jupiter's are pink. The scale is in astronomical units.

The Kuiper belt (pronounced /ˈkaɪpɚ/, to rhyme with "viper")[1] is a region of the Solar System beyond the planets extending from the orbit of Neptune (at 30 AU)[2] to 55 AU from the Sun.[3] It is similar to the asteroid belt, although it is far larger; at least 20 times as wide and 200 times as massive.[4][5] Like the asteroid belt, it consists mainly of small bodies (remnants from the Solar System's formation) and at least one dwarf planet (Pluto). But while the asteroid belt is composed primarily of rock and metal, the Kuiper belt is composed largely of ices, such as methane, ammonia, and water. Image File history File links Size of this preview: 611 × 599 pixelsFull resolution (2708 × 2656 pixel, file size: 314 KB, MIME type: image/png) Legend Red = The Sun Aquamarine = Giant Planet Green = Kuiper Belt Object Orange = Scattered Disk object or Centaur Pink = Trojan of Jupiter Yellow = Trojan of Neptune Axes... Image File history File links Size of this preview: 611 × 599 pixelsFull resolution (2708 × 2656 pixel, file size: 314 KB, MIME type: image/png) Legend Red = The Sun Aquamarine = Giant Planet Green = Kuiper Belt Object Orange = Scattered Disk object or Centaur Pink = Trojan of Jupiter Yellow = Trojan of Neptune Axes... The Minor Planet Center operates at the Smithsonian Astrophysical Observatory (SAO), which is part of the Center for Astrophysics (CfA) along with the Harvard College Observatory (HCO). ... Image of the Trojan asteroids in front of and behind Jupiter along its orbital path. ... The astronomical unit (AU or au or a. ... This chart shows concisely the most common way in which the International Phonetic Alphabet (IPA) is applied to represent the English language. ... Major features of the Solar System (not to scale; from left to right): Pluto, Neptune, Uranus, Saturn, Jupiter, the asteroid belt, the Sun, Mercury, Venus, Earth and its Moon, and Mars. ... Two bodies with a slight difference in mass orbiting around a common barycenter. ... Atmospheric characteristics Surface pressure ≫100 MPa Hydrogen - H2 80% ±3. ... The astronomical unit (AU or au or a. ... To help compare different distances this page lists lengths starting at 1012 m (1000 million km). ... The Sun (Latin: Sol) is the star at the center of the Solar System. ... For details on the physical properties of bodies in the asteroid belt see Asteroid and Main-belt comet. ... A Small Solar System Body (SSSB) is a term defined in 2006 by the International Astronomical Union to describe objects in the Solar System that are neither planets nor dwarf planets: [1] This encompasses: all minor planets apart from the dwarf planets, : the classical asteroids, (except for 1 Ceres, the... Artists impression of Pluto (background) and Charon (foreground). ... The rocky side of a mountain creek near Orosí, Costa Rica. ... Hot metal work from a blacksmith In chemistry, a metal (Greek: Metallon) is an element that readily loses electrons to form positive ions (cations) and has metallic bonds between metal atoms. ... Snowflakes by Wilson Bentley, 1902 Ice is the name given to any one of the 14 known solid phases of water. ... Methane is a chemical compound with the molecular formula CH4. ... Ammonia is a compound with the formula NH3. ... Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ...


Since discovery, the number of known Kuiper belt objects (KBOs) has increased to over a thousand, and more than 70,000 KBOs over 1 km in diameter are believed to reside there.[6] The Kuiper belt is believed to be the main repository for periodic comets, those with orbits lasting less than 200 years. The centaurs, comet-like bodies that orbit among the gas giants, are also believed to originate there, as are the scattered disc objects such as Eris—KBO-like bodies with massive orbits that take them as far as 100 AU from the Sun. Neptune's moon Triton is believed to be a captured KBO.[7] Pluto, a dwarf planet, is the largest known member of the Kuiper belt. Originally considered a planet, it has many physical properties in common with the objects of the Kuiper belt, and has been known since the early 1990s to share its orbit with a number of similarly sized KBOs, now called Plutinos. The Kuiper belt (KYE per) is an area of the solar system extending from within the orbit of Neptune (at 30 AU) to 50 AU from the sun, at inclinations consistent with the ecliptic. ... The following is the IAUs list of periodic comets. ... The centaurs are a class of icy planetoids that orbit the Sun between Jupiter and Neptune, named after the mythical race of centaurs. ... A gas giant is a large planet that is not composed mostly of rock or other solid matter. ... A scattered disk object (or scattered disc object or SDO) is a trans-Neptunian object of the Kuiper belt with a very eccentric orbit. ... Absolute magnitude: −1. ... Adjectives: Neptunian Atmosphere Surface pressure: ≫ 100 kPa (cloud level) Composition: 80% ± 3. ... Triton (trye-tÉ™n, IPA: , Greek Τρίτων), or Neptune I, is the planet Neptunes largest moon. ... Adjectives: Plutonian Atmosphere Surface pressure: 0. ... Artists impression of Pluto (background) and Charon (foreground). ... In astronomy, a plutino is a trans-Neptunian object that has a 3:2 orbital resonance with Neptune. ...


The Kuiper belt should not be confused with the hypothesized Oort cloud, which is a thousand times more distant. The objects within the Kuiper belt, together with the members of the scattered disc and any potential Hills cloud or Oort cloud objects, are collectively referred to as trans-Neptunian objects (TNOs).[8] This image is an artists rendering of the Oort cloud and the Kuiper Belt. ... The scattered disc (or scattered disk) is a distant region of our solar system, thinly populated by icy planetoids known as scattered disk objects (SDOs), a subset of the broader family of trans-Neptunian objects (TNOs). ... The Hills cloud is a hypothetical inner region of the Oort cloud with an outer boundary of 2-3×104 AU, and a less well defined inner boundary at 50 to 3000 AU, proposed in 1981 by J. G. Hill. ... This image is an artists rendering of the Oort cloud and the Kuiper Belt. ... A trans-Neptunian object (TNO) is any object in the solar system that orbits the sun at a greater distance on average than Neptune. ...

TNOs and similar bodies

Contents

The centaurs are a class of icy planetoids that orbit the Sun between Jupiter and Neptune, named after the mythical race of centaurs. ... As of March 2007, there are five[1] known Neptune Trojans (named by analogy to the Trojan asteroids) which have the same orbital period as the planet. ... A trans-Neptunian object (TNO) is any object in the solar system that orbits the sun at a greater distance on average than Neptune. ... In astronomy a cubewano (pronounced ) is a Kuiper belt object that orbits beyond Neptune and is not controlled by an orbital resonance with the giant planet. ... In astronomy, a resonant Trans-Neptunian Object is a Trans-Neptunian Object (TNO) in mean motion orbital resonance with Neptune. ... In astronomy, a plutino is a trans-Neptunian object that has a 3:2 orbital resonance with Neptune. ... The scattered disc (or scattered disk) is a distant region of our solar system, thinly populated by icy planetoids known as scattered disk objects (SDOs), a subset of the broader family of trans-Neptunian objects (TNOs). ... This image is an artists rendering of the Oort cloud and the Kuiper Belt. ...

History

Since the discovery of Pluto, many have speculated that it might not be alone. The region now called the Kuiper belt had been hypothesized in various forms for decades. It was only in 1992 that the first direct evidence for its existence was found. The number and variety of prior speculations on the nature of the Kuiper belt have led to continued uncertainty as to who deserves credit for first proposing it.


The first astronomer to suggest the existence of a trans-Neptunian population was Frederick C. Leonard in 1930, soon after Pluto's discovery, who pondered whether it was "not likely that in Pluto there has come to light the *first* of a *series* of ultra-Neptunian bodies, the remaining members of which still await discovery but which are destined eventually to be detected".[9] An astronomer or astrophysicist is a person whose area of interest is astronomy or astrophysics. ... Frederick Charles Leonard (1896 - 1960) was an astrophysicist at the UCLA who organised the UCLAs Department of Astronomy. ...


Subsequent hypotheses

Astronomer Gerard Kuiper, after whom the Kuiper belt is named

In 1943, in the Journal of the British Astronomical Association, Kenneth Edgeworth hypothesised that, in the region beyond Neptune, the material within the primordial solar nebula was too widely spaced to consense into planets, and so rather condensed into a myriad of smaller bodies. From this he concluded that “the outer region of the solar system, beyond the orbits of the planets, is occupied by a very large number of comparatively small bodies"[10] and that, from time to time, one of their number "wanders from its own sphere and appears as an occasional visitor to the inner solar system,”[11] becoming what we call a comet. Image File history File links . Image from http://history. ... Image File history File links . Image from http://history. ... Gerard Kuiper, circa 1963. ... LCol Kenneth Essex Edgeworth (26 February 1880 - 10 October 1972) was an Irish astronomer, economist and engineer. ... Adjectives: Neptunian Atmosphere Surface pressure: ≫ 100 kPa (cloud level) Composition: 80% ± 3. ... This article or section does not cite any references or sources. ... Comet Hale-Bopp Comet West For other uses, see Comet (disambiguation). ...


In 1951, in an article for the journal Astrophysics, Gerard Kuiper speculated on a similar disc having formed early in the Solar System's evolution, however, he did not believe that such a belt still existed today. Kuiper was operating on the assumption common in his time, that Pluto was the size of the Earth, and had therefore scattered these bodies out toward the Oort cloud or out of the Solar System. By Kuiper's formulation, there wouldn't be a Kuiper belt where we now see it.[12] Gerard Kuiper, circa 1963. ... Adjectives: Plutonian Atmosphere Surface pressure: 0. ...


The hypothesis took many other forms in the following decades: in 1962, physicist Al G.W. Cameron postulated the existence of “a tremendous mass of small material on the outskirts of the solar system,”[13] while in 1964, Fred Whipple, who popularised the famous "dirty snowball" hypothesis for cometary structure, thought that a "comet belt" might be massive enough to cause the purported discrepencies in the orbit of Uranus that had sparked the search for Planet X, or at the very least, to affect the orbits of known comets.[14] Observation, however, ruled out this hypothesis.[13] Alastair G. W. (Graham Walter) Cameron, (1925-2005) was a Canadian astrophysicist and space scientist who was an eminent staff member of the Astronomy department of Harvard University. ... Fred Lawrence Whipple (November 5, 1906–August 30, 2004) was an American astronomer. ... Comet Hale-Bopp Comet West For other uses, see Comet (disambiguation). ... Adjectives: Uranian Atmosphere Surface pressure: 120 kPa (at the cloud level) Composition: 83% Hydrogen 15% Helium 1. ... Planet X is a large hypothetical planet with an orbit beyond that of Neptune. ...


In 1977, Charles Kowal discovered 2060 Chiron, an icy planetoid with an orbit between Saturn and Uranus. He used a blink comparator; the same device that had allowed Clyde Tombaugh to discover Pluto nearly 50 years before.[15] In 1992, another object 5145 Pholus, was discovered in a similar orbit.[16] Today, an entire population, the centaurs, is known to exist in that region. The centaurs' orbits are unstable over periods longer than roughly 100 million years, a relatively short span when compared to the age of the Solar System. From the time of Chiron's discovery, astronomers speculated that it therefore must be frequently replenished by some outer reservoir.[17]. Charles Thomas Kowal (born November 8, 1940) is an American astronomer. ... 2060 Chiron (IPA: ) is an object in the outer solar system with an orbit between those of Saturn and Uranus and a radius of 71±5 km [1]. Although it was initially classified as an asteroid, later dispute arose as to whether it was an asteroid or actually a comet. ... This blink comparator at Lowell Observatory was used in the discovery of Pluto. ... An image of Clyde Tombaugh Clyde William Tombaugh (February 4, 1906 – January 17, 1997) was an American astronomer who discovered the dwarf planet Pluto in 1930. ... Adjectives: Plutonian Atmosphere Surface pressure: 0. ... 5145 Pholus (FOE luss) is a Centaur in an eccentric orbit, with a perihelion near the orbit of Saturn and aphelion near the orbit of Neptune. ... The centaurs are a class of icy planetoids that orbit the Sun between Jupiter and Neptune, named after the mythical race of centaurs. ...


Further evidence for the belt's existence later emerged from the study of comets. That comets have finite lifespans has been known for some time. As they approach the Sun, its heat causes their volatile surfaces to sublimate into space, eating them gradually away. In order to still be visible over the age of the Solar System, they must be frequently replenished.[18] One such area of replenishment is the Oort cloud; the spherical swarm of comets extending beyond 50,000 AU from the Sun first hypothesised by astronomer Jan Oort in 1950.[19]. It is believed to be the point of origin for long period comets, those, like Hale-Bopp, with orbits lasting thousands of years. Volatility in physics is a measure of the speed at which a chemical element or chemical compound evaporates. ... This image is an artists rendering of the Oort cloud and the Kuiper Belt. ... The astronomical unit (AU or au or a. ... Jan Hendrik Oort (April 28, 1900 – November 5, 1992) was an internationally famous Dutch astronomer. ... Comet Hale-Bopp Comet West For other uses, see Comet (disambiguation). ... A close-up of Hale-Bopp Comet Hale-Bopp (formally designated C/1995 O1) was probably the most widely observed comet of the 20th century, and one of the brightest seen for many decades. ...


There is however another comet population, known as short period or periodic comets; those with orbits lasting less than 200 years. By the 1970s, the rate at which short-period comets were being discovered was becoming increasingly inconsistent with them having emerged solely from the Oort cloud.[20] For an Oort cloud object to become a short-period comet, it would first have to be captured by the giant planets. In 1980, in the monthly notice of the Royal Astronomical Society, Julio Fernandez stated that for every short period comet to be sent into the inner solar system from the Oort cloud, 300 would have to be ejected into interstellar space. He speculated that a comet belt from between 35 and 50 AU would be required to account for the observed number of comets.[21]. Following up on Fernandez's work, in 1988 the Canadian team of Martin Duncan, Tom Quinn and Scott Tremaine ran a number of computer simulations to determine if all observed comets could have arrived from the Oort cloud. They found that the Oort cloud could not account for short-period comets, particularly as short-period comets are clustered near the plane of the Solar System, wheras Oort cloud comets tend to arrive from any point in the sky. With a belt as Fernandez described it added to the formulations, the simulations matched observations.[22] Reportedly because the words "Kuiper" and "comet belt" appeared in the opening sentence of Fernandez's paper, Tremaine named this region the "Kuiper belt."[23] The following is the IAUs list of periodic comets that have a number designation. ... The following is the IAUs list of periodic comets. ... This image is an artists rendering of the Oort cloud and the Kuiper Belt. ... The Royal Astronomical Society (RAS) began as the Astronomical Society of London in 1820 to support astronomical research (mainly carried on at the time by gentleman astronomers rather than professionals). ... Julio M. Fernandez (born 1954 in Santiago, Chile) is a Professor in the Department of Biological Sciences at Columbia University, New York. ... The astronomical unit (AU or au or a. ... Scott Tremaine is a Canadian-born Astrophysicist. ...


Discovery

The array of telescopes atop Mauna Kea, with which the Kuiper belt was discovered

In 1987, astronomer David Jewitt, then at MIT, became increasingly puzzled by "the apparent emptiness of the outer Solar System."[24] He encouraged then-graduate student Jane Luu to aid him in his endeavour to locate another object beyond Pluto's orbit, because, as he told her, "If we don't, nobody will."[25] Using telescopes at the Kitt Peak National Observatory in Arizona and the Cerro Tololo Inter-American Observatory in Chile, Jewitt and Luu conducted their search in much the same way as Clyde Tombaugh and Charles Kowal had, with a blink comparator.[25] Initially, examination of each pair of plates took about eight hours,[26] but the process was speeded up with the arrival of electronic Charge-coupled devices or CCDs, which, though their field of view was narrower, were not only more efficient at collecting light (they retained 90 percent of the light that hit them, rather than the ten percent achieved by photographs) but allowed the blinking process to be done virtually, on a computer screen. Today, CCDs form the basis for all astronomical detectors.[27] In 1988, Jewitt moved to the Institute of Astronomy at the University of Hawaii. He was later joined by Jane Luu to work at the University of Hawaii’s 2.24 m telescope at Mauna Kea.[28] Eventually, the field of view for CCDs had increased to 1024 by 1024 pixels, which allowed searches to be conducted far more rapidly.[29] Finally, after five years of searching, on August 30, 1992, Jewitt and Luu announced the "Discovery of the candidate Kuiper belt object" (15760) 1992 QB1;[24] Six months later, they discovered a second object in the region, 1993 FW.[30] Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... Mauna Kea is a dormant volcano in the Hawaiian Islands, one of five volcanic peaks that together form the island of Hawaii. ... David C. Jewitt is a Professor of astronomy at the University of Hawaii Institute for Astronomy. ... Mapúa Institute of Technology (MIT, MapúaTech or simply Mapúa) is a private, non-sectarian, Filipino tertiary institute located in Intramuros, Manila. ... Dr. Jane Luu Dr. Jane Luu (a. ... Adjectives: Plutonian Atmosphere Surface pressure: 0. ... The Kitt Peak National Observatory (KPNO) is a United States astronomical observatory located on a 2,096 m (6,880 ft) peak of the Quinlan Mountains in the Arizona-Sonoran Desert on the Tohono Oodham Nation, 88 kilometres (55 miles) southwest of Tucson. ... Official language(s) English Capital Phoenix Largest city Phoenix Area  Ranked 6th  - Total 113,998 sq mi (295,254 km²)  - Width 310 miles (500 km)  - Length 400 miles (645 km)  - % water 0. ... The Cerro Tololo Inter-American Observatory (CTIO, IAU code 807) is a complex of astronomical telescopes and instruments located at 30. ... A specially developed CCD used for ultraviolet imaging in a wire bonded package. ... This article is about the University of Hawaii system. ... August 30 is the 242nd day of the year (243rd in leap years) in the Gregorian calendar. ... Year 1992 (MCMXCII) was a leap year starting on Wednesday (link will display full 1992 Gregorian calendar). ... (15760) 1992 QB1 (also written (15760) 1992 QB1) was the first trans-Neptunian object to be discovered after Pluto and Charon. ...


Name

Astronomers sometimes use alternative name Edgeworth-Kuiper belt to credit Edgeworth, and KBOs are occasionally referred to as EKOs. However, Brian Marsden claims neither deserve true credit; "Neither Edgeworth or Kuiper wrote about anything remotely like what we are now seeing, but Fred Whipple did."[31] The term trans-Neptunian object (TNO) is recommended for objects in the belt by several scientific groups because the term is less controversial than all others — it is not a synonym though, as TNOs include all objects orbiting the Sun at the outer edge of the solar system, not just those in the Kuiper belt. Brian G. Marsden is an astronomer, the longtime director of the Minor Planet Center. ... Fred Lawrence Whipple (November 5, 1906–August 30, 2004) was an American astronomer. ... A trans-Neptunian object (TNO) is any object in the solar system that orbits the sun at a greater distance on average than Neptune. ... Synonyms can be nouns, adverbs or adjectives, as long as both members of the pair are the same part of speech. ...


Largest KBOs

The Earth Dysnomia (136199) Eris Charon (134340) Pluto (136472) 2005 FY9 (136108) 2003 EL61 (90377) Sedna (90482) Orcus (50000) Quaoar (20000) Varuna

The relative sizes of the largest trans-Neptunian objects as compared to Earth.

Since the year 2000, a number of KBOs with diameters of between 500 and 1200 km (about half that of Pluto) have been discovered. 50000 Quaoar, a classical KBO discovered in 2002, is over 1200 km across. (136472) 2005 FY9 (nicknamed "Easterbunny") and (136108) 2003 EL61 (nicknamed "Santa"), both announced on 29 July 2005, are larger still. Other objects, such as 28978 Ixion (discovered in 2001) and 20000 Varuna (discovered in 2000) measure roughly 500 km across.[4] Image File history File links Download high-resolution version (2750x1995, 1859 KB) Summary Comparison of the eight largest TNOs, based on the public domain NASA image: Image:2006-16-d-print. ... 50000 Quaoar (pronounced kwaa·waar or kwow·ər, English IPA: , Tongva ) [2] is a Trans-Neptunian object orbiting the Sun in the Kuiper belt. ... (also written (136472) 2005 FY9) is a very large Kuiper belt object discovered on March 31, 2005 by the team led by Michael Brown. ... (also written (136108) 2003 EL61), nicknamed Santa, is a large Kuiper belt object, roughly one-third the mass of Pluto, discovered by Mike Browns group at Caltech in the United States and J. L. Ortiz et al. ... July 29 is the 210th day of the year (211th in leap years) in the Gregorian calendar. ... 2005 (MMV) was a common year starting on Saturday of the Gregorian calendar. ... 28978 Ixion (IPA pronunciation: , Wiktionary:Ixion) is a Kuiper belt object discovered on May 22, 2001. ... 20000 Varuna (VAR oo na) is a large classical Kuiper Belt object (KBO). ...


Pluto

The discovery of these large KBOs in similar orbits to Pluto led many to conclude that, bar its relative size, Pluto was not particularly different from other members of the Kuiper belt. Not only did these objects approach Pluto in size, but many also possessed satellites, and were of similar composition (methane and carbon monoxide have been found both on Pluto and on the largest KBOs[4]). Ceres was considered a planet before the discovery of its fellow asteroids, and, based on this precedent, many astronomers concluded that Pluto should also be reclassified. Spectral type: G[8] Absolute magnitude: 3. ... 253 Mathilde, a C-type asteroid. ...


The issue was brought to a head by the discovery of Eris, an object in the scattered disc far beyond the Kuiper belt, that is now known to be 27 percent more massive than Pluto.[32] In response, the International Astronomical Union (IAU), was forced to define a planet for the first time, and in so doing included in their definition that a planet must have "cleared the neighbourhood around its orbit."[33] As Pluto shared its orbit with so many KBOs, it was deemed not to have cleared its orbit, and was thus reclassified from a planet to a member of the Kuiper belt. Absolute magnitude: −1. ... The scattered disc (or scattered disk) is a distant region of our solar system, thinly populated by icy planetoids known as scattered disk objects (SDOs), a subset of the broader family of trans-Neptunian objects (TNOs). ... Logo of the IAU The International Astronomical Union (French: Union astronomique internationale) unites national astronomical societies from around the world. ... Photograph of the planet Neptune and its moon Triton, taken by Voyager 2 as it entered the outer solar system. ... This article or section is in need of attention from an expert on the subject. ...


Though Pluto is the largest KBO, a number of objects outside the Kuiper belt which may have begun their lives as KBOs are larger. Eris is the most obvious example, but Neptune's moon Triton, which, as explained above, is probably a captured KBO, is also larger than Pluto. Triton (trye-tÉ™n, IPA: , Greek Τρίτων), or Neptune I, is the planet Neptunes largest moon. ...


Origins

Image showing Outer Planets and Kuiper Belt: a)Before Jupiter/Saturn 2:1 resonance b)Scattering of Kuiper Belt objects into the solar system after the orbital shift of Neptune c)After ejection of Kuiper Belt bodies by Jupiter

The precise origins of the Kuiper belt and its complex structure are still unclear, and astronomers are awaiting the completion of the Pan-STARRS survey telescope, which should reveal many currently unknown KBOs, to precisely determine its origin.[4] Image File history File links Orbits1. ... Image File history File links Orbits1. ... Pan-STARRS logo Pan-STARRS (an acronym for Panoramic Survey Telescope and Rapid Response System) is a planned astronomical survey that will conduct astrometry and photometry of much of the entire sky on a continuous basis. ...


The Kuiper belt is believed to consist of planetesimals; fragments from the original protoplanetary disc around the Sun that failed to fully coalesce into planets and instead formed into smaller bodies, the largest less than 3000 km in diameter. In cosmogony, planetesimals are objects thought to exist within solar nebulae. ... A protoplanetary disc (also protoplanetary disk, proplyd) is an accretion disc surrounding a T Tauri star. ... The Sun (Latin: Sol) is the star at the center of the Solar System. ...


Modern computer simulations show the Kuiper belt to have been strongly influenced by Jupiter and Neptune, and also suggest that neither Uranus and Neptune could have formed in situ beyond Saturn, as too little primordial matter existed at that range to produce objects of such high mass. Instead, these planets are believed to have formed closer to Jupiter, but to have been flung outwards during the course of the Solar System's early evolution. Work in 1984 by Fernandez and Ip suggests that exchange of angular momentum with a the scattered objects can cause the planets to drift.[34] Eventually, the orbits shifted to the point where Jupiter and Saturn existed in an exact 2:1 resonance; Jupiter orbited the Sun twice for every one Saturn orbit. The gravitational pull from such a resonance ultimately disrupted the orbits of Uranus and Neptune, causing them to switch places and for Neptune to travel outward into the proto-Kuiper belt, sending it into temporary chaos.[35]As Neptune travelled outward, it excited and scattered many TNOs into higher and more eccentric orbits.[36] The NASA Columbia Supercomputer. ... Look up simulation in Wiktionary, the free dictionary. ... Atmospheric characteristics Atmospheric pressure 70 kPa Hydrogen ~86% Helium ~14% Methane 0. ... Adjectives: Neptunian Atmosphere Surface pressure: ≫ 100 kPa (cloud level) Composition: 80% ± 3. ... Adjectives: Uranian Atmosphere Surface pressure: 120 kPa (at the cloud level) Composition: 83% Hydrogen 15% Helium 1. ... Adjectives: Neptunian Atmosphere Surface pressure: ≫ 100 kPa (cloud level) Composition: 80% ± 3. ... This gyroscope remains upright while spinning due to its angular momentum. ...


However, the present models still fail to account for many of the characteristics of the distribution and, quoting one of the scientific articles,[37] the problems "continue to challenge analytical techniques and the fastest numerical modeling hardware and software".


Structure

At its fullest extent, including its outlying regions, the Kuiper belt stretches from roughly 30 to 55 AU. However, the main body of the belt is generally accepted to extend from the 2:3 resonance (see below) at 39.5 AU to the 1:2 resonance at roughly 48 AU. Unlike the asteroid belt, which is fairly thin, the Kuiper belt is quite thick, extending as much as ten degrees outside the ecliptic plane, and better resembles a torus or doughnut than a belt.[38] It is enclined to the ecliptic by 1.86 degrees.[39] The plane of the Ecliptic is well seen in this picture from the 1994 lunar prospecting Clementine spacecraft. ... In geometry, a torus (pl. ...

Orbit classification (schematic of semi-major axes).

The presence of Neptune has a profound effect on the Kuiper belt's structure. Over the age of the Solar System, Neptune's gravity will destabilise the orbits of any objects which happen to lie in certain regions, and either send them into the inner Solar System or out into interstellar space. This means that the Kuiper belt possesses marked gaps in its current layout. From about 40-42 AU, for instance, no objects can retain a stable orbit throughout the age of the Solar System, and any observed in that region must have migrated there relatively recently.[40] Image File history File links TheKuiperBelt_classes. ... Image File history File links TheKuiperBelt_classes. ... The semi-major axis of an ellipse In geometry, the term semi-major axis (also semimajor axis) is used to describe the dimensions of ellipses and hyperbolae. ... Adjectives: Neptunian Atmosphere Surface pressure: ≫ 100 kPa (cloud level) Composition: 80% ± 3. ...


Classical belt

Between ~42 ~48 AU, however, the gravitational influence of Neptune is negligible, and objects can exist with their orbits pretty much unmolested. This region is known as the classical Kuiper belt, and its members comprise roughly two thirds of KBOs observed to date.[41] [42] Because the first modern KBO discovered, 1992 QB1, is considered the prototype of this group, classical KBOs are often referred to as cubewanos ("Q-B-1-os").[43][44] In astronomy a cubewano (pronounced ) is a Kuiper belt object that orbits beyond Neptune and is not controlled by an orbital resonance with the giant planet. ... In astronomy a cubewano (pronounced ) is a Kuiper belt object that orbits beyond Neptune and is not controlled by an orbital resonance with the giant planet. ... (Redirected from 1992 QB1) (15760) 1992 QB1 was the first trans-Neptunian object discovered, in 1992. ... A cubewano is a Kuiper belt object, orbiting beyond Pluto and not controlled by resonances with Neptune. ...


The classical Kuiper belt appears to be a composite of two separate populations. The first, known as "dynamically cold" population, has orbits much like the planets; nearly circular, with an orbital eccentricity of less than 0.1, and with relatively low inclinations (they lie close to the plane of the Solar System rather than at an angle). The second, the "dynamically hot" population, has orbits radically inclined to the ecliptic, at above 30 degrees. The two populations got their names not because of any major difference in temperature, but from analogy to particles in a gas, which increase in relative velocity as they become excited by heat.[45] The two populations not only possess different orbits, but different compositions; the cold population is markedly redder than the hot, suggesting it formed in a different region. The hot population is believed to have formed near Jupiter, and to have been ejected out by movements among the gas giants. The cold population is believed to have formed beyond Neptune, but to have also been swept outwards by Neptune during its migration.[4] (This page refers to eccitricity in astrodynamics. ...


Resonances

Main article: Resonant trans-Neptunian object
Distribution of cubewanos, plutinos and near scattered objects.

There do exist however, islands of stability in the no-man's-land of Neptune's gravitational influence. If an object's orbit happens to share a specific ratio with that of Neptune (called a mean motion resonance), then it might by chance permanently escape disruption. If, for instance, an object is at just the right distance so that it orbits the Sun two times for every three Neptune orbits, then whenever it returns to its original position, Neptune will always be half an orbit away from it, since it will have completed 1½ orbits in the same time. This is known as the 2:3 (or 3:2) resonance, and it lies at ~39.4AU. The 2:3 resonance is populated by about 200 objects,[46] including Pluto and its moon Charon. In recognition of this, the other members of this family are known as Plutinos. Many Plutinos, including Pluto, often have orbits which cross that of Neptune, though their resonance means they can never collide. Many others, such as 90482 Orcus and 28978 Ixion, are more than half as large as Pluto itself.[47][48]The 1:2 resonance (whose objects complete half an orbit for each of Neptune's) lies at ~47.7AU, and is sparsely populated.[49] Its residents are sometimes referred to as twotinos. Minor resonances also exist at 3:4, 3:5, 4:7 and 2:5.[50] In astronomy, a resonant Trans-Neptunian Object is a Trans-Neptunian Object (TNO) in mean motion orbital resonance with Neptune. ... Image File history File links TheKuiperBelt_75AU_All. ... Image File history File links TheKuiperBelt_75AU_All. ... A cubewano is any substantial Kuiper belt object, orbiting beyond about 41 AU and not controlled by resonances with the outer planets. ... In astronomy, a plutino is a trans-Neptunian object that has a 3:2 orbital resonance with Neptune. ... The scattered disc (or scattered disk) is a distant region of our solar system, thinly populated by icy planetoids known as scattered disk objects (SDOs), a subset of the broader family of trans-Neptunian objects (TNOs). ... In celestial mechanics, an orbital resonance occurs when two orbiting bodies exert a regular, periodic gravitational influence on each other. ... Adjectives: Plutonian Atmosphere Surface pressure: 0. ... Charon (shair-É™n or kair-É™n (key), IPA , Greek Χάρων), discovered in 1978, is, depending on the definition employed, either the largest moon of Pluto or one member of a double dwarf planet with Pluto being the other member. ... In astronomy, a plutino is a Pluto-like object, insofar as it has the same relative orbit as Pluto. ... 90482 Orcus (originally known by the provisional designation 2004 DW) is a Kuiper Belt object (KBO) that was discovered by Michael Brown of Caltech, Chad Trujillo of the Gemini Observatory, and David Rabinowitz of Yale University. ... 28978 Ixion (IPA pronunciation: , Wiktionary:Ixion) is a Kuiper belt object discovered on May 22, 2001. ... While a Plutino completes 2 orbits around the Sun in the time it takes Neptune to complete 3 orbits, a Twotino makes 1 orbit around the Sun in the time it takes Neptune to complete 2 orbits. ...


There also exists a relative absence of objects before 39 AU which resonances alone cannot explain. The accepted current hypothesis for this empty region is as Neptune migrated outward, this region for a time fell into an unstable orbital resonance with it, and thus any objects within it were swept up, or gravitationally ejected from the Solar System.[51]


The "Kuiper cliff"

Graph showing the numbers of KBOs for a given distance from the Sun

The 1:2 resonance appears to be an edge. It is not clear whether it is actually the outer edge of the Classical belt or just the beginning of a gap. Objects have been detected at the 2:5 resonance at roughly 55 AU, well outside the classical belt; however, predictions of a large number of bodies in classical orbits between these resonances have not been verified through observation.[52] Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ...


Earlier models of the Kuiper belt had suggested that the number of large objects would increase by a factor of two beyond 50 AU;[53] so this sudden drastic falloff, known as the "Kuiper cliff", was completely unexpected, and its cause, to date, is unknown. Alan Stern of the Southwest Research Institute has claimed that the gravitiational attraction of an unseen large planetary object, perhaps the size of Earth or Mars, might be responsible.[54] Bernstein and Trilling et al. have found evidence that the observed rapid decline in objects of 100 km or more in radius beyond 50 AU is a real decline in the number of objects, and not just an observational effect.[55] This page may meet Wikipedias criteria for speedy deletion. ... Southwest Research Institute (SwRI) is an independent, nonprofit applied research and development organization. ...


Scattered objects

The orbits of objects in the scattered disc; the classical KBOs are blue, while the 2:5 resonant objects are green.

The scattered disc is a sparsely populated region beyond the Kuiper belt, extending as far as 100 AU and farther. Scattered disc objects (SDOs) are set in highly elliptical orbits wildly inclined to the ecliptic. Most models of solar system formation show icy planetoids first forming in the Kuiper belt, while later gravitational interactions, particularly with Neptune, displaced some of them outwards into the scattered disc. The scattered disc (or scattered disk) is a distant region of our solar system, thinly populated by icy planetoids known as scattered disk objects (SDOs), a subset of the broader family of trans-Neptunian objects (TNOs). ... Triton (trye-tÉ™n, IPA: , Greek Τρίτων), or Neptune I, is the planet Neptunes largest moon. ... The centaurs are a class of icy planetoids that orbit the Sun between Jupiter and Neptune, named after the mythical race of centaurs. ... Image File history File links TheKuiperBelt_Projections_100AU_Classical_SDO.svg // Summary Projection of the aligned orbits of the scattered, classical and resonant objects. ... Image File history File links TheKuiperBelt_Projections_100AU_Classical_SDO.svg // Summary Projection of the aligned orbits of the scattered, classical and resonant objects. ... A scattered disk object (or scattered disc object or SDO) is a trans-Neptunian object of the Kuiper belt with a very eccentric orbit. ...


During its period of migration, Neptune is thought to have captured one of the larger KBOs and set it in orbit around itself. Its moon Triton is the only large moon in the Solar System to have a retrograde orbit; it orbits in the opposite direction to Neptune's rotation. This suggests that, unlike the large moons of Jupiter and Saturn, which are thought to have coalesced from spinning discs of material encircling their young parent planets, Triton was a fully formed body that was captured from surrounding space. Gravitational capture of an object is not easy; it requires that some force act upon the object to slow it down enough to be snared by the larger object's gravity. How this happened to Triton is not well understood, though it does suggest that Triton formed as part of a large population of similar objects whose gravity could impede its motion enough to be captured. Spectral analysis of both Triton and Pluto shows that they are largely composed of similar materials, such as methane and carbon monoxide. All this points to the conclusion that Triton was once a KBO that was captured by Neptune during its outward migration.[56] Triton (trye-tÉ™n, IPA: , Greek Τρίτων), or Neptune I, is the planet Neptunes largest moon. ... Methane is a chemical compound with the molecular formula CH4. ... Carbon monoxide, with the chemical formula CO, is a colorless, odorless, and tasteless gas. ...


According to the Minor Planet Center, which officially catalogues all trans-Neptunian objects, a KBO, strictly speaking, is any object that orbits exclusively within the defined Kuiper belt region regardless of origin or composition. Objects found outside the belt are classed as scattered objects.[57] However, in some scientific circles the term "Kuiper belt object" has become synonymous with any icy planetoid native to the outer solar system believed to have been part of that initial class, even if its orbit during the bulk of solar system history has been beyond the Kuiper belt (e.g. in the scattered disk region). These often describe scattered disc objects as "scattered Kuiper belt objects."[58] Other leading trans-Neptunian researchers have been more cautious in applying the KBO label to objects clearly outside the belt in the current epoch. Eris, the recently discovered object now known to be larger than Pluto, is often referred to as a KBO, but is technically an SDO. The Minor Planet Center operates at the Smithsonian Astrophysical Observatory (SAO), which is part of the Center for Astrophysics (CfA) along with the Harvard College Observatory (HCO). ... Absolute magnitude: −1. ...


The centaurs, which are not normally considered part of the Kuiper belt, are also believed to be scattered Kuiper belt objects, only objects scattered inward, rather than outward. The Minor Planet Center groups the centaurs and the SDOs together as scatterd KBOs.[57] The centaurs are a class of icy planetoids that orbit the Sun between Jupiter and Neptune, named after the mythical race of centaurs. ... The Minor Planet Center operates at the Smithsonian Astrophysical Observatory (SAO), which is part of the Center for Astrophysics (CfA) along with the Harvard College Observatory (HCO). ...


Satellites

Satellites are markedly common among trans-Neptunian objects. Of the four largest TNOs, three (Eris, Pluto, and 2003 EL61, possess satellites, and two have more than one. This ratio is higher than that of Kuiper belt satellites as a whole, suggesting that a different formation mechanism was responsible.[59] There are also a high number of binaries (two objects orbiting each other) in the Kuiper belt. The most notable example is the Pluto-Charon binary, but it is estimated that over 1 percent of KBOs (a high percentage) exist in binaries.[60] 2003 EL61 (also written 2003 EL61), nicknamed Santa (non-official designation), is a large and very unusual Kuiper belt object discovered by Mike Brown at Caltech in the United States. ...


Mass and composition

The infrared spectra of both Eris and Pluto, highlighting their common methane absorption lines

Studies of the Kuiper belt since its discovery have generally indicated that its members are primarily composed of ices; a mixture of light hydrocarbons (such as methane), ammonia, and water ice, a composition they share with comets, which are thought to originate there.[61] The temperature of the belt is only about 50K,[62] so many compounds that would remain gaseous closer to the Sun are solid. Image File history File links Near infrared spectrum of possible new planet 2003 UB313, taken with the Gemini 8m telescope. ... Image File history File links Near infrared spectrum of possible new planet 2003 UB313, taken with the Gemini 8m telescope. ... Methane is a chemical compound with the molecular formula CH4. ... Ammonia is a compound with the formula NH3. ... Water Ice, sometimes referred to as Italian Water Ice, is a snack item served during the summer. ... Comet Hale-Bopp, showing a white dust tail and blue gas tail (February 1997) A comet is a small astronomical object similar to an asteroid but composed largely of ice. ...


Due to their small size and extreme distance from Earth, the chemical makeup of KBOs is very difficult to determine. The principal method by which astronomers determine the composition of a celestial object is spectroscopy. When an object's light is broken into its component colours, an image akin to a rainbow is formed. This image is called a spectrograph. Different substances absorb light at different wavelengths, and when the spectrograph for a specific object is unravelled, dark lines (called absorption lines) appear where the elements within it have absorbed that particular wavelength of light. Every element has its own unique spectroscopic signiture, and by reading an object's full spectral "fingerprint", astronomers can determine what it is made of. Extremely high resolution spectrogram of the Sun showing thousands of elemental absorption lines (fraunhofer lines) Spectroscopy is the study of the interaction between radiation (electromagnetic radiation, or light, as well as particle radiation) and matter. ... For Acoustic uses in spectrographs of sound waves, see below. ... A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from an excess or deficiency of photons in a narrow frequency range, compared with the nearby frequencies. ...


Initially, such detailed analysis of KBOs was impossible, and so astronomers were only able to determine the most basic facts about their makeup, primarily their colour.[63] These first data showed a broad range of colours among KBOs, ranging from neutral grey to deep red.[64] This suggested that their surfaces were composed of a wide range of compounds, from dirty ices to hydrocarbons.[64] This diversity was startling, as astronomers had expected KBOs to be uniformly dark, having lost most of their volatile ices to the effects of cosmic rays.[65] Various solutions were suggested for this discrepency, including resurfacing by impacts or outgassing.[63] However, Jewitt and Luu's spectral analysis of the known Kuiper belt objects in 2001 found that the variation in colour was too extreme to be easily explained by random impacts.[66]


Although to date most KBOs still appear spectrally featureless due to their faintness, there have been a number of successes in determining their composition.[62] In 1996, Robert H. Brown et al obtained spectroscopic data on the KBO 1993 SC, revealing its surface composition to be markedly similar to that of Pluto, as well as Neptune's moon Triton, possessing large amounts of methane ice.[67] Adjectives: Plutonian Atmosphere Surface pressure: 0. ... Triton (trye-tÉ™n, IPA: , Greek Τρίτων), or Neptune I, is the planet Neptunes largest moon. ... Methane is a chemical compound with the molecular formula CH4. ...


Water ice has been detected in several KBOs, including 1996 TO66,[68] 2000 EB173 and 2000 WR106.[69] In 2004, Mike Brown et al determined the existence of crystalline water ice and ammonia hydrate on one of the largest known KBOs, 50000 Quaoar. Both of these substances would have been destroyed over the age of the solar system, suggesting that Quaoar had been recently resurfaced, either by internal tectonic activity or by meteorite impacts.[62] (also written (19308) 1996 TO66) is a trans-Neptunian object. ... Ammonia is a compound with the formula NH3. ... Hydrate is a term which means different things in inorganic chemistry and organic chemistry. ... 50000 Quaoar (pronounced kwaa·waar or kwow·ər, English IPA: , Tongva ) [2] is a Trans-Neptunian object orbiting the Sun in the Kuiper belt. ...


Despite its vast extent, the collective mass of the Kuiper belt is relatively low; estimated at roughly a tenth the mass of the Earth.[4] Conversely, models of the Solar System's formation predict a collective mass for the Kuiper belt of 30 Earth masses.[4] This missing >99% of the mass can be hardly dismissed, as it is required for the accretion of any KBOs larger than 100 km in diameter. At the current low density these objects simply should not exist. Moreover, the eccentricity and inclination of current orbits makes the encounters quite "violent," resulting in destruction rather than accretion. It appears that either the current residents of the Kuiper belt have been created closer to the Sun or some mechanism dispersed the original mass. Neptune’s influence is too weak to explain such a massive "vacuuming". While the question remains open, the conjectures vary from a passing star scenario to grinding of smaller objects, via collisions, into dust small enough to be affected by solar radiation.[70]


Size distribution

Illustration of the power law.

Bright objects are rare compared with the dominant dim population, as expected from accretion models of origin, given that only some objects of a given size would have grown further. This relationship N(D), the population expressed as a function of the diameter, referred to as brightness slope, has been confirmed by observations. The slope[71] is inversely proportional to some power of the diameter D. Image File history File links TheKuiperBelt_PowerLaw2. ... Image File history File links TheKuiperBelt_PowerLaw2. ...

where the current measures[72] give q = 4 ±0.5.

The relationship is illustrated on the graph for q=4. Less formally, there is for instance 8 (=23) times more objects in 100-200 km range than objects in 200-400 km range. In other words, for a single object with the diameter of 1000 km it should be there around 1000 (=103) objects with diameter of 100 km. Of course, only the magnitude is actually known, the size is inferred assuming albedo (not a safe assumption for larger objects)


Comets

Main article: Comet
Comet Encke, a Jupiter-family comet

Comets in the solar system can be loosely divided into two categories: short-period and long period. Long period comets are believed to originate in the Oort cloud. There are two recognised categories of short-period comets: Jupiter-family comets and Halley-family comets. The latter group, which is named for its prototype, Halley's Comet, are believed to have emerged from the Oort cloud but to have been drawn into the inner Solar System by the gravity of the giant planets.[18] It is the former type, the Jupiter family, that are believed to have originated from the Kuiper belt. The centaurs are thought to be a dynamically intermediate stage between the Kuiper belt and the Jupiter family.[73] Comet Hale-Bopp Comet West For other uses, see Comet (disambiguation). ... Image File history File links Comet2PEncke. ... Image File history File links Comet2PEncke. ... This image is an artists rendering of the Oort cloud and the Kuiper Belt. ... Halleys Comet, officially designated 1P/Halley and also referred to as Comet Halley after Edmond Halley, is a comet that can be seen every 75–76 years. ...


Despite the fact that many are universally thought to have hailed from the Kuiper belt, there exist a wide array of differences between KBOs and Jupiter-family comets. Although the centaurs share a reddish colouration with many KBOs, the nuclei of comets are far bluer, indicating a fundamental chemical or physical difference.[18] The current hypothesis is that comet nuclei are resurfaced as they approach the Sun by subsurface materials which subsequently bury the older reddish material.[18]


Other Kuiper belts

The debris disks around these two remote stars seem equivalent of our own Solar system's Kuiper Belt. The left image is a "top view" of a wide belt, and the right image is an "edge view" of a narrow belt. The black central circle is produced by the camera's coronagraph which hides the central star to allow the much fainter disks to be seen. Observed with Hubble Space Telescope

As of 2006, nine stars other than the Sun are known to be circled by Kuiper belt-like structures. They appear to fall into two categories: wide belts, with radii of over 50 AU, and narrow belts (like our own Kuiper belt) with diameters of between 20 and 30 AU with relatively sharp boundaries. Most debris discs around other stars are fairly young, but the two imaged at right, taken by the Hubble Space Telescope in January, 2006, are old enough (roughly 300 million years) to have settled into stable configurations.[74] Image File history File links Download high resolution version (2908x1524, 786 KB) The two dusty planetary disks around the nearby stars resemble our Kuiper belt. ... Image File history File links Download high resolution version (2908x1524, 786 KB) The two dusty planetary disks around the nearby stars resemble our Kuiper belt. ... An example image from SOHO - NASA A coronagraph is a telescopic attachment designed specifically to block out the harsh, direct light from a star, so that nearby objects can be resolved without burning out the telescopes optics. ... The Hubble Space Telescope (HST) is a telescope in orbit around the Earth, named after astronomer Edwin Hubble. ...


List of the brightest KBOs

The brightest known KBOs (with absolute magnitudes < 4.0), are: In astronomy, absolute magnitude is the apparent magnitude, m, an object would have if it were at a standard luminosity distance away from us, in the absence of interstellar extinction. ...

Permanent
Designation
Provisional
Designation
Absolute magnitude Albedo[48] Equatorial diameter
(km)[48]
Semimajor axis
(AU)
Date found Discoverer Diameter method
Pluto[75] −1.0 0.6 2320 39.4 1930 C. Tombaugh occultation
136472 2005 FY9[76] −0.3 0.8 ± 0.2 1500.−200+400 45.7 2005 M. Brown, C. Trujillo & D. Rabinowitz assumed albedo
136108 2003 EL61[77] 0.1 0.6 (assumed) 1150.−100+250 43.3 2005 M. Brown, C. Trujillo & D. Rabinowitz assumed albedo
Charon[78] S/1978 P 1 1 0.4 1205 39.4 1978 J. Christy occultation
Orcus 2004 DW 2.3 0.1 (assumed) 946.3 −72.3+74.1 39.4 2004 M. Brown, C. Trujillo & D. Rabinowitz assumed albedo
Quaoar 2002 LM60 2.6 0.10 ± 0.03 844 −190+207 43.5 2002 C. Trujillo & M. Brown disk resolved
Ixion 2001 KX76 3.2 0.25 – 0.50 650 −220+260 39.6 2001 DES thermal
55636 2002 TX300 3.3 > 0.19 < 800 43.1 2002 NEAT thermal
55565 2002 AW197 3.3 0.14 – 0.20 734.6 −108.3+116.4 47.4 2002 C. Trujillo, M. Brown, E. Helin, Steven H. Pravdo,
K. Lawrence & Michael D. Hicks / Palomar Observatory
thermal
55637 2002 UX25 3.6 0.08? 681.2 −114.0+115.6 42.5 2002 Anne S. Descour / Spacewatch assumed albedo
Varuna 2000 WR106 3.7 0.12 – 0.30 500 −100+100 43.0 2000 R. McMillan thermal
2002 MS4 3.8 0.1 (assumed) 726.2 −122.9+123.2 41.8 2002 C. Trujillo, M. Brown assumed albedo
2003 AZ84 3.9 0.1 (assumed) 685.8 −95.5+98.8 39.6 2003 C. Trujillo, M. Brown, E. Helin, Steven H. Pravdo,
K. Lawrence & Michael D. Hicks [1]
assumed albedo

In geometry, the semi-major axis (also semimajor axis) a applies to ellipses and hyperbolas. ... Adjectives: Plutonian Atmosphere Surface pressure: 0. ... Clyde William Tombaugh (February 4, 1906 &#8211; January 17, 1997) was an American astronomer who discovered the planet Pluto in 1930. ... In this July, 1997 still frame captured from video, the bright star Aldebaran has just reappeared on the dark limb of the waning crescent moon in this predawn occultation. ... (also written (136472) 2005 FY9) is a very large Kuiper belt object discovered on March 31, 2005 by the team led by Michael Brown. ... Michael (Mike) E. Brown (born c. ... Chadwick A. Trujillo (born November 22, 1973) is a postdoctoral scholar at Caltech researching the Edgeworth-Kuiper belt and the outer solar system. ... This article or section does not cite its references or sources. ... Albedo is the ratio of reflected to incident electromagnetic radiation. ... (also written (136108) 2003 EL61), nicknamed Santa, is a large Kuiper belt object, roughly one-third the mass of Pluto, discovered by Mike Browns group at Caltech in the United States and J. L. Ortiz et al. ... Michael (Mike) E. Brown (born c. ... Chadwick A. Trujillo (born November 22, 1973) is a postdoctoral scholar at Caltech researching the Edgeworth-Kuiper belt and the outer solar system. ... This article or section does not cite its references or sources. ... Albedo is the ratio of reflected to incident electromagnetic radiation. ... Charon (shair-ən or kair-ən (key), IPA , Greek Χάρων), discovered in 1978, is, depending on the definition employed, either the largest moon of Pluto or one member of a double dwarf planet with Pluto being the other member. ... James Walter Christy (born 1938) is an American astronomer. ... In this July, 1997 still frame captured from video, the bright star Aldebaran has just reappeared on the dark limb of the waning crescent moon in this predawn occultation. ... 90482 Orcus (originally known by the provisional designation 2004 DW) is a Kuiper Belt object (KBO) that was discovered by Michael Brown of Caltech, Chad Trujillo of the Gemini Observatory, and David Rabinowitz of Yale University. ... Michael (Mike) E. Brown (born c. ... Chadwick A. Trujillo (born November 22, 1973) is a postdoctoral scholar at Caltech researching the Edgeworth-Kuiper belt and the outer solar system. ... This article or section does not cite its references or sources. ... Albedo is the ratio of reflected to incident electromagnetic radiation. ... 50000 Quaoar (pronounced kwaa·waar or kwow·ər, English IPA: , Tongva ) [2] is a Trans-Neptunian object orbiting the Sun in the Kuiper belt. ... Chadwick A. Trujillo (born November 22, 1973) is a postdoctoral scholar at Caltech researching the Edgeworth-Kuiper belt and the outer solar system. ... Michael (Mike) E. Brown (born c. ... 28978 Ixion (IPA pronunciation: , Wiktionary:Ixion) is a Kuiper belt object discovered on May 22, 2001. ... The Deep Ecliptic Survey is a project to find Kuiper belt objects, using the facilities of the National Optical Astronomy Observatory. ... (55636) 2002 TX300 (Also written as (55636) 2002 TX300) is a large Trans-Neptunian object discovered in October 15, 2002 by the NEAT program. ... Near Earth Asteroid Tracking (NEAT) is a program run by NASA and Jet Propulsion Laboratory to discover near-Earth objects. ... (55565) 2002 AW197 is a trans-Neptunian object. ... Chadwick A. Trujillo (born November 22, 1973) is a postdoctoral scholar at Caltech researching the Edgeworth-Kuiper belt and the outer solar system. ... Michael (Mike) E. Brown (born c. ... Eleanor Francis Helin is an American astronomer, principal investigator of the Near Earth Asteroid Tracking (NEAT) program of NASAs Jet Propulsion Laboratory. ... Kenneth J. Lawrence is an American astronomer. ... Palomar Observatory is a privately-owned observatory located in San Diego County, California, 90 miles (145 km) southeast of Mount Wilson Observatory, on Palomar Mountain. ... The correct title of this article is (55637) 2002 UX25. ... Spacewatch is a project at the University of Arizona that specializes in the study of minor planets, and including various types of asteroids and comets. ... Albedo is the ratio of reflected to incident electromagnetic radiation. ... 20000 Varuna (VAR oo na) is a large classical Kuiper Belt object (KBO). ... Robert S. McMillan is an astronomer at the University of Arizona, and heads the Spacewatch project, which studies minor planets. ... is a Trans-Neptunian object (TNO). ... Chadwick A. Trujillo (born November 22, 1973) is a postdoctoral scholar at Caltech researching the Edgeworth-Kuiper belt and the outer solar system. ... Michael (Mike) E. Brown (born c. ... , also written as 2003 AZ84, is a Trans-Neptunian object. ... Chadwick A. Trujillo (born November 22, 1973) is a postdoctoral scholar at Caltech researching the Edgeworth-Kuiper belt and the outer solar system. ... Michael (Mike) E. Brown (born c. ... Eleanor Francis Helin is an American astronomer, principal investigator of the Near Earth Asteroid Tracking (NEAT) program of NASAs Jet Propulsion Laboratory. ... Kenneth J. Lawrence is an American astronomer. ... Albedo is the ratio of reflected to incident electromagnetic radiation. ...

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Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... June 1 is the 152nd day of the year (153rd in leap years) in the Gregorian calendar. ... The astronomical unit (AU or au or a. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... June 1 is the 152nd day of the year (153rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... March 9 is the 68th day of the year in the Gregorian calendar (69th in leap years). ... Georgij A. Krasinsky is a Russian astronomer active at the Institute of Applied Astronomy, Russian Academy of Science, St Petersburg. ... Elena Vladimirovna Pitjeva is a Russian theoretical physicist at the Institute of Applied Astronomy, Russian Academy of Sciences, St. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 171st day of the year (172nd in leap years) in the Gregorian calendar. ... For the Manfred Mann album, see 2006 (album). ... is the 171st day of the year (172nd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... June 1 is the 152nd day of the year (153rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 171st day of the year (172nd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... June 14 is the 165th day of the year (166th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 171st day of the year (172nd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 171st day of the year (172nd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 171st day of the year (172nd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 177th day of the year (178th in leap years) in the Gregorian calendar. ... Jan Hendrik Oort (April 28, 1900 – November 5, 1992) was an internationally famous Dutch astronomer. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 171st day of the year (172nd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 171st day of the year (172nd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 171st day of the year (172nd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... June 14 is the 165th day of the year (166th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 174th day of the year (175th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 174th day of the year (175th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... June 24 is the 175th day of the year (176th in leap years) in the Gregorian calendar, with 190 days remaining. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... June 3 is the 154th day of the year (155th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 174th day of the year (175th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 174th day of the year (175th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 174th day of the year (175th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 174th day of the year (175th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 174th day of the year (175th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 174th day of the year (175th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 176th day of the year (177th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 174th day of the year (175th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 174th day of the year (175th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 174th day of the year (175th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 174th day of the year (175th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 174th day of the year (175th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 174th day of the year (175th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... April 2 is the 92nd day of the year (93rd in leap years) in the Gregorian calendar. ... For the Manfred Mann album, see 2006 (album). ... July 16 is the 197th day (198th in leap years) of the year in the Gregorian calendar, with 168 days remaining. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... June 24 is the 175th day of the year (176th in leap years) in the Gregorian calendar, with 190 days remaining. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... June 24 is the 175th day of the year (176th in leap years) in the Gregorian calendar, with 190 days remaining. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 172nd day of the year (173rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 172nd day of the year (173rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 172nd day of the year (173rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 172nd day of the year (173rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 172nd day of the year (173rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 172nd day of the year (173rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 172nd day of the year (173rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 180th day of the year (181st in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 182nd day of the year (183rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... June 1 is the 152nd day of the year (153rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 182nd day of the year (183rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 182nd day of the year (183rd in leap years) in the Gregorian calendar. ...

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The Sun · Mercury · Venus · Earth · Mars · Ceres · Jupiter · Saturn · Uranus · Neptune · Pluto · Eris
Planets · Dwarf planets · Moons: Terrestrial · Martian · Jovian · Saturnian · Uranian · Neptunian · Plutonian · Eridian
Small bodies:   Meteoroids · Asteroids/Asteroid moons (Asteroid belt) · Centaurs · TNOs (Kuiper belt/Scattered disc) · Comets (Oort cloud)
See also astronomical objects, the solar system's list of objects, sorted by radius or mass, and the Solar System Portal

  Results from FactBites:
 
Kuiper Belt Kuiper Belt Kuiper Belt Kuiper Belt Kuiper Belt Kuiper Belt Kuiper Belt Kuiper Belt Kuiper Belt (0 words)
This ring is generally referred to as the Kuiper Belt.
The Kuiper Belt holds significance for the study of the planetary system on at least two levels.
Second, it is widely believed that the Kuiper Belt is the source of the short-period comets.
Kuiper Belt - MSN Encarta (1787 words)
The small icy bodies in the Kuiper Belt sometimes turn into visible comets when their orbits are disturbed to bring them into the inner solar system.
The Kuiper Belt is considered the likely source of short-period comets, which orbit the Sun in the main plane of the solar system in periods shorter than 200 years.
Kuiper and other astronomers expected that a debris belt, similar to the asteroid belt of rocky material that orbits the Sun between Mars and Jupiter but composed of icy material, might lie beyond Neptune.
  More results at FactBites »

 
 

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