90377 Sedna is a trans-Neptunian object, discovered by Michael Brown (Caltech), Chad Trujillo (Gemini Observatory) and David Rabinowitz (Yale University) on November 14, 2003. Its discovery was the farthest distance at which any natural object in the solar system has ever been observed. Sedna is described as a cold planetoid, perhaps as large as two-thirds the size of Pluto. Dr. Michael (Mike) E. Brown has been an associate professor of planetary astronomy at the California Institute of Technology (Caltech) since 2002. ... Chadwick A. Chad Trujillo (born November 22, 1973) is a postdoctoral scholar at Caltech researching the Kuiper belt and the outer solar system. ... David L. Rabinowitz (born 1960) is a professor at Yale University researching the Kuiper belt and the outer solar system. ... November 14 is the 318th day of the year (319th in leap years) in the Gregorian Calendar, with 47 days remaining. ... 2003 is a common year starting on Wednesday of the Gregorian calendar. ... The provisional designation of comets and asteroids are similar to each other: they both follow a pattern set in 1925 by the Minor Planet Center of the IAU. Historical designations At first, astronomers strove to assign symbols to the minor planets: 1 Ceres a stylized sickle 2 Pallas a lozenge... Minor planets, or planetoids are minor bodies of the solar system orbiting the sun that are larger than meteoroids (the largest of which might be taken to be around 10 meters or so across) but smaller than major planets (Mercury having a diameter of about 4880 km). ... A trans-Neptunian object (TNO) is any object in the solar system with all or most of its orbit beyond that of Neptune. ... In astronomy, an epoch is a moment in time for which celestial coordinates or orbital elements are specified. ... January 30 is the 30th day of the year in the Gregorian Calendar. ... 2005 is a common year starting on Saturday of the Gregorian calendar and is the current year. ... 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The orbital period is the time it takes a planet (or another object) to make one full orbit. ... A day is any of several different units of time. ... A Julian year is the length of an average year in the Julian calendar, 365. ... The orbital speed of a body, generally a planet, a natural satellite, an artificial satellite, or a multiple star, is the speed at which it orbits around the barycenter of a system, usually around a more massive body. ... The second (symbol s) is a unit for time, and one of seven SI base units. ... Inclination is one of the six orbital parameters describing the shape and orientation of a celestial orbit and is the angular distance of the orbital plane from the plane of the reference (usually planets equator or the ecliptic), stated in degrees. ... A degree (or in full a degree of arc), usually symbolized °, is a measurement of plane angle, representing 1/360 of a full rotation. ... The Longitude of the ascending node () is one of the orbital elements used to specify the orbit of an object in space. ... The argument of the perihelion is one of the orbital elements describing the orbit of a planet. ... In the study of orbital dynamics the mean anomaly is a measure of time, specific to the orbiting body p, which is a multiple of 2π radians at and only at periapsis. ... To help compare different orders of magnitude this page lists lengths between 106 and 107 m (1,000 and 10,000 km). ... A kilometre (American spelling: kilometer, symbol: km) is a unit of length equal to 1000 metres (from the Greek words khilia = thousand and metro = count/measure). ... Mass is a property of physical objects that, roughly speaking, measures the amount of matter they contain. ... The international prototype, made of platinum-iridium, which is kept at the BIPM under conditions specified by the 1st CGPM in 1889. ... 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Temperature is the physical property of a system which underlies the common notions of hot and cold; the material with the higher temperature is said to be hotter. ... The kelvin (symbol: K) is the SI unit of temperature, and is one of the seven SI base units. ... A trans-Neptunian object (TNO) is any object in the solar system with all or most of its orbit beyond that of Neptune. ... Dr. Michael (Mike) E. Brown has been an associate professor of planetary astronomy at the California Institute of Technology (Caltech) since 2002. ... The California Institute of Technology (commonly known as Caltech) is a private, coeducational university located in Pasadena, California, in the United States. ... Chadwick A. Chad Trujillo (born November 22, 1973) is a postdoctoral scholar at Caltech researching the Kuiper belt and the outer solar system. ... The Gemini Observatory consists of a pair of 8-meter astronomical telescopes. ... David Lincoln Rabinowitz (born 1960) is a professor at Yale University researching the Kuiper belt and the outer solar system. ... For other uses, see Yale (disambiguation). ... November 14 is the 318th day of the year (319th in leap years) in the Gregorian Calendar, with 47 days remaining. ... 2003 is a common year starting on Wednesday of the Gregorian calendar. ... Presentation of the Solar system (not to scale). ... Planetoid (meaning planet-like) is an old synonym of asteroid. ... Atmospheric characteristics Atmospheric pressure 0. ...

General information

Sedna was discovered during a survey conducted with the Samuel Oschin telescope at Palomar Observatory near San Diego, California (USA) and was observed within days on telescopes from Chile, Spain, and the USA (Arizona, and Hawaii). NASA's orbiting Spitzer Space Telescope was also pointed toward the object, but could not detect it — putting an upper-bound on its diameter at roughly three-quarters that of Pluto. The Samuel Oschin telescope is a 48-inch (1. ... 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. ... City nickname: Americas Finest City Location of San Diego within San Diego County County San Diego Mayor vacant Area   â€“Land   â€“Water 372. ... State nickname: The Golden State Other U.S. States Capital Sacramento Largest city Los Angeles Governor Arnold Schwarzenegger (R) Official languages English Area 410,000 km² (3rd)  - Land 404,298 km²  - Water 20,047 km² (4. ... 50 cm refracting telescope at Nice Observatory. ... State nickname: The Grand Canyon State, The Copper State Other U.S. States Capital Phoenix Largest city Phoenix Governor Janet Napolitano (D) Official languages English Only State Area 295,254 km² (6th)  - Land 294,312 km²  - Water 942 km² (0. ... State nickname: The Aloha State Other U.S. States Capital Honolulu Largest city Honolulu Governor Linda Lingle (R) Official languages Hawaiian and English Area 28,337 km² (43rd)  - Land 16,649 km²  - Water 11,672 km² (41. ... This article needs cleanup. ... The Spitzer Space Telescope (SST) (formerly the Space Infrared Telescope Facility (SIRTF)) is an infrared space observatory, the fourth and final of NASAs Great Observatories. ... For the authentication, authorisation, and accounting protocol, see DIAMETER. In geometry, a diameter (Greek words diairo = divide and metro = measure) of a circle is any straight line segment that passes through the center and whose endpoints are on the circular boundary, or, in more modern usage, the length of such...

Because of its cold, distant nature, and because all other planets of the Solar system are named after (Roman and Greek) gods, the scientists who discovered it unofficially named it after Sedna, the Inuit goddess of the sea, who was believed to live in the cold depths of the Arctic Ocean. Presentation of the Solar system (not to scale). ... This article is about the Inuit goddess. ... Inuit mythology has many similarities to the religions of other polar regions. ...

Before Sedna was officially named it had provisional designation 2003 VB₁₂. As of September 28, 2004, the International Astronomical Union has officially accepted the name "Sedna". The provisional designation of comets and asteroids are similar to each other: they both follow a pattern set in 1925 by the Minor Planet Center of the IAU. Historical designations At first, astronomers strove to assign symbols to the minor planets: 1 Ceres a stylized sickle 2 Pallas a lozenge... September 28 is the 271st day of the year (272nd in leap years). ... 2004 is a leap year starting on Thursday of the Gregorian calendar. ... The International Astronomical Union (IAU) unites national astronomical societies from around the world. ...

Orbital characteristics

Sedna has a highly elliptical orbit, with its aphelion estimated at 942 AU and its perihelion at about 76.1 AU. At its discovery, it was about 90 AU from the Sun, approaching perihelion. This is the furthest from the Sun that any solar system object has been observed, although some objects like long-period comets originally observed at closer distances may currently be further from the Sun than Sedna but are too dim to be observable. For comparison, the average distance of Pluto from the Sun is about 40 AU. Sedna's orbit takes about 11,487 years. It will reach perihelion in 2075 or 2076. In mathematics, an ellipse (from the Greek for absence) is a plane algebraic curve where the sum of the distances from any point on the curve to two fixed points is constant. ... In physics, an orbit is the path that an object makes, around another object, whilst under the influence of a source of centripetal force, such as gravity. ... This article is about several astronomical terms (apogee & perigee, aphelion & perihelion, generic equivalents based on apsis, and related but rarer terms. ... The astronomical unit (AU or au or a. ... This article is about several astronomical terms (apogee & perigee, aphelion & perihelion, generic equivalents based on apsis, and related but rarer terms. ... The Sun is the star at the centre of our Solar system. ... Atmospheric characteristics Atmospheric pressure 0. ... A year is the time between two recurrences of an event related to the orbit of the Earth around the Sun. ... Centuries: 20th century - 21st century - 22nd century Decades: 2020s 2030s 2040s 2050s 2060s - 2070s - 2080s 2090s 2100s 2110s 2120s Years: 2071 2072 2073 2074 2075 - 2076 - 2077 2078 2079 2080 2081 Events The one hundrieth anniversary of the Watergate Scandal court verdicts will occur in January 2075 Categories: 21st century... Centuries: 20th century - 21st century - 22nd century Decades: 2020s 2030s 2040s 2050s 2060s - 2070s - 2080s 2090s 2100s 2110s 2120s Years: 2071 2072 2073 2074 2075 - 2076 - 2077 2078 2079 2080 2081 Events July 4 - Tricentennial of the United States - the 300th anniversary of the signing of the United States Declaration...

[Update: the Kujper Belt Object 2003 UB₃₁₃ was detected at 97 AU, and the discovery announced on July 29, 2005. However, its average distance is less than that of Sedna. It is estimated to be 150% the diameter of Pluto.] The title of this article is incorrect due to technical limitations. ... July 29 is the 210th day (211th in leap years) of the year in the Gregorian Calendar, with 155 days remaining. ... 2005 is a common year starting on Saturday of the Gregorian calendar and is the current year. ...

When first discovered, Sedna was believed to have an unusually long rotational period (between 20–50 days). A search was thus made for a natural satellite, the most likely cause for such a long rotation, but investigation by the Hubble Space Telescope in March 2004 observed no such object orbiting the planetoid. New measurements from the MMT telescope suggest a much shorter rotation period, only about 10 hours, rather typical for bodies of its size.[1] Moons of solar system scaled to Earths Moon The common noun moon (not capitalized) is used to mean any natural satellite of the other planets. ... The Hubble Space Telescope is a telescope in orbit around the Earth. ... Wikipedia does not yet have an article with this exact name. ...

Sedna is located in the center of the green circle.

A study done by Hal Levison and Alessandro Morbidelli of the Observatoire de la Côte d'Azur (OCA) in Nice, France suggested that the most likely explanation for Sedna's orbit was that it had been perturbed by a close pass by another star in the first 100 million years or so of the solar system's existence, possibly one of the other stars that formed out of the same collapsing nebula as the Sun. Another, less probable, scenario they proposed that managed to explain Sedna's orbit very well was that Sedna could have formed around a brown dwarf about 20 times less massive than the Sun and was captured by our Solar System when the brown dwarf passed through it. Download high resolution version (874x665, 198 KB)Image of Sedna from BBC web site (http://news. ... Download high resolution version (874x665, 198 KB)Image of Sedna from BBC web site (http://news. ... The Côte dAzur Observatory was founded in 1988, by the merger of two observatories: Nice Observatory The CERGA (Centre dEtudes et de Recherches Géodynamiques et Astronomiques) External links Côte dAzur Observatory official website (English version) ... Night view along the Promenade des Anglais This article is about the city. ... Brown dwarfs are sub-stellar objects (~5 to 90 Jupiter masses) that do not fuse hydrogen into helium in their cores, as do stars on the main sequence, but have fully convective surfaces and interiors, with no chemical differentiation by depth. ...

Another object, 2000 CR₁₀₅, has an orbit similar to Sedna's but a bit less extreme: perihelion is 45 AU, aphelion is 415 AU, and the orbital period is 3420 years. Its orbit may have resulted from the same processes that produced Sedna's orbit. The comet known as 2000 CR105 is the second most distant known object in the solar system after 90377 Sedna. ...

Physical characteristics

Sedna has an estimated diameter of between 1180 and 1800 kilometres (730 to 1470 miles) and at the time of its discovery was the largest object found in the solar system since Pluto was discovered in 1930. The planetoid is so far from the Sun that the temperature never rises above −240°C (−400°F). To help compare different orders of magnitude this page lists lengths between 106 and 107 m (1,000 and 10,000 km). ... Presentation of the Solar system (not to scale). ... 1930 is a common year starting on Wednesday. ... The degree Celsius (°C or ℃ (Unicode 0x2103)) is a unit of temperature named after the Swedish astronomer Anders Celsius (1701–1744), who first proposed a similar system in 1742. ... Fahrenheit is a temperature scale named after the German physicist Gabriel Fahrenheit (1686–1736), who proposed it in 1724. ...

Observations from Chile show that Sedna is one of the reddest objects in the solar system, nearly as red as Mars. Unlike Pluto and Charon, Sedna appears to have very little methane ice or water ice on its surface; Chad Trujillo and his colleagues at the Gemini Observatory in Hawaii suggest that Sedna's dark red color is caused by a hydrocarbon sludge, or tholin, like that found on 5145 Pholus [7]. Its surface is homogenous in colour and spectrum; this is probably because Sedna, unlike objects nearer the sun, is rarely impacted by other bodies, which would expose bright patches like that on 8405 Asbolus [8]. Mars is the fourth planet from the Sun in the solar system, named after the Roman god of war (the counterpart of the Greek Ares), on account of its blood red color as viewed in the night sky. ... State nickname: The Aloha State Other U.S. States Capital Honolulu Largest city Honolulu Governor Linda Lingle (R) Official languages Hawaiian and English Area 28,337 km² (43rd)  - Land 16,649 km²  - Water 11,672 km² (41. ... In chemistry, a hydrocarbon is any chemical compounds that consists only of carbon (C) and hydrogen (H). ... Tholin is a heteropolymer formed by solar ultraviolet irradiation of simple organic compounds such as methane or ethane. ... 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. ... 8405 Asbolus is a Centaur, that is, an icy asteroid that orbits between Jupiter and Neptune. ...

Classification

The discoverers have argued that Sedna is actually the first observed body belonging to the Oort cloud, saying that it is too far out to be considered a Kuiper belt object. Because it is a great deal closer to the Sun than was expected for an Oort cloud object, and has an inclination roughly in line with the planets and the Kuiper belt, they describe the planetoid as being an inner Oort cloud object, situated in the disc reaching from the Kuiper belt to the spherical part of the cloud. This diagram shows the presumed distance of the Oort cloud compared to the rest of the solar system. ... Artists rendering of the Kuiper Belt and more distant Oort cloud. ... Inclination is one of the six orbital parameters describing the shape and orientation of a celestial orbit and is the angular distance of the orbital plane from the plane of the reference (usually planets equator or the ecliptic), stated in degrees. ... Planetoid (meaning planet-like) is an old synonym of asteroid. ...

However, others believe that its inclination and size qualify it as a Kuiper Belt object. These astronomers suggest that previous assumptions about the outer edge of the Kuiper Belt should be revised outward.

Writing in Nature, astronomers Scott J. Kenyon and Benjamin C. Bromley consider Sedna's origin and show that a passing star probably scattered Sedna from the Sun's Kuiper belt into its observed orbit. They estimate the probability that Sedna was captured from the outer disk of the passing star at about 10 percent (Nature 432, 598–602 (02 December 2004); doi:10.1038/nature03136). Nature is one of the oldest and most reputable general-purpose scientific journals, first published on November 4, 1869. ... The word probability derives from the Latin probare (to prove, or to test). ...

The discovery of Sedna has also resurrected the question of which astronomical objects should be considered planets and which should not. On March 15, 2004, articles in the popular press reported that "the tenth planet has been discovered", and some believe its claim on planethood is comparable to that of Pluto. Sedna's discoverers (like others) call it a planetoid, but because the two objects are similar in size and composition, a permanent decision to classify Sedna as a planetoid could re-open questions about whether Pluto should also bear that classification. Isaac Asimov suggested the term mesoplanet be used for planetary objects intermediate in size between Mercury and 1 Ceres, which would include both Pluto and Sedna. A planet (from the Greek πλανήτης, planētēs which means wanderer or more forcefully vagrant, tramp) is an object in orbit around a star that is not a star in its own right. ... March 15 is the 74th day of the year in the Gregorian Calendar (75th in Leap years). ... 2004 is a leap year starting on Thursday of the Gregorian calendar. ... Planet X (or Transpluto) is a hypothetical planet beyond Pluto. ... Atmospheric characteristics Atmospheric pressure 0. ... Dr. Isaac Asimov enthroned with symbols of his lifes work (Rowena Morrill) Isaac Asimov (c. ... Mesoplanet is a term coined by Isaac Asimov to refer to planetary bodies with sizes smaller than Mercury but larger than 1 Ceres. ... Atmospheric characteristics Atmospheric pressure trace Potassium 31. ... 1 Ceres (seer-eez, Latin Cerēs) was the first asteroid to be discovered. ...

Artist's concept of Sedna. Image courtesy of NASA / JPL-Caltech / R. Hurt

Panels showing the location of Sedna in relation to other astronomical objects. Image courtesy of NASA / JPL-Caltech / R. Hurt

Artist's rendition showing Sedna's size in relation to other objects. Image courtesy of NASA / JPL-Caltech

Download high resolution version (900x675, 48 KB) Artists visualization of the newly discovered planet-like object 90377 Sedna, shown where it resides at the outer edges of the known solar system. ... Download high resolution version (900x675, 48 KB) Artists visualization of the newly discovered planet-like object 90377 Sedna, shown where it resides at the outer edges of the known solar system. ... Download high resolution version (900x900, 177 KB)These four panels show the location of trans-Neptunian object 90377 Sedna, which lies in the farthest reaches of the Solar system. ... Download high resolution version (900x900, 177 KB)These four panels show the location of trans-Neptunian object 90377 Sedna, which lies in the farthest reaches of the Solar system. ... Download high resolution version (900x720, 165 KB) The artists rendition shows 90377 Sedna in relation to other bodies in the solar system, including planet Earth, the Moon, Pluto, and 50000 Quaoar —a planetoid beyond Pluto that was until now the largest known object beyond Pluto. ... Download high resolution version (900x720, 165 KB) The artists rendition shows 90377 Sedna in relation to other bodies in the solar system, including planet Earth, the Moon, Pluto, and 50000 Quaoar —a planetoid beyond Pluto that was until now the largest known object beyond Pluto. ...

References

1. Discovery of a candidate inner Oort cloud planetoid (Brown et.al., submitted to ApJ Letters, 16 March 2004)
2. Hurt, Robert. Artist's Concept of Sedna. California, USA: Infrared Processing and Analysis Center. 15 March 2004.
3. Hurt, Robert. Sedna's Orbit Comparisons. California, USA: Infrared Processing and Analysis Center. 15 March 2004.
4. Hurt, Robert. Sedna's Size Comparisons. California, USA: Infrared Processing and Analysis Center. 15 March 2004.
5. JPL. Most Distant Object in Solar System Discovered. Press release: Jet Propulsion Laboratory. 15 March 2004.
6. Whitehourse, David. Sedna has no moon, say astronomers. BBC News. 14 April 2004.
7. McKee, Maggie. [2] Distant planetoid Sedna gives up more secrets. New Scientist. 15 April 2005.
8. Alexander, Amir. [3] Sedna: Mysterious Planetoid Slowly Yielding Up Its Secrets. The Planetary Society. 18 April 2005.

March 16 is the 75th day of the year in the Gregorian Calendar (76th in Leap years). ... 2004 is a leap year starting on Thursday of the Gregorian calendar. ... March 15 is the 74th day of the year in the Gregorian Calendar (75th in Leap years). ... 2004 is a leap year starting on Thursday of the Gregorian calendar. ... March 15 is the 74th day of the year in the Gregorian Calendar (75th in Leap years). ... 2004 is a leap year starting on Thursday of the Gregorian calendar. ... March 15 is the 74th day of the year in the Gregorian Calendar (75th in Leap years). ... 2004 is a leap year starting on Thursday of the Gregorian calendar. ... March 15 is the 74th day of the year in the Gregorian Calendar (75th in Leap years). ... 2004 is a leap year starting on Thursday of the Gregorian calendar. ... April 14 is the 104th day of the year in the Gregorian calendar (105th in leap years). ... 2004 is a leap year starting on Thursday of the Gregorian calendar. ... April 15 is the 105th day of the year in the Gregorian calendar (106th in leap years). ... 2005 is a common year starting on Saturday of the Gregorian calendar and is the current year. ... April 18 is the 108th day of the year in the Gregorian calendar (109th in leap years). ... 2005 is a common year starting on Saturday of the Gregorian calendar and is the current year. ...

See also

• asteroid
• Kuiper belt
• Oort cloud
• planet
• Definition of planet
• Planet X – a hypothetical planet beyond Pluto which does not match the characteristics of Sedna
• plutino
• protoplanetary disc – Sedna's orbit appears to imply a similar origin to the planets and asteroids.
• 50000 Quaoar – a planetoid beyond Pluto's orbit, discovered in 2002.
• Trans-Neptunian object – an object beyond Neptune's orbit

An asteroid is a small, solid object in our Solar System, orbiting the Sun. ... Artists rendering of the Kuiper Belt and more distant Oort cloud. ... This diagram shows the presumed distance of the Oort cloud compared to the rest of the solar system. ... A planet (from the Greek πλανήτης, planētēs which means wanderer or more forcefully vagrant, tramp) is an object in orbit around a star that is not a star in its own right. ... Although planets are the principal component of the solar system other than the sun, a precise definition of the term is surprisingly elusive. ... Planet X is a large hypothetical planet orbiting beyond the orbit of Neptune. ... In astronomy, a plutino is a Pluto-like object, insofar as it has the same relative orbit as Pluto. ... A protoplanetary disc (also protoplanetary disk, proplyd) is an accretion disc surrounding a T Tauri star. ... Artists impression by G. Bacon of STScI / NASA 50000 Quaoar (pronounced kwah·war, kwah·wor, or kwow·ur, Tongva ) [1] is a Trans-Neptunian object orbiting the Sun in the Edgeworth-Kuiper belt. ... 2002 is a common year starting on Tuesday of the Gregorian calendar. ... A trans-Neptunian object (TNO) is any object in the solar system with all or most of its orbit beyond that of Neptune. ...

External links

• NASA's Sedna page
• Mike Brown's Sedna page
• Official press release by NASA JPL/SCC
• Astronomy Picture of the Day 04 July 2004 – Artist's rendering of view from Sedna
• Scenarios for the Origin of the Orbits of the Trans-Neptunian Objects 2000 CR₁₀₅ and 2003 VB₁₂ (Sedna) by Alessandro Morbidelli and Harold F. Levison
• MPEC 2004-S73: Comment on the naming of Sedna
• Distant Object Could Hold Secrets to Earth's Past
• Sedna on The Nine Planets Solar System Tour

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A trans-Neptunian object (TNO) is any object in the solar system with all or most of its orbit beyond that of Neptune. ... Artists rendering of the Kuiper Belt and more distant Oort cloud. ... Atmospheric characteristics Atmospheric pressure 0. ... Charon (shair-un or kair-un, Greek Χάρων) is the only known satellite of Pluto. ... 90482 Orcus (originally known by the provisional designation 2004 DW) is a Kuiper Belt object (KBO) that was discovered by Michael (Mike) E. Brown of Caltech, Chadwick (Chad) A. Trujillo of the Gemini Observatory, and David L. Rabinowitz of Yale University. ... 28978 Ixion (ik SIGH un, sometimes ICK see un) is a Kuiper belt object discovered on May 22, 2001 with a diameter of approximately 1055 km and a semimajor axis of about 39. ... 20000 Varuna (VAR oo na) is a Kuiper Belt object about 1060 kilometers in diameter, estimated from a combination of thermal and optical measurements. ... The title of this article is incorrect because of technical limitations. ... Artists impression by G. Bacon of STScI / NASA 50000 Quaoar (pronounced kwah·war, kwah·wor, or kwow·ur, Tongva ) [1] is a Trans-Neptunian object orbiting the Sun in the Edgeworth-Kuiper belt. ... The title of this article is incorrect because of technical limitations. ... The title of this article is incorrect due to technical limitations. ... See lists of astronomical objects for a list of the various lists of astronomical objects in Wikipedia. ... Presentation of the Solar system (not to scale). ... Below is a list of solar system objects with diameter >500km: The Sun, a spectral class G2 star Mercury Venus Earth Moon Mars Jupiter Io Europa Ganymede Callisto complete list of Jupiters natural satellites Saturn Tethys Dione Rhea Titan Iapetus complete list of Saturns natural satellites Uranus Ariel... This is a list of solar system objects by radius, in decreasing order. ... This is a list of Solar system objects by mass, in decreasing order. ...