This article may require cleanup to meet Wikipedia's quality standards. Please discuss this issue on the talk page or replace this tag with a more specific message. This article has been tagged since September 2006.

Hypothetical astronomical objects are celestial bodies which some believe to exist. These objects might include planets or moons which are inferred to exist based on scientific evidence. Some have yet to be proven or disproven; others are now viewed as protoscience, pseudoscience or obsolete scientific theory. Some such as Tiamat and Nibiru, are fringe science largely grounded in personal interpretations of ancient astrological texts and are not regarded as scientific. Image File history File links Broom_icon. ... A planet (from the Greek πλανήτης, planetes or wanderers) is a body of considerable mass that orbits a star and that produces very little or no energy through nuclear fusion. ... The common noun moon (not capitalized) is used to mean any natural satellite of the other planets. ... This article or section does not cite its references or sources. ... Phrenology is regarded today as a classic example of pseudoscience. ... An obsolete scientific theory is a scientific theory that was once commonly accepted but (for whatever reason) is no longer considered the most complete description of reality by mainstream science; or a falsifiable theory which has been shown to be false. ... Zecharia Sitchin is a best-selling author promoting the ancient astronaut theory of mankinds origins. ... To the Babylonians, Nibiru was the celestial body or region sometimes associated with the god Marduk. ... Fringe science is a phrase used to describe scientific inquiry in an established field that departs significantly from mainstream or orthodox theories. ... An astrological chart (or horoscope) _ Y2K Chart — This particular chart is calculated for January 1, 2000 at 12:01:00 A.M. Eastern Standard Time in New York City, New York, USA. (Longitude: 074W0023 - Latitude: 40N4251) Astrology (from Greek: αστρολ&#959...

There are many planets and planetary bodies which have been proposed to explain apparent irregularities in other planets' orbits, or other observed effects within or outside our solar system. 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. ...

Hypothetical planets

See also: Hypothetical planet See also: List of hypothetical planetary bodies A hypothetical planet is a planet whose existence is not known, but has been inferred from observational scientific evidence. ...

• Antichthon, the "counter-Earth" hypothesized in some Ancient Greek heliocentric conceptions. Disproved by gravitational theory.
• Vulcan: planet proposed by Urbain Le Verrier to explain irregularities of the orbit of Mercury. Disproved by Albert Einstein's theory of general relativity.
• Planet X: Planet proposed by Percival Lowell to explain irregularities in the orbits of Uranus and Neptune. Disproved by Voyager 2, though some scientists have revived it in a different form.
• Theia: Mars-sized protoplanet believed to have collided with the Earth 4 billion years ago and formed the Moon.
• Tenth planet: The various theories of a tenth planet in our solar system, when Pluto was considered the ninth planet.
• Fifth planet: Historically, a handful of solar system bodies have been counted as the fifth planet from the sun. Under the present definition of a planet, this celestial body is Jupiter. Others have included Ceres and a now destroyed planet which fringe scientists have variously termed Phaeton and Tiamat.
• Nibiru, a large planet or brown dwarf with a highly eliptical orbit of aproximately 3,600 years. Similar to Tiamat, this is based on theories propounded by Zecharia Sitchin.

It has been suggested that this article or section be merged into counter-Earth. ... Note: This article contains special characters. ... In astronomy, heliocentrism is the theory that the Sun is at the center of the Universe and/or the Solar System. ... This article covers the physics of gravitation. ... Vulcan was the name given to a small planet proposed to exist in an orbit between Mercury and the Sun in a 19th-century hypothesis. ... Urbain Le Verrier. ... Albert Einstein( ) (March 14, 1879 – April 18, 1955) was a German-born theoretical physicist who is widely considered to have been one of the greatest physicists of all time. ... General relativity (GR) [also called the general theory of relativity (GTR) and general relativity theory (GRT)] is the geometrical theory of gravitation published by Albert Einstein in 1915/16. ... This article or section is not written in the formal tone expected of an encyclopedia article. ... Percival Lowell (March 13, 1855 – November 12, 1916) was an author, mathematician, and esteemed astronomer who fueled speculation that there were canals on Mars, founded the Lowell Observatory in Flagstaff, Arizona, and formed the beginning of the work and theories that led to the discovery of Pluto 14 years after... Adjectives: Uranian Atmosphere Surface pressure: 120 kPa (at the cloud level) Composition: 83% Hydrogen 15% Helium 1. ... Adjectives: Neptunian Atmosphere Surface pressure: (?)≫(?) 100 kPa : is asked the pressure at the cloud level. ... Trajectory Voyager 2 is an unmanned interplanetary spacecraft, launched on August 20, 1977. ... Theia (THAY-uh) is the hypothetical planet that, according to the giant impact theory of the Moons formation, collided with Earth over four billion years ago. ... This article does not cite its references or sources. ... To meet Wikipedias quality standards, this article may require cleanup. ... Adjectives: Jovian Atmosphere Surface pressure: 20–200 kPa[4] (cloud layer) Composition: ~86% H2 ~13% Helium 0. ... 1 Ceres (SEER eez) was the first asteroid to be discovered, with a diameter of 959. ... Fringe science is a phrase used to describe scientific inquiry in an established field that departs significantly from mainstream or orthodox theories. ... It has been suggested that this article or section be merged with Fifth planet (hypothetical). ... To meet Wikipedias quality standards, this article may require cleanup. ... To the Babylonians, Nibiru was the celestial body or region sometimes associated with the god Marduk. ... Tiamat is a mother goddess in Babylonian and Sumerian mythology, and a central figure in the Enûma Elish creation epic. ... Zecharia Sitchins photograph from The 12th Planet Zecharia Sitchin (born 1922)[1] is a best-selling author (The 12th Planet now in its record 45th printing in the U.S.) of books promoting the ancient astronaut theory of mankinds origins. ...

Hypothetical minor planets

• Vulcanoid asteroid: field of minor planets thought to exist within the orbit of Mercury. Named for Vulcan
• Kuiper cliff: sudden dropoff in the number of Kuiper belt objects observed beyond 55 AU. Possibly caused by the gravity of a large, unseen object.

Vulcanoids are hypothetical asteroids that may orbit in a dynamically stable zone between 0. ... This article is about planet. ... Artists rendering of the Kuiper Belt and more distant Oort cloud. ... Artists rendering of the Kuiper Belt and hypothetical more distant Oort cloud. ...

Hypothetical natural satellites

• Mercury's moon, a moon of Mercury, which for a short time was believed to exist
• Neith, a purported moon of Venus, now known not to exist
• Chiron, a disproven moon of Saturn
• Themis, a moon of Saturn, supposedly discovered in 1905, but later shown not to exist after all
• Lilith, Earth's "dark moon," which is used by some astrologers
• Gaga, a satellite of Saturn which gravitational disruption caused by Nibiru's passing may have incited to move outside of Neptune and becomes Pluto.

A moon orbiting Mercury was, for a short time, believed to exist. ... This article is about planet. ... Neith is the name given to an object first sighted by Giovanni Cassini, which he believed to be a moon of Venus. ... Adjectives: Venusian or (rarely) Cytherean Atmosphere Surface pressure: 9. ... Chiron is the name given to a supposed moon of Saturn sighted by Hermann Goldschmidt in 1861. ... Atmospheric characteristics Atmospheric pressure 140 kPa Hydrogen >93% Helium >5% Methane 0. ... On April 28, 1905, William H. Pickering, who had seven years earlier discovered PhÅ“be, announced the discovery of a tenth satellite of Saturn, which he promptly named Themis. ... 1905 (MCMV) was a common year starting on Sunday (link will display the full calendar). ... To meet Wikipedias quality standards, this article may require cleanup. ... An astrological chart (or horoscope) _ Y2K Chart — This particular chart is calculated for January 1, 2000 at 12:01:00 A.M. Eastern Standard Time in New York City, New York, USA. (Longitude: 074W0023 - Latitude: 40N4251) Astrology (from Greek: αστρολ&#959... Adjectives: Plutonian Atmosphere Surface pressure: 0. ...

Hypothetical extrasolar planets

• list of unconfirmed exoplanets: incomplete list of all unconfirmed extrasolar planets

This is a list of unconfirmed extrasolar planets. ...

Hypothetical brown dwarfs

• Nemesis: binary companion to the Sun proposed by astronomer Richard A. Muller to explain an apparent regularity in mass extinctions throughout Earth's history. According to the theory, as it passes through our system's Oort cloud, its gravitational disturbance sends hordes of comets in towards the Sun, making the probability of an extinction level impact much higher.

• Dr. John Murray of the Open University and John Matese of the University of Louisiana at Lafayette believe that the motions of long-term comets in the sky suggest the existence of a large, distant planet, or, more likely, a small substellar companion such as a brown dwarf, in the deep solar system. This hypothetical substellar object is not Nemesis, since its existence is inferred from a different set of data; however there is the possibility that both sets of data could be true for the same object.^[1]

Nemesis is a hypothetical red dwarf star or brown dwarf, orbiting the Sun at a distance of about 50,000 to 100,000 AU, somewhat beyond the Oort cloud. ... Richard Muller Richard A. Muller (January 6, 1944 -) of San Francisco, California, USA, is a physicist who works at the University of California, Berkeley and Lawrence Berkeley National Laboratory. ... An extinction event (also extinction-level event, ELE) is a period in time when a large number of species die out. ... This image is an artists rendering of the Oort cloud and the Kuiper Belt. ... There have been several important people by the name of John Murray (roughly in chronological order): John Murray of Falahill, a Scottish outlaw John Murray, 1st Duke of Atholl (1660-1724) John Murray (MP for Banffshire), 1707-1708. ... The Open University (OU) is the UKs open learning university. ... The University of Louisiana at Lafayette, or UL Lafayette,[1] is a coeducational public research university located in Lafayette, Louisiana, in the heart of Acadiana. ... This brown dwarf (smaller object) orbits the star Gliese 229, which is located in the constellation Lepus about 19 light years from Earth. ...

See also

• List of unconfirmed exoplanets
• Systemic (amateur extrasolar planet search project)
• Category:Fictional planets
• Category:Planets in fiction
• Globus Cassus
• Planets in science fiction
• Tom Van Flandern
• PlanetQuest

This is a list of unconfirmed extrasolar planets. ... Infrared image of 2M1207 (blue) and its planet 2M1207b, as viewed by the Very Large Telescope. ... A top and side view of the Globus Cassus Globus Cassus is a utopian project for the transformation of Planet Earth into a much bigger, hollow, artificial world with an ecosphere on its inner surface. ... Planets in science fiction are fictional planets that appear in various media, especially those of the science fiction genre, as story-settings or depicted locations. ... Tom Van Flandern is a credentialed astronomer with Ph. ... PlanetQuest is a grid computing project for searching new planets from Earth-based observatories images. ...

References

For the Manfred Mann album, see 2006 (album). ... July 22 is the 203rd day (204th in leap years) of the year in the Gregorian Calendar, with 162 days remaining. ...

External links

• http://www.seds.org/nineplanets/nineplanets/hypo.html#planetx
• http://www.todayinsci.com/7/7_24.htm