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Trans-Neptunian Objects
A trans-Neptunian object (TNO), also written transneptunian object, is any minor planet in the Solar System that orbits the Sun at a greater average distance than Neptune, which has an orbital semi-major axis of 30.1 astronomical units (AU). Typically, TNOs are further divided into the Classical Kuiper belt object, classical and Resonant trans-Neptunian object, resonant objects of the Kuiper belt, the scattered disc and detached objects with the sednoids being the most distant ones. As of February 2025, the List of minor planets#Main index, catalog of minor planets contains List of trans-Neptunian objects, 1006 numbered and more than List of unnumbered trans-Neptunian objects, 4000 unnumbered TNOs. However, nearly 5900 objects with semimajor axis over 30 AU are present in the MPC catalog, with 1009 being numbered. The first trans-Neptunian object to be Planets beyond Neptune, discovered was Pluto in 1930. It took until 1992 to discover a second trans-Neptunian object orbiting t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Minor Planet
According to the International Astronomical Union (IAU), a minor planet is an astronomical object in direct orbit around the Sun that is exclusively classified as neither a planet nor a comet. Before 2006, the IAU officially used the term ''minor planet'', but that year's meeting IAU definition of planet, reclassified minor planets and comets into dwarf planets and Small Solar System body, small Solar System bodies (SSSBs).Press release, IAU 2006 General Assembly: Result of the IAU Resolution votes International Astronomical Union, August 24, 2006. Accessed May 5, 2008. In contrast to the eight official planets of the Solar System, all minor planets fail to clearing the neighborhood, clear their orbital neighborhood. Minor planets include asteroids (near- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eris (dwarf Planet)
Eris (minor-planet designation: 136199 Eris) is the most massive and second-largest known dwarf planet in the Solar System. It is a trans-Neptunian object (TNO) in the scattered disc, scattered disk and has a high-Orbital eccentricity, eccentricity orbit. Eris was discovered in January 2005 by a Palomar Observatory–based team led by Michael E. Brown, Mike Brown and verified later that year. It was named in September 2006 after the GrecoRoman Eris (mythology), goddess of strife and discord. Eris is the List of Solar System objects by size, ninth-most massive known object orbiting the Sun and the sixteenth-most massive overall in the Solar System (counting natural satellite, moons). It is also the largest known object in the Solar System that has not been visited by a spacecraft. Eris has been measured at in diameter; its mass is 0.28% that of the Earth mass, Earth and 27% greater than that of Pluto, although Pluto is slightly larger by volume. Both Eris and Pluto have a sur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Discovery Of Pluto
Following the discovery of the planet Neptune in 1846, there was considerable speculation that another planet might exist beyond its orbit. The search began in the mid-19th century and continued at the start of the 20th with Percival Lowell's quest for Planet X. Lowell proposed the Planet Nine, Planet X hypothesis to explain Discovery of Neptune#Irregularities in Uranus' orbit, apparent discrepancies in the orbits of the giant planets, particularly Uranus and Neptune, speculating that the gravity of a large unseen ninth planet could have gravitational perturbation, perturbed Uranus enough to account for the irregularities. Clyde Tombaugh's discovery of Pluto in 1930 appeared to validate Lowell's hypothesis, and Pluto was officially named the ninth planet. In 1978, Pluto was conclusively determined to be too small for its gravity to affect the giant planets, resulting in a brief search for a tenth planet. The search was largely abandoned in the early 1990s, when a study of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
