: 136 The name was published on May 1, 1930. To make sure the name stuck, and that the planet wouldn't suffer changes in its name as Uranus had, Lowell Observatory proposed the name to the American Astronomical Society and the Royal Astronomical Society both approved it unanimously. A vote was taken, and 'Pluto' was the unanimous choice. 'Minerva' was the Lowell staff's first choice but was rejected because it had already been used for an asteroid Cronus was disfavored because it was promoted by an unpopular and egocentric astronomer, Thomas Jefferson Jackson See. Three names topped the list: Minerva, Pluto and Cronus. Upon the announcement of the discovery, Lowell Observatory received over a thousand suggestions for names. The name Pluto is for the Greek/Roman god of the underworld. Mosaic of best-resolution images of Pluto from different angles There are fourteen other known precovery observations, with the earliest made by the Yerkes Observatory on August 20, 1909. Unknown to Lowell, his surveys had captured two faint images of Pluto on March 19 and April 7, 1915, but they were not recognized for what they were. Lowell and his observatory conducted his search until his death in 1916, but to no avail. Pickering had suggested several possible celestial coordinates for such a planet. In 1906, Percival Lowell-a wealthy Bostonian who had founded Lowell Observatory in Flagstaff, Arizona, in 1894-started an extensive project in search of a possible ninth planet, which he termed ' Planet X'. Subsequent observations of Neptune in the late 19th century led astronomers to speculate that Uranus's orbit was being disturbed by another planet besides Neptune. In the 1840s, Urbain Le Verrier used Newtonian mechanics to predict the position of the then-undiscovered planet Neptune after analyzing perturbations in the orbit of Uranus. Many planetary astronomers, however, continue to consider Pluto and other dwarf planets to be planets.įurther information: Planets beyond Neptune In 2006, the International Astronomical Union (IAU) formally redefined the term planet to exclude dwarf planets such as Pluto. These doubts increased following the discovery of additional objects in the Kuiper belt starting in the 1990s, and particularly the more massive scattered disk object Eris in 2005. It was immediately hailed as the ninth planet, but it was always the odd object out, : 27 and its planetary status was questioned when it was found to be much smaller than expected. Pluto was discovered in 1930, the first object in the Kuiper belt. The New Horizons mission was the first spacecraft to visit Pluto and its moons, making a flyby on July 14, 2015 and taking detailed measurements and observations. Pluto and Charon are sometimes considered a binary system because the barycenter of their orbits does not lie within either body, and they are tidally locked. Pluto has five known moons: Charon, the largest, whose diameter is just over half that of Pluto Styx Nix Kerberos and Hydra. Pluto compared in size to the Earth and the Moon Pluto's eccentric orbit periodically brings it closer to the Sun than Neptune, but a stable orbital resonance prevents them from colliding. Light from the Sun takes 5.5 hours to reach Pluto at its average distance (39.5 AU ). Pluto has a moderately eccentric and inclined orbit, ranging from 30 to 49 astronomical units (4.5 to 7.3 billion kilometers 2.8 to 4.6 billion miles) from the Sun. Pluto has only one sixth the mass of Earth's moon, and one third its volume. Like other Kuiper belt objects, Pluto is made primarily of ice and rock and is much smaller than the inner planets. It is the largest known trans-Neptunian object by volume, by a small margin, but is slightly less massive than Eris. It is the ninth-largest and tenth-most- massive known object to directly orbit the Sun. Pluto ( minor-planet designation: 134340 Pluto) is a dwarf planet in the Kuiper belt, a ring of bodies beyond the orbit of Neptune.

Luto picture