When was Pluto discovered, was it originally called planet X, and did people think it a moon to begin with?
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NO, WHEN PLUTO WAS FORMED IT WAS STRAIGH AWAY GIVEN NAME PLUTO WAS DISCOVERED BY  Clyde W. Tombaugh \nDiscovered on February 18, 1930 \nABT THE MISTRY OF PLANET-X THEN ITS THE PLANET SOMEWHERE FAR FROM PLUTO.
806256
The International Astronomical Union decided that Pluto was no longer a planet. The reason is that while Pluto is round, orbits the sun, and has three moons, it has not cleared (via gravity) its own orbit of debris.  Instead, they decided to classify it as a "dwarf planet".\n\nSee the details below.\n\nRESOLUTION 5A\nThe IAU therefore resolves that "planets" and other bodies in our Solar System, except satellites, be defined into three distinct categories in the following way:\n\n(1) A "planet" [footnote 1] is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit.\n\n(2) A "dwarf planet" is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape [footnote 2] , (c) has not cleared the neighbourhood around its orbit, and (d) is not a satellite.\n\n(3) All other objects [footnote 3] except satellites orbiting the Sun shall be referred to collectively as "Small Solar-System Bodies".\n\n\nFootnote 1: The eight "planets" are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.\n\nFootnote 2: An IAU process will be established to assign borderline objects into either dwarf planet and other categories.\n\nFootnote 3: These currently include most of the Solar System asteroids, most Trans-Neptunian Objects (TNOs), comets, and other small bodies.\n\nRESOLUTION 6A\nThe IAU further resolves:\n\nPluto is a "dwarf planet" by the above definition and is recognized as the prototype of a new category of trans-Neptunian objects.
335341
Wow, just asked my 10year old same question.  He said it is a planet they have recently discovered about twice the distance of Pluto.
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yeah i think they might be because what are the chance that we are the ONLY ones , and the real name for Xena is A20031 i think . but their still not sure if Pluto a planet now but that's for scientist to discover. It's only a matter of time before we go out to another arm of the milky way and find the one planet in that solar system ( were not the only solar system ya know ) that has life.
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astronomers are trying to define the word planet but it isn't easy. many astronomers favor the reclassification of the bodies in the solar system into three groups, the rocky terrestrials, the gas giants, and the ice dwarfs. there are hundreds of bodies that orbit the sun farther than neptune known. these include bodies like pluto, quaoar, sedna, 2003 EL61, and 2003 UB313 (the official name of xena). this is also called the kuiper belt. pluto was the first kuiper belt object discovered, and 2003 UB313 is about five percent bigger than pluto.\n\n\nread this:\nhttp://en.wikipedia.org/wiki/Kuiper_belt
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astronomers are trying to define the word planet, but it isn't easy.  many astronomers favor the reclassification of the bodies in the solar system into three groups, the rocky terrestrials, the gas giants, and the ice dwarfs.  there are hundreds of known ice dwarfs, including pluto, quaoar, sedna, 2003 EL61, and 2003 UB313 (the official name of xena).  this is also called the kuiper belt.  pluto was the first kuiper belt object discovered.  2003 UB313 is about five percent bigger than pluto.\n\nhttp://en.wikipedia.org/wiki/Kuiper_belt
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According to Wikipedia, the official designation of this "planet" is 2003 UB313.  Its discoverers claim that it is definitely larger than Pluto, and that it has at least one moon.\n\nThe name is not actually Xena, and this is simply a codename used by the discoverers, and has not been submitted to the International Astronomical Union for consideration as a real name for the planet.\n\nIt's roughly 20 percent larger than Pluto, I guess.  They can't disclose the name that they will be proposing for the planet.\n\nThere is a re-definition of the term "planet" going on right now by the IAU, so it is possible that this will turn out not to be considered an actual planet.\n\nMore info here: http://en.wikipedia.org/wiki/2003_UB313
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The newest planet was catalogued as 2003UB313 by NASA.\n\nThe new planet, which is yet to be formally named, is at least as big as Pluto and about three times farther away from the Sun than Pluto. It is very cold and dark. The planet was discovered by the Samuel Oschin Telescope at the Palomar Observatory near San Diego, Calif., on Jan. 8, 2005.
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Pluto, which was discovered in 1930, is but a dot of light in even the largest Earth-based telescopes. Pluto is 2/3 the size of Earth's moon but 1,200 times farther away, which makes viewing surface detail as difficult as trying to read the printing on a golf ball located thirty-three miles away.
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The name retained for the planet is that of the Roman god Pluto, and it is also intended to evoke the initials of the astronomer Percival Lowell, who predicted that a planet would be found beyond Neptune. The name was first suggested by Venetia Burney, at the time an eleven-year-old girl from Oxford, England. Over the breakfast table, one morning her grandfather, who worked at Oxford University's Bodleian Library, was reading about the discovery of the new planet in the Times newspaper. He asked his granddaughter what she thought would be good name for it. Venetia thought that as it was so cold and so distant it should be named after the Roman God of the underworld. Professor Herbert Hall Turner cabled his colleagues in America with this suggestion, and after favourable consideration which was almost unanimous, the name Pluto was officially adopted and an announcement made by Slipher on May 1, 1930
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There are 6 planets that even the ancients knew about.  From the sun outward, they are Mercury, Venus, Earth, Mars, Jupiter, and Saturn.  (of  course, the ancients did not know that Earth was quite a bit like those little points of light that moved through the heavens).  William Herschel discovered Uranus in 1781. Neptune was discovered on September 23, 1846 by Johann Gottfried Galle. And Clyde Tombaugh discovered Pluto on February 18th, 1930.\n\nA few other discoveries may turn out to be planets.  In 2003 Mike Brown and two other astronomers discovered an object larger than Pluto, temporarily named 2003 UB313.  The International Astronomical Union will make a determination whether UB313 will be called a planet, and they'll also give it a proper name from mythology.  \n\nAnd astronomers have found other planet-sized bodies circling distant stars. As of May 18th, 193 of these "extra-solar" (meaning away from our sun) planets have been discovered.  See the exoplanet link below for more info.\n\nSo, to sum things up, from the sun outward, your list is:\n\nMercury\nVenus\nEarth\nMars\nJupiter\nSaturn\nUranus\nNeptune\nPluto\nUB 313 (maybe)\n\nand 193 planets somewhere else in our Milky Way galaxy.
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2003 UB313 is the name of the object.  "Xena" is the name given to it by the discoverer's team as a code-word.  Even Mike Brown (the guy who found it) says that it should not seriously be considered the name for it.  Brown is also the guy who helped find Sedna, an object a bit smaller than Pluto (2003 UB313 is actually larger than Pluto).\n\nNo planets have officially been added, or taken away, so neither 2003 UB313, nor Sedna are officially planets.  The problem is that there are a heck of a lot of objects the size of Sedna.  We are currently in meetings off and on discussing this "planet or not" issue.\n\nAs far as how long has it been there, we feel that it was formed at the same time all the other largish solid bodies in the solar system were formed, about 4.5 billion years ago.  It is red in color, made of ice, and if it were brought near the sun it would look like a really big comet.  It has always been there, it is just that only really in the last 10-15 years have we had the ability and instruments to really search for small worlds this far away from us.  The discovery of Pluto in 1930 involved a lot of luck.
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http://en.wikipedia.org/wiki/Pluto\n\non 24 august 2006, the international astronomical union reclassified pluto.\n\npluto does orbit the sun, is ball-shaped and is not a satellite, but it does not have an isolated orbit (a bunch of other similar bodies have similar orbits.) so it is not a planet.\n\ni have been waiting for this since i was about ten when i learned that pluto didn't fit the pattern set by the major bodies in the solar system so it was an anomaly. it just felt "out of place". now that astronomers have found hundreds of other bodies with similar orbits, classifying "134340 pluto" as a planet is even more irrational. i feel somewhat satisfied, but i don't know how long this will drag on tho. many planetary astronomers are satisfied that the definition is rigorous enuf. i can accept that the definition is flawed, but i can not accept that "134340 pluto" is a planet.\n\nthis was the right thing to do, believe me. this does not change anything about pluto or the solar system. this just corrects the mistake of classifying pluto as a planet initially.\n\nthis same thing happened has happened before. in 1800, an astronomer found a body orbiting the sun between the orbits of mars and jupiter and thought it was a planet. astronomers finally stopped classifying them as planets after they found several other bodies with similar orbits, and no one thinks ceres, pallas, juno, and vesta are planets today.\n\nmany astronomers consider pluto and charon to be a binary system, but two small bodies orbit that system. they are called nix and hydra.\n\nincidentally, "134340 pluto" was never a moon of neptune. neptune did capture triton. this is why triton has a retrograde orbit
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Pluto Statistics \nDiscovered by Clyde W. Tombaugh \nDate of discovery February 18, 1930 \nMass (kg) 1.27e+22 \nMass (Earth = 1) 2.125e-03 \nEquatorial radius (km) 1,137 \nEquatorial radius (Earth = 1) 0.1783 \nMean density (gm/cm^3) 2.05 \nMean distance from the Sun (km) 5,913,520,000 \nMean distance from the Sun (Earth = 1)) 39.5294 \nRotational period (days) -6.3872 \nOrbital period (years) 248.54 \nMean orbital velocity (km/sec) 4.74 \nOrbital eccentricity 0.2482 \nTilt of axis (degrees) 122.52 \nOrbital inclination (degrees) 17.148 \nEquatorial surface gravity (m/sec^2) 0.4 \nEquatorial escape velocity (km/sec) 1.22 \nVisual geometric albedo 0.3 \nMagnitude (Vo) 15.12 \nAtmospheric composition \nMethane\nNitrogen 0.3
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There are a large number of balls of ice and rock of various sizes scattered around the solar system. Some are small enough that they are irregularly shaped. Some have highly elliptical orbits. Some are very, very small.  So part of the difficulty is that there is not an agreed upon definition of what a 'planet' really is. By one definition, Pluto is not a planet, but rather is the first of a class of medium sized balls of ice and rock to be discovered at the edges of our system (the Kuiper belt objects). There are many others, some of which are comparable in size. Furthermore, these objects are far enough away from the sun that they don't reflect much light back to us, so they are very hard to locate.\n\nOn the other hand, we can estimate the distances to some fairly bright galaxies and determine that they are billions of light years away. That means that the light from these galaxies has taken a billion years to get to us. That, in turn, means that we are seeing now what happened there billions of years ago. This allows us to say what the universe was like at that time with some confidence.
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Pluto is not a planet anymore... it is now a "dwarf planet."\n\nWhen it is outside Neptune's Orbit, it is 8 planets away from the Sun and when it is inside Neptune's Orbit, it is 7 planets away from the Sun.  \n\nPluto has a very eccentric orbit and spends 20 year chunks of time closer to the Sun than Neptune.\n\nAloha
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The International Astronomical Union decided that Pluto was no longer a planet.  Instead, they decided to classify it as a "dwarf planet" because it has not cleared its orbit of debris.\n\nSee the details below.\n\nRESOLUTION 5A\nThe IAU therefore resolves that "planets" and other bodies in our Solar System, except satellites, be defined into three distinct categories in the following way:\n\n(1) A "planet" [footnote 1] is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit.\n\n(2) A "dwarf planet" is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape [footnote 2] , (c) has not cleared the neighbourhood around its orbit, and (d) is not a satellite.\n\n(3) All other objects [footnote 3] except satellites orbiting the Sun shall be referred to collectively as "Small Solar-System Bodies".\n\n\nFootnote 1: The eight "planets" are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.\n\nFootnote 2: An IAU process will be established to assign borderline objects into either dwarf planet and other categories.\n\nFootnote 3: These currently include most of the Solar System asteroids, most Trans-Neptunian Objects (TNOs), comets, and other small bodies.\n\nRESOLUTION 6A\nThe IAU further resolves:\n\nPluto is a "dwarf planet" by the above definition and is recognized as the prototype of a new category of trans-Neptunian objects.