Is Pluto still a planet or is it out of our solar system?
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.
181678
its probably half way to pluto by now. you could write the plutonians and ask them to email it back to you, this may take a few days though.
945846
This issue is very similar to the asteroid belt issue some 150 years ago.  When the first asteroid, Ceres, was found, it was considered a planet.  Only after 15 other "planets" were found in the same orbit regime did astronomers downgrade these asteroids to "minor planets" some 50 years after Ceres' discovery.\n\nIt's unclear if Pluto could ever clear its orbit...it crrently has only 7% of the mass of its orbital neighborhood (as opposed to, say, Earth, which contains some 99.9999% the mass of its orbital neighborhood), so it's only cleared a tiny fraction of its orbit throughout the entire age of the Solar System, 4.5 billion years.\n\nMoreover, other objects in Pluto's orbit (and pluto itself, in fact) are trapped in a 3:2 orbital resonance with Neptune.  This means these "plutinos" are in a very stable orbit, unlikely to be scattered away unless something very big and unexpected comes along.
34826
Pluto's orbit is an elipse, therefore its distance from the earth is actually changing.  However, at its closest point along its orbit it is 2.67 billion miles from earth and at its farthest point it is well over 3 billion miles from earth. Hope this helps
195029
Yes, and the people who found it honestly want to have it called Xena.\n\nOn July 29, 2005, a Trans-Neptunian object called 2003 UB313 was announced, which on the basis of its magnitude and simple albedo considerations is assumed to be larger than Pluto. This caused its discoverers to call it the "10th planet" of the solar system, although there is no consensus yet on whether to call it a planet, and others consider the new discovery to be the strongest argument yet for demoting Pluto to the status of a minor planet.\n\nBut until then, it's being refered to as Planet X.
47426
No. There have been a number of objects discovered recently in the outer solar system, including one which appears to be larger than Pluto. But unless something about the size of Neptune is found (which is possible) none of these are likely to gain official planet status.\n\nIn fact, in many respects Pluto should be "demoted," although that is not going to happen.\n\nThere isn't a real scientific definition of where the boundry is between a planet and, say, a moon, or a Kuiper object. For most objects it's clear what to call them, but for others the classification is ambigious. The reason being, of course, that our classifications are (somewhat) arbitrary and the solar system is composed of a continuum of objects of different sizes, in different orbits, etc.\n\nPluto was called a planet when it was discovered because a 9th planet was expected. Percival Lowell spent a long time looking for such a planet which he predicted from orbital irregularities he calculated with Neptune and Uranus. But he never found what he was looking for. Clyde Tombaugh, a couple of years later, resumed the search and eventually discovered Pluto. However, Pluto is much too small and in the wrong place to be Lowell's suspected planet. Lowell was probably just wrong in his calculations.\n\nBecause a 9th planet was expected and because in 1930 little could be told of Pluto's physical characteristics, I don't think anyone seriously doubted whether or not it should be classified as a planet. It seemed obvious, at the time, that it was.\n\nIn the 1950s and 1960s astronmers began to postulate that comets orginated from a vast pool of objects in the extreme distant regions of the solar system. This lead to the hypothesis of the Oort cloud, and the "closer" Kuiper belt (that being 50 - 100 AU from the Sun).\n\nIt wasn't until the 1990s that a lot of Kuiper-esque objects were actually discovered. (I hedge on the classification, because some objects similar in diamter, etc., have been found inside the orbit of Pluto.)\n\nIf in 1930 Clyde Tombaugh had an inkling of something like a Kuiper belt he probably would not have assumed that Pluto was a planet. If Pluto was discovered today it also would (probably) not be considered a planet.\n\nSo basically, if we could re-do history Pluto would be "demoted." On the other hand, there have been generations of kids who learned the whole 9 planets bit. Because of the the International Astronomical Union - the international organization in charge of naming things - has *officially* declared Pluto a planet. A link to their announcement is below.\n\nI suspect - and I am taking an educated guess - that the new objects in the outer solar system, even though slighly larger than Pluto - won't get "official" planet status.\n\nOf course the reality is more complex, and nature doesn't always fit neatly into human classification schemes.
209097
Pluto is the fartherest planet, there is some discussion about it being a planet or not but for this answer we'll let it be one, from the sun during most of it's orbit. It's 5,913,520,000Km from the Sun.\nThe Main asteriod belt lies between Mars and Jupiter, roughly 374,172,480Km from the sun, the planets run Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune & Pluto.\nThe Kuiper Belt, made up of comets instead of asteriods, lies outside of the orbit of Pluto and some think Pluto is just a comet from this belt. Then going way on out past the Kuiper Belt you run into the Oort Cloud roughly 22,450,348,800,000Km from the Sun and made up of trillions of cometary bodies.
937727
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 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
524966
Possibly, as scientists have yet to make up their mind. One particular object, originally found in 2003 but confirmed two years later by Mike Brown (Caltech), David Rabinowitz (Yale University), and Chad Trujillo (Gemini Observatory), has renewed the old debate about what constitutes a planet since it is at least 5% larger than Pluto with an estimated diameter of 2400 km . It currently has no name, but has been given the provisional designation 2003 UB313, and has been nicknamed "Xena" by its discoverers, after the television character. It has many similarities with Pluto: its orbit is highly eccentric, with a perihelion of 38.2 AU (roughly Pluto's distance from the Sun) and an aphelion of 97.6 AU, and is steeply inclined to the ecliptic plane, at 44 degrees, more so than any known object in the solar system except the newly-discovered object 2004 XR190. Like Pluto, it is believed to consist mainly of rock and ice, and has a moon . Whether it and the largest Kuiper belt objects should be considered planets or whether instead Pluto should be reclassified as a minor planet has not yet been resolved.
327202
The last time I checked there were still 9 planets and they were considering maybe adding a 10th. Pluto is a planet with a moon of it's own named Charon. Astronomers have also identified a couple of other large bodies orbiting beyond Pluto. It has been suggested that there could be two planetoids beyond Pluto that revolve around each other.
973992
Something less than 400 members of the 10,000 member IAU voted under a veil of assumed authority to downgrade Pluto's status as a planet after they rewrote the rule book. Most of the new criteria they established that must be met in order for an object to be considered a planet is met by Pluto. It orbits a star, it has a moon, and it is generally spherical in shape. The disqualifying new rule was that Pluto has not cleared its orbital path around the sun and there are other objects sharing the same orbit. This would mean that if another object enters or is found to exist in the same orbital path of the Earth, the Earth would not be a planet. The IAU also failed to take into consideration as to whether or not Pluto is in the process of clearing its orbital path and just needs a few billion more years.
389936
Nope.  That's my professional (astronomer) opinon.  Here is why:\n\nPluto is a member of a large collection of similar sized objects that orbit the sun in the same region as it.  This is the same situation that Ceres, the largest asteroid is in.  Pluto was simply the first of these icy bodies to be found, we have since found almost 1000 other objects that share orbital space with Pluto.  Many of them are almost the same sice as it, and one (2003 UB313) is in fact larger than Pluto.\n\nNo good defination of planet exists that allows for pluto to be a planet without admitting about 10-100 other objects in as planets as well, unless you simple state that Pluto is a planet in an ad hoc manner.\n\nThe definition that I generally use in my work is that a planet is an object that has cleared it's orbital space of all other small bodies.  All of the main 8 planets satisfy the criteria.  Pluto, 2003 UB313, Ceres and other small bodies do not.
984760
You'd have to contact an observatory to find out where it was in the sky in 11/98 but with an orbital period of 165 years, it hasn't moved far relative to us. Pluto, of course, is no longer considered a planet.
1178690
Right now the international convention in astronomy is debating on how a planet is defined... Pluto appears to be just one of the thousands of objects in the Kuiper belt which is believed to contain objects more massive than Pluto, 2003 ub313 is one prime example and is classified as a Trans-Neptunian object... I have already debated this topic with all the other webdatedotcom friends I have and the arguments are pretty interesting..
425085
Pluto - 1930.\n\nPluto is still considered a planet and all the objects that Mike Brown et.al. have been finding (Sedna, 2003UB313, etc.) have not been granted planetary status, no matter how often Mike Brown says that 2003UB313 is a planet, quite simply it is not.\n\nThe IAU's Division of Planetary Science is currently working on the whole planet issue, and we are supposed to have some sort of resolution to this issue by august of this year.  Right now it seems that we are leaning to either strip Pluto of its planetary status, through making an actually definition of the word "planet," or to make Pluto the arbitrary cut-off line.  This would mean that 2003UB313 would become the 10th planet, but Sedna (being smaller than Pluto) would not.\n\nAs of right now there is no official motion in place to remove planetary status from pluto, although it may loose it through the adoption of a new definition of what a planet is.\n\nAlso, no matter how catchy the name sounds, or how often the BBC calls it that, the official name of 2003UB313 will not be "Xena," that was simply Brown's code name for that object.
351394
Pluto.\n\nPluto\nTiny Pluto is the last planet in our family. The dark, cold planet's average distance from the Sun is a little over 3.5 billion (3,500,000,000) miles. If you tried to step off this distance, you would be over two miles away from your Sun when you reached the location of Pluto. If you got on a jet and flew at 600 miles per hour from the Sun to Pluto, it would take 675 years. If you could drive the same distance, it would take over 5,700 years.
677217
10 planets have been discovered so far. 9 of them have been registered. The 10th one was discovered in 1930 & has been claimed to be larger than pluto & rocky in nature. It is currently about 97 times farther from the sun than Earth, or 97 Astronomical Units (AU). For comparison, Pluto is 40 AU from the sun. The object was so far away, however, that its motion was not detected until they reanalyzed the data in January of this year. In the last seven months, the scientists have been studying the planet to better estimate its size and its motions.