Is there a tenth planet?
104242
Yes! The 10th planet was discovered in 2005, and is temporarily known as 2003 UB313.  However, 2003 UB313 is located in the Kuiper belt, which is made up of numerous objects, and there may be many more that could be counted as planets.  The definition of "planet" is currently a topic of debate, and some argue that neither 2003 UB313 nor Pluto should be considered planets.  I believe that the popular media has sometimes refered to it as "planet x," but this is not its official name.
596996
Out of 10,000 Billion Galaxies out there. No Doubt there is something out there.\n\nEarth will contact something...but not in our lifetimes.\nI even believe there is another planet like ours out there somewhere.\n\nWe would be very naive to think we are the only intelligent planet in the entire Universe.
11810
The 10th planet.\nhttp://science.nasa.gov/headlines/y2005/29jul_planetx.htm
570974
Are you talking about a real planet or Nibiru (aka Planet X)?  Note how I differentiate between the two.\n\nIf you're talking about a real planet (which I hope you are) it will probably depend on whether we end up changing how we define "planet" to accommodate new bodies that are being found beyond the orbit of Pluto.  If Pluto loses its planet status or new bodies are found, it would of course change which body is designated the "tenth planet."\n\nRegarding the 12th of December 2012, you'd probably be better off if you stopped paying so much attention to the Mayan calendar.  I doubt very much that anything of particular consequence is going to happen on that day, despite what New Agers are spouting nowadays.
77240
Our own solar system has 10 planets that we know of:\nMercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto, and the newly discovered 2003 UB313.  That last one is still being contended, and why that debate gets so heated is beyond me.\n\nThere are actually 155 known extrasolar planets, and that number is only going to rapidly increase.  You can find a list on the California & Carnegie Planet Search site below:
84111
There are 9 named planets, and one new one that was recently discovered.
572044
Yes UB313 (which was not discovered last year, but in 2003).\n\nBe careful calling it a planet, however.  Web sites and journalists love to talk about the "tenth planet" because it sounds more exciting that "yet another trans-neptunian object (TNO)."  However, astronomers (the International Astronomical Union, or IAU) do not officially recognize this as a "planet."  This may change later this year (in September) when the IAU is scheduled to come up with a more solid definition of what a "planet" is (how big, what orbit, etc.) ... but until then, you sound more like a real astronomer if you don't call it a "planet."
65145
The newest planet is Sedna. It could be the 10th planet on our solar system.
240127
There could be another planet ... but it will be so far away from the Sun that it may be even more difficult to find than Xena (the 10th planet).\n\nAs to the solar system existing in another planet?  Hmmm .... seriously mate ... no.  Not a chance.
375309
Right now there are officially 9 planets. Depending on what we decide in the next year or so that number will change to 8, stay 9, go to 10, or even larger.  \n\nAn object larger than Pluto (2003 UB313) has been found, but we have not granted it official status as a planet. Don't expect this issue to be resolved any time soon, we've more or less "tabled" the issue until our general meeting in August, but there are a number of scientists in the IAU's Division of Planetary Sciences discussing this issue.\n\nRight now the newer astronomy textbooks generally have a section on "the planet controversy," and spend some time talking about all these newly discovered icy bodies.  They are all part of the Kuiper Belt, just like Pluto, and new books seem to be grabbing onto teaching about these objects much like the asteroids, addressing them as the left-overs of the formation of the solar system.  The Cosmic Perspective (a fairly decent intro astro textbook) for example has a chapter on "Remnants of Rock and Ice: Asteroids, Comets and Pluto"
483118
no there is no 10th planet.\n\nwell scientists argue that pluto is small and should not be called a planet.\n\nso when they discovered Sedna( the 10th planet), it was smaller than pluto and so was considered as a mini planet.
57853
Actually there is no tenth planet. Although Pluto is an official planet, others objects of about the same size, or even slightly larger won't be officially recognized as planets.\n\nAn object would need to be much larger, say the size of Neptune to become and official 10th planet. And some astronomers think that should an object may be out there.
30331
According to the authority of the IAU, there are nine planets in our solar system. In increasing distance from the Sun they are (with the astronomical symbol in brackets):\n\nMercury (☿) \nVenus (♀) \nEarth (♁) with one confirmed natural satellite, Luna (the Moon) \nMars (♂) with two confirmed natural satellites, Phobos and Deimos \nJupiter (♃) with sixty-three confirmed natural satellites \nSaturn (♄) with forty-six confirmed natural satellites \nUranus () with twenty-seven confirmed natural satellites \nNeptune (♆) with thirteen confirmed natural satellites \nPluto (♇) with three confirmed natural satellites, Charon, S/2005 P 1 and S/2005 P 2 \nHowever, there is some pressure for Pluto to be reclassified as a Kuiper Belt object, especially in light of the discovery of 2003 UB313. This object, however, has not yet received a definitive classification from the IAU.\n\nSedna was widely touted as a planet when it was discovered in 2003, as it was the largest object found since Pluto. However, mainly due to its size still being smaller than Pluto's, it did not achieve planetary status from the IAU. However, the discovery in 2005 of 2003 UB313 (nicknamed Xena), with a size and mass larger than Pluto seems to have forced the issue. As of January 2006 it has not yet been accepted as a planet, but the IAU is expected to announce a definition of a planet soon, which will likely either see 2003 UB313 become a planet, or have Pluto stripped of its status.
604824
The astrobiology folks at NASA have calculated that there are between one and thirty billion habitable planets in our Milky Way Galaxy.  If our solar system is typical,  you can multiply that by about 10 to get total planets: between 10 and 300 billion.  \n\nSo where is everybody?
600203
NINE, I think senda is not the 10th planet (because of its small size). Nine planets are:\n\nMercury(Roman god of thieves)\nVenus(God of beauty)\nEarth\nMars(God of War)\nJupiter(Supreme Roman god)\nSaturn(God of agriculture)\nUranus(Ruler of the heavens, father of the Titans\nNeptune(God of the sea)\nPluto.
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.
14964
Nine in our solar system - Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto.