How long has the 10th planet 'Xena' been in existence?
413351
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.
352109
Actually, 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.
490426
In 2003, Mike Brown of Caltech and other scientists (Trujillo and Rabinowitz) discovered another planet-sized body, larger than Pluto, far out beyond Pluto.  Following the convention for temporary names of newly discovered astronomical bodies, it was temporarily named 2003 UB313.  The astronomers who discovered it also used a 'code name' - Xena - among themselves.  But the official name will be decided the the International Astronomical Union, the organization that has the last word on such things.  \n\nXena is a pretty cool name, but there is no chance that it will be the final name.  There are no rules for naming astronomical objects, but since all the others are named for Greek and Roman gods, there's a good chance that this one will have a name from mythology, too.  The bad news is that all the good names have been taken (by planets, moons, asteroids, and other big rocks out there).  \n\nAnd some other potential bad news is that not only is the IAU going to name this thing, but it's going to decide if it even should be called a planet.  Since UB313 is bigger than Pluto, there's a chance that Pluto may also be downgraded - we may end up not with 10 plantets, but only 8 - going backwards!\n\nThe second web site, below, gives lots of great info about UB313, direct from the horses mouth, Mike Brown himself.  It's a well-written web site, written (mostly) in layman's language, and has lots of questions and answers about all kinds of things related to this discovery.  Check it out!
554555
Discovery of the 10th planet!  Recent discovery.  Not much info. yet so no one can say if you are wrong on any point!
57851
There are new planets being discovered all the time, but I assume you mean the new tenth planet in our solar system. \n\nThe discoverer has suggested the name Xena, after the television show. The official name is not due out for some time, and has to be decided by an international committee.
1071483
No, NOT Sedna!  (This is how bad information just multiplies.)\n\nSedna is smaller than Pluto, and unlikely to be classified a planet.  If anything will be classified as our 10th planet it is 2003 UB313, which is larger than Pluto.\n\nBut until then, we only have 9 official planets.
942204
We have 8 'planets' (Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune).  We have several more 'dwarf planets.'  \n\nThe difference is that, during planet formation, a planet's gravity will pull in all the material around it, leaving a planet surrounded \nby empty space.  This is referred to as 'clearing the neighborhood.'  A dwarf planet's gravity is not sufficient to pull in all the material around it, so it does not clear its neighborhood.  \n\nPluto is now a dwarf planet, along with several asteroids and other celestial bodies.  In fact, Pluto is a binary planet, because it and it's moon, Charon, orbit each other (the center of Charon's orbit is not a point inside of Pluto, but rather a point between the two bodies).  So Pluto probably won't even be considered a dwarf planet for long.\n\nThis Xena, as you call it, is twice the size of Pluto.  That's what reignited this whole controversy.  It's real name is 2003UB313.  Xena was only given to it as a temporary name.
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.
1066033
Somewhere around 10 million years. This should be compared to the sun, which will last a total of 10 *billion* years.\n\nHomework?
575467
UB313, the 10th "planet" that is said to be bigger than Pluto.\n\nI'm not lying, read all the sources.\nBTW, the CNN news which adds support to the discovered planet is dated February 2, 2006.
412196
Not in our lifetime.  It takes 1,500 years for it to complete its eliptical orbit between our Sun and a dead sun outside our galaxy.  We have a better chance meeting helpful space visitors before planet X will return.
18186
Often many people get involved in discovering a "planet" as several observations are required to verify and calculate the orbit.  Exactly what a planet is is subject to debate as even Pluto is not completely accepted as one.  The debate includes the question "how big does a rock have to be for us to call it a planet as opposed to an asteroid?"  Planet X was one possibility that seemed to just fade out of the news.  "Buffy" is the nickname of the latest "unusual" object out there (see my source article).  Heheheh, yes, "Xena" came public a few days before "Buffy."  Both are among the many rocks in the Kuiper Belt, including Pluto.  NASA's launching a probe called "New Horizons" to check out Pluto and the Kuiper Belt.
475262
Let's count:\n\nMercury has None\nVenus has None\nEarth has 1\nMars has 2\nJupiter has 63\nSaturn has 46\nUranus has 27\nNeptune has 13\nPluto has 3\nUB-313 has 1\n\nThat makes 155 known moons in the solar system, 156 if you count Xena (UB-313) as a planet.
210190
Well first thing is this planet has not officially been named yet, Xena, Persephone, and Lila are the recent names. The facts about it so far is it has an oliptical orbit, extremely far and its thought to have pluto-like surface. Life? Its highly doubtfull anything could survive. Its orbit takes 560 years.\nI recommend the following weblink: http://www.gps.caltech.edu/~mbrown/planetlila/
1047577
In 2003 planetoid called officially named 90377 Sedna was discovered beyond Pluto. \n\n2003 UB313 was discovered in 2005 (go figure!). It is even further away than Sedna, and is larger than Pluto.\n\nIt hasn't been officially named or given 'planet' status.
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.