What is name of of planet X that the scientists discovered either last year or the year b4?
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!
612729
It is in an elliptical orbit past pluto. It is currently called Planet X because it has not been officially recognized as a planet, more study will be required to confirm if it is. Scientists lovingly call it "Xena" after the Warrior Princess show, and they believe it has a moon they call Gabrielle... Astronomers are such nerds.
164779
we already found a 10th planet in our solar system, but it's still unclear if it's considered as planet (some say it is too small).\nThe name of the "10th planet" is Sedna.
62742
Pluto was discovered by the astronomer Clyde Tombaugh at the Lowell Observatory in Arizona on February 18, 1930 after an extensive search when he compared photographic plates taken on January 23 and 29. After the observatory obtained confirming photographs, the news of the discovery was telegraphed to the Harvard College Observatory on March 13, 1930. The planet was later found on photographs dating back to March 19, 1915. Tombaugh was searching for a "Planet X" to explain discrepancies in the predicted orbit of Neptune. It is now known these discrepancies were an artifact of the slightly incorrect value then assumed for the mass of Neptune.
1127691
First, forget Sedna.  That is a body smaller than Pluto, and it's not the one most likely to be our 10th planet. The one discovered last year, and which is larger than Pluto, is 2003 UB313, commonly known as Xena (although that is not among the names secretly submitted to the IAU as genuine candidates if the thing becomes a planet).\n\nAll the other planets (excluding Earth) are named after Roman gods, with the exception of Uranus, named after a Greek god.  I think we should go Greek again this time ... and it's about time we had another female besides Venus.\n\nSo I propose 'Nyx' (primoridal Greek goddess of the night, and daughter of Chaos).  The Roman equivalent is 'Nox' (which by the way is where we get 'equinox', meaning "equal-night" ... I learned that on West Wing.)\n\nAnd for the moon, one of Nyx's many children:  Hemera ("day"), Moros ("fate" or "doom"), or one of the three fates (Clotho, Atropos, or Lachesis), and there are many other candidates ... she had lots of children, a few of them with her brother Erebus.  (By the way, Erebus would be another good name (as a constant companion) ... but who knows if we'll discover another moon someday.
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.
503211
The X-ray source in the constellation Cygnus, aptly named Cygnus X-1, is the best candidate for a black hole that we know of. Most Scientists now agree that it is a black hole. Stephen Hawking won a nobel prize for demonstrating that black holes do not in fact absorb everything that comes near them, as was previously thought, they can and do emit some particles from near their 'event horizons'. This is known as Hawking radiation.
387020
the object 2003 UB313, unofficially known as xena, is about 5 percent larger than pluto, but many 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 small icy bodies orbiting the sun more distant than neptune i.e. pluto, quaoar, sedna, and 2003 UB313.
60693
Yes, other stars with orbiting planets have been discovered. One is Upsilon Andromedae.
153974
A 10th planet has recently been found in our Solar System. It's designation right now is UB313. Check out the following website for more information:\n\nhttp://channels.isp.netscape.com/news/story.jsp?idq=/ff/story/0001/20060201/1301968801.htm&ewp=ewp_news_0106planet&floc=NI-slot1a
486363
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.
530261
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.
596644
The most recent planet discovered in our our solar system is named Cedna after the Inuit goddess of the sea. It is even smaller than Pluto.
950927
It's a planet discovered November 5, 1999\nCheck this site ; it has all of the information.\nhttp://en.wikipedia.org/wiki/Osiris_(planet)\n\nThis is a planet located in the star system below.\nStar HD 209458 \nConstellation Pegasus \nRight ascension (α) 22h 03m 10.8s \nDeclination (δ) +18° 53′ 04″ \nSpectral type F8-G0V .\n\nIt is gas type planet 220 times the size of  earth.\nIt's science name is HD 209458 b\nHD 209458 b is informally known as Osiris.
871143
Largest known to date is the "puffy planet" HAT-P-1b orbiting the sunlike star ADS 16402 B, one of a binary pair of G0 V stars 450 light yeard away, in the constellation Lacerta. Our sun is of spectral class G2 V i.e. a little cooler than ADS 16402 B.\n\nHAT-P-1b has a radius of 1.36 x the radius of Jupiter. \n\nIt was discovered on 13 September 2006 and is 450 light years away. It has the lowest density of any known extrasolar planet. It also has the name Krais.\n\nIt was announced as follows:\n\n"Using small automated telescopes in Arizona and Hawaii, the HATNet project has detected an object transiting one member of the double star system ADS 16402 AB. This system is a pair of G0 main-sequence stars with age about 3 billion years, at a distance of ~139 parsecs and projected separation of ~1550 AU. The transit signal has a period of 4.46529 days."\n\nNote: Only the radii of transiting planets are known.
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.
98664
There have been no planets added to the current list of nine in our solar system.  There have been several planets found around a number of nearby stars but those are not associated with our solar system.  To get a list of those go to exoplanets.org.\n\nThere have been a number of recent discoveries of object near or at the edge of our solar system.  These can have any number of names such as trans-Neptunian object, Kuiper Belt object, inner Oort cloud member, among others.  These are not planets.  They simply do not fit the criteria necessary to be called a planet but more importantly they have not been designated that title by the official naming authority for professional astronomy, the IAU.  \n\nThese objects resemble Pluto in some aspects but we actually know very little about them because they are so distant and small.  Among the more notable of these discoveries are Sedna, Xena and Quaoar.  They are small icy, rocky bodies that are believed to have changed very little since they formation 4.5 billion years ago whenthe solar system formed.