Is there a Planet X?

Minda asks:

"I am looking for real, legitimate information concerning the planet catalogued as 2003UB313, first photographed with the 48 inch Samuel Oschin Telescope on October 31, 2003 - the so called Planet X. Is it a planet or an asteroid? Is there expected to be any problems associated with this body and its orbit?"

"I've been told some hard to believe stories about the affect it will have in the year 2012. Is this a version of the 'Urban Myth'?"

Jesse Richuso (Morehead Planetarium and Science Center) responds:

"Planet X" is a term used to describe a number of theoretical, undiscovered bodies in our solar system. Some astronomers think that irregularities found in the orbits of a few solar system objects are evidence of Planet X. However, astronomers have also found evidence to disprove the existence of Planet X. To learn more about this topic, visit http://en.wikipedia.org/wiki/Planet_X

The object 2003UB313 has since been named Eris. It has been classified as a Dwarf Planet, along with Pluto and Ceres. It is slightly larger than Pluto, and is usually farther away from the Sun. But, since its orbit is very elliptical, it occasionally gets closer to the Sun than Pluto. For a diagram of Eris' orbit compared to other solar system objects, visit http://en.wikipedia.org/wiki/Image:Eris_Orbit.svg

Any chain emails or websites reporting problems with "Planet X" and its orbit in the year 2012 are completely unscientific and ridiculous.