Is there a 10th planet – the so-called Planet X?
Nothing has been discovered-not for a lack of trying. Recent observations suggest that there are some large asteroids or fragments of planetary bodies beyond the orbits of Neptune and Pluto, but no planet has been found. You can read about the history of the search for ‘Planet X’ here: http://seds.lpl.arizona.edu/billa/tnp/hypo.html#planetx See also NASA-Funded Scientists Discover Tenth Planet.
