Large 'Planet X' May Lurk Beyond Pluto

[mickw]

An icy, unknown world might lurk in the distant reaches of our solar system beyond the orbit of Pluto, according to a new computer model.

The hidden world -- thought to be much bigger than Pluto based on the model -- could explain unusual features of the Kuiper Belt, a region of space beyond Neptune littered with icy and rocky bodies. Its existence would satisfy the long-held hopes and hypotheses for a "Planet X" envisioned by scientists and sci-fi buffs alike.

More:   http://www.space.com/scienceastronomy/080618-planet-x.html

Or should that be Plutoid X