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.
With Pluto now demoted to the first-known plutoid, I think we’re back to looking for Planet IX, not Planet X.
Isn’t Eris planet IX or X?