Is there a hidden planet in our solar system? - Space.com- msnbc.com
MSNBC reports: "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."

Comment: I have to admit that I've always been skeptical about the "Planet X" hypothesis, but this new computer model suggests that it may not be so fanciful. Still, it's worth noting that the planet predicted by this model is not the planet the "Planet X" enthusiasts were hoping to find, it would be far smaller and much farther from the Sun than what they expected. It would not have the mass or eccentric orbit needed to perturb the inner planets as the mythic "Planet X" was supposed to do.