"An as yet undiscovered planet might be orbiting at
the dark fringes of the solar system, according to
new research.

Too far out to be easily spotted by telescopes, the
potential unseen planet appears to be making its
presence felt by disturbing the orbits of so-called
Kuiper belt objects, said Rodney Gomes, an
astronomer at the National Observatory of Brazil
in Rio de Janeiro."

See:

http://news.nationalgeographic.com/n...-space-science