The presence of another planet in the solar system could explain the odd movements of some of the bodies in the Kuiper Belt.

where thousands of objects sit beyond the orbit of Neptune. Pluto, therefore, is not the gravitationally dominant object in its neighborhood — and thus, not a planet, according to the new ...

In 1846, Neptune, the fourth of the giant planets beyond the asteroid belt ... While some people mourned the passing of Pluto from mainstream planet to this new classification, other Pluto ...