Our solar system may have a ninth planet after all, following the declassification of Pluto nearly two decades ago, ...

Caroline Delbert is a writer, avid reader, and contributing editor at Pop Mech. She's also an enthusiast of just about ...

Researchers have found a candidate for the hypothetical Planet Nine, which could be an undiscovered giant planet way out in ...

One of the strongest hints of an undiscovered planet lies in the Kuiper Belt, a disc of icy objects beyond the orbit of Neptune that's home to comets and dwarf planets like Pluto. According to Planet ...

Astronomers may have found a candidate for Planet Nine. This planet is beyond Neptune. The finding could be the first evidence of the theorized Planet Nine. The potential candidate was detected ...

If the object really is Planet Nine, it would be larger than Neptune and exist 700 times further from the sun than Earth.

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