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

Using two infrared space telescopes and a 23-year gap, scientists may have spotted a mysterious, slow-moving object beyond ...

A team of astronomers believes they may have spotted a serious candidate for a ninth planet in our Solar System. This object, ...

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

Astronomers searching for a ninth planet in our solar system say they've found a "good" candidate far beyond Neptune, ...

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

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

The solar system consists of our star, the sun, and everything bound to it by gravity: the planets Mercury, Venus, Earth, ...

A new look through decades-old data has unveiled some of the most compelling evidence yet of a hidden ninth planet in the far ...

For years, astronomers have toyed with the idea that the Sun hides an extra planet so distant and dim that even the best ...