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

“Whether it is real or not, it is 100 percent NOT Planet Nine,” Brown says. “Planet Nine is a prediction based on inferred ...

Astronomers may have found a candidate for Planet Nine. This planet is beyond Neptune. The finding could be the first ...

Discovered in 1930, Pluto was long considered our Solar System's ninth planet, but was unseated in 2006 after the discovery ...

Researchers say they found a curious dot on infrared images taken 23 years apart that seems to be moving in a manner consistent with a large, distant planet.

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

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

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

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

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

An international team used 40 years' worth of data from two space probes to track down what they believe are signs of this ...