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

Astronomers have long speculated about an unseen planet lurking in the solar system's outer edge. This hypothetical world, ...

One set of dots had matching colors and brightness. open image in gallery Is there a possible ninth planet in our solar system? Researchers say they may have found a candidate (Credit: ESO/Tom ...

Astronomers have detected a promising sign of a ninth planet lurking at the the farthest reaches of the Solar System.

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