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

Science textbooks may be in for another revision. Our solar system shrank from nine planets to eight after the International ...

A 9th planet in our solar system might be found — and no, it’s not Pluto - Is there another planet out there? Researchers say ...

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

The solar system is our cosmic neighborhood ... Neptune and then the possible Planet Nine. It's a dynamic system shaped by gravity and time, and while we've learned a lot, it still holds plenty ...

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

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

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 ...

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

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

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