Researchers from Rice University claim to have fresh evidence of Planet Nine - as well as a method to find it.

In the cold, dark outskirts of planetary systems far beyond the reach of the known planets, mysterious gas giants and ...

Astronomers find evidence of a possible ninth planet beyond Neptune, reigniting the debate about the formation of the Solar ...

Pluto has become a beloved object in our solar system ever since the International Astronomical Union (IAU) reclassified it from a planet to a dwarf planet back in 2006 – a decision which has ...

Elon Musk, under the username "Kekius Maximus," has joined William Shatner in advocating for Pluto's reclassification as a ...

This week, an old astronomical controversy is renewed as researchers present new evidence for a hidden "Planet X" in our solar system.

A team of astronomers believes they may have spotted a serious candidate for a ninth planet ... the debate. The Kuiper belt is a region of the Solar System located beyond Neptune's orbit. It is home ...

The presence of this planet would explain a number of quirks in our Solar System, but there is significant debate in the scientific ... along with dwarf planets like Pluto, moons, and millions of ...

Planet Nine, also known as Planet X, is a hypothetical celestial object that would distantly orbit our Sun – but there is significant debate in ... dwarf planets like Pluto, moons, and millions ...

To everyone who was happy about Pluto's planetary demotion, consider this: If Earth rode the same orbital highway as Pluto, it too would be a dwarf planet. In fact, we live on a geological body ...

Feb. 18 marks the 95th anniversary of the discovery of our outermost planet-not-planet. Here's what to know about the short life of what was, for a single human lifetime, the solar system's smallest ...