There have been questions about a mysterious ninth planet in our solar system for nearly a decade. Pluto was unseated as number nine in 2006. Now, a group of international researchers say they may ...

Pluto was reclassified as a dwarf planet in 2006. Our solar system may have a ninth planet after all, researchers say. The possibility that an additional planet may be hidden far into the solar system ...

Astronomers have found new evidence that a mysterious ninth planet may be hiding at the edge of the solar system - rewriting what we know about the cosmos again. An international team from Taiwan, ...

The giant planets weren't always where we find them today. Jupiter, Saturn, Uranus and Neptune formed in a more compact ...

The Solar System might not be as quiet and orderly as we think. Imagine one day looking up and seeing something strange in the sky, a small speck that grows larger and larger. Soon, it becomes clear: ...

There's a new object in the distant reaches of our solar system, and it might just offer clues to a long-standing cosmic mystery. Astronomers have cataloged a frozen minor planet called 2017 OF201, ...

The search for an unknown planet in our solar system has inspired astronomers for more than a century. Now, a recent study suggests a potential new candidate, which the paper’s authors have dubbed ...