Astronomers have searched for Planet X for over a century without success. This video explains why distance, darkness, and technology make it so hard to detect distant worlds. It shows how past ...

A new study has proposed the existence of Planet Y, an alternative Planet Nine candidate that is smaller and closer to Earth than the hypothetical Planet X, which astronomers have been hunting for ...

The curious minds at What If predict the effects if Planet X entered our solar system, revealing orbital chaos, climate changes, and planetary disruption.

Add Yahoo as a preferred source to see more of our stories on Google. An illustration showing Planet Nine, a hypothetical, undiscovered planet in our solar system. New research now suggests the ...

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 ...