A rare discovery beyond Neptune is forcing scientists to rethink early solar system dynamics and the forces that shaped ...

From Voyager 1’s record-breaking journey into interstellar space to Uranus’s sideways spin creating decades-long seasons, the ...

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 ...

Astronomers are closing in on one of the most tantalizing possibilities in planetary science, evidence that a previously unknown world may be lurking in the outer reaches of the solar system. The ...