More than a 150 years ago, before Neptune was ever sighted in the night sky, French mathematician Urbain Le Verrier predicted the planet’s existence based on small deviations in the motion of Uranus.

Forbes contributors publish independent expert analyses and insights. An award-winning reporter writing about stargazing and the night sky. Is there an unseen planet — a "planet X" or "Planet Nine" — ...

Planet Y: In a remarkable discovery that could reshape the prevalent scientific view of our solar system, astronomers have found evidence of a 'hidden' planet on the outskirts of our cosmic ...

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 ...

Add Yahoo as a preferred source to see more of our stories on Google. A newly discovered warp in the outer Solar System may have been created by a small, rocky world, much closer to the Sun than the ...

Astronomers are tracking strange orbital patterns in the outer Solar System that suggest a massive unseen planet may exist beyond Neptune.

The planets are coming! The planets are coming! Only months after announcing the possibility of a 'Planet X' 10 times Earth's mass orbiting 250 times Earth's distance from the sun, a team of Spanish ...