Add Yahoo as a preferred source to see more of our stories on Google. Digital art of distant planet - Dottedhippo/Getty Images On August 24, 2006, our solar system lost a planet. It wasn't by ...

While Planet Y remains hypothetical, new finds in the outer solar system are steadily reshaping the context in which such theories live. Astronomers recently uncovered a massive new trans-Neptunian ...

The solar system’s most giant planet is slightly less of a giant than scientists once thought. Jupiter, a world that is so ...

LONDON — 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 ...

Forbes contributors publish independent expert analyses and insights. An award-winning reporter writing about stargazing and the night sky. The solar system suddenly has a new member. A new object ...

NASA’s newly launched IMAP mission is set to tell us more about the boundary between our Solar System and interstellar space ...

A new Tatooine-like planet outside the solar system may orbit two failed stars, scientists reported Wednesday. Located about 120 light years away, the exoplanet appears to take an unusual path around ...

Planet Y is the latest in a series of hypothetical solar system planets that scientists have proposed in recent years, all with slightly different characteristics but collectively believed to be ...