Why Can't We Find Planet 9? Deep in the outer reaches of our solar system, far beyond Neptune and Pluto, something massive is ...

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 ...

Jupiter harbors more oxygen than the sun, a new study finds, giving astronomers a crucial clue about how our solar system's ...

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 ...

Scientists have discovered more than 6,000 planets beyond our solar system. What if some of them aren't planets at all, but ...

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 ...

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 ...

What was originally thought to be a planet orbiting the Fomalhaut star was probably just the fallout of a wild collision.

A rare triple conjunction of Venus, Mars and Mercury is happening on the opposite side of the solar system to where Earth is, ...

LYNCHBURG, Va. (WSET) — If you're trying to get a beautiful look at the planets in our solar system, you're in luck. Between February 25 and February 28, all seven planets in our solar system will be ...

So far, humanity has yet to find its first "exomoon"—a moon orbiting a planet outside of the solar system. But that hasn't ...

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 ...