There’s less Mercury in the system. Scientists found that Mercury, the solar system’s smallest planet, is shrinking far ...

The solar system's smallest planet has gotten smaller still.

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 ...

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 ...

Planet 9 would fall somewhere in between these categories. It could be what is known as a Super-Earth, a rocky planet larger than our own, or a sub-Neptune, a gaseous world less massive and slightly ...

See more of our trusted coverage when you search. Prefer Newsweek on Google to see more of our trusted coverage when you search. A leading scientist has told Newsweek about new evidence supporting the ...

There may be another world lurking between the orbital lines of our solar system. Astronomers in Japan have published their theory of an “Earth-like planet,” dubbed Planet Nine, that’s hiding in plain ...

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But what exactly is a planet? It seems like an easy question. After all, you’re standing on one right now! But the scientific ...

Forbes contributors publish independent expert analyses and insights. An award-winning reporter writing about stargazing and the night sky. Astronomers have found a distant celestial body — ...

Forbes contributors publish independent expert analyses and insights. An award-winning reporter writing about stargazing and the night sky. Computer simulations suggest that there is an undiscovered ...