For decades, we believed our Solar System ended with Neptune, followed only by icy debris and distant dwarf planets. But ...

The Solar System seems calm, but that tranquility is more fragile than it appears. Now imagine one day looking up and ...

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 ...

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 ...

A distant 'exomoon' the size of Jupiter is changing how we think about the cosmos.

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 ...

Mars is the fourth planet from the sun and has a distinct rusty red appearance and two unusual moons. The Red Planet is a ...

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 — ...

CAPE CANAVERAL, Fla. — Astronomers have discovered a rare solar system in the Milky Way that boasts six planets orbiting in perfect rhythm like a cosmic orchestra, untouched by outside forces since ...

Earth, our home planet, is a world unlike any other. The third planet from the sun, Earth is the only place in the known ...

On August 24, 2006, our solar system lost a planet. It wasn't by cataclysmic destruction, but rather by the vote of the International Astronomical Union, which declared that Pluto, considered the ...