An international team of astronomers has discovered a distant planetary system that challenges long-standing theories of how ...

Over the past century, astronomers have speculated about the existence of a mysterious 9th planet lurking in the outer reaches of our Solar System. Although we've never directly observed the elusive ...

Forbes contributors publish independent expert analyses and insights. Leslie Katz covers the intersection of culture, science and tech. A yellowish-orange glow bathes Phainoterra, a planet of dramatic ...

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 have found new evidence that a mysterious ninth planet may be hiding at the edge of the solar system - rewriting what we know about the cosmos again. An international team from Taiwan, ...

A newly studied solar system breaks the usual planet pattern, raising fresh questions about how rocky and gas planets form.

Astronomers have found a rocky planet where it should not exist, orbiting far from a cool red star. Could this strange ...

As shocking as it sounds today, prior to the 1990s, scientists couldn't be certain that stars beyond the sun also had planets orbiting them. Since the discovery of the first extra-solar planet, or ...

In our Solar System, the inner planets (Mercury to Mars) are rocky, and the outer planets (Jupiter to Neptune) are gaseous.

Gas giants are large planets mostly composed of helium and/or hydrogen. Although these planets have dense cores, they don’t have hard surfaces. Jupiter and Saturn are the gas giants in our solar ...