Mercury, Venus, and Mars sit within the same general neighborhood as Earth, yet each has followed a radically different path.

Is there a massive undiscovered planet on the outer reaches of the solar system? The idea has been around since before the discovery of Pluto in the 1930s. Labeled as planet X, prominent astronomers ...

On May 21, the International Astronomical Union’s Minor Planet Center announced the discovery of 2017 OF 201, which, because of its distance beyond Neptune, is classified as a trans-Neptunian object ...

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 ...

Somewhere at the edge of the solar system a new Earth-sized world might be lurking, dubbed Planet Y. Astronomers have long proposed that there might be hidden planets beyond the Kuiper belt, a region ...

Mike Brown is convinced that beyond Neptune, at the far reaches of our solar system, there's an unseen giant planet. "This is the 5th largest planet in our solar system, lurking out there, waiting to ...

Astronomers have discovered two new exoplanets that are similar to other worlds found in the Milky Way, but unlike any in our ...

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 — ...

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 ...

Add Yahoo as a preferred source to see more of our stories on Google. An image of a fragment of Ksar Ghilane 022, a meteorite found in the Sahara Desert in 2023 which authors of a new study suspect ...