Two faint objects hiding in archival infrared sky maps now sit at the center of a growing scientific argument about whether a ...

As the United States prepares to celebrate its 250th anniversary, the history of the solar system tells its own story of ...

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 ...

A distant, icy body circling the Sun far beyond Neptune has handed astronomers a fresh puzzle. Designated 2023 KQ14 and ...

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. Labelled as planet X, prominent astronomers ...

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 ...

What is Planet Nine, and where is it? The question has fascinated astronomers for years. Scientists believe a massive undiscovered planet may exist in the outer Solar System. Although no telescope has ...