A new study suggests yet another theory for a possible extra planet in our solar system, likely of a size between Mercury and ...

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 ...

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 ...

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 ...

The Solar System might not be as quiet and orderly as we think. Imagine one day looking up and seeing something strange in the sky, a small speck that grows larger and larger. Soon, it becomes clear: ...

There are quite a few other places we might find life in the solar system, including dwarf planets like Ceres. Ceres is ...