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

Far beyond Neptune, strange patterns in the Kuiper Belt suggest something massive may be hiding in darkness. This story ...

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 ...

Our solar system has two ice giants, Uranus and Neptune, but there may have been a third. According to a new study published in the journal Icarus, this extra world might have triggered a violent ...

The search for an unknown planet in our solar system has inspired astronomers for more than a century. Now, a recent study suggests a potential new candidate, which the paper’s authors have dubbed ...

Every once in a while, the outer solar system reminds us that we've only discovered a negligible portion of it, and that the vast majority is still full of surprises. The latest example of this is a ...

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 ...