Something unusual seems to be lurking at the far edge of our Solar System. Some think it could be a hidden, oversized planet.

Space is stranger than you think. Our solar system — the only one we’ve ever called home — is packed with phenomena so bizarre, so extreme, and so counterintuitive that they sound like pure science ...

A newly discovered object speeding through our solar system is sparking excitement among astronomers because it’s not from around here. Believed to be a comet, the object is only the third celestial ...

Learn how a possible ninth planet, the theoretical Planet X, could have acquired its wide orbit in the outer Solar System — a process that’s also applicable for other planets. There could be a ninth ...

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 ...

A mysterious comet from beyond our solar system is giving astronomers a rare glimpse into alien worlds — and it may have formed in a place far colder and stranger than anything around our Sun. The ...

Astronomers have discovered that the Solar System traversed the Orion star-forming complex, a component of the Radcliffe Wave galactic structure, approximately 14 million years ago. This journey ...

New observations of the interstellar comet 3I/ATLAS include the first measurement of the abundance of deuterated water relative to ordinary water in an interstellar object. Astronomers using the ...

From meteorites that impact Earth, to a moon that orbits backwards, to an imposter lurking in the asteroid belt, a variety of strange, wandering worlds are rewriting what we know – and even how we ...