Astronomers measure the speed at which the solar system is hurtling through space by mapping surrounding galaxies and ...

There have been questions about a mysterious ninth planet in our solar system for nearly a decade. Pluto was unseated as number nine in 2006. Now, a group of international researchers say they may ...

Scientists have been trying to find a hypothetical Planet 9 that may exist outside our known solar system based on the unusual orbits of certain dwarf planets. But those orbits might not require a ...

Planet hunters have grown used to strange worlds, but a handful of discoveries now point to something even more radical: ...

Astronomers have spotted an intriguing cluster of objects in the Kuiper belt, an enormous, donut-shaped region of icy objects ...

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 ...

Theia, the world that helped form the Moon, came from the Solar System. Chemical clues in Earth and Moon rocks reveal this ...

Jupiter is already the biggest planet by far in our solar system, but new research suggests it was somehow once even larger than it is now. Twice as large, in fact. To put that into context, those ...