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

When you look at the solar system, you might notice that the planets' orbits are tilted, and oddities in the protoplanetary ...

We all need some space sometimes—but it's harder to find than you might think. How far into our universe do we have to go to reach somewhere truly empty?

A new study suggests our solar system may be hiding yet another mysterious world. Researchers believe an Earth-sized planet, nicknamed Planet Y, could be lurking far beyond Neptune, subtly tugging at ...

The workings of our solar system are roughly the same now as they have been for millions of years. Moons circle their planets, the planets circle the sun, the sun’s magnetic fields and sunspots wax ...