Scientists may have discovered a dwarf planet far beyond Neptune — an unearthing that may disprove a longstanding theory about the possibility of a giant ninth planet. The dwarf planet's existence ...

Pluto was reclassified as a dwarf planet in 2006. Our solar system may have a ninth planet after all, researchers say. The possibility that an additional planet may be hidden far into the solar system ...

New evidence shows that, far beyond Pluto, there may exist a hypothetical planet referred to as Planet X or Planet Nine.

It's not easy to uncover exoplanets, largely lightless objects that either lurk in the dark void of space or are blown out by the light of a nearby star. But astronomers using the James Webb Space ...

As telescopes have become more powerful, it’s turned out our solar system is not the only game in town: There are millions of ...

Astronomers have discovered the earliest seeds of rocky planets forming in the gas around a baby sun-like star, providing a precious peek into the dawn of our own solar system. It’s an unprecedented ...