Add Yahoo as a preferred source to see more of our stories on Google. Scientists think there may be a ninth planet hiding in the distant reaches of the solar system — and a new telescope could finally ...

Planet Nine, the undiscovered planet at the edge of the solar system that was predicted by the work of Caltech’s Konstantin Batygin and Mike Brown in January 2016, appears to be responsible for the ...

In the outer Solar System, far from the light and warmth of the Sun, things can get a little… hinky. There, clusters of rocks have been orbiting in weird loops that some astronomers have attributed to ...

It might be lingering bashfully on the icy outer edges of our solar system, hiding in the dark, but subtly pulling strings behind the scenes: stretching out the orbits of distant bodies, perhaps even ...

The solar system consists of our star, the sun, and everything bound to it by gravity: the planets Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune, along with dwarf planets like ...

In the cold, dark outskirts of planetary systems far beyond the reach of the known planets, mysterious gas giants and planetary masses silently orbit their stars—sometimes thousands of astronomical ...

Pluto was reclassified as a dwarf planet in 2006, but new discoveries and fresh debate are reigniting calls to restore its planet status. Learn why Pluto lost its title, what scientists discovered ...

Mike Brown is convinced that beyond Neptune, at the far reaches of our solar system, there's an unseen giant planet. "This is the 5th largest planet in our solar system, lurking out there, waiting to ...

For decades, our solar system was thought to have nine planets, with Pluto considered the smallest and farthest. But in 2006, Pluto was officially reclassified as a dwarf planet by the International ...

Astronomers have been scouring the outer solar system for signs of a hypothetical ninth planet for almost a decade, without success. However, we may finally be on the cusp of finding it, experts say.