For the first time since Pluto was demoted, the idea of a true ninth planet is edging from speculation toward something ...

There could be a ninth planet in our solar system that's lying in wait to be discovered - and no, it's not Pluto. Our solar ...

Scientists think there may be a ninth planet hiding in the distant reaches of the solar system — and a new telescope could finally prove its existence. | Credit: Nicholas Forder for Live Science Deep ...

NASA's New Horizons spacecraft captured this high-resolution enhanced color view of Pluto that is inserted beneath the Short Wave logo. The image combines blue, red and infrared images taken by the ...

Planet Y is the latest in a series of hypothetical solar system planets that scientists have proposed in recent years, all with slightly different characteristics but collectively believed to be ...

Earlier this year scientists presented evidence for Planet Nine, a Neptune-mass planet in an elliptical orbit 10 times farther from our Sun than Pluto. Since then theorists have puzzled over how this ...

There has been a lot of back and forth about the existence of a mysterious ninth planet, often referred to as "Planet Nine" or even "Planet X." Now, though, researchers say there is likely at least a ...

Earth has a newly-discovered neighbor in the solar system. But the heavenly body – possibly a dwarf planet à la Pluto – isn't a frequent visitor. Located beyond Neptune, its extreme orbit ...