It is a question that feels like it should have a straightforward answer: how many planets are there in our solar system? Since Pluto was relegated back down to dwarf planet status, almost everyone ...

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 ...

Astronomers believe they have uncovered evidence of a previously unknown ninth planet lurking in the not-too-distant reaches of the solar system. This hypothetical world, dubbed "Planet Y," could be ...

Forbes contributors publish independent expert analyses and insights. An award-winning reporter writing about stargazing and the night sky. Is there an unseen planet — a "planet X" or "Planet Nine" — ...

Is there a massive undiscovered planet on the outer reaches of the solar system? The idea has been around since before the discovery of Pluto in the 1930s. Labeled as planet X, prominent astronomers ...

The apparent brightness of celestial objects, rather than their proximity, is the primary factor determining observability. Andromeda Galaxy, despite its vast distance, appears significantly brighter ...

Forbes contributors publish independent expert analyses and insights. An award-winning reporter writing about stargazing and the night sky.

Sign up for CNN’s Wonder Theory science newsletter. Explore the universe with news on fascinating discoveries, scientific advancements and more. Our solar system ...

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 ...

This story is part of Short Wave's series Space Camp about all the weird, wonderful things happening in the universe. Check out the rest of the series. If you were born in the last century you might ...

An unusual planetary system with three known ultra-low density 'super-puff' planets has at least one more planet, according to new observations. An unusual planetary system with three known ultra-low ...