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" — ...

Over the past century, astronomers have speculated about the existence of a mysterious 9th planet lurking in the outer ...

A possible cousin of Pluto seems to be circling the far reaches of the solar system. The dwarf planet candidate 2017 OF201 travels in a superwide orbit, with the sun relatively near one end of its ...

After studying thousands of computer simulations of the solar system, researchers at Rice University and the Planetary Science Institute think there’s a 40% chance an elusive “Planet Nine” or “Planet ...

We’re closer than ever before to knowing whether there is a ninth planet whooshing around the sun – and, alas, it’s not Pluto. Planet X, also called Planet Nine, is a hypothetical planetary body seven ...

A study recently submitted to The Astronomical Journal continues to search for the elusive Planet Nine (also called Planet X), which is a hypothetical planet that potentially orbits in the outer ...

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 ...

An elusive Earth-like planet in our solar system could finally be discovered within the next few years. Known as Planet Nine or Planet X, it is a hypothetical planet that has long been rumoured to ...