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.

A leading scientist has told Newsweek about new evidence supporting the existence of a secret ninth planet lurking at the edge of our solar system. This hypothetical extra planet, often referred to as ...

A possible new dwarf planet has been discovered at the edge of our solar system, so far-flung that it takes around 25,000 years to complete one orbit around the sun. The object, known as 2017 OF201, ...

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An artist's illustration of a possible ninth planet in our solar system, hovering at the edge of our solar system. Neptune's orbit is shown as a bright ring around the Sun. Scientists in Taiwan ...

The camera resting in an impeccably clean, lint-free room at the SLAC National Accelerator Laboratory in Menlo Park, California, resembles an extremely oversized version of the SLR lenses for Nikon or ...

LOS ANGELES -- Our solar system is suffering an identity crisis. For decades, it has consisted of nine planets, even as scientists debated whether Pluto really belonged. Then the recent discovery of ...

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 ...

It's an evocative idea that has long bedeviled scientists: a huge and mysterious planet is lurking in the darkness at the edge of our solar system, evading all our efforts to spot it. Some astronomers ...

Ian Whittaker does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond ...