Is there a massive undiscovered planet on the outer reaches of the solar system? The idea has been around since before the ...

"It is possible that a planet once existed in the solar system but was later ejected, causing the unusual orbits we see today ...

Astronomers have long speculated about the existence of a mysterious planet lurking far beyond Neptune, a world several times ...

A tiny object far beyond Pluto, newly discovered by the Subaru Telescope, could reshape our understanding of the early Solar System. Named 2023 KQ14, this rare “sednoid” follows an unusual orbit that ...

What we know about the search for ‘Planet Nine’ in our solar system - The idea of a massive undiscovered planet has been around since before the discovery of Pluto in the 1930s ...

Astronomers have found 2023 KQ14, nicknamed Ammonite, a rare sednoid with a unique orbit that challenges the Planet Nine ...

A newly discovered dwarf planet called 'Ammonite' (2023 KQ14) has been spotted in the outer solar system, and it could be ...

Planet Fitness will join a revitalized shopping center that recently added Aldi and Tesla. Leaving its former space makes ...

Planet Nine should appear stationary over the course of a single day but show detectable movement over months.

A hypothetical planet that has been described as "the solar system's missing link," Planet Nine (also known as Planet X) has been part of the lexicon for several years, first mentioned in 2014.

Another mystery is how Planet Nine, if it is real, ended up on an orbit that potentially brings it as close as 280 AU and as distant as 1,120 AU, which is far beyond the realm of the other planets.