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

Astronomers hunting for Planet Nine have found some 50 new objects lying beyond the orbit of Neptune – including a few that may help them track down this elusive, distant world.

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.

If their calculations serve them correctly, Planet Nine would have a mass that is about 1.5 to 3 times that of Earth, at 500 times the distance between our home and the sun. Caltech researchers in ...

Planet Nine would alter our understanding of the cosmos If Rubin does find Planet Nine, Brown said, “Our best guess is that it is like Neptune, but we could be totally wrong.

In October 2017, NASA released a statement saying that Planet Nine may be 20 times further from the Sun than Neptune is, going so far as to say "it is now harder to imagine our solar system ...

If any of Planet Nine satellites do get this hot, then they are likely to give off a faint radio signal that could be detected by telescopes that have been fine-tuned to search for them, Chan ...

Scientists have found evidence of a true ninth planet in our solar system. Nicknamed "Planet Nine," the real-life Planet X appears to have the mass of 10 Earths and is 20 times farther from the ...

If Planet Nine is real, it wouldn’t be the first planet discovered from the force it exerts on other objects. In 1846, scientists knew another world must be out there due to the anomalies found ...

“Planet Nine” could explain the seemingly puzzling orbits traced by two of the distant worlds, known as Sedna and 2012 VP113 (which has been nicknamed “Planet Biden” in homage to a ...

The search is more than two years in now. “Planet Nine,” thought to be 10 times the mass of Earth, has yet to show itself, but the planet hunters have just found a new clue.