Planet X has a long and storied history of non-existence. For about 130 years, astronomers have debated the existence of an additional planet or planets to explain discrepancies in the orbits of ...

In an exciting breakthrough in planetary science, a recent study has increased the likelihood of Planet Nine’s existence by up to 40%. This planet, also referred to as Planet X, has remained an ...

Planet X, or Nibiru, is on a crash course with Earth, doomsayers believe — prophecies draw new focus with ‘Planet Nine’ discovery ...

For the dwarf planet candidate, one trip around the sun takes over 24,000 years. Its orbit challenges a proposed path for a hypothetical Planet Nine.

An artist's concept of Planet 9, sometimes referred to as Planet X. Planet 9 is a hypothesized ninth planet in our solar system. It is not about to kill us all.

While searching for the mysterious Planet X that some astronomers believe lurks on the edge of our solar system, researchers instead found an extremely distant object they dubbed “the Goblin.” ...

And if Planet X — also sometimes called Planet Nine — exists, it’s way out there; it’s somewhere between 200 and 1,200 times the distance from the Sun to Earth.

Although the paper is certain to revive the search for Planet X, success is not certain: Previous surveys have failed to detect any Saturn-sized planets going out as far as 10,000 AU.

Planet X, also called Planet Nine, is a hypothetical planetary body seven times the mass of Earth lurking behind Pluto. If found, this gassy, icy beast some 155 billion miles away from the Sun ...

The Nibiru /Planet X/Earth collision story first surfaced in 1995 and gets recycled occasionally into various apocalyptic tales, all of which NASA said are just internet hoaxes.

If Planet X is out there, it’s really, really far away. Brown and Batygin’s educated guess as to where Planet X might be is based on the crooked orbits of 6 very distant objects.

If there is a Planet X out there, it will necessitate a wholesale rewriting of some key chapters of the solar system's history. On the trail of hidden worlds.