A mysterious new world may be hiding in the outer reaches of our solar system. According to arecent study published on arXiv by Amir Siraj of Princeton University and colleagues, a previously unknown ...

The Solar System. It's no longer about the eight main planets anymore. Sorry Pluto. A new planet has entered the fray.

There may be a warp in the Kuiper Belt, possibly caused by “Planet Y” — a Mercury-to-Earth-sized world that orbits the sun way beyond the orbit of Neptune. Is there a mysterious “Planet Y” orbiting ...

A new study has proposed the existence of Planet Y, an alternative Planet Nine candidate that is smaller and closer to Earth than the hypothetical Planet X, which astronomers have been hunting for ...

When Pluto was discovered in 1930, astronomers proclaimed it the ninth planet, initially thinking it to be Planet X. But in the following decades, Pluto was deemed too small to account for the ...