Astronomers propose a new hypothetical planet, Planet Y, beyond Neptune, based on observed orbital anomalies in the Kuiper ...

A new study suggests the existence of Planet Y. This hidden planet may be affecting the Kuiper Belt. The gravity of Planet Y could be causing a tilt in the orbits of some icy objects. Researchers ...

Planet Nine was previously suggested as a possible explanation for distant orbital clustering. It was thought to be ten times Earth’s mass, orbiting far beyond Neptune.

For years, astronomers have searched the outer reaches of our solar system for Planet 9, a theoretical planet that could ...

New discoveries of objects in the Kuiper Belt have also presented challenges for the Planet Nine theory. The latest is known ...

Astronomers have picked up evidence of an Earth-sized world, distinct from the previously hypothesised Planet Nine and Planet ...

Recent research suggests a warp in the orbital plane of Trans-Neptunian Objects (TNOs) between 80 and 400 AU, hinting at the ...

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.

Planet Nine's composition is probably "most like Neptune," due to its distance from the sun, Brown said. "That would put its diameter at something like two times the width of Earth," he added.

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 ...