Scientists examined infrared space surveys to narrow down candidates for Planet 9. Planet 9 would be so far from the Sun that ...

For years, astronomers have toyed with the idea that the Sun hides an extra planet so distant and dim that even the best ...

If the object really is Planet Nine, it would be larger than Neptune and exist 700 times further from the sun than Earth.

Our solar system may have a ninth planet after all, following the declassification of Pluto nearly two decades ago, ...

For about a decade, he and other researchers have been trying to prove that the so-called "Planet 9" exists. So far, the only evidence has come from some oddities in the orbits of small Pluto-like ...