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.

The 950-foot hunk of primordial matter is classified as a "potentially hazardous asteroid," but that doesn't mean it has a ...

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