In the cold, dark outskirts of planetary systems far beyond the reach of the known planets, mysterious gas giants and ...

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

Astronomers find evidence of a possible ninth planet beyond Neptune, reigniting the debate about the formation of the Solar ...

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

Researchers say they found a curious dot on infrared images taken 23 years apart that seems to be moving in a manner consistent with a large, distant planet.

Astronomers may have found a candidate for Planet Nine. This planet is beyond Neptune. The finding could be the first evidence of the theorized Planet Nine. The potential candidate was detected ...

It doesn’t match any known object and appears to have moved just enough to plausibly be a missing planet. “If this candidate is real, it will change what we already know about our own home ...

Astronomers searching for a ninth planet in our solar system say they've found a "good" candidate far beyond Neptune, according to a new preprint study. This could be humanity's first glimpse at ...

In April, astronomers said they had detected a possible signature of life on the exoplanet K2-18b. Now, three independent ...

Scientists examined infrared space surveys to narrow down candidates for Planet 9. Planet 9 would be so far from the Sun that it is just not illuminated by much sunlight. The two space surveys ...

A new member of the solar system has been detected, the second-largest of its kind, suggesting there may be more like it ...