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

A new study, however, identifies a possible candidate. A separate team of astronomers compared 1983 data from the Infrared ...

A 9th planet in our solar system might be found — and no, it’s not Pluto - Is there another planet out there? Researchers say ...

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

The solar system is our cosmic neighborhood ... Neptune and then the possible Planet Nine. It's a dynamic system shaped by gravity and time, and while we've learned a lot, it still holds plenty ...

This week, an old astronomical controversy is renewed as researchers present new evidence for a hidden "Planet X" in our ...

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

The long-theorized Planet 9, which astronomers have speculated could be a Neptune-sized planet that has been lurking on the outer edge of the solar system, could explain the unusual clustering and ...

A team of international scientists has identified a promising Planet Nine candidate by comparing infrared surveys of the sky ...

A ninth planet the size of Neptune may be hidden in the far reaches of the solar system, but the evidence has left some experts skeptical.

Astronomers have long speculated about an unseen planet lurking in the solar system's outer edge. This hypothetical world, dubbed Planet Nine, could explain the unusual clustering ...