A fresh study of the Kuiper Belt’s structure has revived that far-out question, pointing to a possible Earth-sized ...

The search for an unknown planet in our solar system has inspired astronomers for more than a century. Now, a recent study suggests a potential new candidate, which the paper’s authors have dubbed ...

On August 24, 2006, our solar system lost a planet. It wasn't by cataclysmic destruction, but rather by the vote of the International Astronomical Union, which declared that Pluto, considered the ...

UNDATED (WKRC) - A recent study introduces a potential new candidate, dubbed Planet Y, inferred from the tilted orbits of distant objects in the Kuiper Belt, a ring of icy bodies beyond Neptune, CNN ...

Our solar system now, once again, officially consists of only eight planets. Although largely debunked, speculation continued ...

The University of Wyoming Harry C. Vaughan Planetarium will host several live talk programs and the final “Dome After Dark” ...

Pluto is a bit of a loner. The dwarf planet is no longer considered a regular planet; it does not orbit on the same plane as the solar system's eight planets; and its orbit is both highly elliptical ...

Planet Y is the latest in a series of hypothetical solar system planets that scientists have proposed in recent years, all with slightly different characteristics, but collectively believed to be ...