The number of planets that orbit the sun depends on what you mean by “planet,” and that’s not so easy to define ...

Does our Solar System have 9 planets or only 8? Astronomers have gone back and forth on that a lot, with Pluto now being classified as a dwarf planet. However, out beyond Neptune there could be ...

For decades, Pluto was celebrated as the ninth planet of our solar system. However, in 2006, the International Astronomical ...

A U.S. scientist searching for a civilization across 7 Earth clones circling the red dwarf star TRAPPIST-1 says its own alien ...

Bright yellow deposits in Consus Crater provide new evidence of Ceres' cryovolcanic history, reigniting the debate over ...