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, we believed there were nine planets in our solar system—until Pluto was reclassified in 2006. But what if ...

Feb. 18 marks the 95th anniversary of the discovery of our outermost planet-not-planet. Here's what to know about the short ...

Pluto may not be a planet any more, but you still have a chance to see the distant dwarf planet at one of Michigan's ...

Planet demographics reveal a puzzling lack of worlds in a certain size range throughout the galaxy F or centuries our solar system was the only planetary system known to humans. We had no proof other ...

Stock illustration of all the solar system's planets. Mars, Venus ... the alignment throughout January will be between sunset and 9–9:30 p.m. local time. "Venus is the brightest, and visible ...

one which can offer superb views of the other bodies in the solar system. But which one to choose? We've got you covered with our guide to the best telescopes for seeing planets. Now's a great ...