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 ...

Planet demographics reveal a puzzling lack of worlds in a certain size range throughout the galaxy F or centuries our solar ...

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 ...

At 9 km per second (which is close to a whopping ... astronomers could measure only the mass and the radius of planets outside the Solar System. Today, telescopes like ESO's VLT already allow ...

NASA said the system is thought to be moving at least 1.2 million miler per hour, nearly twice as fast as our solar system.