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 ...

If you get the question in Trivial Pursuit “how many plantes are there in the Solar System ... there was another planet, a very big planet, beyond Neptune. The Planet Nine theory was ...