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 ...

Mercury has a rocky surface when, facing the sun, can reach highs of 800 degrees while overnight lows could reach minus 290 ...

That path is called the ecliptic, and it exists because all planets in our solar system orbit around the sun on roughly the same plane. Astronomers, on the other hand, look for more specific ...