What is a Planet?
In our solar system, planets are the major bodies orbiting the Sun. Because we cannot yet observe other planetary systems in similar detail, a universal definition of a planet has not emerged. In general, planets are massive enough for their gravity to make them spherical, but small enough to avoid nuclear fusion in their cores.
Keywords: Astrophysics, Planets
Orbiting our star, the Sun, are the inner rocky planets and the outer gas giant planets, along with their many moons.