General objective of this lecture is to present on What is Planet. The definition of planet, since the word was coined by the ancient Greeks, has included within its scope a wide range of celestial bodies. A planet is a celestial body that is in orbit around the Sun, has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and has cleared the neighborhood around its orbit.
What is Planet?
