Newton's famous mountain projectile diagram, showing the trajectories of a projectile fired from a very high mountain peak (V) on Earth (sphere). It is taken from Isaac Newton's 1687 Principia, his treatise on the laws of motion and gravitation. With this diagram, Newton (1642-1727) was demonstrating that a projectile would never hit the ground if it was launched from high in the Earth's atmosphere with enough initial speed. Instead, it would remain in orbit around the Earth, prevented from flying away by the force of gravity.