Escape Velocity

The escape velocity is a measure of the strength of the gravity of the planet and is important for many things, but, here, we are interested in its effects on atmospheric retention.

The meaning of the escape velocity is that it is the speed with which we must launch a rocket or any projectile from the surface of a planet in order to have the object escape the gravitational pull of the object.

The escape velocity is given by (2GM/R

For the Earth, the escape velocity is ~ 7 miles per second or 25,000 miles per hour!!