<P> In physics, escape velocity is the minimum speed needed for an object to escape from the gravitational influence of a massive body . </P> <P> The escape velocity from Earth is about 11.186 km / s (6.951 mi / s; 40,270 km / h; 25,020 mph) at the surface . More generally, escape velocity is the speed at which the sum of an object's kinetic energy and its gravitational potential energy is equal to zero; an object which has achieved escape velocity is neither on the surface, nor in a closed orbit (of any radius). With escape velocity in a direction pointing away from the ground of a massive body, the object will move away from the body, slowing forever and approaching, but never reaching, zero speed . Once escape velocity is achieved, no further impulse need be applied for it to continue in its escape . In other words, if given escape velocity, the object will move away from the other body, continually slowing, and will asymptotically approach zero speed as the object's distance approaches infinity, never to come back . Speeds higher than escape velocity have a positive speed at infinity . Note that the minimum escape velocity assumes that there is no friction (e.g., atmospheric drag), which would increase the required instantaneous velocity to escape the gravitational influence, and that there will be no future sources of additional velocity (e.g., thrust), which would reduce the required instantaneous velocity . </P>

To escape from a planets gravity an object must reach a speed called the