Frigjøringshastighet

Frigjøringshastighet, sometimes translated as release rate or escape velocity, refers to the minimum speed an object must have to escape the gravitational pull of a celestial body. This speed is not constant but depends on the mass of the body and the distance from its center from which the object is launched. For a spherical body with mass M and radius R, the escape velocity v_e at its surface is given by the formula v_e = sqrt(2GM/R), where G is the gravitational constant. This means that a more massive or denser celestial body will have a higher escape velocity. For instance, the escape velocity from Earth's surface is approximately 11.2 kilometers per second. This concept is fundamental in astrophysics and space exploration, as it dictates the energy required to send spacecraft or probes beyond a planet's or moon's gravitational influence and into interplanetary or interstellar space. It is important to distinguish frigjøringshastighet from orbital velocity, which is the speed needed to maintain a stable orbit around a celestial body without escaping its gravity. An object moving at escape velocity will follow a parabolic or hyperbolic trajectory, while an object at orbital velocity follows an elliptical or circular path.