# Schwarzschild radius

## Description

The Schwarzschild radius (sometimes historically referred to as the gravitational radius) is the radius of a sphere such that, if all the mass of an object is compressed within that sphere, the escape speed from the surface of the sphere would equal the speed of light. An example of an object smaller than its Schwarzschild radius is a black hole. The Schwarzschild radius is proportional to the mass with a proportionality constant involving the gravitational constant and the speed of light:

Related formulas## Variables

r_{s} | The Schwarzschild radius (m) |

G | Newtonian constant of gravitation |

M | The mass of the body (kg) |

c | Speed of light |