where <math>c</math> is speed of light in vacuum, <math>R_E</math> is radius of curvature of space (called ''"[[Einstein's radius]]"''), <math>G</math> is Newtonian gravitational constant, and <math>\rho</math> is density of space | where <math>c</math> is speed of light in vacuum, <math>R_E</math> is radius of curvature of space (called ''"[[Einstein's radius]]"''), <math>G</math> is Newtonian gravitational constant, and <math>\rho</math> is density of space |