The integral form of Gauss law of gravity state ∂v∮g.ds=−4πGm where, ∂v is any closed surface, ds is a vector whose magnitude is the area of an infinitesimally small piece of surface 3v and whose direction of outward pointing surface is normal, m is the total mass enclosed with in the surface 3v. The left hand side of this equation is called the flux of gravitational field.