In a synchronous reference system where g 00 = 1 and g 0 α α = 0 , the time coordinate x 0 = t (we set G = c = 1 ) is also the proper time τ τ = g 00 x 0 and clocks at all points can be synchronized. For a dust-like medium where the pressure is zero, dust particles move freely i.e., along the geodesics and thus the synchronous frame is also a comoving frame wherein the components of four velocity u i = d x i / d s are u 0 = 1 , u α α = 0 . The solution of the field equations yield