Formula_11840

\[d s^{2}=\left(1-\frac{2 m}{r}\right) d t^{2}-\left(1-\frac{2 m}{r}\right)^{-1} d r^{2}-r^{2}\left(d \theta^{2}+\sin ^{2} \theta d \varphi^{2}\right) .\]