Universal gravitation কী?

A point mass $M$ at $O$ attracts a point mass $m$ at $M$ with

$G = 6.67 \times 10^{-11}\,\mathrm{N}\,\mathrm{m}^{2}/\mathrm{kg}^{2}$. A spherically symmetric body attracts outside itself as if its mass were at its center (admitted; a consequence of Gauss’s theorem, Chapter 26).