Gravitational constant

G is the universal gravitational constant:

$G=6.67408(31)\times 10^{-11}\ {\mbox{N}}\ {\mbox{m}}^{2}\ {\mbox{kg}}^{-2}\$

It is used in Newton's formula for the gravitational force between two objects, which is:

$F=G{\frac {m_{1}m_{2}}{r^{2}}}$

where

${F}\$ is the force between the two objects

${m_{1}},{m_{2}}\$ are the masses of each object

${r}\$ is the distance between the two objects.

$g$ is the acceleration Earth's gravitational field exerts on objects at Earth's surface:

$g=9.81\ {\mbox{m}}\ {\mbox{sec}}^{-2}$