<P> Newton's role in relation to the inverse square law was not as it has sometimes been represented . He did not claim to think it up as a bare idea . What Newton did was to show how the inverse - square law of attraction had many necessary mathematical connections with observable features of the motions of bodies in the solar system; and that they were related in such a way that the observational evidence and the mathematical demonstrations, taken together, gave reason to believe that the inverse square law was not just approximately true but exactly true (to the accuracy achievable in Newton's time and for about two centuries afterwards--and with some loose ends of points that could not yet be certainly examined, where the implications of the theory had not yet been adequately identified or calculated). </P> <P> About thirty years after Newton's death in 1727, Alexis Clairaut, a mathematical astronomer eminent in his own right in the field of gravitational studies, wrote after reviewing what Hooke published, that "One must not think that this idea...of Hooke diminishes Newton's glory"; and that "the example of Hooke" serves "to show what a distance there is between a truth that is glimpsed and a truth that is demonstrated". </P> <P> In modern language, the law states the following: </P> <Table> <Tr> <Td> Every point mass attracts every single other point mass by a force pointing along the line intersecting both points . The force is proportional to the product of the two masses and inversely proportional to the square of the distance between them: </Td> <Td> </Td> </Tr> <Tr> <Td> <P> F = G m 1 m 2 r 2 (\ displaystyle F = G (\ frac (m_ (1) m_ (2)) (r ^ (2))) \) where: </P> <Ul> <Li> F is the force between the masses; </Li> <Li> G is the gravitational constant (6.674 × 10 N (m / kg)); </Li> <Li> m is the first mass; </Li> <Li> m is the second mass; </Li> <Li> r is the distance between the centers of the masses . </Li> </Ul> </Td> </Tr> </Table>

When was the universal law of gravitation discovered