# Gravity

Gravity is one of the four fundamental forces of physics.

# Newtonian gravity

Isaac Newton postulated that every piece of matter in the universe attracts every other piece of matter. Two point masses M and m exert attractive forces on each other according to the following force law:

$F = \frac{GMm}{r^2}$

where $F$ is the gravitational force of attraction, $r$ is the distance between the masses and $G$ is a fundamental constant of nature known as the Universal Gravitational Constant.

## History

Gravity was invented by Sir Isaac Newton. Before gravity was invented everything had to be strapped, nailed or glued down. The lack of gravity was a real problem in the southern hemisphere. People kept falling off the globe[1].