Newton's Law of Gravitation: Mathematical expression of gravitational force

Most probably we don't think about gravity on a daily basis, but yet gravity affects our every move. Because of gravity, we fall down (not up), objects crash to the floor, and we don’t fly off into space when we jump in the air. Everything that goes up must come down and this makes perfect sense to everyone because from the day we are born, we are bound to Earth’s surface.

What Newton proposed with his law of universal gravitation was a revolutionary idea. He believed that the force responsible of making objects fall, like an apple falling off a tree, was the same force responsible for keeping the planets in orbit around the sun.

So, what is gravity and where does it come from?

Have a look at these following pages to learn more about this invisible and yet fundamental force!