Gravitational Force

In the years before Newton, a general belief prevailed that different laws governed objects in the sky than objects on Earth. When Kepler wrote down the three laws of planetary motion, explaining in detail the geometrical properties of the planetary orbits around the Sun, there was no immediate idea to discern their connection with more fundamen...

The revolution of the moon around Earth indicates the presence of a force that attracts it toward the orbit's center.

Issac Newton proposed that this attractive force is the same as that which pulls an apple toward the ground.

It was a revolutionary idea, since celestial objects and objects on Earth were believed to follow differen...