From the dawn of time until just a few hundred years ago, people did not even know of gravity’s existence (at least on a universal scale). Like anyone today who has not had basic science lessons, ancient people defined gravity as simply the force that pulls things down to Earth and nothing more.
We know now, of course, that gravitation is inherent to all matter and is responsible for a vast number of phenomena, not the least of which is the orbit of the planets around the Sun. As far back as 4,000 years ago, and probably even farther, early astronomers had already identified five of our solar system’s eight other planets. However, many thinkers decided that the movement of these planets was the result of some mystical heavenly power, not a force that we experience on Earth. In fact, it was also a common belief that the Earth was the center of the universe (this is called a geocentric universe) and that the Sun and all the planets orbited around it. As you will see, it would be necessary to correct these misbeliefs before universal gravitation could be discovered.
