Many of us were taught that gravity was discovered when an apple dropped next to Isaac Newton in 1666. However, the real answer could be more complicated. When was gravity really discovered?
There was a long line of scientists and philosophers, as early as the 4th century BC, who could be considered the pioneers of gravitational theory. These individuals came from Ancient Greece, the Medieval Islamic World, and Renaissance Europe.
Here’s more detail on who these scientists and philosophers were.
We can thank Aristotle for many things like zoology, the field of logic, and even an explanation of why we laugh. It turns out that the theory of gravity is something else he contributed to around the 4th century BC.
Aristotle stated that objects fall because of their composition. Aristotle believed that objects were composed of four elements (earth, air, fire, and water).
He theorized that each of these elements has their natural place that they are attracted to, meaning that objects composed of earth were going to fall back to the ground/earth and objects composed of air were going to go up to the sky. We know this is wrong of course, but at least he came up with one of the first “uniform” rules of why objects fall or rise.
This theory would be popular in Europe through the Middle Ages until the renaissance period when new scholars came up with alternative explanations.
The Islamic world had a huge and often underappreciated contribution to modern science. The so-called Islamic Golden age from the 8th to 14th century was a period when the Islamic world was highly productive in the sciences and arts.
Ibn Sina, known as Avicenna in the west, was a Persian born in present-day Uzbekistan around the year 980. Like Aristotle, he was a master of many trades, he dabbled in physics, chemistry, astronomy, psychology, and medicine to name some of the fields he was known for.
His theory related to gravity was that objects had an inherent quality called “mayl” that had to do with the heaviness of the object. This would determine how the object would move and fall.
While this theory wasn’t as precise as Isaac Newton’s created some good foundations in that it was separate from Aristotle’s incorrect theory about the four elements and correctly assumed that each object had some inherent quality or “mass” as we would later call it.
He’s not just part of the lyrics of a Queen song. Galileo, an Italian born in 1564, also happens to be one of the greatest scientists in history.
Galileo’s crucial breakthrough that helped develop gravitational theory was his discovery of that objects tend to accelerate equally in free fall. This means that if you drop two objects of different weights, both objects will fall to the ground at the same time (unless there is some sort of resistance).
There’s a story that he did this experiment by dropping two cannonballs off the Leaning Tower of Pisa, but that is likely just a legend.
We can’t give Galileo credit for creating a unified theory of Gravity, but he was taking steps in the right direction. He moved away from the Aristotelian framework that dominated Europe and helped create a new framework that would accurately identify gravity.
How It Was All put Together
Newton was able to build on the work of others in order to come up with his law of universal gravitation. This law was that every particle attracts every other particle in the universe with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers.
Newton was essentially able to create a mathematical formula to explain gravity for every object in the universe.
The apple falling from the tree may have given him a bit of inspiration, but it was the scientists that preceded him such as Robert Hooke, Bullialdus, and Borelli that helped him create gravitational theory.
This story, like many good ones, does have some controversy. When Netwon presented his findings to the Royal Society in England, Robert Hooke, another scientist, accused Newton of plagiarism.
There wasn’t necessarily enough proof that Newton plagiarized, but perhaps Hooke did have an influence on Newton as well as many of the other scientists and philosophers that came before him.