Modern science began with the scholars of ancient Greece and the experiments of the late Middle Ages.

For thousands of years following the first human civilizations, our ancestors explained everyday natural occurrences by invoking things like supernatural spirits and deities. That finally began to change around 500 BCE, thanks to the scholars of ancient Greece. They understood that reason, observation and mathematics could be used as tools to explain the world around them.

One such scholar was Anaximander, a philosopher who used those rational methods to explain how rain fell from the sky. It wasn’t the work of a benevolent god, he explained. Rather, evaporation caused water to accumulate in the sky and then fall back to earth.

Not long afterward, another scholar named Democritus theorized that everything in the world was made up of tiny building blocks called atoms. Democritus also reasoned that there must be a finite size to atoms – a point where you can no longer divide these tiny grains of matter. This theory was rooted in the idea of spatial extension: that matter must have size and occupy space. Therefore, atoms must also have a certain indivisible size.

More advancements came in the third century BCE, prompted by philosophers such as Plato and Aristotle, who both contributed to the idea that mathematics could be used as a tool for understanding our universe.

Then there was Ptolemy, born in 100 CE. He created formulas to calculate the movements of planets, thereby allowing us to predict their future positions.

Over a thousand years later, during the Middle Ages, Renaissance scholars such as Copernicus and Galileo returned to the ancient tools of mathematics and reason. This allowed Copernicus to revolutionize astronomy by proving that the orbits of celestial bodies could be better calculated once the sun, not the Earth, was considered the center of the solar system.

Likewise, in the sixteenth century, Galileo was the first to gaze upon the mountains of Earth’s moon, the rings of Saturn, and the moons of Jupiter, thanks to the newly invented telescope. Galileo also tested his hypotheses with rigorous and repeatable experiments, thereby helping to create what came to be known as the scientific method.

One such hypothesis was the belief that all objects fall at a constant speed. However, what Galileo’s tests revealed was that it wasn’t speed, but rather acceleration, or the rate of increased speed, that was constant among falling objects.

This discovery marked the very first mathematical law for earthly bodies: that every second, the speed of any falling object on Earth will increase by 9.8 meters per second.