Dr. KAZ Syed Abuthahir
1.1 Prelude
Gravity is the most mysterious force in nature. While the other three forces fit within a framework called the "Standard Model," gravity refuses to do so. Our theories of gravity are at odds with quantum mechanics, which is remarkably successful in describing the microcosmos. Yet, we can't marry quantum mechanics with gravity in a satisfactory manner. It's like trying to mix oil with water.
Many great minds erred in understanding the nature of gravity. One historically famous mistake was made by Aristotle, who thought that gravity affects things with different masses differently, as dictated by our observation of falling pieces of paper and marbles. After all, one can't blame him, as direct observation fuels the first drafts of our scientific theories, and often they turn out to be wrong! Misconceptions are common in science and they're just part of the culture.
Nearly 1800 years after Aristotle, Galileo Galilei insisted on experimentally testing every theory of natural phenomena. He dispelled the myth propagated by Aristotelian followers by dropping two balls of different masses but made of the same material from the top of the famous Leaning Tower of Pisa, demonstrating that they reach the ground at the same time. In essence, Galileo established the modern scientific approach to explaining natural phenomena.