Important Work in Understanding the Behavior of Gravity and the Density of the Earth
Even today, scientists have not been able to come up with one universal theory regarding the mechanisms of the force and nature of gravity throughout the Universe. However, beginning with Newton in the seventeenth century, the behavior of objects affected by gravity has been thoroughly described and understood. Newton’s Law of Universal Gravitation essentially stated that objects in the Universe are attracted to other objects in the Universe according to a mathematical relationship between force, mass, and distance. But it was Cavendish that ingeniously confirmed this theory a century later with an experiment he designed specifically for that purpose. It was known as the Torsion Balance. There is a school of thought within the scientific community who believe it was Cavendish who conducted the first modern physics experiment because of his meticulous attention to every facet of his experimental process, including the errors.
His scientific contraption led him to determining the mass and density of the Earth with simple calculations since Newton's formula was already established. You can read about the exact formulas in Understanding the Surface Gravity of the Planets. Cavendish became famous for this work, which he published under the title “Measuring the Mass of Earth." The precision and meticulously measured nature of his experimental process became a model for all other scientists to follow.
Think about how staggering that finding is, one scientist, one individual among all the billions of people who ever walked on planet Earth, was able to determine the mass of the entire planet thanks to his firm understanding of earlier scientific discoveries. Future scientists used this information to help them understand how the planets orbit around the Sun and interact with each other. This knowledge also contributed to figuring out what it would take for a rocket to escape the gravity of the Earth and negotiating the significantly lower gravitational forces of the Moon in order to land (and come back, thanks to a quick burst of the only engine they had on the lunar module). So, just like Cavendish built upon the work of the scientists who came before him, future scientists built upon his discoveries about gravity to help us navigate the vast space in our tiny neighborhood in the Universe.
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