However, he used this time to study different branches of mathematics, including geometry and algebra, and other difficult concepts. Furthermore, while he was thinking about the motion of objects, he discovered that mathematics can describe how objects moved and interacted. He then started to study the motions of the moon and planets, and he discovered that not only does gravity act of the objects on Earth, but it also affects the moon and planets. During these 18 months, Newton “conceived his 'method of fluxions' (infinitesimal calculus), laid the foundations for his theory of light and color, and achieved significant insight into the problem of planetary motion, insights that eventually led to the publication of his Principia” (Hatch). Though the bubonic plague was a disaster, Newton took advantage of it and made discoveries that changed the …show more content…
Instead, he published the Philosophiae Naturalis Principia Mathematica, or better know as the Principia, in 1679. In it, he included his three laws of motion. According to Dr Robert A. Hatch in his article about Sir Isaac Newton, his first law states that an object continues in its state of rest, or uniform motion in a straight line, unless an unbalanced force acts on it. This is also known as the law of inertia. His second law states that the force acting on an object is equivalent to the mass of that object times its acceleration, or F=MA. Finally, his third law states that to every action there is always an opposed and equal reaction. The Principia also included Newton's law of universal gravitation, which states that gravity is proportional to the objects’ mass and inversely proportional to the distance between them. Newton explains why the moon orbits the Earth and why planets orbit the Sun with this law. In fact, the discovery of gravity was inadvertent. He began to think about gravity when he saw an apple fall from a tree while he was wondering the moon’s orbit in 1666. That inspired Newton to think that the same force that was applied to the apple could also be applied to the moon as well. The Principia may be the greatest scientific book that has ever been written, because it changed how people viewed and understood physics