In 1669, Newton became a professor of mathematics at Cambridge and joined the Royal Society three years later. This society comprised learned men from all scientific fields. He soon resumed his studies on motion, having already grasped the essential concepts but needing to solve the complex mathematics. Although he overcame the main difficulties, he delayed publishing his findings.
It was not until 1687 that Newton finally published his groundbreaking work, The Mathematical Principles of Natural Philosophy. This book marked the triumph of the Scientific Revolution. Its title is significant: Newton had discovered the mathematical principles governing the movements of celestial and terrestrial bodies, completing the new view of nature initiated by Copernicus and establishing an exact mathematical framework for the world.
In this work, Newton formulated his three laws of motion:
1. First Law (Inertia): A body remains at rest or in uniform motion in a straight line unless acted upon by a force.
2. Second Law: The force applied to a body is proportional to its acceleration.
3. Third Law: For every action, there is an equal and opposite reaction.
Newton also derived a mathematical expression for gravity, a universal force explaining phenomena from a falling apple to the Moon's orbit. He was soon recognized as the leader of English science and became President of the Royal Society in 1703.
Newton's discoveries fundamentally transformed science. The 18th-century poet Alexander Pope famously wrote: "Nature and Nature's laws lay hid in night; God said, Let Newton be! -- And all was light."
Despite his fame, Newton never ceased his work. In his later years, he reflected: "I do not know what I may appear to the world, but to myself I seem to have been only like a boy, playing on the seashore, and now and then finding a smoother pebble or a prettier shell than ordinary, whilst the great ocean of truth lay all undiscovered before me."