Sir Isaac Newton is renowned for his theory of gravity. In the 17th century, he formulated the law of universal gravitation, which posits that every point mass attracts every other point mass in the universe with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them. This groundbreaking theory was articulated in his seminal work, "Mathematical Principles of Natural Philosophy," published in 1687. Newton's insights laid the foundation for classical mechanics and revolutionized our understanding of motion and celestial bodies, influencing scientific thought for centuries.