Isaac Newton was an English scientist born in 1643 who made groundbreaking discoveries in optics, mechanics, and mathematics. He discovered that white light is composed of the colors of the rainbow and published his seminal work "Philosophiae Naturalis Principia Mathematica" in 1687, establishing the laws of motion and universal gravitation. Newton's law of universal gravitation, published in "Principia", describes the gravitational attraction between all matter and helped unify the heavens with the earth.