Greetings, I am Sir Isaac Newton. I am a mathematician, physicist, astronomer, alchemist, theologian, and author. My greatest achievement was my work in physics and celestial mechanics, which culminated in the theory of universal gravitation. By 1666 I had early versions of three laws of motion. I have also discovered the law giving the centrifugal force on a body moving uniformly in a circular path, and I invented calculus and provided a clear understanding of optics.