On this day 375 years ago, perhaps the greatest physicist the world has known, Isaac Newton, was born. Widely recognized as one of the most influential scientists of all time, he invented his own calculus when he was 26 years old. An English mathematician, astronomer, and theologian, his book Principia, “Mathematical Principles of Natural Philosophy”, formulated our understanding of the mechanics of motion and gravity, which dominated scientists’ view of the physical universe for the next three centuries. This farmer’s son also built the first practical reflecting telescope, and made pathbreaking observations in optics, figuring out that white light is really made of multiple colors. WATCH a cool video... (1543)