The Prism on the Windowsill

In 1666, a young Isaac Newton darkened his room at Trinity College, Cambridge, and allowed a single beam of sunlight through a small hole in the shutters. He held up a glass prism, and what had appeared to be simple white light shattered into a full spectrum — red, orange, yellow, green, blue, violet — each color distinct, each one hidden inside what seemed uniform and uncomplicated.…