On the evening of November 8, 1895, a German physics professor named Wilhelm Roentgen was alone in his darkened lab in Wurzburg, fiddling with a sealed glass tube that shot electricity through a gas. He had wrapped the tube in thick black cardboard to block all visible light. To his shock, a small painted screen sitting nearby suddenly began to glow green every time he switched the tube on. Something invisible was passing right through the cardboard. Roentgen, baffled, called the mysterious beams X-rays - X being the math symbol for unknown.
For the next seven weeks he barely left the lab. He even slept and ate there, testing the rays on books, wood, metal, and his own hand. When he held his hand in front of a photographic plate, the bones showed up dark and ghostly inside a fuzzy outline of skin. On December 22 he made his wife Bertha hold her hand still for fifteen minutes and produced the first X-ray photograph of a human body - her bones and her wedding ring floating in shadow. Bertha reportedly gasped, I have seen my death!
Within weeks of the news getting out, doctors all over Europe and America were using X-rays to find broken bones and bullets without cutting anyone open. Roentgen refused to patent his discovery because he believed it belonged to the world, and in 1901 he won the very first Nobel Prize in Physics. Today X-rays peek inside teeth, suitcases at airports, and faraway galaxies. It all started with a curious professor, a glow on the wall, and the brave question - what is that?
