X-ray

Wilhelm Röntgen's glowing screen, Würzburg, November 8, 1895 Röntgen was studying cathode rays and had wrapped his tube in heavy black cardboard, yet a fluorescent screen about nine feet away began to glow. Nothing he knew about could cross that gap, and he spent the following weeks testing the unknown rays, which he called X for that reason. One famous plate showed his wife Bertha's hand with her wedding ring clearly visible. He submitted his first communication on December 28, and within a year X-rays were an established part of diagnosis and therapy. The first Nobel Prize in physics, in 1901, went to him for it.