He Put the “X” in X-Rays

November 8, 1895

German Physics Professor Wilhelm Röntgen stumbles upon what he would later describe as “X-rays” while experimenting with electrical discharge tubes. Curious as to what was causing a faint green glow on a nearby fluorescent screen, Röntgen began systematically studying the unknown rays and published the first paper on the phenomenon less than two months later. He referred to the rays as “X”, indicating that they were an unknown form of radiation at the time. The name has stuck, although in several languages, X-rays are referred to as Röntgen rays, in tribute to his discovery. Incidentally, Röntgen was awarded the very first Nobel Prize in Physics in 1901 for his work on X-rays.