X-rays Discovered: Nov. 8, 1895

A few days after noticing something odd in his laboratory, German physicist Wilhelm Roentgen sets up an experiment late on a Friday afternoon.  He sends an electrical charge through a tube that’s been wrapped in heavy black paper.  And just as he thought he had noticed previously, he now sees clearly that somehow the light has passed through the paper and is creating a fluorescent glow on a chemically-coated screen several feet away.

Roentgen realizes that he has discovered a different type of ray—he calls it an X-ray—one that can pass through substances and cast a shadow of solid objects on pieces of film.

He spends the next few weeks working secretly in his lab--he wants as much proof as possible that X-rays exist before going public with his discovery.  Soon, he produces the first X-ray, an image of his wife's hand that reveals the bones inside. When she sees it, she exclaims, "I have seen my death."

By the end of the year, Roentgen published his first paper on X-rays, titled "On New Kind of Rays" and early in 1896, an Austrian newspaper reported his discovery, noting that the new kind of radiation could have a profound impact on medical diagnosis.

A few days later, Roentgen demonstrated how X-rays worked to Kaiser Wilhelm II in a private meeting and then, at a session of the Wurzburg Physical Medical Society on January 23, he presented his findings and X-rayed the hand of one of the doctors present. The physician was so impressed that he suggested that the name of the radiation be changed to "Roentgen rays," but, ultimately, the name didn't stick.

News of Roentgen's discovery spread quickly through the medical world and, within months, doctors were using X-rays to examine broken bones and gunshot wounds.  Soon, X-ray departments were being set up at hospitals, such as the Glasgow Royal Infirmary in Scotland, where doctors not only produced the first X-ray of a kidney stone, but also the first one of a penny caught in a child's throat.  By 1897, X-rays were being used to diagnose battlefield wounds during the Balkan War.

While scientists were quick to realize the benefits of X-rays, they were much slower to comprehend the harmful effects of the radiation. Initially, it was believed X-rays passed through flesh as harmlessly as light. However, within several years, researchers began to report cases of burns and skin damage after exposure to X-rays, and in 1904, Thomas Edison's assistant, Clarence Dally, who had worked extensively with X-rays, died of skin cancer. Dally's death upset Edison so much that he stopped all of his own research on X-rays.  Still, it wasn't until the 1930s that scientists first recommended lowering exposure to X-rays.

By then Roentgen was dead, a victim of intestinal cancer.  Although he was awarded the first Nobel Prize in Physics in 1901, he died a poor man. He had never tried to patent his discovery and what little fortune he had was wiped out by the runaway inflation in Germany after World War I.

Today, Roentgen's discovery is widely used in medicine, material analysis and, of course, devices such as airport security scanners.  It's estimated that more than five billion X-rays are done every year.