On November 8, 1895, physicist Wilhelm Conrad Roentgen discovered a strange effect related to cathode rays. He called the rays and their effects X-rays. Here are five things you didn't know about X-rays...
X Stands for "Unknown." X-rays were discovered by accident, and Wilhelm Conrad Roentgen, the physicist who discovered the rays, had no idea why they were doing what they did. He was experimenting with cathode rays when he noticed they caused another part of his equipment to glow; he also found that the rays allowed him to see a faint image of the bones in his hand. Because he didn't know why the rays could do all that, he named them X-rays, with the X standing for "unknown."
It Took 9 Years of Unfettered X-Ray Use to Discover They Were Dangerous. Scientists didn't quite understand how dangerous X-rays could be for several years. The rays were quickly put to use in medicine and other investigative fields; people thought they were harmless and used them whenever they were needed or whenever people thought they would be helpful. It wasn't until 1904 that people realized the rays could have adverse effects when Clarence Dally, one of Thomas Edison's assistants, died of skin cancer that was thought to be related to his use of X-rays in research. Even after that, X-rays were widely used in society, even showing up in shoe stores as a way to gauge fit.
They Were Originally Used to Burn Away Moles. If you thought the "shaving" method was nerve-wracking, think again. Scientists noticed that X-rays could burn, and thus they were used to burn away moles on the skin. That practice, thank goodness, has long been gone, but X-rays are still used in treatments such as cancer radiation therapy to kill off cancerous tissue.
Someone Tried to Make Lead Underwear a Thing. In the early years of X-ray use, those rays became popular not just with doctors, but with the public at large. X-rays found their way into popular culture, with speculation about such things as glasses that could make you see through everything, including clothing. (Yes, even in the 1890s people were talking about X-ray specs.) As a result, manufacturers tried to sell lead underwear as a way to prevent potential peeking.
They're Now Used for More Than Just Medical Exams. X-rays are a part of many fields now, from astronomy and archaeology to art and geology. While we think of X-rays as those things at a medical clinic, chances are that if you work in any field that involves physical investigation, you're going to encounter an X-ray machine at some point in your tenure. They can investigate more than just physical items into which you want to see; they've even been used to spot black holes.