Today marks the 26th installment in a series of articles by HumanProgress.org titled Heroes of Progress. This bi-weekly column provides a short introduction to heroes who have made an extraordinary contribution to the well-being of humanity. You can find the 25th part of this series here.

This week, our hero is Wilhelm Röntgen. The German scientist was the first person to identify electromagnetic radiation in a wavelength that we today know as an “x-ray.” Today, x-ray machines are common at most medical facilities.  They are used for dozens of reasons, but the most common usage includes detection of broken and fractured bones, heart problems, breast cancer, scoliosis and tumours. The ability to accurately monitor the internal conditions of our bodies leads to better medical decisions. Every year, x-ray machines are used to help save the lives of millions of people.

Wilhelm Röntgen was born on March 26, 1845 in Lennep, Prussia. In 1862, Röntgen attended a boarding school in Utrecht. He was expelled in 1865, after he was accused of creating a caricature of one of his teachers. Without a high school diploma, Röntgen could only enroll at a university as a visitor, rather than an actual student. The Federal Polytechnic Institute in Zurich did not require a high school diploma and so, having passed the entrance exams, Röntgen enrolled as a student of mechanical engineering in Switzerland.

In 1869, Röntgen obtained a Ph.D. and became an assistant to Professor August Kundt, whom he followed first to the University of Würzburg and then to Strasbourg University. By 1874, Röntgen had qualified as a Lecturer at Strasbourg University. He became a professor in 1876. In 1879, Röntgen became the Chair of Physics at the University of Giessen. Röntgen moved once again in 1888, to become Chair of Physics at the University of Würzburg. It was during his time at Würzburg that Röntgen made his world-changing discovery.

On November 8, 1895, Röntgen was conducting experiments using a cathode ray tube – a specialised vacuum tube that gives off fluorescent light when an electrical charge passes through it. Röntgen noticed that when he used the cathode ray tube, a board on the other side of his lab that was covered in phosphorus began to glow. Intrigued, Röntgen covered the tube in a thick black cardboard box in order to cover the light that the tube emitted. Röntgen noticed that even after the tube’s light had been covered, the phosphorus board continued to glow. It soon became clear to Röntgen that he had discovered a new type of ray. Given the unknown nature of the ray, he named it “x-ray” (the mathematical “x” is often attributed to something unknown).

It is said that Röntgen spent the following weeks sleeping and eating in his laboratory as he investigated the properties of these new rays. After numerous experiments, Röntgen found that many materials were transparent or translucent when interposed in the path of the rays. These materials included paper, wood, aluminium and, most importantly for the medical industry, skin and flesh. Röntgen used a photographic plate to detail the transparency of different objects. Two weeks after his x-ray discovery, Röntgen took the first picture – a radiograph of his wife’s hand. When his wife saw the skeletal image, she exclaimed, “I have seen my own death!”

On December 28, 1895, Röntgen published a paper detailing his discovery titled “On a New Kind of Rays.” By January, Röntgen’s discovery was front-page news in Austrian newspapers. Over the next two years, news about x-rays spread and Röntgen published three papers about his experiments. Röntgen believed that his discovery should be publicly available and never sought a patent for x-rays. In 1900, at the special request of the Bavarian government, Röntgen moved to the University of Munich to be the chair of their physics department.

Röntgen was showered with numerous prizes, medals and honorary doctorates. In 1901, he was awarded the first Nobel Prize in Physics. After receiving the money given to Nobel Prize-winners, Röntgen donated all of it to research at the University of Würzburg. On February 10, 1923, Röntgen died from carcinoma of the intestine. He was 77 years old. In 2004, the chemical element number 111 was named “roentgenium” in his honor.

Röntgen’s discovery of the x-ray fundamentally changed medical practices forever. Every day, his work is being used to help save lives of people across the world. It is for that reason that Röntgen is our 26th Hero of Progress.