ABSTRACT
In this chapter, we turn our attention to the final frontier of the electromagnetic spectrum: x-ray radiation. This invisible form of light was discovered accidentally by Wilhelm Roentgen in 1895. Roentgen was studying the properties of electric discharges inside a vacuum tube when he noticed a glow on a nearby fluorescent screen. After careful experimentation, he deduced that this effect was caused by unknown rays coming from inside the tube. Because of the uncertain nature of the new rays, Roentgen called them “x-rays.” He also discovered one of the most astounding properties of x-rays, their ability to penetrate matter such as human tissue. Roentgen took the first photographic x-ray image of a human skeleton – the “x-ray” of his wife's hand. When she saw the bones of her hand, Mrs. Roentgen exclaimed “I have seen my death!” The discovery of x-rays was a transformational moment for modern medicine. (It also provides a cautionary tale about scientific discovery: five years before Roentgen's work, a University of Pennsylvania physicist and a photographer had observed a similar phenomenon and even taken the first x-ray image – but simply filed away their results as a curiosity! One can only imagine their emotions when Roentgen's work earned him the first-ever Nobel prize in physics.)
