X-Ray or the “unknown” ray
X-rays have eluded mankind for a long time, since the only natural source of X-rays on earth stems from the decay of rare radioactive substances such as Uranium. The discovery of X-rays was an accident: On November 8, 1895 W.C. Röntgen (Ref: Figure 1), a professor at the University of Würzburg in Germany, had been experimenting with a cathode ray tube, similar in construction to a light bulb. After covering up the tube to shield the visible light emitted from it, he noticed that a fluorescent screen present in the room was glowing. He deduced correctly that he discovered a new, mysterious kind of radiation that was different from visible light. He worked feverishly for the next several weeks, mentioning his discovery to no one. Röntgen quickly realized that these rays could penetrate materials that are opaque to visible light and that photographic film could be used to detect their presence. Roentgen himself produced the first X-ray shadowgraphs of bones by simply placing an object in front of a sheet of photographic film and turning his cathode ray tube on.