It was on this day in 1900 that the physicist Max Planck published his theory of quantum mechanics. He was trying describe the behavior of light in his experiments, but found that the only way he could do it was to assume that light travels in little packets, which didn't make sense to him. He called his theory "an act of desperation." He assumed that some future physicist would figure out what he had done wrong. But it turned out that he wasn't doing anything wrong. Physicists have been exploring and describing the strange behavior of light and subatomic particles ever since.
The basic idea behind quantum mechanics is that particles of light, as well as other subatomic particles, are by nature unpredictable. If you shoot them across the room, you can never predict exactly where they will end up. The Danish physicist Niels Bohr once said that a person who was not shocked by quantum theory did not understand it, and theonce said that while only a modest number of people truly understand the theory of relativity, no one understands quantum mechanics. himself died in 1947, and he never came to fully accept the theory he discovered on this day in 1900. But his discovery led to the development of modern electronics, including the transistor, the laser, and the computer.