Hans Bethe publishes the article “Energy Production in Stars,” explaining the CNO (Carbon-Nitrogen-Oxygen) reaction that occurs in stellar nuclei. It will be understood only later that this occurs in stars heavier than the Sun, while for stars like our own Sun, the nuclear fusion reaction is similar but different (the so-called pp-chain reaction). Legend has it that Bethe, out walking with his girlfriend that evening, when she says to him, “Look at how beautiful the stars are,” he replies, “You know, I’m currently the only one on the planet who knows why they shine.”
