On February 27, 1942, a British physicist named James Stanley Hey accidentally found out that the sun emits radio waves. Hey was working for the Army Operational Research Group in the middle of World War II. His job was to find ways to stop the Germans from jamming British radars. He received reports that anti-aircraft radars were experiencing severe noise jamming. In other words, foreign radio-frequency signals were interfering with the radars' ability to operate. When he investigated the signals, he realized that they weren't coming from Nazis — they were coming from the sun! More specifically, they were coming from an active sunspot.