Spectral lines: Radio days

It came as a shock. I hadn´t realized that radio days were over. They ended, it turns out, just after World War II. They began when the first commercial broadcast stations went on the air, circa 1920. As World War II ended, so did radio days. Then television blossomed. It was demonstrated in 1939 at the New York World´s Fair but lay dormant during the war. Though I grew up during radio days, I hadn´t realized how short the era really was until just recently, when I saw Woody Allen´s movie, “Radio Days.” Woody, who himself grew up during radio days, probably thought they´d go on forever. Before I saw the movie, I thought they were still here.