World War II introduced terrifying new weaponry. In the last year of the war, Germany began firing V-2 rockets loaded with one-ton warheads. Traveling 3,500 miles per hour (5,600 km/​hr) at impact, these reached British soil only about five minutes after being launched. Then the United States dropped two atomic bombs on the Japanese cities of Hiroshima and Nagasaki, killing over a hundred thousand people outright. “Allied to the atomic bomb,” explains the Encyclopædia Britannica, “the V-2 foreshadowed the intercontinental ballistic missiles [ICBMs] of the postwar era.”

Dr. Jastrow wrote in Science Digest: “When the Germans were raining V-2s on Britain 40 years ago, they thought they were doing well if a rocket came within 10 miles [16 km] of its target.