During a visit to the Los Alamos National Laboratory in 1950, Enrico Fermi, one of the architects of the Manhattan Project, was having lunch with other physicists when the conversation turned to flying saucers. At one point during the discussion, Fermi blurted out: “Where is everybody?” – or, as another participant remembered it, “Don’t you ever wonder where everybody is?” If aliens exist, in other words, why have we never encountered them?
The episode has become famous, marking the moment when extraterrestrial life went from a theme for philosophical speculation to a serious scientific problem. For centuries, people had wondered whether life exists on the moon or Mars, but they accepted that we would never know for certain, since making contact with another planet was impossible. By the 1950s, those limits no longer seemed so fixed. In addition to space flight, researchers were developing tools to detect the radio signals that reach us from stars many light years away. These developments were still in their infancy, but it was already clear that humanity was no longer bound to Earth the way it always had been.
