Astronomers May Have Been Listening for Aliens on the Wrong Radio Channel

Astronomers May Have Been Listening for Aliens on the Wrong Radio Channel

For decades, the search for extraterrestrial intelligence has quietly agreed on where to listen. Most radio SETI surveys train their instruments on frequencies between 1.42 and 1.66 gigahertz, a band nicknamed the “water hole” because it sits between the natural radio emissions of hydrogen and hydroxyl — two molecules that combine to form water. The logic has always been elegant: a technologically capable civilization might recognize the symboli…