Listening to the secret sounds of Earth's atmosphere

A new global network is breathing life into a dormant branch of geophysics. The study of infrasound, or long‐period acoustic signals in the atmosphere was bustling in the 1950s and 1960s. Prior to 1963, almost all nuclear tests occurred in the atmosphere. After 1963, the USSR and U.S. signed the Limited Test Ban Treaty (LTBT), which eliminated all atmospheric nuclear tests. During the era of atmospheric nuclear testing, infrasound research was in demand, since the massive explosions produced strong, long‐period acoustic waves that were globally observed and could be used to locate and describe the nuclear tests. Interest in this branch of geophysics waned with the end of atmospheric testing.