On April 11, 1960, astronomers began the first scientific experiment that would search for extraterrestrial life. ‘On This Day in Space’ Video Series on Space.com
In 1960, Cornell University astronomer Frank Drake launched Project Ozma, a pioneering search for extraterrestrial intelligence (SETI) experiment at the National Radio Astronomy Observatory in Green Bank, West Virginia. Drake’s objective was to detect interstellar radio waves that might indicate signs of life in distant planetary systems. Using a radio telescope with a diameter of 85 feet, he scanned the stars Tau Ceti and Epsilon Eridani for signals. Drake named the project after Princess Ozma from L. Frank Baum’s Oz series, who supposedly communicated with Oz by radio.
Drake’s experiment received extensive media coverage and was regarded as the first modern SETI experiment. He used a single-channel receiver to scan a 400 kilohertz band around the 1,420 MHz marker frequency, which corresponds to the energy of a photon emitted from a hydrogen atom during “spin-flip” transition. Despite 150 hours of intermittent observation over four months, no recognizable signals were detected, except for a false signal on April 8, 1960, which was later traced to a high-flying aircraft.
“Search for extraterrestrial life, a Delaware, Ohio Connection“
Drake tuned the receiver to wavelengths near 21 cm, the wavelength of radiation emitted naturally by interstellar hydrogen, which he believed would be familiar as a kind of universal standard for anyone attempting interstellar radio communication. In 1972, a second experiment called Ozma II was conducted using a larger telescope (300 feet) by Patrick Palmer and Benjamin Zuckerman, who intermittently monitored 670 nearby stars for about four years. They examined a 10 MHz bandwidth with 52 kHz resolution and a 625 kHz bandwidth with 4 kHz resolution, centered on the 21 cm hydrogen line in the rest frame of each observed star.
The search for extraterrestrial life continues, with the Wow! Signal being one of the most famous detections. The signal was recorded on August 15, 1977, by Radio Big Ear in Delaware, Ohio. The signal was so named because astronomer Jerry R. Ehman wrote “Wow!” on the printout of the signal. However, the signal was never detected again and its origin remains a mystery. Despite numerous searches, no definitive evidence of extraterrestrial intelligence has been found to date.