The Search for Extra-Terrestrial Intelligence (SETI) stirred when researchers deciphered the 72-second radio signal from space on August 15, 1977. Astronomer Jerry Ehman analyzed the signal on a computer printout and deciphered the word “Wow!” which is widely known today as the Wow! signal. The signal was received from the Sagittarius constellation close to the center of the galaxy.
Ehman recalled in an interview that the discovery was the most important thing they had accomplished. The signal, which was received by Big Ear radio observatory of Ohio State University, appeared as 6EQUJ5. So much excitement was all over the group that time with hopes to receive similar transmission in an attempt by space aliens to make contact, but it has not been received since.
But the Wow! signal remains a mystery 37 years later, igniting the theory on the existence of intelligent life beyond Earth.
The Big Ear was used to survey celestial radio sources starting in 1965 as cosmos objects emit large amounts of radio waves. These objects include nebulas, quasars and pulsars. Its mission shifted to constantly surveying radio waves from space in the 1970s, hoping to get extraterrestrial communication.
Many objects in space emit radio waves, but the Wow! signal was very strange. It was resonating on the hydrogen line at 1420 MHz. This line is being referred to as a frequency that is highly possible to communicate intelligent alien life. This likelihood was independently recognized by Frank Drake at the National Radio Astronomy Observatory and Philip Morrison at Cornell University in 1959. According to SETI, advanced civilizations might likely aware that young civilizations like humanity might be already listening there.
For the reason that the frequency of the waves was emitted by neutral hydrogen atoms, the hydrogen line was named as such. This frequency has been protected by the International Telecommunications Union projects to prevent noise on it from earthly sources. It is used by astronomers to make maps based on hydrogen atoms’ emissions in space.
The strength of the Wow! signal, the shifts of its intensity, and the hydrogen line make it a possible candidate for intelligent extraterrestrial communication.