Over half a century ago, in 1959, a couple of physicists at Cornell University speculated that if aliens exist, they would be aware of physics and chemistry and would try to contact us through the frequency 1420 MHz. 1420 MHz is a frequency that is silent on world radio because this frequency is not allotted for radio communications and is saved for the radio astronomers. The frequency is called the Hydrogen line in radio astronomy and you get a signal on this frequency if hydrogen switches between high-energy transmission and low energy transmission.
Almost 20 years later, Jerry Ehman, a volunteer with Search for Extra Terrestrial Intelligence (SETI), Ohio State, found something that surprised the world. A seventy-two second signal was received in August, 1977, via Big Ear, the radio telescope in Ohio State, which at its peak was 30 times stronger than the background noise.
Ehman noticed this transmission three days after it was received because at the time, the readings of the telescope were deciphered by hand and so, were not calculated immediately. Instead, a pile of printouts were given to volunteers like Ehman, who then deciphered readings from a couple of days. Ehman was doing this routine work when the seventy-two second burst caught his attention and he circled the corresponding alphanumeric sequence with red ink and wrote ‘Wow’ besides it. That’s how the signal came to be called the Wow signal.
Some astronomers believe that the Wow signal was sent by aliens since the frequency and the position of the signal indicate an extraterrestrial origin. Also, it falls within the ambit of the Cornell physicists’ theory, that the frequency could be used by aliens to contact us. The signal is supposed to have its source in a cluster of stars called M55 in the constellation Sagittarius. The signal was received for just seventy-two seconds because the earth’s rotation changed the focus of the stationary telescope vis a vis the signal.
Ehman, as well as other radio astronomers, have made numerous attempts to detect the Wow signal again, but it has never been received. This makes it difficult to prove that the signal received was from an alien source. All sorts of theories have been discussed regarding the Wow signal, with one theory even suggesting that the signal had actually originated on earth and was reflected by one of the space debris.
Whatever the theories may be, they haven’t proven anything beyond reasonable doubt and may baffle scientists for a few more years. In this episode, Samanth Subramanian and Padmaparna Ghosh talk to a professor who does not believe that the Wow signal was sent by aliens. He is planning to work on his theory and find a definite answer in a couple of years. Find out more about this theory and the professor on this episode of The Intersection. (http://www.audiomatic.in/show/aliens-radio-wow-via-big-ear/)