The Mysterious Wow! Signal

The quadrilateral of bright stars near the centre, below the Milky Way is a part of the Sagittarius constellation

Us, human beings have always been curious about the existence of extraterrestrial species and are in a constant expedition to make contact with them or least confirm their existence in the universe. The Search for Extra-Terrestrial Intelligence (SETI) Institute is solely devoted to contemplating this with the help of their Allen Telescope Array (ATA). However, there have been innumerable theories, explanations, paradoxes and fallacies as to why we haven’t been able to detect traces of extra life yet.

The Wow! Signal still remains the closest we have reached hearing from alien lifeforms. On August 15, 1977 astronomer Jerry Ehman discovered a bizarre blip while analysing the recorded data which appeared to have originated from a group of stars called ‘Chi Sagittarrii’ located in the Sagittarius constellation. Ehman was working in the SETI programme when he received this 72-second burst of radio waves from the Big Ear radio telescope located in the Ohio State University. This signal read ‘6EQUJ5–111’ when translated to alphanumeric code which Ehman circled and wrote “Wow!” right next to it and hence this signal was popularised by the same name.

One noteworthy signal among them was that signal which precisely has the frequency of 1,420 MHz, that also happens to be the vibration frequency of Hydrogen molecule, the most abundant molecule in the known universe. Hence, physicists thought that if at all extra-terrestrial lifeforms are trying to communicate, they would do so with a radio signal that has a frequency which is fundamental and familiar to all advanced civilizations.

Many astronomers and scientists have put on their thinking caps to find a plausible explanation for this signal over 40 years as of now. Even after trying to look for the signal several times after that, it was all futile. Possible sources like asteroids, exoplanets and even signals from the Earth have been ruled out. Other hypotheses include that the signal might be coming from an interstellar rotating lighthouse, or that it could have been recorded from the comets named 266P/Christensen and 335P/Gibbs since they have hydrogen clouds in millions of kilometres surrounding them. But, none of these theories is popularly accepted by all.

In 2012, on the 35th anniversary of the Wow! Signal, the Arecibo Observatory (Puerto Rico) which has the largest radio telescope antenna, directed a very powerful digital stream at the same region where the signal originated. This digital transmission contained over 10,000 twitter messages from humanity and some videotapes of popular celebrities in order to promote a TV show airing on the National Geographic Channel. The scientists at the Arecibo Observatory attached a repeating sequence header to each message to make it possible for the extra-terrestrial (if at all they are the origin of the signal) to receive, decode and realise that this is an attempt to communicate with them from another intelligent lifeform. However, it would take 25,000 years for this signal to reach the destination and perhaps, until then this signal would still remain a mystery.



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The official blog of SEDS VIT, Indian headquarters of the global NPO, Students for the Exploration and Development of Space.