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They discover the origin of a radio signal sent in 1977 by a supposed alien civilization


The prominent and still mysterious “Wow!” signal that briefly appeared on a radio telescope on the night of August 15, 1977 and is considered to date the signal most likely to have been emitted by an extraterrestrial civilization, could have come from a star similar to the Sun, located 1,800 light years away from Earth.

The radio signal “Wow!” it is still considered the best candidate to be a SETI message (search for extraterrestrial intelligence, according to the acronym in English) that we have captured with our radio telescopes so far. Discovered in 1977, it has motivated a large number of hypotheses and conjectures: now, a new study recently published in the International Journal of Astrobiology proposes a precise location in the Universe from which this mysterious signal would have come.

An enigma that remains open

Immortalized as “Wow!” (equivalent to the expression ¡Guau! in Spanish) due to the annotation made by the astronomer Jerry Ehman upon discovering it, the signal appeared during a SETI search at the Big Ear telescope at Ohio State University, in the United States, specifically on August 15, 1977. Incredibly strong but very brief, the signal recorded a duration of 1 minute and 12 seconds, according to the report written by Ehman himself on the 30th anniversary of the discovery.

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When Ehman saw a printout of an anomalous signal, he wrote “Wow!” on the page and started the “legend”: it is worth remembering that the missing Big Ear telescope searched for extraterrestrial messages in an electromagnetic frequency band that is produced by the element hydrogen. For Ehman, being the hydrogen the most abundant element in the Universe, it is logical to think that an intelligent civilization within the Milky Way could transmit a strong signal in the frequency range related to said chemical element, if its objective is to make its existence evident.

In the new study, carried out by amateur astronomer Alberto Caballero, they analyzed which of the thousands of stars present in the region of the cosmos identified with the signal could have the greatest probability of being the actual source of the messageas long as it comes from a star system similar to ours.

A message from nearly 2,000 light-years away?

Of a total of 66 stars studied, only one could be identified as a star similar to the Sun: it is called 2MASS 19281982-2640123 and is located in the sagittarius constellation, approximately 1,800 light years distant from Earth. According to Caballero himself in his study, it should therefore become an ideal target for new observations, in the search for technological signatures of extraterrestrial civilizations.

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To date, the signal “Wow!” remains the strongest candidate to become the first alien message identified by humans. It has been suggested that the signal was produced by hydrogen clouds from comets 266/P Christensen and P/2008 Y2, but this hypothesis has been ruled out by the scientific community: to date, the exact source of the signal is unknown.

The signal lasted 72 seconds, but since this was the maximum amount of time that the Big Ear radio telescope was able to observe, it is likely that the signal lasted longer. The main problem, however, is that the signal never repeated itself: Follow-up observations of the area by many observatories over several years never detected another similar signal. Despite this, the fact that the signal was never repeated does not necessarily rule out that it was produced by extraterrestrial intelligence: the new discovery seems to reopen the controversy.


An approximation to determine the source of the WOW! Signal. Albert Knight. International Journal of Astrobiology (2022). DOI:https://doi.org/10.1017/S1473550422000015

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