Complex Things in Simple Words | Is the “Wow!” signal really sent by aliens

More than 45 years ago, a radio telescope owned by the University of Ohio caught an amazing signal that went down in history as “Wow!”. A lot of people consider it as a proof of the possible existence of intelligent life outside our planet. However, the opinions of scientists regarding it are much more restrained.

Who sent the “Wow!” signal

1. What is the “Wow!” signal?

On August 15, 1977, Jerry Eyman from Ohio State University, using the Big Ear radio telescope with an antenna measuring 103 × 33 m, explored the starry sky at a frequency of 1420.406 MHz. It corresponds to the radiation of neutral hydrogen and is therefore considered by scientists as the most promising for interstellar communication. The signals received by the antenna had the form of a column of ones, between which larger numbers sometimes appeared.

Suddenly, the scientist saw a group of numbers and letters that attracted his attention. He realized that he was dealing with a very unusual signal, circled a group of characters with a pen, and wrote “Wow!” next to it. It looked like it was really a signal received from deep space. Therefore, for many years, it has been cited as an argument in favor of the existence of extraterrestrial life.

2. What information did it contain?

As you can already guess, the aliens did not exclaim the word  “Wow!”. The researchers were not interested at all in what information the symbols carried. Their equipment recorded only the level of the ratio of pure signal and noise, i.e., random interference. The numbers reflected this dimensionless ratio. After 9, they were replaced with letters. That is, A is actually a 10-fold excess, B is an 11-fold excess, and so on.

Therefore, the sequence “6EQUJ5”, which illustrates this signal, is not a transmitted message. This was just one short peak of radiation lasting 72 seconds that appeared out of nowhere and never happened again.

3. Where did the signal come from?

Since the peak was very short, it was not possible to use other tools to confirm it. Therefore, it was not possible to establish at what distance its source was located. It could be 10 km, 100 AU or 1000 light years away from us. But scientists could determine the direction extremely accurately.

The “Wow!” signal came to us from the constellation Sagittarius, from an area lying near the direction of the core of the Milky Way. There is a very high density of galactic objects. Much later, researchers used the Gaia telescope catalog and found as many as 15 possible stars from which radio waves could come. The most promising of them is 2MASS 19281982-264012, located at a distance of 1800 light years.

4. How do scientists explain all this?

Scientists express different versions of what the “Wow!” signal is, and the message from aliens is not the most popular among them. Eyman suggested that it was the signal of the radio telescope “reflected” from some object near the Earth.

In 2005, two short-period comets were discovered — 266P/Christensen and P/2008 Y2. Analysis of their orbits showed that on the day of receiving the signal, they were in the constellation Sagittarius, i.e., it was from them that the radio waves could come. However, this assumption is rather doubtful because the powerful radiation of these objects at this frequency has never been observed later.

5. Whether someone tried to find the signal afterward

Various radio telescopes have repeatedly tried to find the signal in the place where the Big Ear registered it after 1977. The last time this happened was in 2022. Then all 15 main candidates for the role of its source were investigated. However, no sufficiently powerful signal was received from them. There is also no information about the presence of at least exoplanets there.

Scientists admitted that if there was some kind of source of artificial radiation in the vicinity of the studied stars, over all these years we would most likely “hear” it at least once more. Although there is an assumption that, in fact, the signal came from a fast-moving spacecraft. Therefore, it is necessary to look for it in a completely different place… 

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