Wow! signal mystery: Natural sources may hold the key

Scientists still do not know where the mysterious "Wow!" signal from 1977 originated. Some speculated that it might be a signal sent by an alien civilization, while researchers from the University of Puerto Rico hypothesize that it is a natural signal.

For nearly 50 years, astronomers have been trying to solve the mystery of the signal that surprised scientist Jerry Ehman in 1977 during observations with the Big Ear radio telescope at Ohio State University. This signal lasted 72 seconds and was so unusual and unique that Ehman wrote "Wow!" on the printout. A team of researchers from the University of Puerto Rico, led by astrobiologist Abel Méndez, is trying to explain its origin.

Méndez's team found four signals in archival data from the Arecibo Observatory that had frequencies similar to the famous "Wow!" signal. These signals come from the vicinity of Teegarden's star, a red dwarf located 41 light years away from Earth. Scientists speculate that these signals may be related to clouds of cold hydrogen, which could also explain the origin of the original "Wow!" signal.

The mystery of the "Wow!" signal remains unsolved for nearly 50 years. Since then, it has sparked much speculation about the existence of extraterrestrial civilizations. So far, it has not been possible to pinpoint the source of the signal definitively. However, a breakthrough might be on the horizon.

The "Wow!" signal did not move, making it unlikely that it came from an artificial satellite. It has also never been repeated, suggesting that it was not intentionally transmitted. Additionally, many natural objects emit signals at a frequency of 1420 MHz, which matches the frequency Ehman detected.

According to the hypothesis put forth by researchers from Puerto Rico, the signal could have resulted from a strong radiation burst passing through a cloud of cold hydrogen, causing the emission of an intense radio pulse at a frequency of 1420 MHz. Such a phenomenon is called a maser.

A maser resembles a natural astrophysical laser emitting concentrated radio light. Although Teegarden's star is unlikely to be capable of triggering such a powerful burst, scientists suggest that other cosmic objects, such as magnetars, might be able to do so. Magnetars are neutron stars with extremely strong magnetic fields that can explode in bursts so powerful that we can detect them in intergalactic space.

The hypothesis of Méndez's team seems to provide an explanation for all the features of the "Wow!" signal. It is therefore possible that it was the first recorded astronomical maser burst along the hydrogen line. The researchers plan to continue their work by analyzing archival data from the Arecibo Observatory. They hope this may provide further evidence to support their theory. For now, the results of their research are available as a preprint on arXiv, with the full publication still to come.