Wow! Signal Was Hydrogen, Not Aliens Trying To Make Contact
Alien Life & UFO/UAPs
Sunday 25th, August 2024
In 1977, a radio signal detected by the Ohio State University’s Big Ear radio telescope captured the attention of astronomers worldwide. Known as the Wow! Signal, this powerful and unusual burst of radio waves originated from the direction of the constellation Sagittarius. Its frequency, close to that of neutral hydrogen, led to widespread speculation that it could be a message from an extraterrestrial civilisation. Now, after nearly five decades of mystery, new research suggests a natural explanation for this enigmatic signal.
The Wow! Signal, which lasted for the entire 72-second observation window, was first noticed by astronomer Jerry R. Ehman. When reviewing the data, Ehman was so struck by the intensity of the signal that he wrote “Wow!” beside the corresponding printout, giving the phenomenon its now famous name. The signal’s official designation, 6EQUJ5, refers to how its intensity varied over time, and it has since become a subject of intense interest in the Search for Extraterrestrial Intelligence (SETI).
However, a new study titled "Arecibo Wow! I: An Astrophysical Explanation for the Wow! Signal", led by Abel Méndez from the Planetary Habitability Laboratory at the University of Puerto Rico at Arecibo, points to a natural astrophysical event as the source of the signal. The research, available on the pre-print server arxiv.org, builds on archival data from the now-defunct Arecibo Radio Telescope, gathered between 2017 and 2020.
According to the study, the Wow! Signal may have been caused by a sudden brightening of hydrogen clouds due to a strong transient radiation source, such as a magnetar flare or a soft gamma repeater (SGR). These rare events can cause clouds of neutral hydrogen to emit a bright, narrowband radio signal, which could explain the characteristics of the Wow! Signal observed by Big Ear in 1977.
“Our latest observations, made between February and May 2020, have revealed similar narrowband signals near the hydrogen line, though less intense than the original Wow! Signal”, said Méndez. The data from Arecibo, which is more sensitive and has better temporal resolution than that of Big Ear, detected these similar signals coming from multiple locations. This finding suggests that the Wow! Signal was likely a rare but natural phenomenon.
The study hypothesises that the Wow! Signal was the result of a rare spatial alignment between the source of the radiation, a hydrogen cloud, and the Big Ear telescope. This type of alignment is uncommon, which could explain why such signals are rarely detected.
“The only difference between the signals observed in Arecibo and the Wow! Signal is their brightness. It is precisely the similarity between these spectra that suggests a mechanism for the origin of the mysterious signal”, the authors write. The researchers were able to identify the clouds responsible for the signals but not the exact source. They suggest that the source of the original Wow! Signal was much more distant than the clouds themselves.
“Given the detectability of the clouds as demonstrated in our data, this insight could enable precise location of the signal’s origin and permit continuous monitoring for subsequent events”, the researchers explain.
The study's findings have significant implications for future searches for extraterrestrial intelligence. By identifying a natural source for the Wow! Signal, the researchers have highlighted a new type of false positive that could complicate the search for technosignatures, or signs of alien technology.
“Our hypothesis explains all observed properties of the Wow! Signal, proposes a new source of false positives in technosignature searches, and suggests that the Wow! Signal could be the first recorded event of an astronomical maser flare in the hydrogen line”, the authors conclude.
The Wow! Signal, which lasted for the entire 72-second observation window, was first noticed by astronomer Jerry R. Ehman. When reviewing the data, Ehman was so struck by the intensity of the signal that he wrote “Wow!” beside the corresponding printout, giving the phenomenon its now famous name. The signal’s official designation, 6EQUJ5, refers to how its intensity varied over time, and it has since become a subject of intense interest in the Search for Extraterrestrial Intelligence (SETI).
However, a new study titled "Arecibo Wow! I: An Astrophysical Explanation for the Wow! Signal", led by Abel Méndez from the Planetary Habitability Laboratory at the University of Puerto Rico at Arecibo, points to a natural astrophysical event as the source of the signal. The research, available on the pre-print server arxiv.org, builds on archival data from the now-defunct Arecibo Radio Telescope, gathered between 2017 and 2020.
According to the study, the Wow! Signal may have been caused by a sudden brightening of hydrogen clouds due to a strong transient radiation source, such as a magnetar flare or a soft gamma repeater (SGR). These rare events can cause clouds of neutral hydrogen to emit a bright, narrowband radio signal, which could explain the characteristics of the Wow! Signal observed by Big Ear in 1977.
“Our latest observations, made between February and May 2020, have revealed similar narrowband signals near the hydrogen line, though less intense than the original Wow! Signal”, said Méndez. The data from Arecibo, which is more sensitive and has better temporal resolution than that of Big Ear, detected these similar signals coming from multiple locations. This finding suggests that the Wow! Signal was likely a rare but natural phenomenon.
The study hypothesises that the Wow! Signal was the result of a rare spatial alignment between the source of the radiation, a hydrogen cloud, and the Big Ear telescope. This type of alignment is uncommon, which could explain why such signals are rarely detected.
“The only difference between the signals observed in Arecibo and the Wow! Signal is their brightness. It is precisely the similarity between these spectra that suggests a mechanism for the origin of the mysterious signal”, the authors write. The researchers were able to identify the clouds responsible for the signals but not the exact source. They suggest that the source of the original Wow! Signal was much more distant than the clouds themselves.
“Given the detectability of the clouds as demonstrated in our data, this insight could enable precise location of the signal’s origin and permit continuous monitoring for subsequent events”, the researchers explain.
The study's findings have significant implications for future searches for extraterrestrial intelligence. By identifying a natural source for the Wow! Signal, the researchers have highlighted a new type of false positive that could complicate the search for technosignatures, or signs of alien technology.
“Our hypothesis explains all observed properties of the Wow! Signal, proposes a new source of false positives in technosignature searches, and suggests that the Wow! Signal could be the first recorded event of an astronomical maser flare in the hydrogen line”, the authors conclude.
