In 1977, Ohio State University’s Big Ear radio telescope picked up a signal from space so strange that scientists are still baffled nearly 50 years later.
For decades, scientists have struggled to find any natural process capable of producing the 72-second burst that prompted astronomer Jerry Ehman to write “WOW!” on his telescope readout.
Now, a new analysis of the so-called WOW! signal has revealed that it could have been caused by an extremely powerful laser hitting Earth.
Experts say this was not the first salvo of an alien invasion, but rather the entirely natural product of a rare alignment between a collapsed star and a cloud of cold hydrogen.
Unfortunately for alien hunters, scientists at the University of Puerto Rico at Arecibo say this new evidence shows the WOW! signal is not evidence of life beyond Earth.
For decades, scientists have struggled to find a natural process capable of producing the 72-second burst that prompted astronomer Jerry Ehman to write “WOW!” on his telescope readout.
When the WOW! signal reached Earth, many scientists proposed the idea that this could have been the first “hello” from a distant extraterrestrial civilization.
Not only was the signal exceptionally strong, it also came in an unusually narrow frequency band, around 1,420 MHz, similar to those produced by atomic hydrogen.
Since hydrogen is so abundant in the universe, some have suggested that advanced civilizations might be using its frequency as a calling card to signal to other intelligent species.
Other natural explanations for the signature have been proposed, such as passing comets releasing clouds of gas.
Lacking a good natural explanation, the idea became widespread that the WOW! signal was a “technosignature” from another world.
Now, Professor Abel Méndez and his colleagues believe they have identified a series of similar signals that could explain the origin of the WOW! signal.
They made the discovery by reviewing the archives of the now-collapsed Arecibo Observatory’s Red Dwarf Radio Emissions from Stars (REDS) project.
Since this telescope had a similar experimental setup to the Big Ear radio telescope, I hoped it might reveal whether anything like the WOW! signal had ever been detected.
The researchers detected several signals that appeared extremely similar to the WOW! signal, although considerably weaker.
In 1977, Ohio State University’s Big Ear radio telescope (pictured) picked up a signal from space so strange that scientists are still baffled by it nearly 50 years later.
Researchers have used data from the Arecibo Observatory (pictured) to find signals that match the original WOW! signal. This evidence suggests it could be the product of a giant space laser.
Four of them originated from the small red dwarf star, Teegarden’s Star, which is only 12.5 light-years from Earth.
Professor Méndez says: “Our latest observations, carried out between February and May 2020, have revealed similar narrowband signals near the hydrogen line, although weaker than the original Wow! signal.”
What makes Teegarden’s star unique, however, is that it is surrounded by clouds of cold atomic hydrogen.
When the intense light from the red dwarf hits these clouds of hydrogen atoms, they are stimulated to produce a powerful burst of microwave energy in the 1420 MHz band.
Researchers detected similar energy bands (pictured) occurring at weaker levels in a nearby red dwarf star called Teegarden’s Star. Importantly, this star is surrounded by clouds of atomic hydrogen.
The result is a completely natural microwave laser, or maser, within the hydrogen range, which appears extremely similar to the WOW! signal.
Researchers say the WOW! signal likely occurred when an even more powerful burst of energy collided with a similar hydrogen cloud, producing an even larger maser.
Such a powerful explosion is rare, but could have been produced by a type of neutron star called a magnetar.
They form when a star collapses and explodes in a supernova, leaving behind an ultra-dense, rapidly rotating core with an extremely powerful magnetic field.
If a neutron star explosion were to hit a cloud of cold hydrogen gas, it could trigger a colossal maser burst just like the WOW! signal.
The signal could have been produced by a microwave laser triggered by the collision of energy from a magnetar (artist’s impression in the image) and a cloud of hydrogen gas. This means that the Wow! signal is not evidence of extraterrestrial life.
Since it would be extremely rare for a magnetar to align with a hydrogen cloud in just the right way, this also explains why we haven’t heard the signal again.
If true, this would mean that there is no need to assume that the WOW! signal is evidence of extraterrestrial life.
In their paper, published on arXiv, Professor Méndez and colleagues write: ‘Our hypothesis explains all the observed features of the Wow! signal, introduces another source of false positives in technosignature searches, and suggests that this signal represented the first astronomical maser flare recorded in the hydrogen line.
“We will continue to explore our extensive Arecibo REDS observation sets with Arecibo Wow!. Future studies will incorporate archival data from the Arecibo Observatory.”
WHAT IS FERMI’S PARADOX?
The Fermi paradox questions why, given the estimated 200 to 400 billion stars and at least 100 billion planets in our galaxy, there have been no signs of extraterrestrial life.
The contradiction owes its name to its creator, the Italian physicist Enrico Fermi.
He first raised this question in 1950.
Fermi believed it was too extraordinary that not a single extraterrestrial signal or engineering project had yet been detected in the universe, despite its immense vastness.
Fermi concluded that there must be a barrier limiting the emergence of intelligent, self-aware, technologically advanced space-colonizing civilizations.
This barrier is sometimes called the “Great Filter.”
Italian physicist Enrico Fermi devised the so-called Fermi paradox in the 1950s. It explores why there is no sign of extraterrestrial life, despite 100 billion planets in our galaxy.
If the main obstacle preventing the colonization of other planets does not lie in our past, then the barrier that will stop humanity’s prospects of reaching other worlds must lie in our future, scientists have theorized.
Professor Brian Cox believes that the advances in science and engineering required for a civilization to begin conquering the stars ultimately lead to its destruction.
He said: ‘One solution to the Fermi paradox is that it is not possible to govern a world that has the power to destroy itself and that global collaborative solutions are needed to prevent this.
“The growth of science and engineering may inevitably outstrip the development of political expertise, leading to disaster.”
Other possible explanations for the Fermi paradox include that no other intelligent species have arisen in the universe and that intelligent extraterrestrial species exist but lack the technology to communicate with Earth.
Some believe that the distances between intelligent civilizations are too great to allow any kind of two-way communication.
If two worlds are separated by several thousand light years, it is possible that one or both civilizations will become extinct before a dialogue can be established.
The so-called Zoo hypothesis claims that intelligent extraterrestrial life exists, but deliberately avoids any contact with life on Earth to allow for natural evolution.