by 
Claims by Chinese scientists that their “Sky Eye” telescope could have picked up signals from intelligent aliens have been met with skepticism by an American colleague.
Dan Werthimer, a Search For Extraterrestrial Intelligence (SETI) researcher at the University of Berkeley, California and a co-author of the research project (opens in new tab) who first saw the signals, told Live Science that the narrow-band radio signals he and his fellow researchers found “come from” [human] radio interference, and not from aliens.”
Natural sources usually do not produce such narrowband radio signals. Scientists picked up three of these signals in 2019 and 2022, seemingly from outer space, using the largest radio telescope in the world — the five-hundred-meter-long Aperture Spherical Radio Telescope (FAST), nicknamed “Sky Eye,” which conducted a preliminary study. scan of exoplanets in preparation for an upcoming five-year sky survey.
Related: 9 things we learned about aliens in 2021
News of the possible extraterrestrial origin of the signals first appeared in a report published on Tuesday (opens in new tab) (June 14) in the official newspaper of China’s Ministry of Science and Technology, in which the researchers claimed that the team “identified several cases of possible technological traces and extraterrestrial civilizations from beyond the Soil†
A FAST official not directly involved in the investigation also said a alien origin for the signals was “probably”.
The claims quickly went viral and spread across Chinese state media and Chinese social media platform Weibo before being reported by the international press and Live Science. But Werthimer says that while the signals are certainly artificial, they are almost certainly from humans, not aliens.
“The big problem, and the problem in this particular case, is that we’re looking for alien signals, but what we’re finding are countless terrestrial signals,” Werthimer told Live Science. “They’re very weak signals, but the cryogenic receivers on the telescopes are super sensitive and can pick up signals from cell phones, television, radar and satellites — and there are more and more satellites in the sky every day. It’s kind of new to the game, and you don’t know all these different ways interference can get into your data and damage it, it’s pretty easy to get excited.”
Despite this excitement, Werthimer’s Chinese collaborators were nonetheless careful to shield their more sensational comments, emphasizing the ultimate likelihood that the signals came from Earth.
“These are several narrow-band electromagnetic signals that are different from the past, and the team is currently working on further research,” Zhang Tongjie, chief scientist in the China Extraterrestrial Civilization Research Group at Beijing Normal University, said in the report. “The possibility that the suspected signal is some form of radio interference is also very high and needs to be further confirmed and ruled out. This can be a long process.”
The recent false alarm is one of many instances where alien-hunting scientists have been misled by noise from human activity. In 2019, astronomers saw a signal beamed to Earth from Proxima Centauri – the closest galaxy to our sun (about 4.2 light years away) and home to at least one potentially habitable planet. The signal was a narrow-band radio wave typically associated with human-made objects, leading scientists to harbor the exciting possibility that it came from alien technology. However, studies released two years later suggested the signal was most likely produced by faulty human equipment, Live Science previously reported. Similarly, another famous set of signals once emanating from extraterrestrials and detected between 2011 and 2014 turned out to be actually created by scientists who put their lunch in the microwave†
“A lot of very sophisticated astronomers looked at it and we couldn’t figure out what it was for a long time,” Werthimer said, referring to the microwave lunchtime incidents. “Finally someone found out it happened around lunchtime.”
Radio interference is a major problem for a telescope like FAST precisely because of its scale and sensitivity. The 500-meter-diameter dish is powerful enough to detect radio devices like those on Earth many light-years away, and the data it records contains just under 40 billion observations per second. In this setup, picking up a false positive is a lot like flipping a coin to get twenty heads in a row, Werthimer told the publication Futurism (opens in new tab) – it may seem like a remarkable outcome in its own right, but not when the coin has been flipped trillions or more.
And the less history a particular research team has with a particular radio telescope, the more likely they are not to notice a subtle interference effect. According to Werthimer, the receiver of the FAST telescope can look at 19 different places in the sky at the same time. Scientists are used to rule out interference if it occurs in all 19, but if the interference occurs in only one (as with all three so-called “alien” signatures detected in this case), even experienced researchers can be led astray. brought.
With the ever-growing number of satellites orbiting above our heads, Werhimer says this problem will only get worse.
“100 years ago, we didn’t really know how to do SETI. In 100 years, I don’t think we’ll be able to do it from the ground up,” Wethimer said. “This could be a unique window into our history as Earthlings where we can do pretty good SETI searches, where not all possible radio bands are damaged by our own signals.”
The possibility also remains that if aliens send us signals, or inadvertently leak them, across the vast expanse of the cosmos, they may not be encoded in radio waves, but in ways we haven’t yet developed to understand the technology.
“I wouldn’t be surprised if we were on the wrong track. If you look at SETI’s history, the original ideas proposed about 200 years ago were things like ‘let’s build some great fires on Earth’;” let’s build some big mirrors that reflect sunlight to the Martians” or “let’s build a few miles long right triangles to show aliens we know from the Pythagorean theorem,” and now we look back and say those guys were idiots,” Werthimer said. “So what can I say that in 200 years people won’t look at us and ask why we haven’t used tachyons or subspace communications? But you have to do what you know how to do.”
Despite the discouraging possibility that these signals have an Earth-bound source, SETI astronomers are still reasonably confident that we are not alone in the universe. And that one day we might dig up something real in the midst of all our own chatter.
“I think it would be very strange if we were the only ones. If you look at the numbers, there are a trillion planets in the galaxy – five times more planets than there are stars. A lot of them are little dinky planets like Earth. Many of them have liquid water, so intelligent life, while not as common as bacterial life, can still be fairly common,” Werthimer said. “Maybe they don’t want to interfere with primitive civilizations like us who are still killing each other. Maybe they have us in a big zoo to watch. Or maybe they got a little tired of technology and growth and are more interested in music and poetry.”
Live Science reached out to Zhang Tongjie for comment, but had heard nothing at the time of publication.
Originally published on Live Science.
