Update, 6/17/22, 9:03 a.m. ET: The scientists involved in the research have now clarified to Newsweek that they definitely have not found evidence of alien life and that the radio signals detected were from Earth.
Zhang Tongjie, a Chinese extraterrestrial intelligence expert at Beijing Normal University who took part in the research has now told Newsweek: "I did not say it was an extraterrestrial (ET) signal. These signals are from radio interference; they are due to radio pollution from Earthlings, not from ET. The technical term we use is 'RFI'—Radio frequency interference. RFI can come from cell phones, TV transmitters, radar, satellites, as well as electronics and computers near the observatory that produce weak radio transmissions."
Dan Werthimer, a radio astronomy expert at the Astronomy Department and Space Sciences Lab at the University of California, Berkeley, who also took part in the study, told Newsweek: "These signals are definitely radio interference, and not ET."
The original article below has not been updated or amended.
Scientists in China say they have detected what could be the trace of a signal from an alien civilization.
The researchers have identified what they have called "suspicious" signals from space as part of a search for evidence of aliens, and work is ongoing to determine what they might be.
The signals were detected by China's FAST radio telescope, also referred to as the "Sky Eye" telescope. With a dish diameter of 1,600 ft, it is the largest of its kind in the world, and since 2020 the telescope has been involved in researching possible alien life.
On Tuesday, the Chinese state media outlet Science and Technology Daily reported that researchers under professor Zhang Tongjie, described as chief scientist of the China Extraterrestrial Civilization Research Group at Beijing Normal University, had found a number of "possible technological traces" from intelligent civilizations elsewhere in the cosmos.
The FAST telescope works by scanning the skies for specific radio signals that could be produced artificially. These narrow-band signals must be picked out from the background noise of other radio emissions that come from deep space, so sensitive equipment is necessary. In some cases the telescope targeted exoplanets—planets that orbit stars other than the sun.
Science and Technology Daily reports that Tongjie and his team identified two groups of what were referred to as "suspicious" signals back in 2020 and that a further signal was identified this year.
The signals are certainly not proof of alien life just yet. Tongjie told the media outlet: "The possibility that the suspicious signal is some kind of radio interference is also very high, and it needs to be further confirmed and ruled out. This may be a long process."
He added that the team would use the telescope to repeat observations of the so-called suspicious signals to see if any further information can be obtained.
All quotes from Science and Technology Daily were translated from Chinese using Google Translate.
Unidentified radio signals from space are nothing new and often provoke speculation about a potential intelligence source. Often, though, such signals can be explained as probably having a natural source such as a highly energetic star.
Perhaps the most famous mysterious space signal ever detected was the Wow! signal, detected by the Big Ear telescope at Ohio State University in 1977.
The incredibly strong signal blipped for little over a minute at a popular radio astronomy frequency that scientists thought an alien civilization might use. When the signal appeared in a data print-out, Jerry Ehman, a scientist working with the telescope, circled it in red pen and wrote "Wow!" next to it. The source of the signal is still unknown.
Still, scientists think it's possible that an alien civilization that is as advanced or more advanced than we are could be sending artificial radio signals into space for us to detect, just like us humans did with the 1974 Arecibo message—an interstellar radio signal that contained information about humanity and Earth.
The SETI Institute is one group that has dedicated itself to searching for such radio signals for years, using large radio telescope arrays. To date, no radio signals have ever been detected that can be considered to have certainly come from an alien civilization.
The apparent lack of aliens has given rise to what's known as the Fermi paradox, which describes the contradiction between mathematical predictions that alien life should exist in our galaxy and the fact that we've not seen any.
Some researchers, for instance, have suggested that there should be tens of thousands of alien civilizations in our galaxy.
Some potential solutions to the Fermi paradox include that we're overestimating how common intelligence life might be; that intelligent life has decided not to transmit information; or that we're simply not seeing or understanding such information.
Update, 6/15/22, 9:45 a.m. ET: This article has been updated with more information for context.