Researchers Find Mysterious Radio Signal in Data From China’s Giant Telescope
The signal came from the direction of a distant star system, but the evidence points more strongly to human interference than to a message from space.
A Chinese research team found a mysterious signal in data from the world’s largest radio telescope, resembling the kind of signal alien hunters hope to detect. But analysis points more strongly to human interference than to a message from space.
A Chinese-led research team reanalyzed data from the world’s largest radio telescope, built in a natural depression in southwestern China, and found a narrow frequency line that shifted gradually over time. It wasn’t a sound or a message anyone could decipher. Still, it was just the kind of phenomenon alien hunters hope to detect, which is why the finding made headlines. According to a report by the Israeli news site Walla, the signal drew interest because it resembled the kinds of signals researchers search for in the hunt for extraterrestrial life.
Why This Star System?
The telescope’s dish, about 500 meters across, was pointed at the K2-155 star system, roughly 238 light-years away. Three planets larger than Earth orbit the star, and one lies near a region where liquid water might exist. There is no evidence of water or life there, and no evidence that the signal came from the system.
What Did the Data Reveal?
The researchers developed machine-learning software to screen observations made in 2021. Of more than 139,000 initial detections, two stood out. One was ruled out as terrestrial interference. The other, at a frequency of about 1,148 MHz, was examined more closely. Its frequency, or the number of oscillations per second, changed over time, as it would if a source were moving relative to a receiver. A train whistle, for example, sounds different as a train approaches than as it moves away. This is the Doppler effect, and a transmitter on a moving planet could produce a similar shift in frequency.
Signs of Terrestrial Interference
The signal appeared only in the telescope’s central beam, aimed at K2-155. Nothing similar appeared in the other 18 beams, which scanned nearby regions of the sky. The telescope’s two reception channels, sensitive to different polarizations of radio waves, also recorded the signal at high intensity in only one channel. That could point to interference in the reception system itself. When the telescope was pointed at three other star systems, similar signals appeared at nearby frequencies. The researchers wrote in The Astronomical Journal that their findings do not establish the signal’s origin and that there are signs it came from human technology.
Questions & answers
Were aliens found?
No. The researchers could not determine the signal’s origin, and the available evidence points more strongly to human interference.
Why were researchers interested in the K2-155 star system?
Three planets larger than Earth orbit the star, and one lies near a region where liquid water might exist. There is currently no evidence of water or life there.