Solved the mystery of the strange radio signal picked up in 2019

Two studies have identified what caused the signal picked up in the direction of Proxima Centauri. No alien origin, but only an interference produced by terrestrial technologies.

A mysterious radio signal had been picked up in 2019 in the direction of Proxima Centauri by the Breakthrough Listen Project. There were many hypotheses about what could have caused it, with many who already gave for certain the alien origin and predicted a possible contact with alternative life forms to Earth, but now two studies have revealed the truth (and turned off the enthusiasm of many): the signal was caused by interference produced by terrestrial technologies. Both researches have been published in Nature Astronomy.

The radio signal picked up in 2019

On April 29, 2019, the Parkes radio telescope in Australia had detected a radio signal called Blc1 (Breakthrough Listen Candidate 1). It had been named precisely because it was believed to be the first, true, candidate extraterrestrial signal picked up by the Breakthrough Listen Project, an ambitious $100 million privately funded program to look for signs of technologies developed by alien intelligences. Blc1 persisted for as long as five hours in the observations and was present only in the direction of Proxima Centauri.

Studies revealing what caused the radio signal

The new studies compared Blc1 with 60 other signals, both local and human-generated, and eventually dashed hopes that we might be looking at an alien message. The observations showed that, again, we were dealing with "man-made radio interference from some technology on the surface of the Earth," explained Sofia Sheikh, an astronomer at the University of California at Berkeley and co-author of both studies.

Although the researchers could not pinpoint the specific source that emitted the signal in 2019, it is very likely that it was caused by a malfunction of some electronic instrument - for example, from oscillators that are commonly used in computers, phones and radios - that was located a few hundred kilometers away from the telescope. The discovery allowed the researchers to improve their techniques for unmasking "false positive" signals and to develop a useful decalogue for future observations of the Parkes telescope and other instruments as well.

Recently, however, a mysterious radio signal also arrived from Venus, while a group of scientists detected an unprecedented number of fast radio flashes. Another radio signal has finally been found at the center of our galaxy.

Stefania Bernardini