The mystery of repetitive radio signals hitting the Earth

The Earth’s magnetic field protects it from the continuous interactions that come from deep space, in the form of cosmic rays. This common bombardment is made up of radio and microwave signals emitted by distant stars, black holes, and other celestial bodies. But there is an intergalactic light signal that is puzzling scientists and their measuring instruments.

These are ultra-strong and ultra-bright radio signals, known as fast radio waves (FRBs). They last only a few milliseconds and are believed to originate billions of light years away. But what is most puzzling is that its precise source is still unknown.

The new results (announced on January 9 in two articles in the journal Nature, and at the 233rd meeting of the American Astronomical Society in Seattle), account for 13 new detections of these FRB signals, which has increased the population. known by 20 percent.

An animation shows the random appearance of fast radio bursts (FRB). Astronomers recently discovered 13 of the mysterious signals, including one that was repeated from the same location for several months. Credit: NRAO Outreach / T. Jarrett (IPAC / Caltech); B. Saxton, NRAO / AUI / NSF

Its origin is an enigma for scientists

The discovery team analyzed observations from the Canada Hydrogen Intensity Mapping Experiment (CHIME), a new advanced radio telescope in the Okanagan Valley in British Columbia.

The radio emissions are so intense that CHIME was not even operating at full capacity when it made the new detections. All 13 FRBs were detected over the course of a few weeks in July and August 2018, with the last of their six known flashes observed in late October.

FRBs are as enigmatic as they are spectacular. The emissions, lasting only a few milliseconds, release the energy equivalent to 100 years of our Sun.

And, if there are powerful emissions continually coming from deep space, why are FRBs so mysterious?

Since astronomers first discovered them in 2007, only about 60 have been observed. But now, those numbers are growing rapidly.

Two sources have been detected , still unknown , from which these cosmic rays come. The first repeater, known as FRB 180814.J0422 + 73, is located about 1.5 billion light years from Earth, astronomers determined. It’s twice as close as the other repeater, FRB 121102, which is known to have fired dozens of bursts in recent years.

Canada’s CHIME radio telescope (seen at night here) recently detected 13 mysterious fast radio bursts (FRBs), including only the second repeating FRB. Credit: Courtesy of the Canadian Hydrogen Intensity Mapping Experiment (CHIME)

What is the explanation for these flashes?

Although their provenance is still unknown, scientists believe they can rule out some origins : These repetitive signals flashed from the same location six times over the course of several months. According to the study authors, this delayed repetition rules out cataclysmic events, such as supernovae, as a likely source of the repeated outbursts, as explosions from an exploding star would be expected to occur only once.

Astronomers have offered a number of possible explanations for the explosions, some of them natural, such as merging neutron stars; Nor can it be ruled out that they come from advanced alien civilizations.

But let’s not get excited. Most likely, the phenomenon has a natural explanation.

Furthermore, the new discoveries from the CHIME team suggest that FRBs are probably much more common than current technology may reflect. In other words, they probably have a natural origin that human technology is simply not able to detect yet.