A strange burst of radio waves from outer space exhibited rhythm. During the few seconds in December 2019 during which the burst was noticed, it maintained a constant rhythm. This tempo provides insight into the possible origin of the mystery outburst, which belongs to the class of radio flares known as rapid radio bursts.
The vast majority of the hundreds of previously detected rapid radio bursts endure only milliseconds. Daniele Michilli and colleagues report on July 14 in Nature that this one endured for nearly three seconds. Multiple short pulses were repeated approximately every two-tenths of a second.
Scientists have witnessed repeating radio bursts with a delay of minutes or days. With this one, it was a sequence of pulses, like a heartbeat. An astronomer from the University of Nevada, Las Vegas named Bing Zhang who was not involved in the study claims that this is what sets the short radio burst apart. Quick radio bursts have been detected in the past, but “this is a completely separate species.”
Scientists still do not know how quickly radio bursts are formed, but evidence is mounting that they are related with neutron stars and, in particular, magnetars, which are highly magnetic neutron stars (SN: 6/4/20). This burst was found by the Canadian Hydrogen Intensity Mapping Experiment, a radio telescope in British Columbia. The consistent repeat rate suggests what may have triggered this explosion.
These pulses, which like a metronome, are produced by only a limited range of astronomical events. For instance, neutron stars can give off radio waves that can periodically blow past Earth, giving the impression that the star is pulsing as it rotates. Similar to the pulsating rapid radio burst, neutron stars have their own rhythms. The explosion was far brighter than typical neutron star pulses, suggesting that the radiation was magnified by some unknown process.
According to a second theory, large outbursts on magnetars could set off starquakes that jolt the stars’ solid crusts, resulting in consistent radio wave barrages. The pulsing of the rhythmic burst is consistent with a frequency with which magnetars could be shaking, according to astrophysicist Cecilia Chirenti of the University of Maryland, College Park, who was not involved in the current study.
Alternatively, the pulsing could be caused by two neutron stars that orbit one another. When the magnetic zones surrounding each neutron star interact, outbursts may occur at regular intervals along the orbit. Scientists are uncertain as to whether all fast radio bursts are produced in the same manner. This anomaly may have a different origin narrative than more typical one-off explosions. According to Zhang, this makes it difficult to draw conclusions about other quick radio bursts. I would not simply extrapolate from this situation to the other individuals.