Scientists have detected a strange radio signal in space that resembles a heartbeat. Astronomers estimate that it comes from a galaxy about a billion light-years away, although the exact location and cause of the eruption are still unknown. A study about this was published in the journal Nature on July 13.
Fast radio bursts (FRBs) are intense bursts of radio waves that last for milliseconds. Their origin is unknown. The first FRB was discovered in 2007, and since then we have witnessed hundreds of similar events.
Many FRBs emit very bright radio waves for a few milliseconds at most, which soon fade completely. As far as we know, they are repeated with some regularity in only 10% of cases. Consequently, the phenomenon is so short-lived and sudden that it is quite difficult to observe it.
One of the instruments used to detect such radio signals is the CHIME telescope. It constantly monitors the sky and, along with FRBs, is also sensitive to radio waves emitted by hydrogen in the distant universe.
Astronomers using CHIME on December 21, 2019, observed a multifaceted unusual radio signal, later named FRB 20191221A. It lasted for about three seconds, which is a thousand times longer than the duration of a typical FRB. Consequently, the signal they observed is the longest-lasting FRB to date.
“It was unusual. Not only did it last for a very long time, but it also had distinct periodic peaks at intervals—boom, boom, boom—like a heartbeat,” says Daniel Mitchell, a researcher at the Massachusetts Institute of Technology, MIT. when the signal itself is periodic”.
Although FRB 20191221A has not yet repeated itself, the signal is produced by successive peaks that are about 0.2 seconds apart.
According to Michil, the research team still does not know exactly which galaxy the signal came from. Their estimated distance is also quite inaccurate. While CHIME is good at finding radio signals, it isn’t nearly as good at locating their starting points.
Nevertheless, according to the scientist, as part of the future project, CHIME will observe the sky together with several other telescopes in order to attribute the radio signals to specific galaxies. It should also be taken into account that there are still some hints about the origin of the signal and the reasons for its generation.
The team of researchers will continue to observe through CHIME, so that additional or simply similar periodic signals from this radio burst do not escape. It is possible that the frequency of radio waves and the regularity of their variation will help astronomers to understand more about the expansion rate of the universe.