getty Astronomers have detected a radio signal from a distant galaxy that blinks for up to three seconds on a regular basis. At a distance of more than a billion light years, the signal is called FRB 20191221A and is classified as a “fast radio burst” – a radio pulse. About 1,000 times larger than most FRBs, FRB 20191221A is now the longest-lasting and most regular radio signal known in the entire night sky. It was detected using the CHIME radio telescope in British Columbia, Canada, which detected over 500 FRBs in its first year of operation. The results were published in Nature. Scientists believe the radio signal may be coming from a neutron star – what’s left of the core of a giant star that has collapsed after exploding as a supernova. Neutron stars rotate rapidly. Although the origin of FRBs is mysterious, we hope that the frequency of each one, and how they vary with distance from us, could tell scientists about the exact rate at which the universe is expanding. The first FRB was discovered in 2007. FRB 20191221A was first detected on December 21, 2019. “It was unusual,” said Daniele Michilli, a postdoctoral fellow at MIT’s Kavli Institute for Astrophysics and Space Research. “Not only was it very long, about three seconds long, but there were periodic spikes that were extremely precise, sending out every split second – boom, boom, boom – like a heartbeat.” Artwork depicting a fast radio burst. Magnetos are types of neutron stars that have extremely … [+] strong magnetic fields, trillions of times stronger than Earth’s field and even stronger than normal neutron stars. Recently, astronomers have suggested that asteroids may orbit some of these objects, leading to the emission of fast radio bursts (FRBs). The idea is that asteroids orbiting in the magnet wind – a stream of fast particles emitted from its surface – carve a wake in the wind, leading to the creation of an electric current around the wind. When the magnetar wind cuts through the wave, a magnetic disturbance is created that creates an extremely intense, narrow beam of radio energy. In 2020, astronomers detected the first FRB from a magnetar – called SGR 1935+2154 – located in our own galaxy. The whole event was over in a split second. getty So what could be the source of FRB 20191221A? “There aren’t many things in the universe that emit strictly periodic signals,” Michilli said. “Examples we know in our own galaxy are radio pulsars and magnetars, which rotate and produce a beacon-like beam emission. And we think this new signal could be a magnet or a pulsar on steroids.” Types of neutron stars a pulsar is a neutron star that emits beams of radio waves and appears to pulsate as the star rotates while a magnetar has extreme magnetic fields. The signal FRB 20191221A is a million times brighter than the pulsars and magnetars in our Galaxy. “From the properties of this new signal, we can tell that around this source, there is a cloud of plasma that must be extremely turbulent,” Michilli said. “Future telescopes promise to discover thousands of FRBs a month, and at that point we may find many more of these periodic signals.” I wish you clear skies and open eyes.
