Astronomers have noticed a strange radio signal from a distant galaxy. Scientists’ discovery may finally help pinpoint the source of fast radio bursts (FRBs).
Most FRBs, which can be described as bursts of strong radio waves from galaxies billions of light-years away, last only a few milliseconds before fading. This new signal – FRB 20191221A – can last up to three seconds, thousands of times longer than average FRBs, and also shows the clearest repeating pattern yet discovered.
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“It was unusual” said Daniele Michilli, a researcher at the Massachusetts Institute of Technology’s Kavli Institute for Astrophysics and Space Research. “Not only was it very long, lasting about three seconds, but there were periodic spikes that were remarkably precise, radiating out in fractions of a second — boom, boom, boom — like a heartbeat. This is the first time the signal has been repeated” he added.
In the future, researchers will try to detect additional bursts from the same source, which could help to more conclusively reveal what causes these FRBs.
They also hope that FRB 20191221A can be used as a kind of “astrophysical clock” thanks to its extremely reliable periodicity.
Because the frequency of this burst changes as the source moves away from Earth, the changes could be used to measure the expansion of the universe.
Since their discovery in 2007, FRBs have been a mystery to astronomers, who have been able to trace these bursts back to their galaxy of origin, but have been unable to pinpoint the exact source of the emission.
According to scientists, the objects responsible for emitting FRBs may be types of neutron stars called radio pulsars and magnetars Space.com reported about it.
“There aren’t many things in the universe that emit strictly periodic signals” Michilli said. “Known examples in our own galaxy are radio pulsars and magnetars, which rotate and emit lighthouse-like beams. We think this new signal could be a steroid magnetar or pulsar.”
Pulsars are neutron stars that spin rapidly and emit intense radiation, while magnetars are stellar remnants with extremely strong magnetic fields. All types of neutron stars form when massive stars reach the end of their lives, run out of fuel for nuclear fusion, and can no longer sustain themselves against gravitational collapse. This results in a massive supernova explosion that leaves behind a cosmic remnant, a neutron star so dense that a teaspoon’s component weighs 3.9 trillion kilograms.
Studying FRB 20191221A could help astrophysicists better understand these objects in general.
The cover photo is an illustration.
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