A repeating radio wave signal first seen early in 2019 continues to date. The cause remains a mystery, but that longevity may give a clue to its origin.
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The 180916.J0158+65 FRB is repeating radio signals from space coming and going every 16 days from one point in the sky, now continuing for over 500 days. The cause and the source remain astronomers with numerous mysteries.
Fast radio bursts (FRBs) are one form of a highly-energetic explosion in deep space, thought to be caused by small, massive objects. The exact nature of these objects is still in question.
The energy released in these explosions can outshine the entire galaxies in which they reside. But 180916.J0158+65 FRB events fade in a small fraction of a second.
It seems the source for this bursts is a region 500 million light-years from Earth – outside our Milky Way galaxy. The most active FRB yet detected, and one of the nearest to Earth is in an active star formation just outside a massive spiral galaxy.
A new study published in the journal Nature claimes that this fast radio bursts are likely a periodic event such as a rotating object. Another option is radio waves that may amplify on a regular repeating pattern. Chances that a repeating signal is a random event now seem slim.
Kiyoshi Masui, assistant professor of physics at MIT’s Institute for Astrophysics and Space Research, said:
“In 38 bursts recorded from 16 September 2018 to 4 February 2020 UTC, we find that all bursts arrive in a five-day phase window, and 50 percent of the explosions come in a 0.6-day [14 hours 24 minute] phase window. This cycle repeats once every 16 days, including four noisy days, followed by 12 days of silence.
“It’s the most definitive pattern we’ve seen from one of these sources. And it’s a big clue that we can use to start hunting down the physics of what’s causing these bright flashes, which nobody really understands.”
One possibility to examine is these events are caused by a single dense object like a neutron star. Periodic eruption might be the result of one of these ultradense stellar corpses wobbling while it rotates. This type of movement, called precession, can be seen as a toy top slows down.
Another idea holds that those radio blusts may occur in systems where one neutron star orbits another neutron star or a black hole. If the pair have orbits that bring them close to each other, the material may be passed from one body to another, triggering output of radio waves. This display would repeat each orbit, setting up the cycle seen by astronomers.
Another stranger idea holds that an object emitting powerful radio waves signal orbits a star surrounded by a dense atmosphere. With each orbit, the star passes through the gas cloud, temporarily magnifying the strength of the signal.
“Maybe the source is always giving off these bursts, but we only see them when it’s going through these clouds because the clouds act as a lens,” Masui explains.
Another theory postulates that the outburst may center around magnetars — neutron stars with powerful magnetic fields. These objects, although poorly understood, are known to release large amounts of radiation, including radio frequencies occasionally.
In late April 2020, a signal resembling an FRB spotted emanating from a magnetar, 30,000 light-years from Earth, as it erupted in flares. If confirmed by further research, this event could be the first FRB ever spotted within our galaxy. This finding would also lend significant evidence for the idea that magnetars are at the center of the mysterious fast radio bursts.
What are the chances that these radio signals from an extraterrestrial civilization? Not likely, say scientists. But the mystery remains unanswered.
