A lucky moment has helped astronomers solve a cosmic mystery: What causes powerful but fleeting radio explosions that can zigzag and zigzag through space?
Scientists have been aware of these energy pulses – known as rapid radio bursts – for about 13 years and have seen them coming from outside our galaxy, which has led to tracing the cause. they become more difficult. What’s even more difficult is that they happen so quickly, in just a few milliseconds.
Then this April, a rare but significantly weaker explosion that originated from within our Milky Way was discovered by two different telescopes: a set of manual antennas from a study. lifesaving in California, including actual cake pan, the other being a Canadian $ 20 million observatory.
They tracked that fast radio explosion to a strange star called a magnet 32,000 light years from Earth, according to four studies in the journal Nature on Wednesday.
This is not only the first fast radio explosion to originate from a single source, but the first to emanate from our galaxy. Astronomers say there might be other sources for these explosions, but now they̵7;re sure of the sinful side: magnetic fields.
Magnets are incredibly dense neutron stars, with a mass 1.5 times the mass of our sun being pressed into a space the size of Manhattan. According to McGill University astrophysicist Ziggy Pleunis, co-author of the Canadian study, they have enormous magnetic fields that emit squeaking and crackling sounds, and sometimes X-rays and radio waves erupt from them.
The magnetic fields around these magnets are “so strong that any nearby atoms are ripped apart and strange aspects of fundamental physics can be seen,” said astronomer Casey Law of the California Institute of Technology. people not participating in the study, said.
There may be about a dozen of these magnets in our galaxy, obviously because they are too young and are part of the star formation process, and the Milky Way doesn’t have as many stars born as galaxies. Another, Shami Chatterjee, Cornell University, said. do not belong to any discovery group.
This less than a second explosion contains the same amount of energy our sun produces in a month, and is still much weaker than radio explosions discovered coming from outside our galaxy, radio astronomer Christopher Bochenek of Caltech said. He helped detect explosions with the manual antenna.
These radio explosions do not pose a danger to us, or even more powerful ones from the outside of our galaxy, astronomers say.
Things that come from outside our galaxy and travel millions or billions of light-years are “tens of thousands to millions of times stronger than anything we have found in our galaxy”, co-author Daniele Michilli, astrophysicist at McGill and part of the Canada team.
Scientists think these happen so often that they can happen more than 1,000 times per day outside of our galaxy. But finding them is not easy.
“You have to look at the right place at the right millisecond,” says Cornell’s Chatterjee. “Unless you’re very, very lucky, you won’t see either of these.”
Although this is a frequent phenomenon outside the Milky Way, astronomers don’t know how often these explosions occur within our galaxy.
“We still don’t know how lucky we have been,” Bochenek said. “This could be something that happens once every five years or maybe a few events happen every year.”
Bochenek antennas cost around $ 15,000. Each one is “the size of a large bucket. It was a 6-inch long metal tube with two pans surrounding it, ”said the graduate student. They are primitive tools designed to look at a giant portion of the sky – about a quarter of it – and see only the brightest rays of radio light.
Bochenek thinks he might have a 1 in 10 chance of spotting a rapid radio explosion in a few years. But after a year, he returned his salary.
The Canadian Observatory in British Columbia is more concentrated and refined but targets a much smaller part of the sky, and it can accurately pinpoint the source of magnetic field in the constellation Vulpecula.
Since explosions are affected by all the matter they pass through in space, astronomers can use them to better understand and map invisible matter with us between galaxies. and cosmic “scales,” said Jason Hessels, head of astronomy team at the Dutch Institute of Radio Astronomy, who was not involved in the study.
Astronomers have had 50 different theories about the cause of these fast radio bursts, including aliens, and they stressed that magnetic fields may not be the only answer. Especially since there appear to be two types of rapid radio explosions. Some, like the case discovered in April, happen only once, while others repeat it regularly.
Michilli says his team has been watching an explosion every 16 days in a nearby galaxy and is getting closer to traceability.
Some of these young magnets are only a few decades old, “and that’s what gives them enough energy to create fast, repetitive radio explosions,” says Cornell’s Chatterjee.
Tracking a single outbreak is a welcome surprise and a key finding, he said.
“Nobody really believed we were so lucky,” said Chatterjee. “To find one of our galaxy, it just needs to put the cherry on top.”
Follow Seth Borenstein on Twitter at @borenbears.
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