It may be hard to miss, but unimaginably strong bursts of cosmic radiation happen possibly a thousand times every day. They are bright enough to overwhelm our radio telescopes from billions of light-years away.
However, fast radio bursts (FRBs) were not detected until 2007. Despite over a decade of investigation, they remain one of the most intriguing mysteries in astrophysics. Recent research offers new and promising clues about their origins, while also revealing why these space phenomena are so perplexing in the first place.
When FRBs were first discussed in seminars, the big question wasn’t “What astrophysical cause is causing this?” Instead, it was, “Isn’t this just a mechanical failure?”
FRBs last about 1 millisecond and spread out in frequency in a manner very similar to a blip from a pulsar. But the problem is, they don’t come from any known pulsars, they don’t repeat like pulsars, and they’re clearly much more powerful than any pulsar pulses we’ve seen before.
To make matters worse, for many years the only telescope that observed FRBs was the Parkes Observatory in Australia. The debate became even more heated when it turned out that some of the FRB-like bursts observed by Parkes did not come from astronomical sources.
These bursts, called “peritons,” were always suspected to be of terrestrial origin. But clever detective work by astronomers solved the case. Dr. Emily Petrov and her colleagues showed that Periton had a strong correlation with local lunchtime. In reality, radiation leaked from the observatory’s microwave when the door opened too early.
It was eventually revealed that the FRBs were indeed from far away in space. More radio telescopes were configured to record very short bursts of radio waves, and detection rates began to skyrocket.
Those bursts came from all over the sky, suggesting they didn’t originate in our galaxy. In the first decade after the discovery, theorists produced a huge number of papers explaining the possible origins of the bursts.
In 2012, repeated FRBs were discovered, ruling out origins requiring complete destruction, such as supernovae. It was soon discovered that there were many more repeated bursts, mostly occurring at irregular intervals.
As more outbursts are discovered, there is growing evidence that FRBs may be associated with extraordinarily powerful magnetars: neutron stars that rotate in extremely strong magnetic fields.
Recent evidence suggests that at least some FRBs originate from nearby spiral galaxies rather than elliptical galaxies.
Astronomers will need to continue collecting clues, looking for suggestive patterns in the data, and eagerly awaiting observational upgrades that will allow them to pinpoint the FRBs’ local environment.
Whatever the outcome, the fast radio burst is a great example of the fact that in science, when we look at the universe in new and different ways, we almost always discover something surprising that no one had ever thought to look for.
Source: www.sciencefocus.com
