“It’s not often that scientists get to discover and study a brand new phenomenon; a fresh new puzzle to talk about,” says McGill astrophysicist, Victoria Kaspi. “It’s currently an open mystery.”
Scientists have, for decades, been observing mysterious bursts of powerful emissions–some discharging more energy than 500 million Suns–coming from far beyond our own Milky Way galaxy. They call them fast radio bursts–or FRBs.
“We really don’t know what fast radio bursts are…” says Kaspi.
The signals last just a few milliseconds and are sourced billions of light-years away. They initially seemed to be one-off events, leading experts to speculate that they could be neutron stars collapsing into black holes.
However the mystery deepened in 2016, when researchers discovered a repeating FRB signal in the star-forming region of a dwarf galaxy three billion light-years away.
The main problem has been that conventional telescopes could only observe a miniscule portion of the sky at any one time. This left it up to luck to catch an FRB when it went off.
“We think they’re going off something like 1000 times across the whole sky each day, but you never know in what direction,” says Kaspi.
Without the ability to observe a large area of the sky, deep study of the phenomena was impossible.
Luckily, a new revolutionary telescope called CHIME (Hydrogen Intensity-Mapping Experiment) was completed in British Columbia in a scientific collaboration, giving scientists new hope.
Instead of focusing on a single point in the sky, CHIME gathers radio signals along a broad range, running from north to south.
“CHIME was originally designed to explore the history of the universe and help us understand our energy,” says McGill astrophysicist, Matt Dobbs. “It turned out to be an ideal design to discover fast radio bursts as well.”
CHIME can see around 1000 times more of the sky at one time, compared to conventional telescopes. Each night, it can record the entire northern sky as the Earth rotates, allowing scientists to catch between a few, and a few dozen FRBs.
What CHIME observes will be processed as it’s gathered. The amount of data is huge–as much as all the data flowing around the entire global mobile networks.
But accurate detection is difficult, since a flash burst of radio waves spreads out by the time it reaches the Earth.
“For the very brightest ones though, we are going to be able to record a small snippet of data right around the pulse,” says UBC astronomer, Ingrid Stairs.
“We’re going to then be able to dig into it on really short time scales, and hopefully that’ll help us to figure out a little bit more about how these bursts are emitted at their source–whatever the sources might be,” she adds.
Scientists on the team say they feel excited and privileged to be able to make progress on this astrophysical mystery of the universe.
“We’re really looking forward to making great progress on two hot scientific topics: Dark Energy and fast radio bursts,” says McGill astrophysicist, David Hanna.
And exciting progress is indeed being made.
Brand new discoveries were welcomed last week on April 28, when scientists recorded, for the first time, an FRB coming from a magnetar right within our own Milky Way galaxy–around 30,000 light-years away.
It flared with a single, millisecond-long burst of incredibly bright radio waves–a signal so powerful that CHIME’s system couldn’t quite quantify it. It was also caught emitting X-ray and gamma rays.
“Something like this has never been seen before,” said astronomer Shrinivas Kulkarni of Caltech, according to ScienceAlert.
“This sort of–in most people’s minds–settles the origin of FRBs as coming from magnetars,” he continued.
Scientists have yet to complete analysis of the burst’s spectrum to see if it’s similar to the spectra of the extragalactic FRBs. But even so, the origins of FRBs may turn out to be numerous.
One source of FRBs was even found to be repeating on a 16-day cycle–only further deepening the sense of unknown.
For now, the phenomena remains a mystery–a mesmerising puzzle that’s gripping the scientific community.