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Hundreds of mysterious radio bursts detected from deep space


Radio bursts have been picked up coming from the far off reaches of space Credits: PA)

Mysterious radio bursts are coming from space, say scientists.

A new telescope has detected more than 500 of the signals – during its first year of operation.

They have been blamed on black holes, stars colliding – or even an alien civilisation trying to contact Earth.

Fast Radio Bursts (FRBs) are very short but very intense pulses of radio waves.
They were only discovered in 2007 – but their origins remain unknown to astronomers.

It’s hoped the CHIME instrument in Canada will soon get to the bottom of the phenomenon.

With more observations, astronomers should be able to pin down the precise cause of the extreme and curiously bright beams.

Team member Kaitlyn Shin, a physicist at MIT (Masachusetts Institute of Technology) in the US, said it nearly quadruples the number to date.

She said: ‘Before CHIME, there were less than 100 total discovered FRBs. Now, after one year of observation, we’ve discovered hundreds more.

‘With all these sources, we can really start getting a picture of what FRBs look like as a whole, what astrophysics might be driving these events and how they can be used to study the universe going forward.’

To catch sight of one is to be extremely lucky. The odd flashes of light blaze for a few milliseconds – before vanishing without trace.

They register in the radio band of the electromagnetic spectrum. A telescope has to be point in the right place – at exactly the right time.

The brief beacons have been spotted in various and distant parts of the universe – as well as in our own galaxy. They are utterly unpredictable.

Now, the large stationary radio telescope in British Columbia has caught 535 new FRBs in just 12 months from 2018 to 2019.

The Andromeda Galaxy. (Credits: Russell Atkin / SWNS.COM)

The results from CHIME (Canadian Hydrogen Intensity Mapping Experiment) were presented at the virtual American Astronomical Society Meeting.

They are already yielding clues. The bursts fall into two distinct categories – those that repeat, and those that don’t.

Scientists identified 18 FRBs in the former – while the rest appear to be one-offs.
The repeaters also look different with each lasting slightly longer and emitting more focused radio frequencies than single cousins.

It suggests they arise from separate mechanisms and astrophysical sources.

The machine comprises four massive parabolic radio antennas – roughly the size and shape of snowboarding half-pipes.

It receives radio signals each day from half of the sky as the Earth rotates.

Most radio astronomy is done by swivelling a large dish to focus light from different parts of the sky.

CHIME stares, motionless – and focuses incoming signals using a correlator.

The powerful digital signalling processor works at about seven terabits per second – equivalent to a few percent of the world’s internet traffic.

Dr Kiyoshi Masui, also from MIT who led the group’s conference presentation, said: ‘Digital signal processing is what makes CHIME able to reconstruct and ‘look’ in thousands of directions simultaneously.

‘That’s what helps us detect FRBs a thousand times more often than a traditional telescope.’

Mapping showed the bursts were evenly distributed in space – seeming to arise from all parts of the sky.

The researchers calculated for the first time about 9,000 a day occur across the entire sky.

Dr Masui said: ‘That’s kind of the beautiful thing about this field – FRBs are really hard to see, but they’re not uncommon.

‘If your eyes could see radio flashes the way you can see camera flashes, you would see them all the time if you just looked up.’

Interstellar gas, or plasma, can distort a burst as they travel across space.

The degree to which it is dispersed can reveal how much gas it passed through – and the distance it has travelled from its source.

For each of the 535 FRBs, the researchers found most likely came from far, far away – within distant galaxies.

The fact they were bright enough to be ‘seen’ suggests they must have been produced by extremely energetic sources.

As the telescope detects more, the scientists plan to pin down exactly what kind of exotic phenomena could generate such ultrabright, ultrafast signals.

Ms Shin, a PhD student, said: ‘Each FRB gives us some information of how far they’ve propagated and how much gas they’ve propagated through.

‘With large numbers of FRBs, we can hopefully figure out how gas and matter are distributed on very large scales in the universe.

‘So, alongside the mystery of what FRBs are themselves, there’s also the exciting potential for FRBs as powerful cosmological probes in the future.’


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