The first burst was uncovered 11 years ago in 2007 and since then astronomers have added just dozens more examples to the list. But in the space of only a year researchers using the CSIRO’s Australian Square Kilometre Array Pathfinder in the Shire of Murchison have recorded 20 fast radio bursts, including one about 100 million light years away — the closest ever observed. What makes these bursts of radio energy so interesting is also what makes them so hard to study. They last milliseconds and leave no trace of their origin; a telescope will only capture them if it’s pointed in the right place at the right time. To boost their chances, the Australian researchers used eight ASKAP radio telescopes to create a “fly’s eye” view of a patch of night sky.

Curtin University senior lecturer Jean-Pierre Macquart, who led the project with researchers from the CSIRO and Swinburne University of Technology, said by studying the rate at which radiation “dribbled” in over the time bursts were observed, scientists could unearth clues as to their origin and their path to Earth. “Some of these bursts set off on their journey when the universe was about half its current age,” he said. As radiation from the bursts travelled across the intergalactic void certain wavelengths dispersed, or slowed down, meaning some reached Earth-based telescopes before others. The Australian Square Kilometre Array Pathfinder in the Shire of Murchison in Western Australia. Credit:ICRAR/Curtin University Not only does this dispersion give clues as to the distance the bursts travelled and the energy required to blast them across the universe, but by studying the patterns of dispersion created when the radiation hits gas and other matter on its journey, researchers hope to gain an insight into what lies in the vast space between galaxies.

The Australian team's research is published in the Nature Astronomy scientific journal this week. “These are very energetic events,” Swinburne University researcher Ryan Shannon said. “And one of the great mysteries of fast radio bursts is how they got so much energy in these bursts.” The energy is so intense, Dr Shannon said, that if it were released by our own sun it would be enough to instantaneously microwave enough popcorn to fill out to the far-flung gas planet Neptune. Dr Shannon said the research was a “very important finding in the field”, as it demonstrated dispersion in the radiation signal was caused by intergalactic gas and matter.

“This shows fast radio bursts will become a very valuable tool for studying the structure of the universe,” he said. How much stuff is out there in the universe, or more accurately how much isn’t out there, has puzzled physicists for years. Loading The puzzle is an “embarrassing” one, Dr Macquart admits because when all observable matter — stars, planets and the like — is tallied, scientists come up short. Dark matter and dark energy are the names given to material and forces at play in the universe astronomers can’t directly observe, but their presence is inferred by the gravitational effect they have on stars and galaxies.

The figure doesn’t correlate with what’s seen when astronomers look at galaxies and the forces holding them together and pushing them across the night sky. Astronomers hold the theory that, as big stars throw out stellar winds or eventually explode, material is ejected from galaxies into the intergalactic void. “It’s a process called feedback, where eventually galaxies get to a certain size, and then they just stop growing,” Dr Macquart said. “And it’s these limiting processes that apparently stop them growing, and so if we can see all of this matter that’s being expelled out into the intergalactic medium, we can get a handle on how that actually operates. “It’s an embarrassing problem — we don’t know what dark energy is, we don’t know what dark matter is, but we can’t even find half of the stuff that ought to be easy to find.

“And it’s all because it sits out there, we think, in this very tenuous medium at a temperature which makes things very difficult to find.” But while the new data opens windows to our cosmic neighbourhood, just what exactly creates the powerful bursts is an enduring mystery. Loading Rapidly spinning cores of dead stars throwing out radio waves, known as pulsars, had been floated as potential sources, as had merging black holes or neutron stars — violent, explosive events that literally warp the fabric of space itself. However Dr Macquart said pulsars were too weak to blast out the kind of radiation observed in fast radio bursts, and black holes and neutron star mergers didn’t happen often enough to account for the bursts.