They are fleeting bursts of radio waves that flash across the universe in just a few milliseconds before disappearing almost as soon as they appeared.
But, for the first time, astronomers have detected these short bursts of radio waves repeatedly coming from the same location far beyond our own galaxy.
The source of these ‘fast radio bursts’, as they are known, has baffled scientists since they were first detected in 2007.
Previously all of these bursts have appeared to be one-off events caused by an as yet unidentified event in deep space.
However, the latest findings have brought scientists closer to identifying the source of these mysterious signals.
The latest fast radio bursts to be spotted appear to come from an ‘extremely powerful object’ which occasionally produces multiple bursts in under a minute.
Professor Jason Hessels, an astronomer at the University of Amsterdam and the Netherlands Institute for Radio Astronomy who led the research team, said they hoped to use the direction the pulses are coming from to pin down what might be creating them.
He said: ‘Finding the host galaxy of this source is critical to understanding its properties.
‘Once we have precisely localised the repeater’s position on the sky, we will be able to compare observations from optical and X-ray telescopes and see if there is a galaxy there.’
Previously, scientists have suggested fast radio bursts may be caused by cataclysmic incidents that destroy their source.
These could include a star exploding in a supernova or a neutron star collapsing into a black hole.
However, the new discovery, published in the journal Nature, suggests some fast radio bursts may have another, more permanent origin.
The signal was spotted by astronomers sifting through data from the Arecibo radio telescope in Puerto Rico, the world’s largest radio telescope.
Captured between May and June, the signal showed several bursts with properties consistent with another fast radio burst detected in 2012.
Paul Scholz, an astronomer at McGill University who first spotted the signal, said the repeating signal was ‘exciting’.
He said: ‘I knew immediately that the discovery would be extremely important in the study of fast radio bursts.’
In total, he and his colleagues found 10 new fast radio bursts.
The researchers said the bursts must have come from a ‘very exotic object’, such as a rotating neutron star with unprecedented power.
It is possible the finding represents the first discovery of a sub-class of the cosmic fast-radio-burst population.
‘Not only did these bursts repeat, but their brightness and spectra also differ from those of other fast radio bursts,’ said Dr Laura Spitler, lead author of the study at the Max Planck Institute for Radio Astronomy in Bonn, Germany.
Fast radio bursts are thought to originate in distant galaxies based on measurements of an effect known as plasma dispersion.
Pulses that travel through the cosmos are distinguished from man-made interference by the influence of interstellar electrons, which cause radio waves to travel more slowly at lower radio frequencies.
The 10 newly discovered bursts, like the one detected in 2012, have three times the maximum dispersion measure that would be expected from a source within the Milky Way.
However, the discovery contradicts the results of another study published in Nature last week.
That research found that fast radio bursts are related to cataclysimic events such as short gamma-ray bursts which can’t generate repeat events.
Professor Victoria Kaspi, an astrophysicist at McGill University, said: ‘However, the apparent conflict between the studies could be resolved, if it turns out that there are at least two kinds of fast radio burst sources.’