The unexplained radio signals only last a fraction of a second and have been dubbed by astronomers Fast Radio Bursts or FRBs. The first radio burst was encountered in 2007 after Australian researchers found an anomaly in a 2001 dataset. Since then, astronomers have nearly 100 more of the short-lived radios signals including ones that repeat themselves. The discovery has led scientists to speculate whether the FRBs are natural in origin or an attempt to communicate by an alien species.
What are Fast Radio Bursts? Where do they come from?
There is no scientific consensus on the origin of these enigmatic radio bursts.
Most FRBs, with the exception of repeaters, only last a millisecond, making it incredibly hard to trace them back to a definite source.
FRBs are also pretty weak and have been compared to the signal emitted by a phone dropped on the surface of the Moon.
But in June this year, astronomers made a groundbreaking discovery when they traced back an FRB to its home galaxy.
The radio blast was found to have originated on the outskirts of a galaxy approximately four billion light-years away.
Radio signals from life: Mysterious radio signals have been detected on Earth (Image: GETTY)
Could FRBs be evidence of past alien life?
Because of the distances FRBs travel before they can reach the Earth, the likelihood of them being transmitted by an alien civilisation is incredibly small.
There are, however, some who believed the radio signals are evidence of alien spacecraft or long-gone civilisations in neighbouring galaxies.
But with very little evidence to support the theory, the Search for Extraterrestrial Intelligence (SETI) Institute thinks the signals can be explained by natural phenomena.
When astronomers in Canada found a new repeater FRB in January this year, the SETI institute joined the debate about their origin.
Seth Shostak, a senior astronomer at SETI, said: “Obviously, there’s fame and tenure awaiting anyone who can figure out exactly what powers fast radio bursts. But could it be that these signals are due to aliens?
I doubt it will be aliens
Seth Shostak, SETI Institute
“Probably not, especially when you look at astronomical history. Aliens are frequently given the credit for causing new celestial phenomenon.
“A half-century ago, Soviet scientists suspected that quasars were actually signals broadcast by highly advanced societies far, far away.
“In the 1960s, British radio astronomers temporarily referred to pulsars as Little Green Men.”
A key clue as to why FRBs are not alien in origin, the SETI Institute said, is the radio signals appears all over the sky.
If FRBs come from galaxies billions of light-years away, they need to powered by incredibly powerful sources of energy.
Astronomers speculate these could be black holes colliding with one another or neutron stars.
Aliens broadcasting short-lived messages across the cosmos are incredibly unlikely.
Mr Shostak said: “I think you can reckon on some clever theoretician coming up with an explanation for these bizarre phenomena within a year or two. I doubt it will be aliens.”
However, some astronomers believe the alien hypothesis should not be discounted without any concrete evidence either way.
Professor Abraham Loeb from the University of Harvard told Express.co.uk an alien origin for FRBs is still on the table.
He said: “We still have no new clue on whether the origin is artificial or natural.
“The origin of FRBs is still a mystery. The data at hand is not sufficient to reveal the identity of their sources.”