Fast radio bursts are among the strangest and powerful events in the universe. Despite thousands reportedly occurring every day only a couple dozen FRBs have ever been seen. Approximately 80 of these millisecond-long cosmic events have so far been detected, but their causes remain a mystery.
The universe looks quite alien when viewed outside of the visible spectrum.
We should be keeping our minds open both to how we try and interpret the signals and how we look for them
And such is the power of FRBs that if radio waves were visible to our eyes, these fast radio waves would be among the brightest lights in the entire sky.
Such is the incredible energy involved, it is equivalent to the amount released by the Sun in 80 years.
Vikram Ravi, a Caltech professor of astronomy who works with the radio telescopes at the Owens Valley Radio Observatory (OVRO), puts this almost incomprehensible power into context.
He told Express.co.uk: “The particular fast radio burst would be about as strong as a mobile phone about 10 metres away, if it was brought to the Milky Way.”
Fast radio bursts: FRBs are among the strangest and powerful events in the universe
Fast radio bursts: Only a couple dozen FRBs have ever been seen
Professor Ravi’s team was responsible for pinpointing the latest – FRB 190523 – to a particular galaxy 7.9 billion light years away.
This is important because identifying the areas from which these radio bursts belch is a crucial step towards solving the mystery of their cause.
There have been two localised FRBs announced in the last week: one by our Caltech team and another in Australia.
Both of these new discoveries are in galaxies of about the same mass and type as the Milky Way.
However, forming a likely hypothesis of their cause has been made more difficult due to their diverse origins.
Professor Ravi said: “The first FRB detection back in 2017 came from a much smaller galaxy which was forming stars much more rapidly.
“That tells us there are probably different channels making fast radio bursts because otherwise it is very weird to see such a dichotomy in the characteristics of these galaxies.”
The Caltech team currently think something most likely a highly magnetised, fast rotating neutron star is the cause.
FRBs: The Deep Synoptic Array-10 dishes, located at Caltech’s Owens Valley Radio Observatory
Fast radio burst: 80 of these millisecond-long cosmic events have so far been detected
However, Harvard University’s eminent Professor Abraham Loeb, a former colleague of Professor Ravi believes it is scientifically sound to speculate FRBs’ cause could have an intelligent alien cause.
He told Express.co.uk: “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.
“A small fraction of FRB sources repeat and the galaxies in which FRBs are found are both dwarf galaxies with young stars and giant galaxies with old stars.
“It is possible that we are looking at a mix of source populations.
“Until we find a smoking gun that would reveal the identity of FRB sources, we should keep an open mind and include all possibilities on the table.”
In a earlier 2018 study, Harvard’s Loeb had examined the possibility that fast radio bursts come from radio transmitters constructed by an advanced alien civilisation — perhaps evidence of powerful energy beams used to propel alien starships.
However, Professor Ravi disagrees with his former associate’s “specific” predictions, although allows it is important to keep an open mind.
He told Express.co.uk: “I think is it always good to keep an open mind, however Professor Loeb’s predictions for, for example leakage radiation from microwave-powered light sails, are quite specific.
FRB: Understanding where these radio bursts belch is a crucial step towards knowing their cause
“That said, doing these sort of searches for these very fast, very bright events – even just expanding the range of possible signals that we are sensitive to – is always an important thing to do, not just in the search for extraterrestrial intelligence, but also just to further our understanding of the universe.
“So by all means we should be keeping our minds open both to how we try and interpret the signals and how we look for them.
“We already think there are two ways of making fast radio bursts, both of which could well be related to expanded products of stellar evolution, but that is not to say these are the only two ways.
“There is a long, long way to go and we are only beginning to understand what they mean.