Are aliens trying to contact Earth? Scientists discover twisted fields around a fast radio burst – in breakthrough that could finally reveal the source of the mysterious signals
- Fast radio bursts have been hot topic in astronomy since discovery 15 years ago
- Now an international team of scientists think they have established their origins
Mysterious radio signals have been a hot topic in astronomy ever since their discovery hinted that aliens might be trying to contact Earth.
These oddly bright flashes of light, registering in the radio band of the electromagnetic spectrum, appear temporarily and randomly from space.
Known as fast radio bursts (FRBs), they were first detected just 15 years ago but scientists have never known where they originate from.
Now, an international team of experts has made a breakthrough that could finally offer clues to the source.
They say one such FRB known as 20190520B likely originates from a binary system on the outskirts of a metal-poor dwarf galaxy nearly 3 billion light-years from Earth.
Mysterious: Scientists say a fast radio burst (FRB) known as 20190520B appears to be coming from a ‘compact object’ which is next to a massive star with strong stellar winds (depicted)
It is unclear exactly what is the source – raising the prospect that extraterrestrial life might be responsible – but it appears to be coming from a ‘compact object’ which is next to a massive star with strong stellar winds.
Unusual FRB lasts up to three seconds – 1,000 times longer than the average – READ MORE
Signal-labelled FRB 20191221A is currently the longest-lasting FRB
Scientists involved in the new study said the object could be a black hole or highly magnetised neutron star – known as a magnetar – although neither theory quite fits ‘when considering all the data’.
They came to their conclusion after discovering that the FRB twice changed its signal in dramatic fashion while they were analysing it.
The only explanation for this, the experts said, is that the magnetic fields surrounding it must have been reversed or twisted by a ‘turbulent’ force.
They believe that to have produced something ‘as messy as a ball of wool’ the signal must have passed through ‘the dense and variable stellar wind of a companion star’ relatively close to its source.
Some FRBs seem to be one-off events, which is why a catastrophic explosion such as an extreme supernova was thought to be a possible explanation for them.
But less than 5 per cent of the hundreds spotted have been seen to repeat, occasionally on a regular pattern.
FRB 20190520B was the first persistently active repeating FRB ever discovered.
It was the focus of the new study and was analysed by researchers at the National Astronomical Observatories of the Chinese Academy of Sciences (NAOC) and West Virginia University using the Parkes Telescope in Australia and the Green Bank Telescope in the US.
In their paper the scientists said they had discovered ‘turbulent magnetic fields surrounding the repeating FRB’.
‘This observation suggests that the pulses of radio wave emission may come from a compact object accompanied by a binary companion with strong stellar winds,’ they added.
Conclusion: Scientists involved in the new study said the object could be a black hole or highly magnetised neutron star – known as a magnetar – although neither theory quite fits ‘when considering all the data’
The researchers claimed that a neutron star or black hole might be the source as both had previously been found in binary systems with companions that have massive stellar winds.
One such example is SS433, which is associated with a supernova-like radio nebula, W50.
However, when pouring over all the data they said neither theory quite fits, meaning more research is needed.
Dr Li Di and his team from the NAOC now want to learn more about the magnetised environment surrounding FRBs in the hope of taking another step forward in their understanding of where exactly these signals come from.
FRBs – described as ‘brief and mysterious beacons’ – have been spotted in various and distant parts of the universe, as well as in our own galaxy.
Not only are their origins are unknown but their appearance is also unpredictable.
Previous observations strongly suggest that repeaters and one-offs arise from separate mechanisms and astrophysical sources.
As radio waves travel across space, any interstellar gas or plasma along the way can distort or disperse the wave’s properties and trajectory.
The degree to which a radio wave is dispersed can give clues to how much gas it has passed through, and possibly how much distance it has travelled from its source.
Most of the bursts flare just once and are then never seen again – making them impossible to predict, according to astronomers.
Some show repeat activity, but until recently that was found to be completely random.
The presence of a regular sequence in the burst activity could imply that the powerful bursts are linked to large-scale cosmic phenomenon.
These could include the orbital motion of a massive star, a neutron star in a binary system or a black hole.
The new study has been published in the journal Science.
FAST RADIO BURSTS ARE BRIEF RADIO EMISSIONS FROM SPACE WHOSE ORIGIN IS UNKNOWN
Fast radio bursts, or FRBs, are radio emissions that appear temporarily and randomly, making them not only hard to find, but also hard to study.
The mystery stems from the fact it is not known what could produce such a short and sharp burst.
This has led some to speculate they could be anything from stars colliding to artificially created messages.
Scientists searching for fast radio bursts (FRBs) that some believe may be signals sent from aliens may be happening every second. The blue points in this artist’s impression of the filamentary structure of galaxies are signals from FRBs
The first FRB was spotted, or rather ‘heard’ by radio telescopes, back in 2001 but wasn’t discovered until 2007 when scientists were analysing archival data.
But it was so temporary and seemingly random that it took years for astronomers to agree it wasn’t a glitch in one of the telescope’s instruments.
Researchers from the Harvard-Smithsonian Center for Astrophysics point out that FRBs can be used to study the structure and evolution of the universe whether or not their origin is fully understood.
A large population of faraway FRBs could act as probes of material across gigantic distances.
This intervening material blurs the signal from the cosmic microwave background (CMB), the left over radiation from the Big Bang.
A careful study of this intervening material should give an improved understanding of basic cosmic constituents, such as the relative amounts of ordinary matter, dark matter and dark energy, which affect how rapidly the universe is expanding.
FRBs can also be used to trace what broke down the ‘fog’ of hydrogen atoms that pervaded the early universe into free electrons and protons, when temperatures cooled down after the Big Bang.
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