Scientists SOLVE the mystery of ‘alien’ signal received from outer space

Scientists have finally discovered the mysterious origins of an ‘alien‘ signal received from outer space.

In 2022, a radio telescope detected a burst of energy coming from a galaxy about 200 million light-years from Earth.

Although the burst only lasted milliseconds, it contained enough energy to outshine entire galaxies and was theorised to have been a signal from an advanced alien civilisation. 

Now, scientists from MIT have discovered that this ‘fast radio burst’ (FRB) originated from a small area extremely close to a rotating neutron star, the ultra-dense remains of a dead sun.

The researchers argue that the burst must have come from the layer of powerful magnetic fields surrounding the star known as the magnetosphere.

Although thousands of FRBs have been detected, this is the first time that astronomers have been able to pin down the origin of one of these mysterious signals.

Co-author Professor Kiyoshi Masui says: ‘Around these highly magnetic neutron stars, also known as magnetars, atoms can’t exist — they would just get torn apart by the magnetic fields.

‘The exciting thing here is, we find that the energy stored in those magnetic fields, close to the source, is twisting and reconfiguring such that it can be released as radio waves that we can see halfway across the universe.’

Neutron stars are formed when a star about seven to 19 times the size of our sun explodes in a violent supernova, leaving behind a dense core of compressed matter.

Although they are only a few miles wide, these alien stars contain up to twice as much matter as the sun.

These stellar cores are so dense that a sugar cube-sized chunk of neutron star material would weigh one billion tonnes on Earth – making them the densest objects we can directly observe.

Surrounding these strange worlds are violent magnetic fields which can be trillions of times stronger than those surrounding the Earth.

Since the first FRB was spotted in 2007, researchers have detected thousands of these brief but intense bursts everywhere from our own galaxy to 8 billion light-years away.

Although these bursts don’t contain enough energy to be dangerous, they have presented scientists with a perplexing mystery.  

Some scientists have suggested that these could be created by the powerful magnetic fields surrounding distant neutron stars – but not all astronomers agree.

Lead researcher Dr Kenzie Nimmo says: ‘In these environments of neutron stars, the magnetic fields are really at the limits of what the universe can produce.

Researchers believe this powerful signal originated from within the magnetic fields surrounding a neutron star, the ultra-dense remains of a dead star. As this burst passed through gases in another galaxy it split into multiple paths (illustrated) causing the signal to flicker in brightness

The signal was detected by the Canadian Hydrogen Intensity Mapping Experiment (pictured). By looking at how the signal flickered, researchers calculated that it must have emerged from a region no larger than 10,000 km (6,200 miles) across 

‘There’s been a lot of debate about whether this bright radio emission could even escape from that extreme plasma.’

Some models suggest that the bursts of energy are formed in the turbulent magnetosphere while others argue that they originate from much farther out as part of a shockwave coming from the star itself.

In their study, published in Nature, the researchers focused on a radio pulse spotted in 2022 by the Canadian Hydrogen Intensity Mapping Experiment (CHIME).

Using four large radio receivers shaped like half pipes, scientists detected a two-millisecond pulse which was named FRB 20221022A.

Based on the highly polarised light that the FRB produced, the researchers worked out that its source is very likely to be rotating – something that has been seen in fast-spinning neutron stars called pulsars.

But to figure out exactly where FRB 20221022A originated, Dr Nimmo and her co-authors looked at a property called ‘scintillation’.

If you see a star in the night sky from Earth, it appears to twinkle or ‘scintillate’ because the light from the star is filtered through gasses in the atmosphere.

Yet this effect doesn’t just affect stargazers since light from any small, bright source will be bent as it passes through an obstruction like the gasses surrounding a galaxy.

The researchers argue that the burst would have come from the magnetic fields within hundreds of thousands of kilometres of a neutron star. This is the first evidence that a neutron star’s magnetosphere (illustrated) is capable of releasing a fast radio burst.

The smaller and farther away the source of light is the more it scintillates, which is why planets like Jupiter and Mars don’t appear to twinkle when you see them.

If the FRB originated from a shockwave tens of millions of kilometres from the neutron star the area of origin would be so large that researchers wouldn’t expect to see any scintillation at all.

But when Dr Nimmo and her colleagues analysed the energy from FRB 20221022A they saw that the mysterious flash was twinkling like a star in the sky. 

Dr Nimmo says: ‘This means that the FRB is probably within hundreds of thousands of kilometres from the source.’

By identifying the gas cloud that the flash must have passed through, the researchers were able to zoom in on its origin within unprecedented accuracy.

Although the FRB emerged from a galaxy more than ten times the distance to our nearest neighbouring galaxy, the researchers found that its source was an area just 10,000km (6,200 miles) wide.

For comparison, that is equivalent to the distance from Edinburgh to Cape Town, South Africa.

Professor Masui says: ‘Zooming in to a 10,000-kilometer region, from a distance of 200 million light years, is like being able to measure the width of a DNA helix, which is about 2 nanometers wide, on the surface of the moon.’

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.