Scientists detect 'alien' signal from distant galaxy

Scientists have detected a mysterious signal known as fast radio bursts coming from an ancient galaxy billions of light years away.

Some experts have suggested that these fast radio bursts (FRBs), an intense burst of radio waves from deep space, could be extraterrestrials attempting to contact Earth, while others suspect black holes or collapsed stars are the source.

Researchers from Northwestern University detected an FRB that produced 21 pulses, lasting a few milliseconds, from February through July 2023. What made the new discovery unique is that it was traced back to a 'dead' galaxy no longer producing stars.

This is an unprecedented home for a phenomenon previously associated with much younger galaxies, suggesting that the origins of these mysterious cosmic events might be more diverse than previously thought.

Before this revelation, scientists theorized that FRBs only came from much younger galaxies that are still producing stars. 

The team pinpointed the source to an 11.3-billion-year-old neighboring galaxy located two billion light-years from Earth.  One light year is equal to six trillion miles. 

They honed in on the galaxy, finding it to be 'extremely luminous and incredibly massive — 100 billion times the mass of our sun.'

Radio Astronomer Tarraneh Eftekhari said: 'It seems to be the most massive FRB host galaxy to date. It's among some of the most massive galaxies out there.'

Flaring up and disappearing within milliseconds, FRBs are brief, powerful radio blasts that generate more energy in one quick burst than our sun emits in an entire year. 

It is not currently known what produces fast radio bursts, but they are generally thought to be emanated by dying stars in distant galaxies, also known as magnetar stars.

Magnetar stars have a powerful magnetic field, which scientists speculate is shooting out radio waves through space.

Some bursts seem to be one-off events- less than five percent of the hundreds spotted have been seen to repeat, occasionally on a regular pattern.

But the latest discovery produced more than a dozen pules, six of which researchers detected using a ground based radio telescope in Canada.

'The prevailing theory is that FRBs come from magnetars formed through core-collapse supernovae,' said Eftekhari. 

'That doesn't appear to be the case here. While young, massive stars end their lives as core-collapse supernovae, we don't see any evidence of young stars in this galaxy. 

'Thanks to this new discovery, a picture is emerging that shows not all FRBs come from young stars. Maybe there is a subpopulation of FRBs that are associated with older systems.'

The team found that instead of finding a young galaxy, they observed the FRB coming from one without stars.

Galaxies are considered dead when they stop creating stars, which can take hundreds of millions of years.

This can happen when a galaxy runs out of gas or when it merges with another galaxy. And the former appeared to be the case during the observations.

Vishwangi Shah, a doctoral student at McGill University Canada and co-author of the study, said: 'This is not only the first FRB to be found outside a dead galaxy, but compared to all other FRBs, it's also the farthest from the galaxy it's associated with.

'The FRB's location is surprising and raises questions about how such energetic events can occur in regions where no new stars are forming.'

Astronomers have detected thousands of FRBs since 2007, but only around 100 have been traced to a specific source - all near actively forming stars.

'This particular FRB is really an outlier, and it challenges our theories about what is producing FRBs,' Shah said.