Astronomers detect a strange radio signal that pulsates "like a heartbeat" from an unknown galaxy

Scientists have detected a heart-pulsing radio signal coming from an unknown galaxy billions of light years from Earth.

Its source emits pulses that are a million times brighter than comparable stars in our own galaxy, and its radio bursts are a thousand times longer than normal.

According to the researchers, the signal, which is a form of fast radio burst, appears to flash with surprising regularity.

However, the origin of the explosion recorded by Canadian telescopes remains a mystery. Fast radio bursts (FRBs) mostly originate from unknown sources in space and typically last only a few milliseconds.

This can last up to three seconds, which is almost 1,000 times longer than the typical FRB.

The researchers identified bursts of radio waves that repeat every 0.2 seconds at a rate similar to that of a beating heart. The team claims it is the clearest and longest-lasting fast radio burst ever discovered.

Its origin is unknown, however, it is located in a distant galaxy a few billion light years from Earth.

The team believes it could have originated from a radiopulsar or a magnetar, both of which are forms of neutron stars: the compact, fast-spinning cores of massive stars.

The signals it emits, such as the frequency of the bursts and how they vary as the source moves away from Earth, can be used to calculate the expansion rate of the universe.

Since the discovery of the first fast radio burst in 2007, hundreds of similar bursts have been detected across the cosmos.

Between the years 2018 and 2020, scientists identified the first fast radio bursts that appeared to consistently generate radio waves.

This signal consisted of four days of random bursts repeated every sixteen days.

The 16-day schedule gave the gusts their regularity, but the gust signals were random.

On December 21, 2019, a telescope in British Columbia, Canada, detected the new discovery.

Dr. Daniele Michilli was operating the telescope, which is part of the Canadian Hydrogen Intensity Mapping Experiment, when the strange signal occurred.

He explained: "It was unusual. Not only was it very long, lasting about three seconds, but there were periodic spikes that were remarkably precise, emitting every fraction of a second—boom, boom, boom—like a heartbeat."

Scientists discovered parallels between this and radiopulsar and magnetar emissions from our galaxy.

Radio pulsars are neutron stars that emit beams of radio waves, which appear to pulsate as the star rotates, while magnetars create a comparable emission as a result of their strong magnetic fields.

However, the emissions from the next radio burst were almost a million times brighter.

Dr. Michilli speculates that the bright flashes originated from a distant radio pulsar or magnetar that is normally dimmer when spinning but which for an unexplained reason emitted a sequence of bright bursts in a rare three-second window that the team had the lucky to capture. 

He added: "CHIME has now detected many fast radio bursts with different properties.

"We have seen some that live inside clouds that are very turbulent, while others appear to be in clean environments.

"From the properties of this new signal, we can say that around this source there is a cloud of plasma that must be extremely turbulent."

The team hopes to observe the strange explosion again in the future to learn more about its origin and neutron stars in general.

Dr Michilli, from the Massachusetts Institute of Technology in the US, added: "This detection raises the question of what could cause this extreme signal that we have never seen before, and how we can use this signal to study the universe."

Future telescopes are expected to detect tens of thousands of fast radio bursts each month, at which point we will be able to discover many more of these periodic signals.

Reference