Astronomers detect a powerful burst of radio waves emanating from what appears to be a merger of galaxies dating back approximately 8 billion years – marking the oldest-known instance of a phenomenon known as a fast radio burst, a mystery that scientists have yet to fully understand.
In a fraction of a millisecond, Astronomers detect this burst unleashed an amount of energy equivalent to what our sun emits over three decades, as explained by researchers. The Australian SKA Pathfinder, a radio telescope located in Western Australia, enabled the detection. The European Southern Observatory’s Very Large Telescope, one of the most powerful optical telescopes in existence, determined the precise location of this burst.
A fast radio burst, or FRB, is a brief pulse of radio-frequency electromagnetic radiation. Although it lasts only a fraction of a second, it outshines most other sources of radio waves in the vast expanse of the universe. Radio waves have the longest wavelengths on the electromagnetic spectrum.
Astronomer Ryan Shannon from Swinburne University of Technology in Australia, who co-led the study published this week in the journal Science, compared the energy in FRBs to the radio waves used in microwave ovens and stated, “The amount of energy in this FRB is the equivalent to microwaving a bowl of popcorn twice the size of the sun.”
Until now, the oldest-known FRB dated back to about 5 billion years ago, making this one 3 billion years older. For context, the universe itself is approximately 13.8 billion years old, while Earth is about 4.5 billion years old. Observing objects and events from the distant past, astronomers are effectively peering across vast cosmic distances, which also makes this burst the farthest FRB ever detected.
Astronomer Stuart Ryder from Macquarie University in Australia, another co-leader of the study, remarked, “We now know that fast radio bursts have been around for more than half the age of the universe.”
The discovery of fast radio bursts dates back to 2007. According to Shannon, “The most likely source is a hyper-magnetized neutron star, called a magnetar. These stars are stellar remnants with the mass of the sun but only the size of a small city. They are among the most extreme objects in the universe, necessary to produce such extreme bursts.”
Stellar explosions or Black hole
Shannon further added, “There are more energetic events in the universe, associated with stellar explosions or a black hole tearing apart a star. However, FRBs are unique in that they produce all their energy in radio waves, with nothing seen in other bands – optical light or X-rays, for example – and these signals are extremely brief.”
Additionally, FRBs are relatively common, with an estimated daily occurrence of over 100,000 in the universe. However, only a few have been detected, and of those, only about 50, including this one, have been traced back to the galaxy from which they originated.
Shannon explained that “Galaxies in the distant universe look different than those nearby – they don’t have nice spiral arms – so it wasn’t clear if what we were seeing was one galaxy with a few clumps, or a few smaller galaxies. It is likely that the source is a few galaxies, possibly merging.”