A Canadian-led team of scientists recently picked up 13 new fast radio bursts (FRBs) from deep space, in a discovery that could alter our understanding of these mysterious signals attributed to everything from a neutron star to extra-terrestrial intelligence in the past.
Astronomers detected ultra-brief repeating energy bursts from deep space for only the second time in history, which experts believe could be a breakthrough in offering scientific evidence of advanced alien life.
The researchers detailed their latest findings in two papers (available here and here) which were published in the journal Nature on Wednesday. Scientific American reported that Deborah Good, an astronomer at the University of British Columbia in Vancouver, Canada, first told a meeting of the American Astronomical Society in Seattle on January 7.
What are FRBs?
Fast radio bursts, or FRBs, are short pulses of radio waves presumed to originate from far beyond our galaxy, probably billions of light years outside the Milky Way. In radio astronomy, an FRB is what is referred to as a high-energy astrophysical phenomenon of unknown origin, which manifests as a transient radio pulse, usually lasting a few milliseconds on average.
When the FRBs are polarised, it indicates that they are emitted from a source contained within an extremely powerful magnetic field. Although the exact origin and cause of these bursts are unfounded, the scientific community is largely in agreement about their extragalactic nature. While some claim it originates from a rapidly rotating super-dense neutron star and a black hole, some believe it to be signal emitted by alien civilisations.
Implications of the repeating bursts
The first FRB was discovered by accident by Duncan Lorimer, an astrophysicist at West Virginia University, and his student David Narkevic in 2007 when they were looking through archival pulsar survey data collected in 2001. Since then, researchers have observed more than 60 FRBs, including the first repeating burst recorded by the Arecibo radio telescope in Puerto Rico in 2015.
During the recent research, the team in Canada noticed additional pulses from one of the 13 new bursts, making it only the second known repeater to date.
“Until now, there was only one known repeating FRB,” co-author of the study Dr Ingrid Stairs, told the Guardian. “Knowing that there is another suggests that there could be more out there. And with more repeaters and more sources available for study, we may be able to understand these cosmic puzzles — where they’re from and what causes them,” the astrophysicist from University of British Columbia said.
CHIME: The telescope that detected the FRB
Over a three-month period in the summer of 2018, the team in British Columbia collected their data using the Canadian Hydrogen Intensity Mapping Experiment (CHIME), a new kind of radio telescope that has no moving parts.
The telescope is located in Dominion Radio Astrophysical Observatory in Okanagan Valley, Canada. The telescope consists of four adjacent 100-metre-long, semi-cylindrical reflectors. Each cylinder is lined with 256 dual-polarisation antennas that receive radiation from the northern horizon to the southern horizon of the sky. As a result, CHIME has an enormous field of view. The antennas have sensitivity from 400 to 800 MHz.
The analog signals received from these inputs are fed to the FPGA-based F-Engine that digitises them at 13 terabits per second. This digital signal is then sent to the GPU-based X-Engine where the data is processed to either create sky maps, detect FRBs in the FRB backend search engine, or monitor pulsars in the Northern sky through a pulsar timing monitor.
At the the time of discovery, CHIME was in its pre-commissioning phase and running at only a fraction of its full capacity.
More pieces for the FRB puzzle
The CHIME team’s research does not just prove that the previously discovered repeating FRB wasn’t a cosmic anomaly; it also changes what we knew so far about detecting the waves and their points of origin.
Most of the newly discovered FRBs showed signs of “scattering”, which could provide crucial clues into the environment near the source of an FRB. It further raises the possibility that the wave originates from powerful astrophysical objects in locations with special characteristics.
Moreover, CHIME has also detected the lowest-frequency FRB known so far. In the past, researchers discovered most FRBs at a frequency near 1400 MHz, but CHIME detected an FRB at wavelengths of 400 MHz, breaking the previous record of 700 Mhz.
Studying lower-frequency FRBs, and the way in which their radiation is scattered on the way to Earth, can reveal more about the environment in which the bursts were born. This includes whether there is a lot of turbulent gas such as in a star-forming region.
Seven of the new bursts registered at the lower end of the frequency graph. This certainly proves the need to reconsider what we thought we knew about this cosmic phenomenon.
Among the alien theorists is Professor Avi Loeb from the Harvard-Smithsonian Centre for Astrophysics, who believes that the FRBs indicates the existence of incredibly advanced alien technology, especially considering the double repeat feat.
In 2017, Loeb and his Harvard colleague Manasvi Lingam had proposed that FRBs could be leakage from planet-sized alien transmitters powering interstellar probes in distant galaxies. Rather than being designed for communication, they would more likely be used to propel giant spaceships powered by light sails which bounce light, or in this case radio beams, off a huge reflective sheet to provide thrust, the scientists said.
Qrius reached out to the CHIME team for clarification. In an email, Dr Richard Shaw, a member of the cosmology team at CHIME and a postdoctoral fellow at the University of British Columbia, wrote, “Given that we don’t have a full understanding of what FRBs are you can’t completely rule it [aliens] out, but given what we do know about their properties, similarities to other astrophysical objects we do understand, and their spatial distribution it seems very unlikely they are related to aliens.”
This article was updated at 1:09 pm IST on January 12, 2019, to include Dr Richard Shaw’s reply.
All images in this article are courtesy of the CHIME collaboration, and have been reproduced with permission.
Prarthana Mitra is a staff writer at Qrius. Aditi Agrawal is a sub editor at Qrius.