A group of scientists has observed a mysterious burst of radio waves that traveled for 8 billion years before reaching Earth. This fast radio burst (FRB) stands out as one of the most remote and energetic events ever detected.
Fast radio bursts, or FRBs, are brief bursts of radio waves lasting mere milliseconds, and their origins remain unknown. The first FRB was identified in 2007, and since then, astronomers have recorded hundreds of these rapid cosmic flashes originating from various points across the universe.
This particular burst, named FRB 20220610A, lasted less than a millisecond but emitted the equivalent energy of our Sun’s emissions over a 30-year period. These fleeting and intense radio bursts are challenging to observe due to their brevity.
Researchers utilized radio telescopes to pinpoint these rapid cosmic phenomena, including the ASKAP array of radio telescopes situated in Western Australia on Wajarri Yamaji Country. In June 2022, astronomers used ASKAP to detect this FRB and trace its source.
Dr. Stuart Ryder, an astronomer at Macquarie University in Australia and a co-author of the study, explained, “Using ASKAP’s array of radio dishes, we were able to determine precisely where the burst came from. Then we used the European Southern Observatory’s Very Large Telescope in Chile to search for the source galaxy, finding it to be older and farther away than any other known FRB source, likely within a small group of merging galaxies.”
The research team traced the FRB to a cluster of two or three galaxies in the process of merging, interacting, and generating new stars. This finding aligns with current theories suggesting that fast radio bursts may originate from magnetars, highly energetic objects formed from stellar explosions.
Scientists believe that FRBs could serve as a unique tool for estimating the universe’s mass by measuring the unaccounted-for matter between galaxies.
Ryan Shannon, a professor at Swinburne University of Technology in Australia and a co-author of the study, stated, “If we count up the amount of normal matter in the Universe — the atoms that we are all made of — we find that more than half of what should be there today is missing. We think that the missing matter is hiding in the space between galaxies, but it may just be so hot and diffuse that it’s impossible to see using normal techniques.”
The results of current methods used to estimate the universe’s mass do not agree, indicating that a significant portion of the universe’s mass remains unaccounted for.
Shannon explained, “Fast radio bursts sense this ionized material. Even in space that is nearly perfectly empty, they can ‘see’ all the electrons, and that allows us to measure how much stuff is between the galaxies.” This technique was first demonstrated by Australian astronomer Jean-Pierre Macquart in 2020.
Ryder added, “Some recent fast radio bursts appeared to break this relationship. Our measurements confirm the Macquart relation holds out to beyond half the known Universe.”
To date, nearly 50 fast radio bursts have been traced back to their sources, with about half of them being discovered using ASKAP. Scientists anticipate that future radio telescopes, currently being constructed in South Africa and Australia, will enable the detection of thousands more FRBs at even greater distances.
Shannon expressed optimism, saying, “The fact that FRBs are so common is also amazing. It shows how promising the field can be, because you’re not just going to do this for 30 bursts, you can do this for 30,000 bursts, make a new map of the structure of the universe, and use it to answer big questions about cosmology.”