Imagine witnessing a sudden burst of light over a million trillion times brighter than our Sun. Astronomers have discovered the reason behind the brightest, most energetic light bursts in the universe. Gamma-Ray Bursts (GRB) are large outbursts of energy produced by star-forming galaxies. The reason behind this massive flare of energy whose origin has not been known until now has been discovered by astronomers for the first time.
It could shed light on some of the biggest mysteries of the universe, including Dark Matter and Dark Energy. According to a study published in the journal Nature, until now it has been unclear what causes gamma rays – one of the most energetic forms of light in the Universe – to appear in patches of seemingly ’empty sky’. Dr. Matt Roth of the Australian National University, the lead author of the paper, said that the discovery of the origins of the gamma-ray emission is a significant milestone since it resolves a mystery that astronomers have been trying to solve since the 1960s.
Gamma-ray bursts – what is it?
Gamma-ray bursts, which are the most energetic form of light, can last anywhere between a few milliseconds and a few minutes. About one million trillion times brighter than the Sun, these bursts are hundreds of times brighter than a typical supernova. The biggest mystery in high-energy astronomy, GRBs were discovered by US military satellites in the late 1960s when they ‘were looking for Soviet nuclear testing in violation of the Atmospheric Nuclear Test Ban Treaty’.
The gamma-ray detectors onboard the satellite detected bright bursts of gamma rays from beyond the solar system. Astronomers have found that there are two types of GRBs: long-duration and short-duration. The long-duration bursts can last anywhere from two seconds to a few hundreds of seconds, but the short-duration bursts are those that last under two seconds, averaging just over two seconds on average.
Finding the source of Gamma-Ray Bursts
Originally, many researchers thought they originated from gas falling into supermassive black holes, which are in the centres of all galaxies. However, new research shows that they originate from star formation in their disks. Researchers have modeled the gamma-ray emission from galaxies in the Universe and compared it with other predictions, finding that star-forming galaxies are largely responsible for diffuse gamma-ray emission and not the AGN process, according to the study. After gaining a better understanding of how cosmic rays – particles that travel very close to the speed of light – move through the gas between the stars, researchers were able to discover what caused the mysterious gamma rays.
The Hubble Space Telescope and Fermi Gamma-Ray Space Telescope were used to analyzing data about galaxies, including their star formation rates, total mass, size, and distances from Earth. Researchers are now focused on producing gamma-ray sky maps that will inform upcoming gamma-ray observations with the help of next-generation telescopes.