Astronomers solve mystery of the brightest light in the universe – India Today

Imagine what it would be like to witness a sudden burst of light equivalent to over a million trillion times brighter than our Sun. But, is it even possible. YES, IT IS! Astronomers have now found the reason behind the brightest, most energetic blasts of light that happens in the universe.

Star-forming galaxies are responsible for this massive outburst of energy known as the Gama Ray Bursts (GRB). This is for the first time that astronomers have identified the reason behind this massive flare of energy that until now had not been associated with a known origin. The discovery could shed light on some of the biggest mysteries of the universe including Dark Matter and Dark Energy.

The study published in the journal Nature states that until now it has been unclear what created gamma-rays - one of the most energetic forms of light in the Universe - that appear in patches of seemingly "empty sky". "It's a significant milestone to finally discover the origins of this gamma-ray emission, solving a mystery of the Universe astronomers have been trying to decipher since the 1960s," Dr Matt Roth of the Australian National University, who is the lead author of the paper.

The short-lived bursts of gamma-ray light that are the most energetic form of light last anywhere from a few milliseconds to several minutes. These bursts shine hundreds of times brighter than a typical supernova and about a million trillion times as bright as the Sun.

According to Nasa, GRBs, the biggest mystery in high-energy astronomy were discovered in the late 1960s by US military satellites "which were on the lookout for Soviet nuclear testing in violation of the atmospheric nuclear test ban treaty." The gamma-ray detectors onboard the satellite picked up bright bursts of gamma rays from beyond the solar system.

Researchers used data from Hubble Space Telescope and Fermi Gamma-Ray Space Telescope and analysed information about galaxies. (Photo: Getty)

When astronomers delved into the nuances of this phenomenon, they found there are two types of GRBs long-duration and short-duration. While the long-duration bursts last anywhere from two seconds to a few hundreds of seconds, short-duration bursts are those that last less than 2 seconds, from anywhere from a few milliseconds to 2 seconds with an average duration of about 0.3 seconds.

While initially, researchers had said that the source of these bright lights could be from gas falling into the supermassive black holes which are found at the centres of all galaxies, new research shows that it is associated with star formation in the disks of galaxies.

"We modelled the gamma-ray emission from all the galaxies in the Universe and compared our results with the predictions for other sources and found that it is star-forming galaxies that produce the majority of this diffuse gamma-ray radiation and not the AGN process," Dr Roth said in a statement. The researchers were able to pinpoint what created these mysterious gamma rays after obtaining a better understanding of how cosmic rays - particles that travel at speeds very close to the speed of light - move through the gas between the stars.

Researchers used data from Hubble Space Telescope and Fermi Gamma-Ray Space Telescope and analysed information about galaxies including their star-formation rates, total masses, physical size and distances from Earth. The tea is now looking to producing maps of the gamma-ray sky that can be used to inform upcoming gamma-ray observations from next-generation telescopes.

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Astronomers solve mystery of the brightest light in the universe - India Today