“THE BOAT”, the “brightest of all time” was the nickname given to the most powerful gamma-ray burst (GRB) ever recorded by astronomers. More officially called GRB 221009A, it was discovered for the first time on the morning of October 9, 2022 and has already been the subject of publications in The Astronomer’s Telegram, a service for the rapid dissemination of information about new astronomical observations. These are still ongoing to understand the origin of this event, which could very well be the “birth cry” of a new black hole, according to the scientists cited by the site Ars-Technica this October 17.
Gamma ray bursts, giant explosions
Gamma-ray bursts are very high-energy explosions that occur in distant galaxies and last from milliseconds to hours. On Earth, they reach us through a bombardment of gamma rays, as well as the formation of a peculiar light curve in the sky. These phenomena were observed for the first time in the late 1960s and the launch of the American Vela satellites. While aiming to detect signs of Russian nuclear weapons testing, the latter picked up these strange unearthly flashes, experts have found after more investigation.
Research has also identified two classes of gamma ray bursts. First, the rarest (30%), those lasting less than two seconds. According to the hypotheses, they come from regions where few stars form. They would be the result of the merger between two neutron stars or of a neutron star with a black hole. Long bursts of more than two seconds (70%), on the other hand, will generally be associated with the death of massive stars (supernovae) in galaxies where they form rapidly. The formation of a black hole would produce jets of high-energy particles, powerful enough to emit X-rays and gamma rays all the way to us.
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An extraordinary and educational event
GRB 221009A would belong to this second category. Gamma rays have been detected by NASA’s space telescopes – they Fermi Gamma-ray Space Telescope and its LAT (Large Area Telescope), the Swift (Neil Gehrel’s Swift Observatory) and the WIND – among other things from the constellation of the arrow (Sagitta). This powerful signal would have traveled to Earth for 1.9 billion years. Above all, the phenomenon would have lasted unusually long, followed by ten hours of LAT. Brendan O’Connor, a member of the team from the US universities of Maryland and George Washington, who studied its afterglow, explains in a press release:
The unusually long GRB 221009A is the brightest gamma-ray burst ever recorded, and its afterglow is unprecedented at all wavelengths. Because this outburst is so bright and so close, we believe it is a once-in-a-century opportunity to address some of the most fundamental questions about these outbursts, from black hole formation to testing models of dark fabric. .
However, the term “near” should be put into perspective: GRB 221009A took place in a galaxy very far from the Milky Way – but at a “ridiculous” distance on the scale of the universe. This explains why he had no ill effects on Earth. However, it may prove more problematic (although unlikely) if it occurs less than 5,000 to 8,000 light-years away and in the direction of our planet: the DNA of living systems would be damaged, the chemical reactions of disturbed atmosphere and the depleted ozone layer… The Ordovician-Silurian extinction about 450 million years ago could also be the result of such an event, scientists suggest.
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