📚 A Supernova 'Destroyed' Some of Earth's Ozone For a Few Minutes In 2022

An anonymous reader quotes a report from the New York Times: On Oct. 9, 2022, telescopes in space picked up a jet of high energy photons careening through the cosmos toward Earth, evidence of a supernova exploding 1.9 billion light-years away. Such events are known as gamma ray bursts, and astronomers who have continued studying this one said it was the "brightest of all time." Now, a team of scientists have discovered that this burst caused a measurable change in the number of ionized particles found in Earth's upper atmosphere, including ozone molecules, which readily absorb harmful solar radiation. "The ozone was partially depleted -- was destroyed temporarily," said Pietro Ubertini, an astronomer at the National Institute of Astrophysics in Rome who was involved in discovering the atmospheric event. The effect was detectable for just a few minutes before the ozone repaired itself, so it was "nothing serious," Dr. Ubertini said. But had the supernova occurred closer to us, he said, "it would be a catastrophe." The discovery, reported Tuesday in a paper published in the journal Nature Communications, demonstrates how even explosions that occur far from our solar system can influence the atmosphere, which can be used as a giant detector for extreme cosmic phenomena. To study the effects of last year's gamma ray burst on Earth, Dr. Ubertini and his colleagues looked for signals at the top of the ionosphere using data from the China Seismo-Electromagnetic Satellite, an orbiter designed to study changes in the atmosphere during earthquakes. They identified a sharp jump in the electric field at the top of the ionosphere, which they correlated to the gamma ray burst signal measured by the European Space Agency's International Gamma-Ray Astrophysics Laboratory, a mission that launched in 2002 to observe radiation from faraway celestial objects. The researchers found that the electric field rose by a factor of 60 as gamma rays ionized (essentially knocking away electrons from) ozone and nitrogen molecules high in the atmosphere. Once ionized, the molecule is unable to absorb any ultraviolet radiation, temporarily exposing Earth to more of the sun's damaging rays.

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