THE stronger gamma ray burst (Gamma-Ray Burst, GRB), ever recorded, hit Earth raising questions about the consequences that an exploding star can have on our planet.

On October 9, 2022 at 3:21 pm Greek time, an extremely bright and long-lasting GRB burst was detected by many of the satellites in Earth orbit, including the European Space Agency’s (ESA) Integral space telescope that detects such bursts.

This burst, dubbed GRB 221009A, was anything but ordinary. “It was probably the brightest gamma-ray burst we’ve ever detected,” notes Mirco Piersanti of the University of L’Aquila in Italy, and lead author of the team publishing these results today in the journal Nature Communications. One of the authors, Pietro Ubertini of the National Institute of Astrophysics in Rome and principal investigator for Integral’s IBIS instrument, calls it “the most powerful” GRB ever measured. Statistically a GRB burst of this size only reaches Earth once every 10,000 years.

This flare was the result of the explosion of a star nearly two billion light-years away. The explosion triggered lightning detectors in India, over which the peak of the GRB was recorded. The flare’s photon stream lit up Europe, Africa, Asia and parts of Australia, while instruments in Germany detected signs that the Earth’s ionosphere was disrupted for several hours by the explosion.

The ionosphere is the layer of Earth’s upper atmosphere, at an altitude of 50 km to 950 km, that contains electrically charged gases (plasma). The ionization stability of the Earth’s atmosphere plays a fundamental role in the evolution and maintenance of life. In this particular case there was a strong change in the electric field on the upper side of the ionosphere and an increase in ionization on the lower side of the ionosphere.

ESA points out that analyzing the impact of the explosion could provide information about mass extinctions in Earth’s history. Also, this particular event reinforces the idea that a supernova star explosion in our own Galaxy could have serious consequences, damaging the ozone layer and allowing the Sun’s dangerous ultraviolet radiation to reach the Earth’s surface.