Scientists Say Gamma Ray Bursts Disturb Earth’s Upper Atmosphere

WASHINGTON – About two billion years ago in a galaxy far beyond our Milky Way, a massive star met its end in a massive explosion called a supernova that released a huge burst of gamma rays, which store the most energy in the universe in the electromagnetic spectrum.

The wave traveled across the cosmos and finally reached Earth last year. These gamma-ray bursts, researchers said Tuesday, caused significant disturbances in Earth’s ionosphere, a layer of the planet’s upper atmosphere that contains electrically charged gases called plasma.

Scientists previously determined that this was the most powerful explosion ever detected.

The ionosphere is located about 30-600 miles (50-950 km) above the Earth’s surface, stretching to the edge of space. This helps form the boundary between the vacuum of space and the lower atmosphere inhabited by humans and other earthlings.

Gamma rays from the explosion impacted the Earth’s atmosphere for a time span of about 13 minutes on October 9, 2022. They were detected by the European Space Agency’s Integral space observatory (International Gamma Ray Astrophysics Laboratory) and various satellites orbiting near Earth.

Gamma rays cause strong variations in the ionospheric electric field, according to Mirko Piersanti, a space weather researcher at the University of L’Aquila in Italy and lead author of the study published in the journal Nature Communications.

“This is similar to what generally happens during solar flares,” said Piersanti, referring to powerful bursts of energy from the sun.

But the gamma-ray burst occurred at a very large distance – a distance of about two billion light years – compared to the relative proximity of the Sun, showing how even events occurring at very large distances can affect Earth. A light year is the distance light travels in a year, 5.9 trillion miles (9.5 trillion km).

Instruments on Earth showed that the gamma rays disturbed the ionosphere for several hours and even triggered lightning detectors in India. This disturbance reaches the lowest layers of the ionosphere.

Scientists since the 1960s have measured gamma-ray bursts – the outpouring of energy released in supernovae or mergers of two neutron stars, which are the dense, collapsed cores of massive stars. According to scientists, an explosion as strong as the one detected last year is expected to reach Earth once every 10,000 years.

The ionosphere, which helps protect life on Earth by absorbing harmful ultraviolet rays from the sun, is very sensitive to changes in magnetic and electrical conditions in space, which are usually associated with solar activity. It also expands and contracts in response to solar radiation.

Although these gamma ray bursts did not have any adverse effects on life on Earth, it is hypothesized that powerful gamma ray bursts originating from the Milky Way and heading straight for us could cause harm – including mass extinction – by causing the Earth’s surface to be flooded. from harmful ultraviolet radiation.

However, “the chances of this happening are very small,” said astronomer and study co-author Pietro Ubertini of the National Institute of Astrophysics in Italy.

The effects of these gamma ray bursts were studied with the help of the China Seismo-Electromagnetic Satellite (CSES), also called Zhangheng, a Sino-Italian mission launched in 2018.

“Here we are lucky because we use the power of the EFD (electric field detector) instrument at CSES which is capable of measuring electric fields with unprecedented resolution,” said Piersanti.

Ubertini said that the disturbances that occurred in the ionosphere were not visible to anyone in the field.

“Nobody detected anything, but we don’t know if it would be possible to see a visible signal at that exact time in the sky,” Ubertini said.