Gamma rays, which have the highest energy of any wave in the electromagnetic spectrum, were released in a tremendous explosion known as a supernova, which occurred around two billion years ago in a galaxy far beyond our Milky Way.
After traveling through space, the waves arrived on Earth last year. According to scientists, this gamma-ray burst significantly disrupted the ionosphere, a region of the planet’s upper atmosphere home to electrically charged gases known as plasma.
This explosion was the strongest of its kind that scientists had ever observed.
Stretching to the extreme edge of space, the ionosphere is located between 30 and 600 miles (50 and 950 km) above the surface of the Earth. It contributes to the formation of the border that separates Earth’s lower atmosphere, which is home to humans, from the vacuum of space.
On October 9, 2022, the burst’s gamma rays had an approximate 13-minute duration of impact on Earth’s atmosphere. Several satellites in close Earth orbit and the Integral (International Gamma-Ray Astrophysics Laboratory) space observatory of the European Space Agency were able to identify them.
Lead author of the research published in the journal Nature Communications and space weather expert Mirko Piersanti of the University of L’Aquila in Italy states that the gamma rays enormously varied the electric field in the ionosphere.
Piersanti remarked, “It was similar to what happens in general during a solar flare event,” alluding to the sun’s intense outbursts of energy.
However, in contrast to the sun’s relative proximity, the gamma-ray burst happened far away, with the radiation traveling roughly two billion light years. This illustrates how even distant occurrences can have an impact on Earth. The distance that light travels in a year is 5.9 trillion miles (9.5 trillion kilometers), or one light year.
According to instruments on Earth, the gamma rays disrupted the ionosphere for several hours and even triggered lightning detectors in India. The disturbance had an impact on the ionosphere’s lowest levels.
Since the 1960s, scientists have measured gamma-ray bursts, energy explosions from supernovas, or the merger of two neutron stars—dense, collapsed cores of massive stars. Scientists estimate that a blast as powerful as the one discovered last year will come close to Earth once every 10,000 years.
The ionosphere is extremely sensitive to changes in magnetic and electrical conditions in space, typically related to solar activity. The ionosphere shields life on Earth by absorbing damaging UV rays from the sun. It also reacts to solar light by contracting and expanding.
Although this gamma-ray burst did not negatively impact life on Earth, it has been suggested that a powerful one that originated in the Milky Way and was directed directly toward us could be dangerous and even cause mass extinctions by flooding the Earth’s surface with dangerous UV radiation.
But according to Italian astronomer and research co-author Pietro Ubertini of the National Institute for Astrophysics, “the probability that this happens is really negligible.”
With the aid of the Chinese-Italian mission Zhangheng, also known as the China Seismo-Electromagnetic Satellite (CSES), launched in 2018, the impacts of this gamma-ray burst were investigated.
“Here we were lucky since we used the power of the EFD (electric field detector) instrument on board the CSES that is able to measure the electric field with unprecedented resolution,” Piersanti stated.
According to Ubertini, no one on Earth knew of the ionosphere disturbance. “Nobody detected anything, but we don’t know if it could have been possible to see some visible signal looking at the right time in the sky,” Ubertini stated.
