the phenomenon was always in front of our noses

2024-10-02 22:49:52

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Large storm clouds often emit gamma rays continuously, which cannot be detected from the ground, according to two studies published this Wednesday, which describe a phenomenon that is much more common than previously thought.

There are up to 40,000 storms a day on Earth, producing more than 8 million lightning bolts every day, but the science behind this phenomenon is still “not well understood”, according to physicist Joseph Dwyer who specializes in storms, in an article presenting these studies. in the diary Nature.

In the 1990s, NASA satellites dedicated to detecting high-energy particles from solar storms, star explosions or black holes recorded gamma-ray bursts coming from Earth. However, apart from nuclear power plant reactors, this phenomenon did not appear to have a terrestrial source.

Since then, numerous opinions have concluded that they originated from storms and classified them as flashes and gamma-ray bursts, two phenomena invisible to the human eye.

The first, lasting a few minutes over a distance of just 20 km, would make the tops of the storm clouds glow. The latter, like a shock, would last no more than a thousandth of a second.

“In fact, almost all large storms generate gamma rays continuously and in various forms,” ​​according to Steve Cummer, co-author of the two studies and professor of engineering at Duke University in the United States.

To confirm this, an international team of researchers conducted a month-long observation campaign in Florida in 2023.

The study made it possible to fly over 20 km altitude, ten storm systems, nine of which gave evidence of a broad gamma-ray spectrum that was more dynamic than expected.

“It looks and behaves like a giant ‘bubble pot’ of gamma glory”, explains the first study, dedicated to radiation and signed by Martino Marisaldi, professor of physics at the University of Bergen, Norway.

The storm clouds studied glow with numerous gamma-ray emissions that turn on and off for a few seconds, for hours, and over areas of thousands of square kilometers.

The second study announces that it has also been discovered, thanks to the observation campaign, that there is a possible “missing link” between flashes and gamma-ray bursts.

Signed by Nikolaï Østgaard, professor of space physics at the University of Bergen, This investigation observed what he describes as oscillating flasks.