Antimatter Storms Observed (On Earth!)


Using the Fermi Gamma-ray Space Telescope, researchers have detected beams of antimatter produced above thunderstorms, a phenomenon never before seen on earth. Scientists be;ieve the antimatter particles are formed in terrestrial gamma-ray flashes (TGFs) – brief energy bursts produced inside thunderstorms and known to be associated with lightning. About 500 TGFs occur daily worldwide, but most go undetected.

Although Fermi’s Gamma-ray Burst Monitor (GBM) is designed to observe high-energy events in the distant reaches of the universe, it also monitors the entire celestial sky and the Earth below. The GBM team has identified 130 TGFs since Fermi’s launch in 2008, because when antimatter strikes Fermi it collides with a particle of normal matter and both particles immediately are annihilated – and transformed into gamma rays. The GBM has detected gamma rays with energies of 511,000 electron volts, a signal indicating an electron has met its antimatter counterpart, a positron.

“The Fermi results put us a step closer to understanding how TGFs work,” explains Steven Cummer from Duke University. “We still have to figure out what is special about these storms and the precise role lightning plays in the process.”

Scientists have long theorized that TGFs arise from the strong electric fields near the tops of thunderstorms. Under the right conditions, they say, the field becomes strong enough that it drives an upward avalanche of electrons. Reaching speeds nearly as fast as light, the high-energy electrons give off gamma rays when they’re deflected by air molecules. Normally, these gamma rays are detected as a TGF.

“These signals are the first direct evidence that thunderstorms make antimatter particle beams,” said Michael Briggs, a member of Fermi’s GBM team at the University of Alabama in Huntsville. He presented the findings during a news briefing at the American Astronomical Society meeting in Seattle.
Casey Kazan via Motherboard


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