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NASA's Fermi Gamma-ray Space Telescope has found evidence of thunderstorms on Earth shooting antimatter particles into space.
According to New Scientist, thunderstorms are known to shoot out terrestrial gamma-ray flashes (TGFs), which Fermi observed in several instances. Sometimes, gamma-rays interact with atoms in the atmosphere to form electrons and their antimatter opposite, positrons. Fermi was also able to detect these rare occurrences.
"While observing [TGFs]," writes New Scientist, "Fermi also detected a separate set of gamma rays with an energy of 511 kiloelectronvolts. These rays were produced when a barrage of positrons struck the spacecraft's detectors and were annihilated by making contact with electrons there."
"These signals are the first direct evidence that thunderstorms make antimatter particle beams," said Michael Briggs, who presented his team's findings on January 10 at a meeting of the American Astronomical Society in Seattle, Washington.
"What seems to have happened is that positrons created by the lightning were herded into a tight beam by Earth's magnetic field," Briggs told his audience, according to National Geographic. "The beam funneled positrons from the Namibian storm to the Fermi spacecraft. [...] A few milliseconds after hitting the spacecraft, the beam struck a more northerly section of Earth's magnetic field [...] This caused some of the positrons to bounce back the way they had come, hitting the spacecraft with a second beam, like an echo."
PopSci reports that scientists now believe that all TGFs create beams of electrons and positrons, though not all thunderstorms produce TGFs.
"The Fermi results put us a step closer to understanding how TGFs work," said Duke University's Steven Cummer, who was not a member of Briggs's Fermi research team. "We still have to figure out what is special about these storms and the precise role lightning plays in the process."
Take a look at the video and photos (below) to see depictions of terrestrial gamma-ray flashes in action, as observed by Fermi, and visit the NASA Fermi mission page to learn more about this discovery. Then, take a look through our slideshow of NASA's most stunning images from 2010.