‘Piercing the atmosphere’: Hurricane lightning blasted antimatter at the Earth
On 23 October 2015, the NOAA Airborne Detector for Energetic Lightning Emissions (ADELE) flew through the eyewall of the category five storm. In order to be classified as a category five, a hurricane must have sustained winds exceeding 156mph (70 m/s; 136kn; 251kph).
The crew became the first humans to witness a terrestrial gamma-ray flash (TGF) from within a hurricane. The blast was so powerful it unleashed a reverse beam of positrons – also known as antimatter.
A positron is the elementary antiparticle of an electron, that holds the same mass and spin but is positively, not negatively, charged. The findings of the incredible mission were published earlier this month.
"I don't ask pilots to fly into thunderstorms, but if they're going anyway I'll put an instrument on board," said one of the researchers, physicist David Smith from UC Santa Cruz.
TGFs can occur thousands of times during protracted lightning storms, but each lasts just milliseconds, making them extraordinarily difficult to observe anywhere but from orbit. NASA frequently records TGFs from satellites. Since the 1990s scientists had predicted that gamma ray flashes, which fire outward from the Earth towards space, would have a corresponding downward beam of positrons.
"This is the first confirmation of that theoretical prediction, and it shows that TGFs are piercing the atmosphere from top to bottom with high-energy radiation," Smith said. “We saw it from below because of a beam of antimatter (positrons) sent in the opposite direction."
NASA releases SPECTACULAR image of majestic Crab Nebula in the constellation of Taurus https://t.co/0prbualt0K— RT (@RT_com) March 19, 2018
Thanks to the NOAA Hurricane Hunter crew, TGFs should now be easier to detect without the need for such extreme measures – ground-based detectors positioned at high altitudes should suffice.
"We detected it at an altitude of 2.5km (1.5 miles), and I estimated our detectors could have seen it down to 1.5km (0.9 miles)," Smith explains. "That's the altitude of Denver, so there are a lot of places where you could in theory see them if you had an instrument in the right place at the right time during a thunderstorm."
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