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17 April 2014 12:48 pm ,
Vol. 344 ,
Officials last week revealed that the U.S. contribution to ITER could cost $3.9 billion by 2034—roughly four times the...
An experimental hepatitis B drug that looked safe in animal trials tragically killed five of 15 patients in 1993. Now,...
Using the two high-quality genomes that exist for Neandertals and Denisovans, researchers find clues to gene activity...
A new report from the Intergovernmental Panel on Climate Change (IPCC) concludes that humanity has done little to slow...
Astronomers have discovered an Earth-sized planet in the habitable zone of a red dwarf—a star cooler than the sun—500...
Three years ago, Jennifer Francis of Rutgers University proposed that a warming Arctic was altering the behavior of the...
- 17 April 2014 12:48 pm , Vol. 344 , #6181
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ScienceShot: Thunderstorms Make Antimatter
11 January 2011 12:58 pm
SEATTLE, WASHINGTON—Thunderstorms produce beams of antimatter. That's the surprising finding reported here yesterday at the 217th meeting of the American Astronomical Society. Scientists already knew about flashes of high-energy gamma-rays from Earth, which are associated with large thunderstorms. Every day, about 500 of these terrestrial gamma-ray flashes (TGFs) are produced worldwide by accelerated electrons interacting with air molecules. Now, astrophysicists working with NASA's Fermi Gamma-ray Space Telescope have found that some of the high-energy gamma-ray photons from TGFs are converted into pairs of electrons and positrons, the positively charged antiparticles of electrons. Every now and then, the orbiting space telescope is hit by some of these antimatter particles, which rush through Earth's magnetic field. When the positrons collide with electrons in the atoms that make up the spacecraft, they annihilate each other, producing gamma-ray photons with a telltale energy in the process. The role of lightning in the production of gamma rays and antimatter is still unclear, but the new discovery might help physicists better understand the mysterious TGF's.
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