Particles divided in the warm belly of a ray. The radioactive particles decompose in the subsequent brightness. Gamma rays go down to Earth.
Teruaki Enoto, a physicist at Kyoto University in Japan, demonstrated for the first time, in an article published on November 23, that rays work as accelerators of natural particles. The results of Enoto and his coauthors confirm for the first time that speculation dates back to 1925 on this phenomenon. Back then, scientists suggested that energized and radioactive particles could pbad through the booms and lightning of a thunderstorm. These particles emit energy at precise wavelengths, which Enoto and his colleagues are the first to detect. [Electric Earth: Stunning Images of Lightning]
Here's what that means:
When the light is turned on, the electrons shoot at high speed between the clouds and the surface of the Earth (or between two clouds). But the particles do not travel through empty space. On the way, they crash again and again in the atmospheric gas molecules. All these collisions heat the gas in a state called plasma, which shines with black-body radiation (a type of electromagnetic radiation emitted by some opaque objects).
Part of that glow, people can see, in the bright flash characteristic of lightning. But part of the emission takes place at frequencies, including X-rays and gamma rays, well above what the human eye can detect.
Enoto's results show that these invisible energy rays – especially gamma rays – excite environmental nitrogen and oxygen in the atmosphere, eliminating neutrons from the molecules that find the gamma rays. In other words, the process results in nuclear fission. Now, things get really exciting. The nuclei of nitrogen with 14 neutrons are stable. But remove one of those neutrons and you'll have nitrogen-13, an unstable radioactive isotope. Similarly, oxygen-16 is stable, but -15 … not so much.
Soon, all those N-13 and O-15 molecules break down. Each unstable isotope triggers an additional neutrino and positron (the antimatter companion of the electron); both are elementary particles with exotic properties. The neutrinos move away, almost undetectable. But the positrons, or antielectrons, come to collide with their twins: environmental electrons in the atmosphere. And when matter and antimatter meet, they annihilate with a flash of energy.
In this case, that signature is a gamma ray with an energy of 0.511 megaelectronvolts. And that's what Enoto and his colleagues detected when descending from a thunderstorm, which shows that a thunderhead is a giant natural particle accelerator that drifts through the sky.