A study by Japanese researchers shows how storms emit gamma rays after matter and antimatter particles are created during lightning strikes.
Gamma rays, the highest energy form of electromagnetic radiation, can be generated during violent astronomical events, such as supernovae or during the annihilation of matter and antimatter.
However, we have known for some years now, thanks to NASA’s Fermi telescope, that gamma radiation bursts could have a terrestrial origin. More specifically, gamma rays are produced by thunderstorms.
Now, a team of Japanese researchers has just proved that thunderclouds can work like particle accelerators or stars and generate antimatter via lightning strikes.Lightning strikes result in matter/antimatter annihilation.Click To Tweet
Thunderclouds, Natural Particle Accelerators
Thunderstorms create enough energy to split atoms and create unstable isotopes.
Thunderclouds thus sometimes behave like natural particle accelerators via lightning that produces gamma-ray flashes known as TGFs (Terrestrial Gamma-ray Flash).
In the early 1990s, NASA’s BATSE (Burst and Transient Source Experiment) discovered for the first time TGFs and their association with thunderstorm activity.
The Fermi Gamma-ray Space Telescope, which has been orbiting Earth since 2008, is dedicated to the detection and study of gamma rays in space.
However, six years ago, Fermi’s Gamma-ray Burst Monitor team announced the detection of antimatter beams above thunderstorms. NASA scientists believed these antimatter beams were associated with lightning.
Between its launch and 2011, Fermi did observe nearly 130 TGFs, but NASA estimates that on average around undetected 500 TGFs occur every day around the globe.
There’s Matter/Antimatter Annihilation Wherever There’s Lightning
*Spoiler alert for Thor Ragnarok*
Now, thanks to the work of a Japanese research team, we know just how deadly Thor’s lightning sword can be.
The team, led by Teruaki Enoto from The Hakubi Center for Advanced Research at Kyoto University, showed that gamma rays generated by lighting’s own ability to create matter/antimatter annihilation then further interact with gas molecules in the atmosphere, and create a sustained gamma-ray afterglow.
The lightning strike begins the process like this:
- Electrons flung at high speeds in lightning collide with gas molecules
- Repeated collisions heat gas to a plasma state
- Blackbody radiation occurs, creating some visible light and also gamma rays
- Gamma rays agitate nitrogen and oxygen, separating neutrons from gas molecules (nuclear fission)
- Unstable isotopes are created, and as they decay, positrons are also released
- Positrons are attracted to ambient electrons and annihilate causing further gamma-ray bursts
After running out of funding, Enoto and his team launched a crowdfunding campaign, thanks to which they could build and install small gamma-ray detectors on western and northwestern coastal areas in Japan.
In February 2017, the instruments detected three distinct GRBs (gamma-ray bursts) that respectively took less than a millisecond, several milliseconds, and about one minute.
After analyzing data, the team knew the first burst was caused by the lightning strike. As for the origins of the second afterglow and third emissions, researchers explain in a press release:
“… determined that the second afterglow was caused by the lightning reacting with nitrogen in the atmosphere. Essentially, gamma rays are capable of causing nitrogen molecules to lose a neutron, and it was the reabsorption of these neutrons by other atmospheric particles that produced the gamma-ray afterglow. The final, prolonged emission was the result of unstable nitrogen atoms breaking down.”
The study, Photonuclear reactions triggered by lightning discharge, was published in Nature.