Japanese netizens help scan lightning for gamma rays
A storm system approaches: the sky darkens, and the low rumble of thunder echoes from the horizon. Then without warning... Flash! Crash! -- lightning has struck.
This scene, while familiar to anyone and repeated constantly across the planet, is not without a feeling of mystery. But now that mystery has deepened, with the discovery that lightning can result in matter-antimatter annihilation.
In a collaborative study appearing in Nature, researchers from Japan describe how gamma rays from lightning react with the air to produce radioisotopes and even positrons -- the antimatter equivalent of electrons.
"We already knew that thunderclouds and lightning emit gamma rays, and hypothesized that they would react in some way with the nuclei of environmental elements in the atmosphere," explains Teruaki Enoto from Kyoto University, who leads the project.
"In winter, Japan's western coastal area is ideal for observing powerful lightning and thunderstorms. So, in 2015 we started building a series of small gamma-ray detectors, and placed them in various locations along the coast."
But then the team ran into funding problems. To continue their work, and in part to reach out to a wide audience of potentially interested members of the public as quickly as possible, they turned to the internet.
"We set up a crowdfunding campaign through the 'academist' site," continues Enoto, "in which we explained our scientific method and aims for the project. Thanks to everybody's support, we were able to make far more than our original funding goal."
Spurred by their success, the team built more detectors and installed them across the northwest coast of Honshu. And then in February 2017, four detectors installed in Kashiwazaki city, Niigata recorded a large gamma-ray spike immediately after a lightning strike a few hundred meters away.
It was the moment the team realized they were seeing a new, hidden face of lightning.
When they analyzed the data, the scientists found three distinct gamma-ray bursts. The first was less than one millisecond in duration; the second was a gamma-ray afterglow that decayed over several dozens of milliseconds; and finally there was a prolonged emission lasting about one minute.
Enoto explains, "We could tell that the first burst was from the lightning strike. Through our analysis and calculations, we eventually determined the origins of the second and third emissions as well."
The second afterglow, for example, was caused by lightning reacting with nitrogen in the atmosphere. The gamma rays emitted in lightning have enough energy to knock a neutron out of atmospheric nitrogen, and it was the reabsorption of this neutron by particles in the atmosphere that produced the gamma-ray afterglow.
The final, prolonged emission was from the breakdown of now neutron-poor and unstable nitrogen atoms. These released positrons, which subsequently collided with electrons in annihilation events releasing gamma rays.
"We have this idea that antimatter is something that only exists in science fiction. Who knew that it could be passing right above our heads on a stormy day?" says Enoto.
"And we know all this thanks to our supporters who joined us through 'academist'. We are truly grateful to all."
The team still maintains over ten detectors on the coast of Japan, and are continually collecting data. They look forward to new discoveries that may await them, and Enoto hopes to continue seeing the participation of ordinary citizens in research, expanding the bounds of scientific discovery.
The paper "Photonuclear reactions triggered by lightning discharge" appeared 23 November 2017 in Nature, with doi: 10.1038/nature24630
Kyoto University is one of Japan and Asia's premier research institutions, founded in 1897 and responsible for producing numerous Nobel laureates and winners of other prestigious international prizes. A broad curriculum across the arts and sciences at both undergraduate and graduate levels is complemented by numerous research centers, as well as facilities and offices around Japan and the world. For more information please see: http://www.
Raymond Kunikane Terhune | EurekAlert!
PR of MCC: Carbon removal from atmosphere unavoidable for 1.5 degree target
22.05.2018 | Mercator Research Institute on Global Commons and Climate Change (MCC) gGmbH
Monitoring lava lake levels in Congo volcano
16.05.2018 | Seismological Society of America
At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.
At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...
There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?
At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...
A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.
The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...
02.05.2018 | Event News
13.04.2018 | Event News
12.04.2018 | Event News
22.05.2018 | Life Sciences
22.05.2018 | Earth Sciences
22.05.2018 | Trade Fair News