World-First Study Reveals How Lightning Sparks Gamma-Ray Flashes
The very moment two electrical currents slam together to form a lightning bolt has been captured, revealing for the first time the role this process plays in generating powerful gamma rays right here on Earth.
The observation confirms the hypothesis that the terrestrial gamma-ray flashes, or TGFs, associated with lightning are the result of a powerful electrical field accelerating electrons to nearly the speed of light.
In observations conducted in Kanazawa City in Japan's Ishikawa Prefecture, a team of researchers led by physicist Yuuki Wada of the University of Osaka used a cutting-edge, multi-sensor setup to capture colliding lightning in slow motion across multiple wavelengths.
"The ability to study extreme processes such as TGFs originating in lightning allows us to better understand the high-energy processes occurring in Earth's atmosphere," Wada explains.
Although cloud-to-ground lightning formation is fast, it's not instantaneous, and requires a path to be cleared by a lightning leader. Air is naturally not very conductive, but the buildup of charge in the atmosphere as a result of storm activity can generate an ionized channel of air along which electric currents can flow. This is a lightning leader, and they can emerge downwards from the clouds, or upwards from the ground.
TGFs are thought to be the result of the acceleration of electrons to near-light speeds in strong electric fields generated by thunderstorms. These cascades are known as relativistic runaway electron avalanches, and they're widely accepted as the explanation for TGFs.
When the electrons decelerate suddenly, deflected by collisions with atomic nuclei in the atmosphere, the loss of energy manifests as gamma rays – a form of deceleration radiation known as bremsstrahlung radiation.
The researchers set up a ground-based apparatus to monitor lightning across radio, optical, and high-energy wavelengths, able to capture details on microsecond timescales.
Fascinatingly, their results showed that TGFs and lightning are not simultaneous; rather, the TGF occurs before the lightning bolt. But we're talking about absolutely minuscule increments of time; to our eyes, it would absolutely seem simultaneous. Only with state-of-the-art equipment can we see the reality.
The team observed two lightning leaders, one negatively charged and streaking down from a thundercloud to a ground-based television broadcast tower, the other positively charged and snaking upwards from the tower.
Just before the two oppositely charged leaders met, a highly concentrated electric field emerged between them, in which electrons were accelerated to relativistic speeds.
The first gamma-ray photon was detected just 31 microseconds – 31 millionths of a second – before the leaders collided. The full TGF burst lasted until 20 microseconds after the leaders met to form the lightning strike.
This is the first time scientists have observed and recorded this process, offering new and highly detailed insight into how lightning storms can produce enough energy to create gamma radiation – the most energetic form of light in the electromagnetic spectrum.
"The multi-sensor observations performed here are a world-first," says physicist Harufumi Tsuchiya of the Japan Atomic Energy Agency. "Although some mysteries remain, this technique has brought us closer to understanding the mechanism of these fascinating radiation bursts."
The research has been published in Science Advances.
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Yahoo
23-05-2025
- Yahoo
When lightning bolts collide, do they unleash powerful gamma-ray flashes?
When you buy through links on our articles, Future and its syndication partners may earn a commission. The most powerful explosions in the known universe come from what are known as gamma-ray bursts — though they may not sound particularly exciting, scientists usually speak about these incredible blasts of electromagnetic radiation in the same breath as giant collapsing stars and black holes. We've catalogued quite a few of these events since the 1960s, and even used them to help us understand more about galaxy superclusters, but one particular kind of gamma-ray burst has remained somewhat of a mystery. It's called a terrestrial gamma-ray flash (TGF), and it erupts inside thunderstorms on Earth hundreds of feet above our heads. Yuuki Wada, a professor at Osaka University in Japan, has been studying TGFs for years. He's the lead author on a new study that examines the mysterious relationship between TGFs and lightning bolts — and, according to this study, scientists have observed a TGF synchronized with a lightning discharge that arose from a collision of leaders, which guide lighting flow, coming from opposite directions. "TGFs are one of the most energetic natural phenomena in the atmosphere," Wada told Wada's work focuses on high-energy phenomena in lightning flashes and thunderclouds. To gather data about lightning for study, the team traveled two hours north of Osaka to the seaside city of Kanazawa, located in Ishikawa Prefecture on the Northern coast of Honshu, Japan's main island. "We prepared an observation network around television transmission towers in Kanazawa," Wada said. The researchers used a "state-of-the-art multi-sensor setup "that could detect optical, radio-frequency and high-energy radiation. The multi-sensor observations they performed were a world first, senior author Harufumi Tsuchiya said in a statement, and that the combination of sensors helped them learn more about the mechanism for TGFs. However, conducting the research for the study was challenging — and Wada said it required a bit of luck — as the study relied on being able to observe lightning bolts in action. "Lightning is hard to predict now," Wada said. "So, there is a risk of performing intensive observations because detection ranges are limited." "There was a risk that we would detect nothing," Wada added. "Fortunately, we detected a TGF with the full network." Scientists know thunderstorms emit very short TGFs, as well as longer gamma-ray flashes, which can last from minutes to hours. But thunderstorms still hold their share of mysteries. The strong currents of air in thunderstorms can cause air and water to shoot up and down very quickly. When this happens, crystals of ice begin to collide inside the air currents, causing them to shed electrons and generate a lightning-producing electric field. While scientists think that, under specific conditions, TGFs arise from discharges of lightning during thunderstorms, they still don't understand the exact relationship between the two. "TGFs have been mostly detected by satellites, and a detail of how lightning produces gamma rays remains a mystery," Wada said. "Our ground-based observation gives us a clue to understand TGFs." Using the sensors on the transmission towers, the researchers caught a snapshot of lightning discharges along two paths. One path came from the thundercloud and led down to a transmission tower. The other path ascended in the opposite direction. The researchers observed the TGF right before the two discharge paths converged and created a highly concentrated electric field that the researchers say accelerated the electrons shooting through the air to near light speed. One second contains one million microseconds. The team recorded the first photon of the TGF just 31 microseconds before the paths met. The full burst lasted 20 microseconds after the paths formed a lightning strike. Related Stories: — Lightning on alien worlds may fail to spark life, simulations suggest — The most powerful explosions in the universe could reveal where gold comes from — New research on 'Death Star' that looks like a cosmic pinwheel reduces gamma-ray burst threat to Earth This new study follows previous work delving into TGFs from a number of scientific organizations, including NASA and European Space Agency (ESA). In August 2023, NASA pilots flew into thunderstorms aboard a high-altitude science aircraft to gather data on TGFs. In May 2019, ESA created the first-ever photo of a TGF, which arose from a thunderstorm over the island of Borneo, in Southeast Asia. To study the TGFs, they used a special observatory aboard the International Space Station. The work to understand TGFs is far from finished. "The relation between lightning and TGF is not clear," Wada says. "That is why we are continuing this study." "We are targeting winter thunderstorms in Japan," he added. "Because they have unusual features compared to other thunderstorms, such as lower cloud bases, we expect more mysteries will be resolved by observations in Japan." The study was published on May 21 in the journal Science Advances.
Yahoo
22-05-2025
- Yahoo
World-First Study Reveals How Lightning Sparks Gamma-Ray Flashes
The very moment two electrical currents slam together to form a lightning bolt has been captured, revealing for the first time the role this process plays in generating powerful gamma rays right here on Earth. The observation confirms the hypothesis that the terrestrial gamma-ray flashes, or TGFs, associated with lightning are the result of a powerful electrical field accelerating electrons to nearly the speed of light. In observations conducted in Kanazawa City in Japan's Ishikawa Prefecture, a team of researchers led by physicist Yuuki Wada of the University of Osaka used a cutting-edge, multi-sensor setup to capture colliding lightning in slow motion across multiple wavelengths. "The ability to study extreme processes such as TGFs originating in lightning allows us to better understand the high-energy processes occurring in Earth's atmosphere," Wada explains. Although cloud-to-ground lightning formation is fast, it's not instantaneous, and requires a path to be cleared by a lightning leader. Air is naturally not very conductive, but the buildup of charge in the atmosphere as a result of storm activity can generate an ionized channel of air along which electric currents can flow. This is a lightning leader, and they can emerge downwards from the clouds, or upwards from the ground. TGFs are thought to be the result of the acceleration of electrons to near-light speeds in strong electric fields generated by thunderstorms. These cascades are known as relativistic runaway electron avalanches, and they're widely accepted as the explanation for TGFs. When the electrons decelerate suddenly, deflected by collisions with atomic nuclei in the atmosphere, the loss of energy manifests as gamma rays – a form of deceleration radiation known as bremsstrahlung radiation. The researchers set up a ground-based apparatus to monitor lightning across radio, optical, and high-energy wavelengths, able to capture details on microsecond timescales. Fascinatingly, their results showed that TGFs and lightning are not simultaneous; rather, the TGF occurs before the lightning bolt. But we're talking about absolutely minuscule increments of time; to our eyes, it would absolutely seem simultaneous. Only with state-of-the-art equipment can we see the reality. The team observed two lightning leaders, one negatively charged and streaking down from a thundercloud to a ground-based television broadcast tower, the other positively charged and snaking upwards from the tower. Just before the two oppositely charged leaders met, a highly concentrated electric field emerged between them, in which electrons were accelerated to relativistic speeds. The first gamma-ray photon was detected just 31 microseconds – 31 millionths of a second – before the leaders collided. The full TGF burst lasted until 20 microseconds after the leaders met to form the lightning strike. This is the first time scientists have observed and recorded this process, offering new and highly detailed insight into how lightning storms can produce enough energy to create gamma radiation – the most energetic form of light in the electromagnetic spectrum. "The multi-sensor observations performed here are a world-first," says physicist Harufumi Tsuchiya of the Japan Atomic Energy Agency. "Although some mysteries remain, this technique has brought us closer to understanding the mechanism of these fascinating radiation bursts." The research has been published in Science Advances. The Universe Is 'Suspiciously' Like a Computer Simulation, Physicist Says Seismic Waves From Intense Storms Can Ripple Through Earth's Core New Theory Suggests Dark Matter Is Frozen Relics of Light-Speed Particles
Gizmodo
21-05-2025
- Gizmodo
Scientists Just Caught Lightning Firing Off a Gamma-Ray Blast
For the first time, scientists have caught lightning in the act of unleashing a powerful burst of gamma radiation known as a terrestrial gamma-ray flash (TGF). Researchers at the University of Osaka led the work—an intimate look at one of the most powerful and mesmerizing natural phenomena on our planet. The work also marks a step forward in the quest to understand how thunderstorms manage to pump out radiation we generally associate with the universe's most extreme objects: black holes and neutron stars. The team's study describing the observation was published today in Science Advances. Using a cutting-edge multi-sensor system in Kanazawa City, Japan, the team observed a lightning discharge split between two paths—one descending from a thundercloud, the other arcing up from a ground-based transmission tower. The scientists found that a gamma flash occurred just 31 microseconds before the two discharges met in the air. 'Most TGFs have been detected by satellites, but spaceborne observations can provide limited information,' said lead author Yuuki Wada, a researcher at the University of Osaka, in an email to Gizmodo. 'In this research, we performed a ground-based observation to see TGFs in detail.' TGFs were first detected from space in the 1990s, but despite more than two decades of research, their exact origin has remained elusive. Last year, a pair of papers in Nature revealed gamma-ray 'glows' and flickering flashes during tropical thunderstorms—radiation that scientists recorded by flying a retrofitted spy plane directly into storm systems. That research hinted at a wider family of radiation events lurking inside thunderclouds, with TGFs representing some of the briefest and most intense bursts. While those plane-based observations revealed where and when TGFs occur, the Osaka team's setup reveals the conditions in which they form. The gamma burst in this case appeared just before the two lightning leaders collided, indicating that a supercharged electric field accelerated electrons to near light speed, producing the energetic event. 'The recent Nature papers are based on airborne observations,' Wada said. 'They are also very interesting, but ground-based observations can be achieved much less expensively.' And unlike the weaker 'flickering gamma-ray flashes' recently discovered in tropical skies, this TGF was tightly synchronized with a lightning strike. While the previous papers provided a sweeping overview of how many gamma-ray events occur in a given tropical thunderstorm, the recent paper scrutinized one particular event to understand how lightning produces enough energy to generate gamma rays. 'The multi-sensor observations performed here are a world-first; although some mysteries remain, this technique has brought us closer to understanding the mechanism of these fascinating radiation bursts,' said co-author Harufumi Tsuchiya, a researcher at the Japan Atomic Energy Agency, in a University of Osaka release. Studying TGFs could help illuminate one of the most remarkable and powerful natural phenomena in our skies—so intense it was once attributed to the gods. The recent study shows that there's more to lightning than meets the eye—its might produces radiation associated with some of the universe's most powerful explosions.
