A high-speed camera captured an image showing several lightning rods trying to connect to the downdraft. The two downward branches visible in the image are part of the same lightning strike that eventually hit the building on the right. Thanks to the high-speed camera and the chance to be in the right place at the right time, physicists Marcelo Saba and Ph.D. Candidate Diego Ramon of the National Institute for Space Research (INPE) in Brazil has succeeded in obtaining a rare image of a lightning strike that shows connections to nearby buildings in intricate detail.
The picture is so unique that it was placed on the cover of the issue. Geophysical Research Letters (GRL) A well-known scientific journal in this field, dated December 28, 2022. The magazine also featured an article written by Saba for the first time. Saba’s research on this subject was supported by FAPESP.
“The image was taken on a summer evening in São José dos Campos. [ штат Сан-Паулу ], as negatively charged lightning approaches the ground at a speed of 370 km per second. At several tens of meters above ground level, lightning rods and tall objects on the roofs of nearby buildings created positive upward discharges to connect with the downward shock. The last front connection image was obtained in 25 thousandths of a second before the lightning struck one of the buildings,” he said. There is a remarkable image on the cover of the magazine.
He used a camera that shoots 40,000 frames per second. When the video is played in slow motion, it shows how lightning discharges behave and how dangerous they can be if the protection system is not properly installed: Although there are more than 30 lightning rods nearby, the crash is not about them. but to a chimney at the top of one of the buildings.
“A mistake in the installation left the area unprotected. The impact of the 30,000 amp discharge caused extensive damage,” he said.
On average, 20% of all lightning strikes involve the exchange of electrical discharges between clouds and the ground. The remaining 80% takes place in the clouds. Almost all ground-touching shocks are cloud-to-ground discharges. Elevations also occur, but are rarely caused by the top of tall structures such as mountains, skyscrapers, towers, and antennae. Lightning can also be classified as negative or positive depending on the charge transferred to the ground.
“Lightning can reach 100 km in length, and the current can reach 30,000 amps, which is equivalent to the current used by 30,000 100-watt light bulbs at the same time. In some cases, the current can reach 300,000 amps. The temperature of a typical lightning strike is 30,000 °C, which is the Sun. “It’s five times the temperature of the surface of the Earth,” he said.