https://weather.com/en-IN/india/sci...ice-in-the-same-place-scientists-now-know-why
Science
Lightning Does Strike Twice in the Same Place, Scientists Now Know Why
By Jan Wesner Childs
14 hours ago
TWC India
Lightning over Hyderabad
(Ramoorthy P, TOI, Hyderabad, BCCL)
At a Glance
Researchers using the LOFAR array of telescopes, originally designed for radio astronomy observations, have for the first time documented lightning “needles.” They think these needles, more than 300 feet long and about 15 feet wide, carry positive charges that are not discharged on the ground during an initial lightning strike back up to the thundercloud, creating successive strikes.
Their findings were published this week in the journal Nature.
“The LOFAR data allow us to detect lightning propagation at a scale where, for the first time, we can distinguish the primary processes," Dr. Brian Hare of Groningen University, lead author of the story, said in a press release from the Karlsruhe Institute of Technology.
To put it simply, lightning is basically a giant electrical charge. It starts when ice crystals collide in a thundercloud and create electrical charges. Those charges in turn can lead to a highly electrically conducive plasma channel, which makes it way to the ground in channels called lightning leaders.
“A stepped leader is the electricity from the sky and clouds trying to find the easiest way to the ground, often taking steps, twists and turns to get to there,” Jonathan Belles, a weather.com meteorologist, explained. “A second leader comes up from the ground, usually a tree or other tall structure, as positive and negative charges attract to each other. When these two leaders reach each other, they explode and become what is normally referenced to as lightning.”
As for that myth that lightning never strikes twice? Linguists say it’s actually just a metaphor to illustrate how rare it is for something spectacular to happen to a person more than once. Not only can multiple strikes happen in the same lightning flash, as the researchers studied, but lightning from different storms can strike the same location separated by days, months or years.
The National Weather Service says the odds of being struck by lightning in any given year are about a million to one. Yet being struck twice isn't unheard of. A Texas man, for example, told a reporter he was hit by two bolts of lightning in 2013. A man in New Mexico told a local TV station he was hit three times.
The study by the LOFAR research team showed that positively and negatively charged plasma channels behave differently during lightning initiation because of the needles they observed.
"The scientists assume that the charge of a positive plasma channel is not discharged entirely during a lightning strike, but that part of the charge returns to the thundercloud via the needles," according to the release from the Karlsruhe institute. "The stored charge could then initiate further discharges. This would explain why lightning does not discharge at once, as was thought for a long time, but can strike several times within seconds."
Science
Lightning Does Strike Twice in the Same Place, Scientists Now Know Why
By Jan Wesner Childs
14 hours ago
TWC India
Lightning over Hyderabad
(Ramoorthy P, TOI, Hyderabad, BCCL)
At a Glance
- Researchers for the first time observed lightning "needles."
- They think the needles carry undischarged electricity back up to clouds, creating more lightning bolts.
Researchers using the LOFAR array of telescopes, originally designed for radio astronomy observations, have for the first time documented lightning “needles.” They think these needles, more than 300 feet long and about 15 feet wide, carry positive charges that are not discharged on the ground during an initial lightning strike back up to the thundercloud, creating successive strikes.
Their findings were published this week in the journal Nature.
“The LOFAR data allow us to detect lightning propagation at a scale where, for the first time, we can distinguish the primary processes," Dr. Brian Hare of Groningen University, lead author of the story, said in a press release from the Karlsruhe Institute of Technology.
To put it simply, lightning is basically a giant electrical charge. It starts when ice crystals collide in a thundercloud and create electrical charges. Those charges in turn can lead to a highly electrically conducive plasma channel, which makes it way to the ground in channels called lightning leaders.
“A stepped leader is the electricity from the sky and clouds trying to find the easiest way to the ground, often taking steps, twists and turns to get to there,” Jonathan Belles, a weather.com meteorologist, explained. “A second leader comes up from the ground, usually a tree or other tall structure, as positive and negative charges attract to each other. When these two leaders reach each other, they explode and become what is normally referenced to as lightning.”
As for that myth that lightning never strikes twice? Linguists say it’s actually just a metaphor to illustrate how rare it is for something spectacular to happen to a person more than once. Not only can multiple strikes happen in the same lightning flash, as the researchers studied, but lightning from different storms can strike the same location separated by days, months or years.
The National Weather Service says the odds of being struck by lightning in any given year are about a million to one. Yet being struck twice isn't unheard of. A Texas man, for example, told a reporter he was hit by two bolts of lightning in 2013. A man in New Mexico told a local TV station he was hit three times.
The study by the LOFAR research team showed that positively and negatively charged plasma channels behave differently during lightning initiation because of the needles they observed.
"The scientists assume that the charge of a positive plasma channel is not discharged entirely during a lightning strike, but that part of the charge returns to the thundercloud via the needles," according to the release from the Karlsruhe institute. "The stored charge could then initiate further discharges. This would explain why lightning does not discharge at once, as was thought for a long time, but can strike several times within seconds."
