Environment Lightning strikes twice

Lightning strikes twice

When thunder calls, you better bolt. It seems lightning does strike twice and now we know why.

The Australian National University researcher Harvey Butcher says the first strike creates a channel through which another may follow.

“This happens in structures called needles that have never been described before,” he says.

“Through these needles, a negative charge may cause a repeated discharge to the ground.”

Emeritus Professor Butcher led the development of the telescope used by the international team – a special radio telescope comprised of thousands of small antennas spread across northern Europe.

Able to focus on the distant universe as well as things on earth, the telescope recorded high definition, 3D images of lightning flashes.

That allowed scientists to study them in detail never seen before.

“The reason why a lightning channel is reused had been a mystery until now,” Professor Butcher says.

“This new research shows the negative charges inside a thundercloud are not drained all in one flash but are, in part, stored alongside breaks in the main lightning channel.”

The research team chose the name “needles” for these breaks in keeping with their potentially prickly nature.

It is estimated lightning kills around 10 people in Australia every year.

Experts recommend staying indoors during storms. If caught outside avoid tall objects that may attract strikes.

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