Brainy Quote of the Day

Thursday, April 25, 2013

Dark Lightning...

No, not him...

Star Wars Wiki

Scientists in the US say they have found a dramatic new electrical-discharge mechanism that could explain how thunderstorms can produce flashes of gamma radiation. Called "dark lightning", the effect is silent, invisible to the eye and a potential threat to aeroplane passengers – at least according to the researchers' models. This is because such lightning has the potential to produce intense terrestrial gamma-ray flashes (TGFs) and could deliver a radiation dose equal to a full-body X-ray-tomography (CT) scan to nearby air travellers.

TGFs are extremely bright pulses of gamma rays emanating from the Earth's atmosphere. They last just a few tenths of a millisecond but are capable of temporarily blinding satellite-based instruments located hundreds of kilometres away. Scientists have known about TGFs since the early 1990s, when they were discovered by accident by instruments designed to measure gamma rays from distant astrophysical sources such as supernovae and black holes.

Physics World: Dark lightning sheds light on gamma-ray mystery

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