At http://phys.org/print296718236.html … airline pilots often reported seeing strange lights, nicknamed sprites. They observed them when flying during storms, sometimes high above the actual clouds and stormy weather. Atmospheric scientists, in general, displayed little interest. It was not part of the science learned and residing in their memory bank. We may also think in terms of disbelief – that pilots could observe something outside the mainstream knowledge base. Now, with undeniable evidence as a result of modern cameras and space telescopes there is no hiding place for the scientists – and the actuality of sprites is recognised (and they are being studied). Sprites are now characterised as electrical discharges – like lightning, but different. Lightning occurs below or within clouds but sprites occur above clouds – very often far above clouds (as much as 50 miles up in the air). They are also very large affairs – but come and go quickly, flashing on and off.
Scientists have also found sprites create low frequency radio bursts which have been picked up for years by instruments but the sources was otherwise unknown. Large bursts of gamma rays, emanating from Earth rather than space, evident during electrical thunderstorms, is a puzzle. The exact relaltionship to sprites is unclear. It is possible sprties even alter the chemical composition of the upper atmosphere. However, finding a gamma ray link between sprites and electric sparks from Earth might cause a relook of gamma ray activity from other star systems.