RED SPRITES OVER THE USA


Around Earth's northern hemisphere, thunderstorm season is in full swing. That means it's a great time to see sprites.  Paul Smith photographed these specimens on July 14th:


"I was at Kaw Lake in Oklahoma when the sprites started leaping up from the thunderheads," says Smith. 
Sprites are an exotic form of upward-directed lightning, reaching from the tops of electrical storms all the way up to the edge of space. 

Because they emerge from the tops of storms, the best place to see sprites is from a distance where the camera can point over the edge of the thunderhead.
"I was about 140 miles from the storm in Kansas that produced these sprites," says Smith. 
This weather map shows the location of his camera (blue pushpin) and where it was pointing (blue arrow):

People have been seeing sprites since at least the 19th century, but the first reports were met with skepticism. Sprites entered the mainstream in 1989 when researchers from the University of Minnesota finally captured them on film. Subsequent video footage from the space shuttle cemented their status as an authentic physical phenomenon.

In recent years, citizen scientists like Smith have been photographing sprites in record numbers. One reason is raised awareness. More photographers know about sprites, so more sprites are being photographed. Another reason might be a genuine increase in sprite activity. 

Some researchers think that sprites are linked to cosmic rays. Subatomic particles from deep space strike the top of Earth's atmosphere, producing secondary electrons that trigger the upward bolts. Cosmic rays are now intensifying due to the decline of the solar cycle.

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