Jets and sprites are weird, fleeting events that occur above thunderstorms — and for a long time, scientists were convinced they did not exist. Once in a rare while, an eyewitness would report seeing branching structures, colored red or sometimes blue, above a thunderstorm, almost like backwards lightning. But nobody could ever photograph one because they are so faint and so brief, and being that it seemed to require pure luck to spot one, collecting proof seemed as impossible as the claims of such things.
Impossible until 1989, that is. On July 6, a team from the University of Minnesota were preparing experiments for a later sounding rocket flight. That night, they were performing a calibration exercise involving very low-light cameras when they observed a strange flash over the horizon. It took some time to work out what they had captured on their camera, and in 1990 they published their first tentative conclusion that they had photographed some strange kind of upwards lightning from one of the summer thunderstorms so common out on the plains. Inspired by this, other teams started analyzing video footage from low-light cameras flown aboard the Space Shuttle and found more examples. In a few years, the phenomenon had become firmly established as a space weather phenomenon (because it occurs strictly above the tropopause, sometimes reaching as high as the aurora), and acquired a name: sprites.
By the 21st Century, sprite research had gone from a curiosity to a serious area of research, and a new form of “upwards lightning” had been discovered: jets. Often blue while sprites are often red, jets are much taller, stretching for dozens of miles into space, but are every bit as transient. Today, with low-light cameras now available to the general public (or at least those members with a serious astrophotography habit) which are far superior to those available in 1989, sprite photography has become something of a sport among amateur astrophotographers, although even now, most are captured by chance while photographing other things.
Take this spectacular image of a blue jet terminating in a red structure like a sprite (though the presence of the jet means scientifically the whole thing is considered a jet). The photographer, Phebe Pan, had set up his fisheye camera to photograph the Perseids in Guangdong, China last weekend. There was a thunderstorm in the distance, but his eyes were on the meteors. Then he and other observers saw the jet climbing up out of the cloud, branching like a tree, and then disappearing in under a second. The whole, ephemeral structure could easily be fifty miles tall; it’s really a staggering thing to contemplate.
Now go on over to Spaceweather.com and check out the full gallery of this jet. Especially check out the fisheye version (as far as anyone knows, the only fisheye image ever taken of a jet) and the close-up version. They’re obviously all really various cropped versions of the same original, but it’s worth looking at them all, and reading Pan’s amazing account of seeing this spectacular sight.