When cosmic rays crash into Earth's atmosphere, they produce a spray of secondary particles that is most intense at the entrance to the stratosphere.
Physicists Eric Reneger and Georg Pfotzer discovered the maximum using balloons in the 1930s and it is what we are measuring today.
The answer is "yes." Unlike sprites, which flicker so rapidly that they are difficult to see with the unaided eye.
Gigantic Jets can lasts for hundreds of milliseconds, long enough for human eyes to register their purple glow.
These energies span the range of medical X-ray machines and airport security scanners.
These balloons are equipped with radiation sensors that detect cosmic rays, a surprisingly "down to Earth" form of space weather.
Cosmic rays can seed clouds, trigger lightning, and penetrate commercial airplanes.
"It looks like it may have reached as high as 90 km above the ground." "Gigantic Jets are much more rare than sprites," says van der Velde.
"While sprites were discovered in 1989 and have since been photographed by the thousands, it was not until 2001-2002 that Gigantic Jets were first recorded from Puerto Rico and Taiwan." Only dozens of Gigantic Jets have ever been photographed.