March 6, 2006—Snapping 5,000 frames per second, a high-speed camera has captured the best images ever of elusive sprites, flashes of light associated with intense thunderstorms.

The findings, published by Steven Cummer of Duke University and his team in a recent online edition of Geophysical Research Letters, show how sprites develop.

They could also help scientists get a better handle on the chemical make up of the upper atmosphere, a region that is too high to analyze with planes and too low for satellites.

"They substantially improved the time resolution of the observation of sprite events," said Victor Pasko, associate professor of electrical engineering at the Pennsylvania State University.

"That immediately brought some very interesting results in comparison to previous studies," said Pasko, who is not involved in the research.

To date, the fastest images ever taken of sprites have been at a speed of 1,000 frames per second. From those and previous studies, scientists had some insights into these so-called transient luminous events that burst and fade out faster than the blink of a human eye.

For example, they knew that sprites occurred 20 to 50 miles above powerful thunderstorms; that they happened after unusually strong lightning strikes; that they had a branching structure; and that they were often characterized by intense bright spots that persisted seconds after the sprite disappeared.

Cummer and his team rented a camera typically used to film such high-speed action as crash tests, rocket launches, and explosions. They turned its lens on several thunderstorms in Fort Collins, Colo., over a six-week period in the summer of 2005.

Team members watched monitors that displayed live video from the conventional cameras. When intense lighting flashes indicative of sprites occurred, a scientist would press a trigger that remotely opened the shutter on the high-speed camera.