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http://thunder.nsstc.nasa.gov/bookshelf/pubs/sprites.html
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http://thunder.nsstc.nasa.gov/bookshelf/pubs/sprites.htmlTHE ROLE OF THE SPACE SHUTTLE VIDEOTAPES IN THE DISCOVERY OF SPRITES, JETS AND ELVES
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Abstract. The sequence of video tape observations of the upper atmospheric optical flashes called sprites, jets, starters, and ELVES are described in the successsive phases of search, discovery, confirmation, and exploration for the years before 1993. Although there were credible eyewitness accounts from ground observers and pilots, these reports did not inspire a systematic search for hard evidence of such phenomena. The science community would instead wait for serendipitous observations to move the leading edge of this science forward. The phenomenon, now known as a sprite, was first accidently documented on ground based videotape recordings on the night of July 6, 1989. Video observations from the space shuttle acquired from 1989 through 1991 provided 17 additional examples to confirm the existence of the sprites phenomenon. Successful video observations from a mountain ridge by Lyons, starting July 7, 1993, and night-time aircraft video observations by Sentman and Wescott on July 8, 1993 established the basic science of the sprite phenomena by acquiring and analyzing data based on hundreds of new events. The 1994 Sprites campaign and the video titled "Red Sprites and Blue Jets" popularized the name sprite and provided a vocabulary of terms to describe the visual attributes. Prior to this video, investigators used a variety of vague descriptive words to describe the individual events. Also, during the 1994 campaign, Wescott and coworkers obtained the first quantative measurements of jets and provided the name "blue jets". A third phenomenon was discovered in video from the STS-41 mission (October 1990) in the lower ionosphere directly above an active thunderstorm. It consisted of a large horizontal brightening several hundred kilometers across at the altitude of the airglow layer. In 1995, Lyons and associates confirmed the existence of this type of very brief brightening which they named Emissions of Light and Very Low Frequency Perturbations From Electromagnetic Pulse Sources (ELVES). Because sprites, jets, and ELVES have appeared for millennia, their discovery was inevitable. The partial history related in this paper outlines the unsophisticated activities using shuttle video and the dissemination of the results by video presentations during the early phases of sprite research. This paper does not attempt to evaluate the advances in the science based on the measurement campaigns of Lyons, Sentman and the many other investigators. [continued]
Sprites, jets, and elves are all types of transient luminous events (TLEs) that occur in the upper atmosphere. They are caused by electrical discharges in the atmosphere, and can appear as bright flashes or glows of light.
Sprites, jets, and elves are formed when lightning strikes or other electrical discharges create a strong electric field in the upper atmosphere. This electric field then ionizes the gas in the atmosphere, creating the bright flashes of light that we see.
No, sprites, jets, and elves are not dangerous to humans. They occur at high altitudes in the atmosphere and do not reach the ground. However, they can be indicators of severe weather, so their study can be important for predicting storms.
Sprites, jets, and elves were first observed in 1989 by scientists studying lightning. They were initially thought to be camera anomalies, but were later confirmed to be real phenomena. Since then, they have been studied extensively using high-speed cameras and other advanced technology.
Understanding sprites, jets, and elves can help us better understand the complex dynamics of our atmosphere. Studying these phenomena can also provide insights into the effects of lightning on the Earth's upper atmosphere and how it may impact our planet's climate. Additionally, their study can aid in the improvement of weather forecasting and aviation safety.