Just above the clouds, on the other side of the sky is a phenomenon that’s caught the eye science, Sprites.
Sprites are a relatively newly discovered – 1989 – high altitude atmospheric optical emission – flash – they are a large-scale electrical discharge that occur high above thunderstorm clouds, or cumulonimbus, giving rise to a quite varied range of visual shapes flickering in the night sky. They are triggered by the discharges of positive lightning between an underlying thundercloud and the ground. Sprites only last for milli-seconds and can be quite dim compared to the lightning flash below the clouds. They look like recoil from lightning.
Sprites are often inaccurately called upper-atmospheric lightning. However, sprites are cold plasma phenomena that lack the hot channel temperatures of tropospheric lightning, so they are more akin to a fluorescent tube discharges than to lightning discharges.
The first photo’s taken on July 6, 1989 – by accident – scientists from the University of Minnesota captured the Sprite using low light cameras. Since then they have been photographed all over the world, anywhere a thunderstorm discharges lightning. Prior to 1989, Scottish physicist C. T. R. Wilson predicted in the 1920′s that electrical breakdown should occur in the atmosphere high above large thunderstorms causing this kind of effect.
The Sprites Campaign conducted by the Geophysical Institute of Alaska set out to answer many of the questions about sprites, how often do they ocure, dimensions, height, duration, speed, colour and other optical properties. Two jets and a ton of camera gear was used to collect footage of Sprites in action during June and July 1994.
It turns out Sprites occur when a large scale electrical discharges occurs high above a thunderstorm cloud, they stretch over a hundred kilometers high, don’t occur very often and have a reddish colour in general. Unlike lightning there is no heat or energy associated with the sprites flash. Sprites appear in quite varied range of visual shapes, and only appear over about 1 percent of lightning bolts. They were named after the mischievous sprite (air spirit) Puck in Shakespeare’s Midsummer Night’s Dream.
There are actually a number of other phenomenon in this new category of science. Blue jets which differ from sprites in that they project from the top of the thunderstorm, display a different colour and shape and also tend to be lower in the atmosphere. Also Jets are not associated directly with lightning. Along with Blue jets there are Blue starters, Gigantic Jets and Elves, all of which are different kinds of flashes occurring in the upper atmosphere.
Science making new discoveries all the time.
Buddha’s Brother out…