Red sprites, blue jets and elves are upper atmospheric optical phenomena associated with thunderstorms that have only recently been documented by using low light level television technology.
Sprites are predominantly red and they usually last no more than a few milliseconds.
However, if ones eyes are sufficiently dark-adapted, one can actually detect them without any visual aid. Now they are simply referred to as sprites, a whimsical term that evokes a sense of their fleeting nature, while at the same time remaining nonjudgemental about physical processes that have yet to be determined. Though they can be accompanied by sprites, the causative mechanism is of an entirely different nature. Predicted to exist in the early 1990's and discovered in 1994, elves got their name as an acronym for E mission of L ight and V ery Low Frequency perturbations due to E MP S ources. Sprite halos are even more recently discovered.