Storm watching,
am I seeing things?

by Paul Gill

Red sprites are a scientific term, not for fairies in a forest, but an upper atmosphere phenomenon. While still mysterious, they were attributed to early aviation myth and lore.

Pilots had reported seeing a red flash above the tops of thunderstorms, but no one had ever been able to take any photos of them. The first images of a sprite were accidently obtained in 1989 during military flights recording with high speed photography. Suddenly videos of large but weak luminous flashes appeared directly above an active thunderstorm. They can be small single or multiple vertically elongated structures, that I feel resemble a long jellyfish.

These can extend from above the cloud tops to altitudes up to almost 60 miles. Sprites are predominantly red and they usually last no more than a few milliseconds. So, don’t rely on getting a “good look” at them.

The brightest region lies in the altitude range 40 to 45 miles, above which there is often a faint red glow or wispy structure that extends to about 60 miles. Below the bright red region, blue tendril-like filamentary structures often extend downward to as low as 20 miles. Because of their dimness, they have can only be seen at night, preferably with highly sensitive cameras. However, if ones eyes are sufficiently dark-adapted, one can actually detect them without any visual aid.

I prefer to use a cardboard square, like that of the back of a pad of paper to hold up at the level of the lightning flash. Then I focus on the region above that and the cardboard helps keep my eyes dark adapted.

If I think I saw a red flash, then it is likely I did, since the brain can not process light flashes down to a millisecond in length. Currently science views the sprite as a form of TLE (trans·luminous event) related to ground to cloud lightning strikes and it is still being deciphered with ongoing research.