A vocabulary of landscape — a landscape of words
1367 entries
elve
An elve is a ring of light that expands across the underside of the ionosphere, about fifty-five miles up, when the electromagnetic pulse from a lightning stroke below reaches it and sets the air glowing. The ring spreads outward at the speed of light and can reach two hundred miles across. The whole event lasts under a thousandth of a second, which is why nobody knew they existed until high-speed cameras were pointed at the tops of storms.
Etymology
The name is a joke that stuck, and then a committee built an acronym to justify it, as with STEVE. The family of upper-atmosphere discharges was named out of folklore first: sprites, elves, blue jets, and trolls, chosen because these were fleeting, elusive things nobody could photograph and the researchers were enjoying themselves. Afterward, ELVES was expanded to stand for emissions of light and very low frequency perturbations due to electromagnetic pulse sources, which is transparently reverse-engineered.
Notes
Elves are the most common of these events, making up roughly half of everything in the category. The first was captured from the Space Shuttle in 1990. C.T.R. Wilson predicted discharges above thunderstorms in 1925 and was ignored for sixty-five years, until a camera at the University of Minnesota accidentally recorded a sprite in 1989 while being tested for something else.