ELVES (upper-atmospheric lightning)

ELVES, an acronym for Emissions of Light and Very Low Frequency Perturbations due to Electromagnetic Pulse Sources, are transient luminous events that appear in the ionosphere roughly 100 kilometers above a thunderstorm. They typically take the form of a dim, flattened glow that expands to around 400 kilometers in diameter and fades within about a millisecond, their red color coming from nitrogen molecules excited by electrons energized by the electromagnetic pulse of a lightning discharge below. The phenomenon was first recorded on October 7, 1990, by the Mesoscale Lightning Experiment team aboard a Space Shuttle mission observing storms off French Guiana. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/