Sprites, blue jets, & other mysterious lights in our upper atmosphere explained

Nearly 30 years ago, scientists in aircraft miles above the ground finally managed to capture a phenomenon never before confirmed on film. This flash of red light, lasting no longer than a few milliseconds, was the first color photograph of a sprite. It doesn’t look at all like the ones in a storybook, but they’re just as mystical, mysterious, and elusive.

Over the years more and more of these red flashes have been recorded, alongside other fleeting flashes of color above clouds. Scientists gave these events whimsical names such as ELVES, SPRITES, TROLLS, blue jets. All now classified as as Transient Luminous Events (TLEs), a much more scientific acronym for these short-lived electrical discharges in our upper atmosphere.

An Electric Balancing Act in Earth’s Atmosphere

While much is still unknown about this rare atmospheric phenomenon, scientists have a good idea about what causes them- nature balancing electric charges above and below strong thunderstorms. 

Most lightning produced in a thunderstorm is of the negative variety, transferring a negative charge to the ground below, but roughly 5% of lightning is positive- transferring a much more powerful positive electrical charge from the cloud. This positive lightning strike electrically disrupts the air high above the storm- creating a light display that arcs upwards in columns extending into the Mesosphere, 50 miles above Earth, far above the storm that produced the sprite way down in the Troposphere. 

You could call it “upper atmospheric lightning,” however that’s a bit misleading as these are made up of cold plasma- akin to fluorescent lights, unlike white hot lightning. The dim red hue of sprites is produced as nitrogen molecules in the thin air of our upper atmosphere become excited and glow- if only for a fraction of a second. Going frame by frame with slow motion cameras from patient skywatchers shows complex features our eyes cannot- jellyfish like tendrils and columns that spread out for upwards to 30 miles! This sight could easily be mistaken for an extraterrestrial visitor from outer space.

That said, sprites are otherworldly- literally.

Just last year, NASA’s Juno mission observed a transient luminous event in Jupiter’s atmosphere, the first seen on another planet. It’s hypothesized that Jupiter’s sprites are blue- not red, as hydrogen, not nitrogen makes up the majority of the Jovian atmosphere. 

Above our own planet, aboard the International Space Station- astronauts continue to find more and more of these natural electrical flashes above storms with the hope that these sightings will reveal more about these stunning atmospheric events- so mysterious that they required names right out of a fairytale. 

Storm Team 2 Meteorologist David Dickson