Are spirits under the clouds of Jupiter? The answer could be yes! A paper recently published in the Journal of Geophysical Research: Planets found what appears as "sprites" in Jupiter's atmosphere.
In European folklore, "sprites" (derived from the Latin "spirit" or spirit) were elementary and ethereal beings who visited the earth. The term fits to “lightning sprites”, a natural meteorological phenomenon with many testimonies, but which was only recorded in front of the camera in 1989. Sprites are generated by lightning discharges in the earth's atmosphere and belong to a larger family of phenomena known as TLEs or "transient" Luminous Events, "which last only fractions of a second.
Dancing fairies (sprites) by the Swedish painter August Malmström – Public Domain
When light falls between clouds or between clouds and the surface of the earth, a pulse of electromagnetic and electrostatic energy is emitted into the upper atmosphere. This radiation can excite nitrogen molecules (N2) in the air and create TLEs, including "Sprites", "Sprite Halos" and "Elves". Sprites are generated by lightning strikes from cloud to cloud and appear as glowing, tendril-like columns with a width of 25 to 50 km, a height of 90 km (the Kármán line, which defines the boundary between atmosphere and space, is 100) and only takes 5 milliseconds. Sprite halos are diffuse and disc-shaped, have a radius of 100 km and last 2-10 ms at similar heights. Elves are formed by strikes from cloud to ground, creating diffuse rings up to 300 km wide and lasting less than 1 ms. TLEs are faster than the blink of an eye (100-150 msec) and difficult to see, but some incredible photos were taken. You can even hunt sprite!
First color image of a sprite taken in 1994 during a NASA / University of Alaska airplane campaign to investigate sprites. The event was recorded with an intensified color television camera. It was then determined that the red color was caused by nitrogen fluorescence emissions stimulated by a lightning strike in the thunderstorm below. Caption from Wikipedia – C. Public Access Domain / NASA https://en.wikipedia.org/wiki/Sprite_(lightning)
We know that there is lightning on other worlds. Voyager 1 took pictures of lightning storms on Jupiter's night side in 1979. Although it was speculated that lightning storms on other planets could create TLEs similar to those on Earth, we had not yet observed them. When the researchers checked the Juno data for the past two years, multiple flashes in both visible and ultraviolet light indicated that Juno had observed 11 sprites in Jupiter's clouds. In contrast to Earth, these sprites only lasted 1.4 ms, but were much larger from 500 km to 2200 km in diameter. They appeared 269 km above 1 bar atmospheric pressure (corresponds to the atmospheric pressure of the earth at sea level, similar to Jupiter's "surface"). The lightning strikes that create these sprites occur between clouds at lower elevations made up of both water and ammonia. While the earth's atmosphere creates red sprites from nitrogen, Jupiter's sprites appear blue when hydrogen is excited.
Lightning bolt on Jupiter captured by Voyager 1-c NASA / JPL
Speaking of storms on Jupiter
While the sprites were noted in Juno's ultraviolet spectrograph instrument, the JunoCam, which sees in visible light, also noted the brief flashes that indicate sprites.
8 by Giles et al. 2020. “The images shown here were created by combining the data from the red and green JunoCam filters. The positions of the bright flashes are indicated by the red crosses and the folded filament areas are marked by the lines. “C NASA / Giles et al. 2020.
Our world is so different from that of the largest gas giants in our solar system. Yet, by studying these other worlds, we find similarities that help us better understand our own. As the researchers note, "comparing and comparing TLE observations between Jupiter and Earth will help improve our understanding of electrical activity in planetary atmospheres."
Happy Halloween and watch out for sprites!
More to discover:
Juno data indicates sprites or elves frolicking in Jupiter's atmosphere – NASA
Possible transient light events in the upper atmosphere of Jupiter – Rohini S. Giles et al. 2020
Here is Jupiter from Juno's newest flyby universe today
See a 360-degree Juno-Eye view of Jupiter during an Io solar eclipse – Universe Today
What are lightning sprites? – EarthSky
Atmospheric layers of the earth – NASA