JUNO, a NASA space probe orbiting the planet Jupiter- recently captured images of colorful bursts of lightning-like electricity high in Jupiter’s atmosphere. For the first time, these bright, unpredictable, and extremely brief flashes of light, also known as transient luminous events, or TLE’s, are seen in another world.
The discovery of these bright flashes of light suggests that either “sprites” or “elves” could be dancing in Jupiter’s upper atmosphere.
Giles, a Juno scientist and the lead author of the paper, said, “Juno’s ultraviolet spectrograph instrument (UVS) was designed to characterize Jupiter’s beautiful northern and southern lights. But we discovered UVS images that showed not only Jovian aurora but also a bright flash of UV light over in the corner where it wasn’t supposed to be. The more our team looked into it, the more we realized Juno might have detected a TLE on Jupiter.”
Almost resembling a jellyfish, sprites are transient luminous events triggered by lightning discharges from thunderstorms far below.
Elves (short for Emission of Light and Very Low-Frequency perturbations due to Electromagnetic Pulse Sources), on the other hand, appear as a flattened disk glowing in Earth’s upper atmosphere. They, too, brighten the sky for mere milliseconds but can grow larger than sprites – up to 200 miles (320 kilometers) across on Earth.
Giles said, “Their colors are distinctive as well. On Earth, sprites and elves appear reddish due to their interaction with nitrogen in the upper atmosphere. But on Jupiter, the upper atmosphere mostly consists of hydrogen, so they would likely appear either blue or pink.”
On Jupiter, these 11 large-scale bright events were detected in a region where lightning thunderstorms are known to form. They were simply mega-bolts of lightning because they were found about 186 miles (300 kilometers) above the altitude where most of Jupiter’s lightning forms – its water-cloud layer.
Giles said, “We’re continuing to look for more telltale signs of elves and sprites every time Juno does a science pass. Now that we know what we are looking for, it will be easier to find them on Jupiter and other planets. And comparing sprites and elves from Jupiter with those here on Earth will help us better understand electrical activity in planetary atmospheres.”
- Rohini S. Giles et al. Possible Transient Luminous Events observed in Jupiter’s upper atmosphere. DOI: 10.1029/2020JE006659