Juno’s data suggests that “goblins” or “elves” have fun in the atmosphere of Jupiter – …

Scientists predicted that these bright, super-fast flashes should also be present in Jupiter’s immense atmosphere, but their existence remained theoretical. In the summer of 2019, researchers working with data from Juno’s ultraviolet spectrograph (UVS) discovered something unexpected: a bright, narrow strip of ultraviolet emission that disappeared in a flash.

“UVS was designed to feature Jupiter’s beautiful northern and southern lights,” said Giles, a Juno scientist and lead author of the paper. “But we discovered UVS images that not only showed Jupiter’s aurora, but also a bright flash of UV light in the corner where it shouldn’t be. The more our team looked at him, the more we realized that Juno might have recognized him. “A TLE on Jupiter.”

Short and bright

Sprites, named after a mischievous and witty character in English folklore, are transient light events triggered by lightning strikes from thunderstorms far below. On Earth, they occur up to 60 miles on intense, towering thunderstorms and illuminate a region of the sky tens of kilometers across, but only last a few milliseconds (a fraction of the time it takes to blink). .

Sprites are almost like a jellyfish and have a central bright spot (15 to 30 miles or 24 to 48 kilometers in diameter on Earth) with long tendrils that extend both downward and upward. Elves (short for light emission and very low frequency disturbances due to sources of electromagnetic pulses) appear as a flattened disk that glows in the earth’s upper atmosphere. They also light up the sky for a few milliseconds, but they can be larger than sprites – up to 320 kilometers wide on Earth.

Their colors are also unmistakable. “On Earth, sprites and elves appear reddish due to their interaction with nitrogen in the upper atmosphere,” Giles said. “But on Jupiter, the upper atmosphere is mostly hydrogen, so it will probably appear blue or pink.”

Location, location, location

The appearance of goblins and elves on Jupiter has been predicted by several previously published studies. Consistent with these predictions, the 11 large-area light events detected by the Juno UVS instrument occurred in a region known to be thunderstorms. The Juno scientists were also able to rule out that they were just mega lightning bolts, as they were found some 300 kilometers above the height at which most of Jupiter’s lightning forms – its water cloud layer. And UVS recorded that the spectra of light flashes were dominated by hydrogen emissions.

A solar-powered rotating spacecraft, Juno, arrived on Jupiter in 2016 after a five-year journey. Since then, the gas giant has made 29 scientific flyovers, each lasting 53 days.

“We look for telltale signs of elves and goblins every time Juno takes a science pass,” Giles said. “Now that we know what we are looking for, it will be easier to find them on Jupiter and other planets. If we compare the Sprites and Elves of Jupiter with those here on Earth, we can better understand the electrical activity in planetary atmospheres. ”

Learn more about the mission

JPL, a division of Caltech in Pasadena, California, administers the Juno mission for Principal Investigator Scott Bolton of the Southwest Research Institute in San Antonio. Juno is part of NASA’s New Frontiers program, administered at NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington. Lockheed Martin Space in Denver built and operates the spaceship.

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