NASA Spacecraft Captures Blue 'Sprites' and 'Elves' Dancing in Jupiter's Atmosphere

Published October 29th, 2020 - 11:46 GMT
(Shutterstock/ File Photo)
(Shutterstock/ File Photo)
Sprites and elves are common on Earth, but this is the first time they have been observed on another world

NASA's Juno spacecraft has captured electric blue 'sprites' and 'elves' dancing in Jupiter's atmosphere.

Such transient luminous events occur on Earth during a thunderstorm, but these are the first to be observed on another world.

The bright, unpredictable flashes of lights typically form on our planet about 60 miles above large thunderstorms, creating flares that last just milliseconds.

The flashes, which are deemed sprites, resemble a jellyfish with long tendrils flowing down toward the ground, and elves appear as a flattened glowing disc that can stretch up to 200 miles across the sky.

Juno scientists spotted the cosmic displays 186 miles above the altitude where the majority of the gas giant's lightning forms -its water-cloud layer. 

Juno's ultraviolet spectrograph instrument (UVS) detected the transient luminous events( TLE), which appeared as a bright, narrow streak of ultraviolet emission that disappeared in a flash.

Rohini S. Giles, lead study author and Juno planetary scientist, said: 'UVS was designed to characterize Jupiter's beautiful northern and southern lights.'

'But we discovered UVS images that not only showed 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 may have detected a TLE on Jupiter.'

The occurrence of sprites and elves on Jupiter were predicted by several previously published studies, but Juno has confirmed these theories to be true.

The craft capture 11 large-scale bright events in a region where lightning thunderstorms are known to form. 

Juno scientists could also rule out that these were simply mega-bolts of lightning because they were found about 186 miles above the altitude where the majority of Jupiter's lightning forms - its water-cloud layer. 

And UVS recorded that the spectra of the bright flashes were dominated by hydrogen emissions.

Sprites, which are named after the mischievous English folklore, were first documented on Earth in 1990.

These objects form up to 60 miles above violent thunderstorms and can light up the night sky tens of miles across, but the brilliant display lasts only a few milliseconds.

The typically grow a bright red on Earth, but on Jupiter the appear as a glowing blue. 

Elves (short for Emission of Light and Very Low Frequency perturbations due to Electromagnetic Pulse Sources) appear as a flattened disk glowing in Earth's upper atmosphere.

These occur high above energetic cloud-to-ground lightning of positive or negative polarity, and were confirmed in 1992 by a camera on the International Space Station. 

Just like their fellow sprites, these last just milliseconds but can grow larger - up to 200 across on Earth.

'On Earth, sprites and elves appear reddish in color due to their interaction with nitrogen in the upper atmosphere,' said Giles.

'But on Jupiter, the upper atmosphere mostly consists of hydrogen, so they would likely appear either blue or pink.' 

A rotating, solar-powered spacecraft, Juno, arrived at Jupiter in 2016 after making a five-year journey. Since then, it has made 29 science flybys of the gas giant, each orbit taking 53 days.

'We're continuing to look for more telltale signs of elves and sprites every time Juno does a science pass,' said Giles. 

'Now that we know what we are looking for, it will be easier to find them at Jupiter and on other planets. And comparing sprites and elves from Jupiter with those here on Earth will help us better understand electrical activity in planetary atmospheres.'

This article has been adapted from its original source.

© Associated Newspapers Ltd.

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