Jupiter’s other worldly gloss of polar auroras is occasionally illuminated by short but intense early morning displays known as morning storms. Now, for the first time, scientists have discovered where morning storms come from, how they grow, and that they are even more powerful than expected.
Scientists knew about morning storms from telescopes in space and beyond Land. But most of these instruments gave only a few glimpses of the storms, showing what was to be seen on the sun-facing side of Jupiter.
Enter Juno’s mission. The Ultraviolet Spectrograph on NASA’s Juno spacecraft filled the gaps by capturing this glorious wonder from above for eight hours at a time, “from its inception to the end and from the night side of the aurora to side of the day, “has never been done before, according to a new study.
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Juno revealed that the storms of the day form like bright isolated places in auroras on the night side of the planet. As Jupiter orbits, the storms travel to the side of the day and shine even brighter, spewing up to thousands of gigawatts of ultraviolet light into space. At the clearest storms, a morning emits at least 10 times as much energy as the normal auroras of Jupiter do, the scientists wrote.
“The energy in these morning aurorae is another example of how powerful this vast planet is,” said study co-author Scott Bolton, Juno’s principal investigator from the Southwest Research Institute in San Antonio, Texas , said in a statement.
“More lively than usual”
The auroras of Jupiter are among the most powerful in us solar system, and occur when energetic electrons flow over the gas giant ‘s magnetosphere and pour into the upper atmosphere to stimulate and illuminate atmospheric gases, according to NASA. This creates shiny rings that are visible at the north and south poles of the planet.
Ideas from the Hubble Space Telescope had already revealed a glow in the daytime side of Jupiter’s pole auroras that were likely to last one to two hours, caused by particles – mostly electrons – was “more energetic than usual,” said the study’s lead author. Bertrand Bonfond, research associate at the Université de Liège Space sciences, Technologies and Astrophysics Research (STAR) in Belgium.
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“Some of those morning storms, including one that Hubble saw while Juno was approaching Jupiter before it was launched in 2016, are listed as the brightest auroras that we’ve never seen Jupiter, “Bonfond told Live Science in an email.
“However, we weren’t sure if they formed at the break of day and stayed there, or if they started on the night side and then headed to the morning,” Bonford said. Since Hubble ‘s comments were limited to just 40 minutes at a time, “we were also not sure how they improved after that,” he said. “And while we were convinced that those dramatic auroras should respond to some dramatic events in the magnetosphere, we weren’t at all sure which ones.”
“Beautiful new photo”
With polar aurora data collected by Juno during 20 orbits, the scientists collected “a neat new picture of human storms,” according to the study. They discovered that a storm surge began the morning before midnight and then shone over the next few hours, intensifying as Jupiter turned toward the sun. A few hours after formation, the first clear zone was divided “by a poleward moving finger,” the scientists wrote. Fill a space between the sloping arcs with clarity as the arcs grew, and then finally reduced the whole feature. Starting to end, the storm lasted between 5 and 10 hours, the study authors wrote.
The scientists were also surprised to discover that Jupiter’s morning storm auroras shared features that were common with a type of Earth aurora called substorms, which shows a clear illumination. sudden and intense stimulation by a “short circuit” of plasma flow. This appearance initially bothered the scientists, as the shape of an aurora magnetospheres Earth and Jupiter differ in many ways, such as their size, composition and distance from the sun, Bonford said in the email.
“Based on our study, we now assume that both the Earth’s substrates and Jupiter’s human storms arise from the collapse of the magnetosphere after they have exerted too much mass and energy. accumulation in the magnetotile, “which is the side of the magnetosphere facing the sun, Bonford explained.
However, this accumulation of energy and mass occurs for different purposes in the magnetospheres of the two planets. For the Earth, the excited particles come from solar winds, and for Jupiter, additional ionized material is sprayed into space by the volcanic moon Io. But despite having different origins, the results – morning storms on Jupiter and substrates on Earth – are surprisingly similar.
“Different factors lead to the same outcome,” Bonford said. “It wasn’t expected at all.”
The findings were published online March 16 in the journal AGU Advances.
First published on Living Science.