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Home / Science / NASA’s Juno spacecraft reveals Jupiter’s unusual electrical storms: “shallow lightning” and “mushrooms”

NASA’s Juno spacecraft reveals Jupiter’s unusual electrical storms: “shallow lightning” and “mushrooms”



Shallow lightning on Jupiter

This illustration uses data obtained by NASA’s Juno mission to represent high-altitude electrical storms on Jupiter. The sensitive camera of Juno’s Star Reference Unit detected unusual lightning on the dark side of Jupiter during the next flying of the planet. Credit: NASA / JPL-Caltech / SwRI / MSSS / Gerald Eichstädt

It is possible that the spacecraft has located where the colorless gas has hidden on the largest inhabitant of the planet in the solar system.

New results from NASAmission Juno a Jupiter suggest that the largest planet in our solar system hosts what is called a “shallow ray.” An unexpected form of electric discharge, shallow lightning comes from clouds containing a solution of ammonia water, while lightning on Earth comes from clouds of water.

Other new findings suggest that the violent storms by which the gas giant is known may form grenade stones that are rich in ammonia, which Juno’s science team calls “balls”; they consider that mushrooms essentially sequester ammonia and water into the upper atmosphere and transport them to the depths of Jupiter’s atmosphere.

The shallow jet findings will be published Thursday, Aug. 6, in the journal Nature, while mushroom research is currently available online in the Journal of Geophysical Research: Planets.

Since NASA’s Voyager mission first saw Jovian lightning flash in 1979, it has been thought that the planet’s lightning is similar to that of Earth, which occurs only in storms where there is water in all directions. its phases: ice, liquid and gas. On Jupiter this would place storms about 45 to 65 kilometers below visible clouds, with temperatures hovering around 32 degrees. Fahrenheit (0 degrees Celsius, the temperature at which water freezes). Voyager saw lightning as bright spots on top of Jupiter’s clouds, suggesting that the flashes originated in deep water clouds. But the lightning observed on the dark side of Jupiter by Juno’s Star Reference Unit tells a different story.

“Juno’s upcoming flybys from the cloudheads allowed us to see something amazing, smaller and lower, originating at much higher altitudes in Jupiter’s atmosphere than could be assumed before,” said Heidi Becker, director of NASA’s Propulsion Laboratory’s Juno Radiation Monitoring Research South. California and the lead author of the paper Nature.

Jupiter clouds

At the center of this JunoCam image are small bright “pop-up” clouds that appear above the surrounding features. Clouds are thought to be the peaks of violent storms responsible for “shallow lighting.” Credit: NASA / JPL-Caltech / SwRI / MSSS / Kevin M. Gill © CC BY

Becker and his team suggest that Jupiter’s powerful storms throw crystals of icy water into the planet’s atmosphere, more than 16 kilometers (25 kilometers) above Jupiter’s water clouds, where they meet with steam. atmospheric ammonia that melts the ice, forming a new ammonia-water. solution. At this high altitude, temperatures are below 126 degrees Fahrenheit (minus 88 degrees Celsius), too cold for pure liquid water to exist.

“At these altitudes, ammonia acts as an antifreeze, decreasing the melting point of water ice and allowing the formation of a cloud with ammonia liquid,” Becker said. “In this new state, falling drops of ammonia liquid and water can collide with the water ice crystals that appear and electrify the clouds. This was a big surprise, as there are no clouds of d on Earth. ‘water with ammonia. “

Shallow rays become another puzzle about the inner workings of Jupiter’s atmosphere: Juno’s Microwave Radiometer instrument discovered that ammonia was running out — that is, missing — for the most part. of Jupiter’s atmosphere. Even more puzzling is that the amount of ammonia changes as it moves within Jupiter’s atmosphere.

“Previously, scientists realized that there were small pockets of missing ammonia, but no one realized how deep those pockets were or that they covered most of Jupiter,” said Scott Bolton, Juno’s lead researcher. to the Southwest Research Institute of San Antonio. “We were struggling to explain the depletion of ammonia just by the ammonia rain, but the rain couldn’t deepen to meet the observations. I realized that a solid, like a hailstone, could deepen and catch more ammonia. “When Heidi discovered a shallow ray, we realized that we had evidence that ammonia mixes with water raised in the atmosphere, and therefore lightning was a key piece of the puzzle.”

Lightning and mushroom factory

This graph shows the evolutionary process of “shallow ray” and “mushroom ball” on Jupiter. Credit: NASA / JPL-Caltech / SwRI / CNRS

Jovian mushrooms

A second paper, published yesterday in the Journal of Geophysical Research: Planets, predicts the strange beer of 2/3 of water and 1/3 of ammonia gas that becomes the seed of Jovian quarries, known as balls. Consisting of layers of ammonia smoothie with water and ice covered by a thicker water ice crust, mushroom balls are generated similarly to hail on Earth, growing as they move up and down. down through the atmosphere.

“Eventually the mushrooms get so big, even the updates can’t stand them and they fall deeper into the atmosphere, finding even warmer temperatures, where they finally evaporate completely,” said Tristan Guillot, co- Juno University researcher. Côte d’Azur in Nice, France, and main author of the second work. “Its action drags ammonia and water to deep levels in the planet’s atmosphere. This explains why in these places we don’t see him much with the Juno microwave radiometer. “

“Combining these two results was instrumental in solving Jupiter’s missing ammonia mystery,” Bolton said. “As it turned out, ammonia is not actually found; it is only transported downwards while disguised, having been coated by mixing with water. The solution is very simple and elegant with this theory: when water and l ‘ammonia are in a liquid state, they are invisible to us until they reach a depth where they evaporate, and that’s pretty deep.’

Understanding the meteorology of Jupiter allows us to develop theories of atmospheric dynamics for all the planets in our solar system, as well as for the discovery of exoplanets outside our solar system. Comparing how violent storms and atmospheric physics work through the solar system allows planetary scientists to test theories under different conditions.

Learn more about the mission

Jupiter’s solar explorer, launched nine years ago, on August 5, 2011. And last month marked the fourth anniversary of its arrival on Jupiter. Since entering the orbit of the gas giant, Juno has conducted 27 scientific flybys and recorded more than 300 million kilometers (483 million kilometers).

JPL, a Caltech division in Pasadena, California, manages Juno’s mission for principal investigator Scott Bolton of the San Antonio Southwest Research Institute. Juno is part of NASA’s New Frontiers Program, which is managed at NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the Washington Agency’s Scientific Mission Directorate. Lockheed Martin Space in Denver built and operates the spacecraft.

References:

“Little Lightning from Shallow Electric Storms on Jupiter” by Heidi N. Becker, James W. Alexander, Sushil K. Atreya, Scott J. Bolton, Martin J. Brennan, Shannon T. Brown, Alexandre Guillaume, Tristan Guillot, Andrew P Ingersoll, Steven M. Levin, Jonathan I. Lunine, Yury S. Aglyamov, and Paul G. Steffes, August 5, 2020, Nature.
DOI: 10.1038 / s41586-020-2532-1

Storms and Ammonia Exhaustion on Jupiter: I. Microphysics of “Mushrooms” by Tristan Guillot, David J. Stevenson, Sushil K. Atreya, Scott J. Bolton, and Heidi N. Becker, August 5, 2020, Journal of Geophysical Research: Planets.
DOI: 10.1029 / 2020JE006404

“Storms and Ammonia Exhaustion on Jupiter: II. Explicating the Juno Observations” by Tristan Guillot, Cheng Li, Scott J. Bolton, Shannon T. Brown, Andrew P. Ingersoll, Michael A. Janssen, Steven M Levin, Jonathan I. Lunine, Glenn S. Orton, Paul G. Steffes and David J. Stevenson, August 3, 2020, Journal of Geophysical Research: Planets.
DOI: 10.1029 / 2020JE006403




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