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Home / Science / NASA’s Juno Spacecraft Reveals Unusual Electric Jupiter Storms: “Shallow Lightning” and “Mushballs”

NASA’s Juno Spacecraft Reveals Unusual Electric Jupiter Storms: “Shallow Lightning” and “Mushballs”



Shallow lightning on Jupiter

This illustration uses data from NASA’s Juno mission to describe high-altitude electrical storms on Jupiter. The camera of Juno Sensitive Stellar Reference Unit detected unusual lightning strikes on the dark side of Jupiter during close flights to the planet. Credit: NASA / JPL-Caltech / SwRI / MSSS / Gerald Eichstädt

Space may have found where colorless gas is hidden in the largest planetary inhabitant of the solar system.

New results from NASAJuno mission in Jupiter suggest that the largest planet in our solar system is home to what is called “shallow lightning”. A sudden form of electrical discharge, shallow lightning emanates from clouds containing a solution of ammonia water, while lightning on Earth emanates from clouds of water.

Other new findings suggest that violent storms of which the gas giant is known to form ammonia-rich bursts of what Juno’s scientific team calls “mushrooms”; they theorize that the fungi essentially snatch ammonia and water into the upper atmosphere and carry them deep into Jupiter’s atmosphere.

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

Since NASA’s Voyager mission first pulsed the Jovian lightning pulse in 1979, it has been thought that the planet’s lightning is similar to that of Earth, occurring only in storms when water exists in all its phases – ice , liquid and gas. On Jupiter this would place storms about 28 to 40 miles (45 to 65 kilometers) below visible clouds, with temperatures ranging around 32 degrees degrees Fahrenheit (0 degrees Celsius, the temperature at which water freezes). Voyager saw lightning as bright spots on top of Jupiter clouds, suggesting the sparks originated in deep-water clouds.

“Juno’s close flights from the tops of the clouds allowed us to see something startling – smaller, shallow flares – originating at much higher altitudes in Jupiter’s atmosphere than previously thought possible,” said Heidi Becker, leader of Juno Radiation Monitoring Investigation at the Southern California Jet Propulsion Laboratory and lead author of the journal Nature.

Jupiter Clouds

At the center of this JunoCam image, small, bright “pop-up” clouds are seen rising above the surrounding features. Clouds like these 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 her team suggest that powerful Jupiter storms of ice water crystals flow up into the planet’s atmosphere, over 16 miles (25 kilometers) above Jupiter’s water clouds, where they encounter atmospheric ammonia vapor that melts the ice, forming a new ammonia water solution. At such a high altitude, temperatures are below minus 126 degrees Fahrenheit (minus 88 degrees Celsius) – too cold to have clear liquid water.

“At these altitudes, ammonia acts as an antifreeze, lowering the melting point of water ice and allowing the formation of a cloud of aqueous ammonia liquid,” Becker said. “In this new state, the droplets of ammonia water liquid can collide with the ice crystals with the water removed and electrify the clouds. This was a big surprise, as ammonia water clouds do not exist on Earth. “

Shallow lightning factors in another enigma about the inner workings of Jupiter’s atmosphere: The Juno Microwave Radiometer Instrument found that ammonia was depleted – that is, extinct – from most of Jupiter’s atmosphere. Even more troubling was that the amount of ammonia changes as it moves inside Jupiter’s atmosphere.

“Previously, scientists realized that there were small pockets of lost ammonia, but no one realized how deep these pockets went or that they covered most of Jupiter,” said Scott Bolton, Juno’s lead investigator at the Institute of Southwest Research in San Antonio. “We were struggling to explain ammonia depletion only with rain with ammonia water, but the rain could not go deep enough to match the observations. I realized that a solid, like a hailstone, could go deeper and “Take more ammonia. When Heidi discovered shallow lightning, we realized we had evidence that ammonia mixed with high water in the atmosphere, and so lightning was a major part of the puzzle.”

Mushroom plant and shallow-lightning

This graph describes the evolutionary process of “shallow lightning” and “mushrooms” on Jupiter. Credit: NASA / JPL-Caltech / SwRI / CNRS

Mushballs Jovian

A second paper, published yesterday in the Journal of Geophysical Research: Planets, predicts the bizarre production of 2/3 of water and 1/3 of ammonia gas that becomes the seed of the Jovian hailstones, known as mushrooms. Composed of layers of water-ammonia moisture and ice covered by a thick crust of water ice, the fungi form in a similar way to hail on Earth – growing larger as they move up and down through the atmosphere.

“Eventually, the fungi get so big, even the up-to-date crafts can’t hold them, and they fall deeper into the atmosphere, encountering even warmer temperatures, where they eventually completely evaporate,” said Tristan Guillot, a co-investigator of Juno from Université Côte d’Azur in Nice, France and lead author of the second paper. “Their action reduces ammonia and water down to deep levels in the planet’s atmosphere. This explains why we do not see many of them in these places with the Juno Microwave Radiometer. “

“Combining these two results was essential to solving the mystery of Jupiter’s lost ammonia,” Bolton said. “As it turned out, ammonia is not really missing; it is simply transported down while in disguise, after wearing the mantle mixed with water. The solution is very simple and elegant with this theory: When water and ammonia are in a liquid state “They are invisible to us until they reach a depth where they evaporate – and that is deep enough.”

Understanding the meteorology of Jupiter enables us to develop theories of atmospheric dynamics for all the planets in our solar system, as well as for exoplanets that have been discovered outside our solar system. By comparing how violent storms and atmospheric physics work throughout the solar system, planetary scientists allow planetary scientists to test theories under different conditions.

More about Mission

The solar-powered Jupiter 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 flights and recorded over 300 million miles (483 million kilometers).

JPL, a Caltech division in Pasadena, California, manages the Juno mission for lead investigator Scott Bolton of the Southwestern Research Institute in San Antonio. Juno is part of NASA’s New Frontiers Program, which is managed 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 manages the spacecraft.

For more on this research, read “Mushballs”: Ammonia-rich exotic rock bursts shed new light on Jupiter’s weather.

References:

“Small Lightning Strikes by 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, 5 August 2020, nature.
DOI: 10.1038 / s41586-020-2532-1

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

“Ammonia Storms and Destruction on Jupiter: II. Explanation of 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, 3 August 2020, Journal of Geophysical Research: Planets.
DOI: 10.1029 / 2020JE006403




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