On August 17, 2022, NASA’s ‘Juno’ spacecraft traversed from north to south (yellow trajectory) above Jupiter’s atmosphere, detecting a cluster of radio emissions originating from lightning strikes (blue symbols indicate the instrument’s orientation for each impulse). A background map, captured by the Hubble Space Telescope, pinpointed the lightning’s source to an isolated “hidden superstorm.” This research has been published in the journal AGU Advances.
The ancient Greeks could never have fully grasped how accurate they were in naming the planet Jupiter after Zeus himself. New observations reveal that lightning on the king of planets is over 100 times more potent than its terrestrial counterparts—and possibly even stronger.
Detailed scrutiny of lightning on Jupiter offers fresh insight into the planet’s atmospheric dynamics beyond its massive storms. It also paves the way for new enigmas, given the surprising magnitude of the power detected.
Jupiter is exceptionally active in terms of electrical storms, which often makes precisely locating the origins of lightning difficult. A lull in storm activity occurred in the North Equatorial Belt in 2021 and 2022; this provided researchers with an opportunity to focus both the Hubble Space Telescope and amateur telescopes on the region under investigation by NASA’s Juno probe, which has been studying Jupiter’s atmosphere since 2016, among other objectives.
Juno cannot observe lightning directly, but it measures the microwave signals emitted by the electrical discharge. Knowing the storm’s location made it possible to calculate the lightning’s power relative to Earth. Lightning emissions serve as a window into atmospheric behavior.
“Jupiter’s lightning tells us about convection—how the atmosphere mixes and transports heat from below,” explains lead author Michael Wong from the Space Sciences Laboratory at the University of California, Berkeley. “Convection on Earth and Jupiter functions somewhat differently because Jupiter’s atmosphere is predominantly hydrogen, meaning moist air is heavier and harder to lift upwards.”
Wong stresses that uncertainties remain regarding the absolute power measurement. Terrestrial lightning measurements are often gauged using different radio frequencies, so the true intensity might vary. And it might not be smaller—some discharges could be 500 to 10,000 times more powerful.
Such power implies a higher voltage potential between Jupiter’s thunderclouds. Indeed, Jovian storm clouds reach altitudes ten times greater than those on Earth, but it is unclear how the discharge intensity scales with this difference. This disparity could stem from variations in the chemical makeup of these clouds or the atmosphere as a whole.
“This is where the intriguing details emerge, leading one to wonder: ‘Could the key difference be the hydrogen- or nitrogen-based atmosphere, or perhaps the fact that storms on Jupiter are taller, resulting in a greater distance between cloud layers?'” Wong added. “Or maybe more energy is available because moist convection on Jupiter demands more heat before a lightning-capable storm can even form?” he concluded. “This is a rapidly evolving research area.”
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