On Jupiter, lightning releases titanic energy: up to a million times the power of those we know on Earth.
This information owes much to NASA's Juno mission. Since its arrival in 2016, the probe has been using its instruments to capture radio emissions, providing finer measurements than previous visual observations, which were often disrupted by the planet's thick cloud layer.
Artist's illustration of lightning distribution in Jupiter's northern hemisphere, combining a JunoCam photo and creative additions.
Credit: NASA/JPL-Caltech/SwRI/JunoCam
To isolate the lightning signals, scientists overcame significant obstacles. Jupiter most often experiences several storms simultaneously, which blurs the identification of their origin. A period of calm in the northern equatorial belt in 2021 and 2022 allowed focusing on individual storms, nicknamed "stealth super-storms."
By relying on radio emissions, the team established that the measured lightning typically ranged between a power comparable to its counterpart on Earth and about a hundred times greater. These results now constitute the most reliable estimates. Much higher values, up to a million times Earth's power, are even mentioned in some estimates that remain to be refined.
Jupiter's atmosphere, mainly composed of hydrogen, has a distinct composition from Earth's. This difference affects convection, the mechanism that transports heat. On Jupiter, the moist air is denser, requiring more energy to rise, which could explain the intensity of lightning during storms.
However, the processes of lightning formation appear similar to those on our planet, with the condensation of water vapor in cold heights. Yet, the exact cause of their power remains to be clarified, as planetary scientist Michael Wong indicated in a statement from Berkeley University.