During 12 passes, Juno detected 613 microwave pulses from lightning, ranging in strength from similar to a lightning bolt on Earth to at least 100 times greater. There is uncertainty in interplanetary comparisons, so it is possible that Jupiter’s lightning could be up to a million times more powerful than Earth’s.
Lightning on Jupiter likely occurs by a mechanism similar to Earth’s atmosphere, where ice crystals within clouds acquire an electrical charge, and the voltage difference causes lightning to strike from cloud to cloud or from cloud to ground.
There are notable differences between the planets as well. There is no true surface on Jupiter, and ice crystals inside the Jovian atmosphere consist of water and ammonia. On Earth, it’s just water. Atmospheric convection also works differently on Jupiter, where moist air tends to sink because it is heavier than the surrounding hydrogen-rich atmosphere. Nitrogen, which is heavier than water, dominates Earth’s atmosphere, so moist air rises.
Therefore, it is not only Jupiter’s enormous size that causes such large and powerful storms. Much more energy is required to move moist air aloft, resulting in stronger winds and more intense cloud-to-cloud lightning. There is still a mystery about why lightning is so intense on Jupiter.
“Could the main difference be the hydrogen versus nitrogen atmosphere, or could it be that the storms at Jupiter are longer and therefore cover greater distances?” said Michael Wong, a planetary scientist at the Space Science Laboratory at the University of California, Berkeley. Wong is the lead author of the Jupiter lightning study.
“Or could it be that there is more energy available because with moist convection at Jupiter, you have a larger accumulation of heat needed before you can generate a storm to generate electricity?” Wong said in a press release. “This is an active area of research.”
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