Over the course of 12 passes, Juno detected 613 microwave pulses from lightning, at least 100 times stronger than that of lightning on Earth. There is uncertainty in interplanetary comparisons, so Jupiter’s lightning could be a million times stronger than Earth’s.
Lightning on Jupiter is likely sparked by a mechanism similar to what happens in Earth’s atmosphere, where ice crystals in clouds become electrically charged and voltage differences cause lightning to strike from cloud to cloud or from cloud to ground.
There are also noticeable differences between the planets. Jupiter has no true surface, and the ice crystals inside the Jovian atmosphere contain 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 just Jupiter’s enormous size that causes such large and powerful storms. It takes more energy to move moist air aloft, resulting in stronger winds and more intense cloud-to-cloud lightning. What causes lightning on Jupiter to be so extreme is still a mystery.
“Could the main difference be the hydrogen versus nitrogen atmosphere, or are the storms longer on Jupiter and therefore greater distances?” said Michael Wong, a planetary scientist at the University of California, Berkeley Space Science Laboratory. Wong is the lead author of the Jupiter lightning study.
“Or could there be more energy, because in order to generate thunderstorms with moist convection on Jupiter, more heat must be built up before the storm can form?” Wong said in a press release. “This is an active area of research.”
