What causes lightning on Jupiter and how strong is it?
A water cloud thunderstorm northwest of the Great Red Spot taken by the Galileo spacecraft. The white cloud in the center is a tall, thick cloud 1000km across and 25km high. The New Horizons mission used Jupiter for a gravity assist in 2007 while on its way to Pluto. Night side imaging captured lightning strikes near Jupiter's North and South poles and equator. Some of the bolts were 10 times as powerful as anything ever recorded on Earth, but may be the sum of multiple strikes at a single location while the image was taken. Lightning was also seen by the Galileo Jupiter mission in the 1990s and Voyager in 1979.
As on Earth, Jupiter storms are caused by the process of convection. Gases, including water vapor, rise from deep within the planet. As they freeze, ice particles rub past each other, building a charge, which is discharged as lightning. The storms on Jupiter are much larger than Earth's perhaps resulting in the more powerful lightning.
Bright storms can be seen at two latitudes in the left image and at three latitudes in the right image. Each storm was made visible by multiple lightning strikes during the exposure.
While lightning had been observed at lower latitudes on Jupiter, this is the first time lightning was imaged near the poles. New Horizons observed 6 lightning strikes in Jupiter's north pole region, 7 in the south pole and 5 near the equator. Scientists were pleased with the New Horizon observations which confirmed their belief that Jupiter radiates heat uniformly throughout the planet out to space.