12.03.20

Juno Discovers “Shallow Lightning” Above Jupiter’s Water Cloud

• Jovian lightning was thought to originate in deep liquid water clouds, as on Earth.
• Juno’s star camera observed lightning flashes at an altitude where water is frozen (-88º C).
• The flashes suggest a liquid exists in clouds much higher than expected.

Jovian lightning was thought to originate in deep liquid water clouds but has been observed in high altitude shallow clouds filled with an ammonia-water solution by Juno’s star camera.

SRU image of shallow lightning on Jupiter’s dark side.

• Ammonia gas is Jupiter’s antifreeze that melts water ice high in the atmosphere.
• The solution forms clouds containing a liquid similar to that of window-cleaning solution.
• Such clouds do not exist on Earth, but may be common to giant planets throughout our galaxy.

Credit: (Becker et al., Nature, 584, 55-58, 2020)

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