10.3 Giant Planet Atmospheres
The gas giants (Jupiter, Saturn) and ice giants (Uranus, Neptune) have deep hydrogen/helium atmospheres with no solid surface. Spectacular bands, storms, and weather systems.
Jupiter
Composition
H₂ 89%, He 10%, CH₄, NH₃, H₂O clouds
Great Red Spot
Anticyclonic storm, 400+ years old, larger than Earth
Saturn
Similar to Jupiter but with lower density (would float on water). Famous hexagonal polar vortex at north pole.
Ice Giants
Uranus
98° axial tilt. H₂, He, methane (blue color). Extreme seasons.
Neptune
Fastest winds (2100 km/h). Dynamic despite being farthest from Sun.