Rocky Core
Silicate and iron-nickel · Only 0.55 Earth masses · Less than 20% of planet radius · Temperature ~5,000 K · Pressure ~8 million bar

Icy Mantle
Hot dense fluid of water, ammonia, and methane · 13.4 Earth masses · Sometimes called "water-ammonia ocean" · High electrical conductivity · Superionic water possible

H₂/He Atmosphere
Gaseous hydrogen and helium envelope · ~0.5 Earth masses · Extends for last 20% of radius · Gradual transition to liquid interior · No solid surface

Cloud Layers
Water clouds at depth, ammonium hydrosulfide mid-level, methane ice crystals in upper troposphere · Methane gives cyan color

Thermosphere
Extends to 50,000 km · Uniform 800–850 K (paradoxically hot) · Heat source unknown · Denser ionosphere than Saturn or Neptune