PX158 - H3 - planets

inner planets
- metallic core (chiefly iron and nickel)
- mantle composed of silicates
- secondary atmospheres due to outgassing (volcanism) and comet impacts
outer planets
- lower density, composed of hydrogen and helium
- metallic (
) and silicate core - jupiter has a liquid hydrogen shell around its core
- primary atmosphere (gases accumulated during formation) of ammonia, carbon dioxide, and methane
- many moons
comets
- icy
- delivered molecules to planets via collisions