Comparing Internal Structures of the Planets

Nebular theory
Explains formation of solar system
Sun and planets formed from solar nebula
Rotating cloud of gas and dust
Solar nebula contracted and formed hot protosun
Planetesimals formed
Planetesimals became protoplanets

Terrestrial (Earth-like) planets
Mercury, Venus, Earth, and Mars
Small, dense, rocky
Large cores of iron and nickel
Low escape velocities

Jovian (Jupiter-like) planets
Jupiter, Saturn, Uranus, and Neptune
Large, low density, gaseous
Massive
Thick atmospheres composed of hydrogen, helium, methane, and ammonia
High escape velocities