Our Solar System

Solar system includes

• Sun
• Eight planets and their satellites + dwarf planets
• Asteroids
• Comets
• Meteoroids

The Planets

A planet's orbit lies in an orbital plane, similar to a flat sheet of paper. The orbital planes of the planets are inclined. Planes of seven planets lie within 3 degrees of the Sun's equator, Mercury's is inclined 7 degrees, Pluto's is inclined 17 degrees

Two groups of planets occur in the solar system :

• Terrestrial (Earth-like) planets
  • Mercury through Mars
  • Small, dense, rocky
  • Low escape velocities
• Jovian (Jupiter-like) planets
  • Jupiter through Neptune
  • Large, low density, gaseous
  • Massive
  • Thick atmospheres composed of hydrogen, helium, methane, and ammonia
  • High escape velocities
• Dwarf Planets
  • Pluto, Ceres, etc.