P1

P1

1. The solar system and the stars

   • Centre of the solar system is a star = The Sun
     • 8 planets in our Solar System
       • The planets are spherical and have circular orbits around the sun
       • Four planets closest to the sun are solid rock
         • Mercury, Venus, Earth and Mars
       • Four other planets are gas giants
         • Jupiter, Saturn, Uranus and Neptune
     • Each planet has a number or moons (Balls of rock) in near circular orbit around it
     • Asteroids -Irregular lumps of rock, near circular orbit between Mars and Jupiter
     • Comets - Small objects made of rock and ice, very elongated orbits around the sun
     • Dwarf Planets - Pluto; are small spherical lumps of rock in orbit around the sun
   • Nearly all (99%) id the solar system's mass is in the sun
   • Jupiter is the heaviest planet, followed by Saturn, Uranus, Neptune, Earth, Venus, Mars and Mercury
   • Neptune has the largest orbit, followed by Uranus, Saturn, Jupiter, Mars, Earth, Venus and Mercury