THE UNIVERSE

THE UNIVERSE

1. What is it like?

   • Theories
     • Geocentric
       • Ptolomy. He propuse that the Earth was the center
     • Heliocentric
       • N.Copernicous. He propuse that the Sun was the center
   • What makes up it?
     • Galaxies, stars, planets, natural satellites

2. How big is it?

   • The Earth seems huge but compare to the Sun it is small.
   • What units of measurment do astronomers use?
     • Astronomical
       • Distance from one planet to the Sun
     • Light -year
       • Distance light travel in one year

3. What makes up the Solar System?

   • The Sun, planets, drawf plants, small solar system bodies
   • How do the planets move?
     • Rotation
       • Rotate on an invisible axi
     • Revolution
       • C.B rovolve around other C.B.
     • Orbit
       • C.B. follow in its revolution around another C.B.

4. Inner planets

   • 4 planets closest to the Sun
   • Mercury, Venus, the Earth and Mars
   • They are rocky

5. Outer planets

   • 4 planets further to the Sun
     • Jupiter, Saturn, Uranus and Neptune
     • they are gas

6. Small Solar System bodies

   • Asteriods
     • Rocky object which are irregular in shape
   • Comets
     • Small bodies travel around the Sun in highly elliptical