1. The Solar System Sun, Moon and Stars… In the Old Days…
Appear to rise in East
Move at 15o per hour
Appear to set in West
In the Old Days…
Earth was in the center
Celestial objects revolved around Earth
This was called the GEOCENTRIC MODEL

2. Geocentric Model Celestial bodies revolve around Earth Epicycles
Moon is closest
Planets move in small
circles called epicycles
Epicycles
Observations raised doubt
about this model…
And it was gradually
Replaced with a new idea!

3. Heliocentric Model Planets revolve around the SUN This model explains
Mercury is closest
Planets move in
elliptical orbits
-Moon revolves
around Earth
This model explains
all motions of celestial
Bodies!
Don’t Forget: The Solar
System is 4.6 billion years old!

4. The Inner Planets…
Small, dense, made of rock

5. The Outer Planets…
Large, low density, made of gas

6. Sun and 8 planets (plus Pluto) and other stuff
Solar System…
Sun and 8 planets (plus Pluto) and other stuff
The Sun is a “medium” sized yellow star
The Sun contains
> 99% of solar system mass

7. “I’m sorry Pluto, you’re just not big enough”

8. “Planet Gossip!!”

9. Sun with Other Yellow Stars…
Sun is really not that big!

10. Sun with Red Giant Stars…
Sun is pretty darn small!

11. WAY OUT in the Solar System
Asteroid belt located between Mars and Jupiter
The Kuiper Belt is out past Neptune… source of comets
Farther out is the Oort cloud

12. Asteroids! Large Rocks too small to be planets
Can be up to 1000km wide!
Mostly in the Belt between Mars and Jupiter

13. Comets! Dirty Ice Balls Really LONG ORBITS Very Eccentric Orbits
Come from the Kuiper Belt/Oort clooud
Comet Hale-Bopp, 1997

14. Meteors!
Streak of light from a meteoroid going through Earth’s atmosphere
Meteoroid is a boulder sized rock in space
Meteorite is left over rock that hits Earth

15. Beyond the Solar System…GALAXIES
Billions of stars! Home: The Milky Way
Contain other solar systems too!
Come in spiral, ring, and sombrero shapes

16. Beyond the Solar System…UNIVERSE
Lots of SPACE
Billions of GALAXIES
EVERYTHING there IS!
In order from smallest to largest…
Planet (smallest)
Star
Solar System (one star, several planets)
Galaxy (many solar systems and stars)
Universe!