1. GALAXIES Pages 639-642

2. Galaxies Def: large scale groups of stars (approx. 100 billion) bound by gravitational attraction- rotates around a center Def: large scale groups of stars (approx. 100 billion) bound by gravitational attraction- rotates around a center Also contain nebulae, planets, dark matter (90%), space, etc.. Also contain nebulae, planets, dark matter (90%), space, etc..

3. Is the center of every galaxy a supermassive black hole?

4. Small Magellanic Cloud Nearest galaxy 150,000 ly

5. Andromeda (M31) A large galaxy neighbor A large galaxy neighbor 2,900,000 ly 2,900,000 ly

6. Milky Way Structure Structure Barred spiral galaxy Barred spiral galaxy About 100,000 light-years wide About 100,000 light-years wide Sun is 30,000 light- years from the center Sun is 30,000 light- years from the center Rotates every 200 million years around “galactic center” Rotates every 200 million years around “galactic center”

7. Milky Way

8. Face-on view of the Milk Way Galaxy

9. Edge-on view of the Milk Way Galaxy

10. Galaxy Song from Monty Python http://www.youtube.com/watch?v=vIy76M- 4txo&feature=related&safety_mode=true& persist_safety_mode=1&safe=active http://www.youtube.com/watch?v=vIy76M- 4txo&feature=related&safety_mode=true& persist_safety_mode=1&safe=active http://www.youtube.com/watch?v=vIy76M- 4txo&feature=related&safety_mode=true& persist_safety_mode=1&safe=active http://www.youtube.com/watch?v=vIy76M- 4txo&feature=related&safety_mode=true& persist_safety_mode=1&safe=active

11. Types of Galaxies

12. M105 NGC 3384

13. Elliptical galaxy 60% of all galaxies 60% of all galaxies Contain older stars Contain older stars small small

14. LMC Large Magellanic cloud

15. NCG 6946 Spiral galaxies 30% of all galaxies 30% of all galaxies Older in center; younger in arms Older in center; younger in arms

16. A barred spiral galaxy

17. Merger of two Spirals to form an Elliptical

18. Irregular galaxy 10% of all galaxies 10% of all galaxies Contain young stars Contain young stars

19. M104 (The Sombrero Galaxy)

20. Hubble’s Law Galaxies are receding at a speed proportional to their distance Galaxies are receding at a speed proportional to their distance Farther galaxies are moving faster than nearby galaxies Farther galaxies are moving faster than nearby galaxies

21. http://hyperphysics.phy-astr.gsu.edu/hbase/astro/hubble.html#c3

22. Raisin bread analogy of an expanding universe

23. What would cause this? EXPANDING UNIVERSE! EXPANDING UNIVERSE! Cosmological red shift- supports this Cosmological red shift- supports this

24. Local group Local Group Local Group Milky way and nearest galaxies Milky way and nearest galaxies Contains at least 28 galaxies Contains at least 28 galaxies

25. What pattern do galaxies form in the universe?

26. AMAZING FACT Our known Universe contains at least 1,000,000 billions ( Thats One Million, Billions) of other Galaxies...like our own Milky Way. There is no doubt that there are other vast Universes in existence on top of our Universe Our known Universe contains at least 1,000,000 billions ( Thats One Million, Billions) of other Galaxies...like our own Milky Way. There is no doubt that there are other vast Universes in existence on top of our Universe

27. What is your galactic address

28. Power of Ten http://micro.magnet.fsu.edu/primer/java/sci enceopticsu/powersof10/index.html http://micro.magnet.fsu.edu/primer/java/sci enceopticsu/powersof10/index.html http://micro.magnet.fsu.edu/primer/java/sci enceopticsu/powersof10/index.html http://micro.magnet.fsu.edu/primer/java/sci enceopticsu/powersof10/index.html