1. Galaxies in our Universe

2. Edwin Hubble Review: ✓ Studied at the Wilson Telescope in the 1920’s ✓ Took pictures of galaxies ✓ Figured out we are in a galaxy ✓ Noticed that the galaxies are all moving ✓ Figured our that galaxies are moving away from Earth, RED SHIFT ✓ Hubbles’ Law: far galaxies are moving faster than the closer galaxies that are moving slower

3. Galaxy: billions of stars, dust, and gases held together by gravity Galaxy cluster: billions of galaxies Galaxies are categorized according to their shape

4. Galaxy Cluster

5. Spiral galaxies are disc-shaped and look like a spiral pick one and draw it

6. Elliptical galaxies vary in shape, but are mostly round or oval pick one and draw it

7. Irregular galaxies do not have a specific shape pick one and draw it

8. A large spiral galaxy 100,000 light years wide 10,000 light years thick at the center The Milky Way Galaxy

9. 100,000 light years Top View Side View 10,000 light years aka: nucleus or central bulge draw both of these

10. There are over 200 billion stars in the Milky Way Our solar system is located near the end of one arm We are not in the middle, if we were there would be no life !!!

13. stars and galaxies make up most of visible matter but, most of the matter out there is invisible, dark matter... dark matter is inferred from the way it affects the gravity of light (black holes) Matter in the Universe (stuff)

14. 60 second summary

15. Review #1Which is bigger, the width of the milky way galaxy or the height? ๏ answer: the width because it is 100,000 light years wide, the tallest part is the center but it is only 10,000 light years.

16. Review #2Where is our solar system located in the milky way? in the middle of the galaxy at the end of one arm near the end of one arm it is not located in the milky way at all

17. ๏ near the end of one arm (two thirds of the way from the center means it is near the tip, but not actually the tip of the arm)

18. one two three four Review #3How many types of galaxies exist?

19. Review #4 The universe is mostly made of... visible matter dark matter

20. ๏ there is more dark matter than visible

21. Review #5What makes up most of the visible matter in the universe? planets stars

22. ๏ stars make up most of the visible matter in the universe