The Universe 1 Galaxies Groups of

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The Universe 1 Galaxies Groups of Powered By Docstoc
					      1. Galaxies
Groups of stars, dust, and
gases held together by gravity.
2. How big is the Milky Way galaxy?
100,000 light years wide and 10,000 LY thick
3. What is the center of a galaxy called?
            Galactic Nucleus
4. How many galaxies do
scientists believe exist in the universe?

    Hundreds of billions
5. What are the names of the three
kinds of galaxies?

  Spiral, Elliptical, Irregular
6. What is the shape of a spiral galaxy?
             Dish Shaped
7. What is the shape of an elliptical galaxy?
               Round to oval
8. What is the shape of an irregular galaxy?
             Irregular Shapes
9. Galaxies are grouped in _______________.
10. Our galaxy is part of a galaxy
cluster called the Local Group. How
many galaxies are thought to be in
our cluster?
            28 Galaxies
     11. What is Hubble’s Law and what
     does it tell us about galaxies?
- States that other galaxies are moving away from us
      - Indicates that the universe is expanding
12. What does the Big Bang Theory state?

 The universe began as a violent explosion
13. How long ago do scientists
think the Big Bang occurred?

 About 13.7 billion years ago
14. How were the stars and galaxies
supposed to have formed?
 Gases from the big bang cooled and
 condensed to form stars and galaxies