2. Galaxies

3. We will be making a foldable for our notes on Galaxies.

4. Page 4 Irregular Galaxies Page 3 Elliptical Galaxies Page 2 Spiral Galaxies Page 1 Intro Name ________________Per_____ Galaxies General Notes.

5. Page 4 Irregular Galaxies Page 3 Elliptical Galaxies Page 2 Spiral Galaxies Drawing: Definition: Fact #1 Fact #2

6. Our Galaxy and Clusters The Milky WayClusters

7. What is a Galaxy? groups of stars and interstellar matter pulled together by gravity. contain millions to trillions of stars 100,000+ light years across, and millions of light years apart (Remember: A light year is 10 trillion km or 6 trillion miles)

8. The Size of Galaxies

9. How are Galaxies formed? Current theory is: 1.Galaxies form out of a large ball cold gas in space. 2.Gravity makes the gas fall in on itself, forming stars. 3.The type of galaxy depends on how fast it spins: –If it spins quickly it forms a spiral galaxy. –If it spins slowly it makes an elliptical galaxy. A third type of Galaxy, irregular galaxies, are created when other types of galaxies hit each other and combine.

10. Disk Shaped, Rotates old stars in middle, young stars on sides Round or Oval Shape, old stars, larger, most common No definite Shape, young stars 3 Kinds of Galaxies: 1.Spiral 2.Elliptical 3.Irregular

11. Huge; contain stars, gas, and dustHuge; contain stars, gas, and dust Held together by gravityHeld together by gravity No regular shapeNo regular shape Usually rich in gas and dustUsually rich in gas and dust Young and old stars are presentYoung and old stars are present Huge; contain stars, gas, and dustHuge; contain stars, gas, and dust Held together by gravityHeld together by gravity Round-to-oval shapeRound-to-oval shape Little cool gas and dustLittle cool gas and dust Mainly old stars are presentMainly old stars are present Huge; contain stars, gas, and dustHuge; contain stars, gas, and dust Held together by gravityHeld together by gravity Pinwheel shape or needle shaped.Pinwheel shape or needle shaped. Rich in gas and dustRich in gas and dust Young and old stars are presentYoung and old stars are present Irregular galaxies Elliptical galaxies Spiral galaxies

12. Spiral Galaxies

13. Elliptical Galaxies

14. Irregular Galaxies

15. The Milky Way The Milky way is the spiral galaxy we live in. It is ~100,000 light years across and ~10,000 light years thick. Our sun is located two-thirds of the way in on the Orion arm.

16. Clusters of Galaxies Galaxies come in clusters. The Milky Way is part of a cluster called the Local Group.

17. The Local Group

18. Other Galaxy Clusters

19. Hubble Deep Field