1. November 19, 2012 Sanders 8-11 Stars Unit 8: Astronomy

2. Astronomy Stars’ Classification Stars are classified by temperature and luminosity. –Temperature can be seen by the color of the star. A red star is coolest A blue star is hottest –Luminosity is the rate at which the star emits energy compared to the sun.

3. August 2, 2015Astronomy

4. Changing Knowledge People have observed the stars for thousands of years, using them to find direction, note the passage of time, and to express their values and traditions.

5. Astronomy Changing Knowledge People have observed the stars for thousands of years, using them to find direction, note the passage of time, and to express their values and traditions. As our technology has progressed, so has understanding of celestial objects and events.

6. Astronomy Nuclear Fusion Fusion releases great amounts of energy over millions of years.

7. Astronomy Nuclear Fusion Fusion releases great amounts of energy over millions of years. Hydrogen is fused to make helium.

8. Astronomy Nuclear Fusion Fusion releases great amounts of energy over millions of years. Hydrogen is fused to make helium. When hydrogen is consumed, more and larger elements are consumed.

9. Astronomy Fusion

10. Astronomy Milky Way Our Sun is a medium-sized star within a spiral galaxy of stars known as the Milky Way.

11. Astronomy Milky Way Our Sun is a medium-sized star within a spiral galaxy of stars known as the Milky Way. Our galaxy contains billions of stars, and the universe contains billions of such galaxies.

12. Astronomy Stars Life Cycle Stars have a life cycle.

13. Astronomy Stars Life Cycle Stars have a life cycle. The first stage in a star's life cycle is a protostar.

14. Astronomy Main Sequence The second stage in a star's life cycle is the main sequence stage.

15. Astronomy Main Sequence The second stage in a star's life cycle is the main sequence stage. A medium-sized star becomes first a white dwarf and then a black dwarf.

16. Astronomy Main Sequence The second stage in a star's life cycle is the main sequence stage. A medium-sized star becomes first a white dwarf and then a black dwarf.

17. Astronomy The Rosette Nebula Stars form when gravity causes clouds of molecules to contract until nuclear fusion of light elements into heavier ones occurs.

18. August 2, 2015Astronomy Ring Nebula Deep Field

19. August 2, 2015Astronomy Young Stars in the Rho Ophiuchi Cloud

20. Astronomy Stars Young and Old

21. Astronomy Crab Pulsar Wind Nebula

22. Astronomy The Crab Nebula from Hubble