1. Table of Contents Telescopes The Scale of the Universe Characteristics of Stars Lives of Stars Star Systems and Galaxies The Expanding Universe Stars, Galaxies, and the Universe

2. Telescopes Refracting and Reflecting Telescopes A refracting telescope uses convex lenses to focus light. A reflecting telescope uses a curved mirror to focus light.

3. Refracting and Reflecting Telescopes What are the similarities and differences between the two? Telescopes

4. Where do the Optical, Radio and X-ray telescopes work best?

5. Parallax of Stars The apparent movement of a star when seen from a different position is called parallax. The Scale of the Universe

6. Scale of the Universe Scientists often uses scientific notation to help describe the vast distances in space. The Scale of the Universe

7. Characteristics of Stars Star Color and Temperature Stars vary in size, color and temperature.

8. Chemical Composition The lines on the spectrums below are from four different elements. Which elements have the strongest lines in Stars A, B, and C? Characteristics of Stars

9. Hertzsprung-Russell Diagram The H-R diagram shows the relationship between surface temperature and absolute brightness of stars. Characteristics of Stars

10. Life of a Star A star's lifetime depends on its mass. Lives of Stars

11. What are the missing stages on the diagram? Lives of Stars

12. An alien civilization is in orbit around a high-mass supergiant star. Should they stay? Lives of Stars

13. Invisible Partner A dim companion star might not be visible from Earth, but its existence can be inferred, like the invisible dancer. Star Systems and Galaxies

14. Major Types of Galaxies Star Systems and Galaxies

15. Moving Galaxies The galaxies in the universe are like raisins in bread dough. Where will the new positions of the raisins be when the dough rises? The Expanding Universe

16. Expansion of the Universe Why do scientists think the universe will expand forever? The Expanding Universe

17. The Big Crunch The small diagram represents the expansion of the universe until now. The Expanding Universe

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