Earth Science Unit 9 Lesson 3

6. Type of variable star used to calculate true brightness output.
7. Amount of space between two distinct objects.
12. Studied spherical globular clusters to determine Earth's position in space.
14. Distance measurement method that could not reach far-off stars.
15. Instrument used to measure precise object diameters.
17. Metric unit used to measure large distances.
19. Representation used to study systems or objects.
20. Tool used for measuring model system distances.
21. Collection of stars, gas, and dust held together by gravity.

1. Distance that light travels in a vacuum in one year.
2. Mapped the Milky Way as a giant disk with stars orbiting.
3. Space and all of the energy and matter within it.
4. Central star of our solar system model.
5. Technology or tool used to observe distant stars and objects in space.
8. Relationship between model and actual measurements.
9. First astronomer to observe the Milky Way through a telescope.
10. Mathematical notation indicating how many times a number multiplies itself.
11. Planet located furthest from the model Sun.
13. Shape of the Milky Way galaxy as mapped by early astronomers.
16. Galaxy photographed by Edwin Hubble using a large telescope.
18. Force holding stars, gas, and dust together inside a galaxy.