Astronomy Review

3. A planet outside of our solar system.
8. The cosmological microwave ___________ is considered the first visible light in the cosmos.
10. _________ lensing is a method of determining the mass of objects in space that we cannot see.
13. The famous equation that gives us the probability of communicating with alien life forms.
14. The theoretical structure of the universe at the moment of the big bang
17. The effect that motion has on the wavelength of light and sound.
18. What happens to the light of a star that is traveling away from you.
20. Most of the matter in the universe is thought to be made of this mysterious substance.
21. A packet of light energy.
22. The study of the time after the big bang is broken up into sections of time called __________.
23. The zone near a planet where planetary water remains liquid.

1. __________ redshift, the stretching of light due to the expansion of space.
2. These galaxies are often formed when two spiral galaxies collide.
4. ______ Energy, the still poorly understood force that acts against gravity, and is thought to be causing the expansion of space.
5. A large collection of stars, nebulae, and planets that are held together by their own gravity.
6. What happens to the light of a star that is traveling towards you.
7. A cloud of interstellar gas and dust.
9. The cosmological ___________ is the rate at which the universe is expanding.
11. When a planet passes in front of its star, obscuring our view of the star.
12. The most common form of galaxy.
15. The light collecting tool that is used to analyze EM radiation from around the universe.
16. Directly after the big bang the four fundamental forces of gravity were all combined into one force called the ________.
19. The study of the cosmos.