8. State whether the following statements are true or false.

1. The expansion of the universe can be viewed as the flow of material from the Big Bang into empty space.

2. Hubble’s law can be inverted to give the approximate age of the universe.

3. The cosmological redshift can be viewed as a consequence of the expansion of space itself.

4. The cosmic microwave background radiation spectrum fits a blackbody curve with an average temperature of 273 kelvins.

5. Counting all the known luminous material in all the stars and galaxies yields only about one percent of the matter needed to keep the universe from expanding forever.

6. According to our present understanding of Hubble's law, every point in the universe is expanding away from every other point, but the universe has no preferred center.

7. The 3-kelvin background radiation is emission from intergalactic gas.

8. We seem to be completely surrounded by the origin of the universe.

9. The average density of the universe is similar to the density of water.

10. If the universe is closed, it will begin to collapse in about 10 billion years.

11. Cosmological redshifts are caused by the motion of the Milky Way through space.

12. If the average density of matter in the universe is greater than the critical density, then the universe will be closed.

13. The observable universe is infinite in extent.

14. Olbers’s paradox concerns why the sky is dark at night.

15. If quasars are really at the distances they seem to be, then we see them as they were when the universe was young.

16. The average density of the universe being constant is compatible with the expansion of the universe.

17. All points in space appear to be at the center of the expanding universe.

18. The universe appears to be younger than its oldest stars.

19. As it travels through space, a photon's wavelength increases at the same rate as the universe is expanding.

20. Recent observations of supernovae suggest the universe is no longer expanding.