Across
- 4. Man who proved Einstein right
- 6. Second person on the Moon
- 8. A NASA project that includes two probes
- 10. Invented the telescope
- 12. One of the best physicists of all time
- 14. A famous government agency that deals with astronomy
- 16. The branch of science to do with space
- 18. Two trillion are known in the observable universe
- 19. Our planet
Down
- 1. The distance of the universe we can see
- 2. Our galaxy
- 3. Revolves around the Earth
- 4. What the Earth spins on
- 5. A famous telescope launched in 1990
- 6. The theory of how the universe was made
- 7. Person who made the first sun-centered model
- 9. Man who made the laws of motion
- 11. Someone who studies astronomy
- 13. What keeps people on the ground
- 15. First man on the Moon
- 17. Fourth planet from the Sun