Across
- 2. when matter formed planets and stars
- 3. the universe will return to one point and time
- 5. made of protons, neutrons and electrons
- 7. opposite of a proton
- 9. how fast light travels
- 10. identical to matter but with an opposite charge
- 12. how dense something is
- 13. a kind of measure of temperature
- 14. if the density of the universe is less than critical density
Down
- 1. how hot or cold something is
- 4. the study of the universe
- 6. can be measured in seconds, minutes, hours
- 8. light particles
- 11. when a light source moves away and the light shifts to the red spectrum