Across
- 3. an English astronomer
- 9. discovered cosmic microwave background radiation
- 13. an American astronomer
- 14. a physicist and activist
- 15. is an instrument that splits
- 16. wavelengths we can see
- 17. things get bluer if it's moving closer
- 18. is the study of space
Down
- 1. faint radiation that represented the first light
- 2. explains that the universe was a dense singularity 13.8 billion years ago
- 4. is the ability to do work
- 5. an American physicist
- 6. is the most common element
- 7. things get redder if it's moving away
- 8. is a collection of galaxies
- 10. the spectrum of light
- 11. is a light, common gas
- 12. is a collection of solar systems and dust