Across
- 4. travel possible as universe cooled
- 5. Space Telescope NASA telescope launched in 1990 that takes clear pictures from space
- 10. total space containing everything: stars, galaxies, planets
- 12. orbit stars forming solar systems
- 13. particles electrons, protons, neutrons formed after the Big Bang
- 14. grouped into galaxies
- 17. massive balls of hot gases
- 20. pulled particles together to form stars, planets, galaxies
- 21. scientist who studies space
Down
- 1. Law galaxies move away from each other; farther galaxies move faster
- 2. atmosphere distorts images for ground telescopes
- 3. Bang event about 13.8 billion years ago, beginning the universe
- 6. Hubble discovered that the universe is expanding
- 7. cooling allowed particles to form atoms and molecules
- 8. Way galaxy where Earth is located
- 9. very small, hot, dense point from which the universe expanded
- 11. huge groups of billions of stars
- 15. System a star and all planets orbiting it
- 16. anything with mass and volume formed by atoms and molecules
- 18. Bang expansion rapid expansion causing huge temperature increase
- 19. closest star to Earth