Across
- 2. the smallest planet in the Solar System
- 5. a rocky body often found between Mars and Jupiter
- 7. region of extreme gravity that light cannot escape
- 9. visible part of the Moon is shrinking
- 13. the vast area beyond Earth's atmosphere
- 14. an icy object forming a glowing tail near the Sun
- 15. everything that exists, including galaxies
- 16. galaxies recedes faster as their distance increases
- 20. the planet humans live on
- 22. the galaxy containing the Solar System
- 23. product of nuclear fusions in a star
- 24. orbits a planet, either natural or artificial
- 25. the farthest planet in the Solar System
Down
- 1. whirling ring of matter surrounding a massive object
- 3. season during June to August in the Northern Hemisphere
- 4. state of matter that composes gas giants
- 6. typical shape of an orbit
- 8. the most common element in the Universe
- 10. a giant cloud of dust and gas in space
- 11. force pulling objects toward each other
- 12. stretching of light toward the red end of spectrum
- 17. distance light travels in one year
- 18. the star in the Solar System
- 19. an aging star that has expanded and cooled
- 21. the time day and night are equal in length