Across
- 5. object whose gravity is so great that no light can escape
- 8. spreads light into different wavelengths
- 14. the shift to a different wavelength
- 15. measure of how bright an object appears from Earth
- 16. a cloud of gas and dust
- 17. matter that emits no light
- 19. the distance light travels in one year
- 20. where hot gas moves up towards the surface and cooler gas moves deep into the interior
- 21. the true brightness of an object
Down
- 1. the surface of a star
- 2. a shell of cooler hydrogen surrounding a stars core
- 3. orange-red layer above the photosphere
- 4. huge collections of stars
- 6. the average distance betweem Earth and the Sun
- 7. wide outermost layer of a stars atmosphere
- 9. when nuclei of several atoms combine into one larger nucleus
- 10. enormous explosion that destroys a star
- 11. star dense core of neutrons that remains after a supernova
- 12. theory on how the universe is constantly expanding
- 13. large ball of gas held together with a hot core
- 18. hot dense slowly cooling sphere of carbon