Across
- 2. The core expands into this as its outer layers cool.
- 4. A mass of gas in the 1st stage of the formation of stars.
- 8. It is released in nuclear fission.
- 10. The formula by Albert Einstein.
- 12. The explosion that occurs after a star collapses.
- 14. A system of billions of stars held together by the gravitational force.
- 15. When light atomic nuclei fuse.
- 19. How long a star stays here depends on its mass.
- 20. A repulsive force that pulls away.
- 21. The central part of an atom.
- 22. Primarily converts hydrogen to helium.
Down
- 1. Holds particles together in the nucleus.
- 3. The force that pulls you toward earths core.
- 4. When a white dwarfs outer layers expand and drift from the core.
- 5. Composed of neutrons.
- 6. A huge cloud of gas and dust.
- 7. The stage that a star glows brightly.
- 9. A region of space with a gravitational field which nothing can escape.
- 11. A white dwarf that no longer emits heat
- 13. Another word for brightness.
- 16. Nuetrally charged subatomic particles
- 17. Primarily burn hydrogen.
- 18. Positively charged subatomic particles.
- 19. Burns helium into carbon.