The Big Bang, Stars, and Elements

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Across
  1. 2. If a massive star isn't massive enough to turn into a black hole, it will be come one of these.
  2. 3. After the red giant stage of a low- to medium-mass star a carbon core will be surrounded by this.
  3. 6. The temperature of the universe has gradually _________ over time.
  4. 7. This force is balanced by the energy released by nuclear fusion to stabilize a star.
  5. 13. A reaction in which two light nuclei combine to produce a nucleus of heavier mass, resulting in the release of a large amount of energy.
  6. 14. an explosion that happens at toward the end of a massive star's life.
  7. 16. The heaviest one of these that a star can fuse is iron.
  8. 18. The interior of massive stars are organized in ______ ordered by lightest elements to heaviest elements.
  9. 19. These first formed around 380,000 years after the big bang.
  10. 20. Nuclear fusion of hydrogen into helium produces a large amount of this.
  11. 21. Every star is formed in one of these.
  12. 22. Elements _________ than iron are formed during supernova nucleosynthesis.
  13. 23. Has an atomic number of 26, and is the heaviest element a star can produce through nuclear fusion.
  14. 24. The lightest element that all stars use as fuel during nuclear fusion.
Down
  1. 1. The longest stage of a star's life; during this time the star is fusing hydrogen into helium.
  2. 4. This element has an atomic number of 2, and is the only major product that our Sun will fuse.
  3. 5. This theory states that the universe began as a very small, hot, dense "something" that rapidly expanded 13.8 billion years ago.
  4. 8. The number of protons in an atom's nucleus.
  5. 9. The final stage of a supermassive star's life after it has gone supernova.
  6. 10. The formation of heavier atoms from lighter atoms.
  7. 11. A celestial body that is stabilized due to the crushing force of gravity, and the outward pressure due to the release of energy from nuclear fusion.
  8. 12. The number of protons and neutrons in an atom's nucleus.
  9. 15. After the main sequence stage of a massive star, it will develop into this.
  10. 17. Our sun will spend the end of its life as this type of star.