Big History Crossword Puzzle

7. These events are the Earth's way of maintaining equilibrium during periods of change.
8. The process by which the planet's chemical composition is determined.
14. they formed out of galaxies.
15. they formed out of a galaxy cluster.
17. They are created from the atom clouds that are left over.
18. It is a energy.
19. Some energy is converted when you add energy to a pot of water or a group of atoms.
20. They begin to light up all over the universe.

1. They will simply burn out if there isn't enough fuel.
2. created gas clouds by bringing together individual hydrogen and helium atoms.
3. A star will eventually consume all of these substances to power its nuclear fusion.
4. It takes a lot of heat to fuse them together.
5. Formed by the dramatic explosions of dying stars.
6. What will only very large stars end up froming?
9. This condition may result in a continuation of life on Earth.
10. They could be big and composed of gases or smaller and composed of rocks like our Earth.
11. group of stars formed what?
12. They produce enough helium to begin burning helium when the hydrogen fuel runs out.
13. It is the death and massive explosion of a star.
16. This was a relatively cool and uniform place before stars.