Across
- 4. Fusion process of atomic particles being smashed together
- 8. a point of infinite mass and heat
- 9. the second simplest atom
- 10. the universe is doing this even now
- 11. the theory galaxies are moving away at constant speeds
- 13. how fast light can travel in the vacuum of space
- 15. the amount of matter in an object
- 18. created all complex elements through nuclear fusion
Down
- 1. clusters of billions of starts and other pieces of matter
- 2. the act that brought the universe into existence
- 3. all existing matter, space and energy as a whole
- 5. the universe started really hot but now it is ____
- 6. the densest things in the universe
- 7. smallest particles that everything in the world is made of
- 8. a system of planets orbiting a sun
- 9. the simplest atom
- 12. the universe is _______ of years old
- 14. force of attraction that keeps us stuck on Earth
- 16. the star at the center of our solar system
- 17. to move around another object in a curved path