Across
- 3. a planet that is not in our solar system
- 5. when a white dwarf runs out of fuel entirely
- 6. a huge explosion of a massive star
- 8. a ball of ice and dust that revolves around a star and has a "tail"
- 9. this substance makes up 90% of the universe
- 11. a big ball of light hot enough for fusion of hydrogen
- 12. when a star's core starts to run out of fuel
- 13. when a star's outer layer comes off
- 14. a highly dense star made entirely of neutrons
- 17. when a star first starts to form
- 18. the left over remains of the creation of a solar system
- 19. a starlike object that does not have enough mass for fusion
- 20. the distance light travels in a year
- 22. the remains of a supernova
Down
- 1. a satellite of a planet
- 2. this is the very first stage of a star's life
- 4. this is so massive that it creates a hole in space-time
- 7. 3.6 light-years
- 10. when a star expands, it becomes this
- 15. when a massive star expands it becomes this
- 16. a satellite of a star
- 21. a cluster of stars