Across
- 4. Quark that makes up 2/3 of a proton
- 5. Acronym for an American space program
- 8. Causes planets to tear apart
- 9. Coldest possible temperature
- 10. Number of moons belonging to 11 DOWN, in Roman numerals
- 12. Particle that travels backwards in time
- 15. Had fruitful thoughts
- 16. Breaking the light barrier (photonic boom)
- 18. Unification of two fundamental forces
- 19. Total energy in a system must be _
Down
- 1. Consequence of falling into a black hole
- 2. Why in space no one can hear you scream
- 3. Types include alpha, beta, and gamma
- 6. Largest man-man particle accelerator
- 7. "Spooky action at a distance"
- 11. Largest planet in the solar system
- 13. Winner of two Nobel prizes, one in physics and one in chemistry
- 14. Length of 6 DOWN (kilometers)
- 16. May be dead or alive
- 17. Third time derivative of position