Across
- 3. interaction of electric currents or fields and magnetic fields
- 4. is an area of such immense gravity
- 6. Field of study about the physical universe
- 7. something on your watch
- 12. any of the four basic forces
- 13. a 'shift' of light waves traveling away from Earth
- 15. the distance light travels in one year
Down
- 1. Fireball alternative term for the radiation era in the Big Bang Theory
- 2. A bond or molecule whose ends have opposite charges
- 5. the Standard International unit of thermodynamic temperature
- 8. The explosively rapid expansion of space-time
- 9. a limited extent in one, two, or three dimensions
- 10. gaps between the constituent particles
- 11. stars which brighten and dim periodically
- 14. collection of gas, dust, and billions of stars and their solar systems