Across
- 3. a unit of distance it equals about 3.26 light years
- 5. universe a sphere of space centered on earth
- 10. natural physical force that pulls objects toward each others
- 11. Fusion a reaction where two light atomic nuclei are combined
- 12. magnitude the measure of the true brightness of a star or space object
- 13. a negative charge subatomic particle
Down
- 1. method step-by-step process used to explore observations
- 2. magnitude a measure of how bright other objects look in a sky
- 4. a push or pull upon an object
- 6. the total amount of radiant energy emitted by a star or celestial body per unit of time
- 7. a tiny positive subatomic particle
- 8. a neutral charge subatomic particle
- 9. curved path that an object takes around in space
- 12. basic building block of life
- 14. year a unit of distance, not time in space