Across
- 3. distance light travels in a year
- 5. solar burst of energy
- 6. effect of Earths rotation
- 9. lowest layer of atmosphere
- 11. spinning of Earth on its axis
- 12. force exerted by air
- 15. time it takes for half a radioisotope to decay
- 16. distance from Earth to the Sun
- 17. splitting an atom
Down
- 1. equal daylight and darkness
- 2. layer of gases that surround Earth
- 4. discovered planets orbits
- 7. two atoms combine
- 8. radar technology
- 10. low flat planes on the moon
- 13. large, glowing ball of gas
- 14. path that circles the sun