Across
- 3. natural satellite of Earth
- 4. study of earthquakes
- 7. three-quarters of moon
- 8. a piece of rock from outer space
- 11. a part of the thermosphere
- 13. person trained to travel in spacecraft
Down
- 1. a natural calamity
- 2. hottest planet of solar system
- 3. an important greenhouse gas
- 5. meteoroids burn up in this layer
- 6. this gas comprises 78% of air
- 9. sudden shaking of Earth
- 10. layer in which jet planes fly
- 12. hot molten rocks inside Earth