Across
- 4. Space with intense gravity
- 6. Travels at 300,000 km/s
- 7. Orbits a star like the sun
- 8. Fourth planet from the sun
- 9. Balls of burning gas
Down
- 1. Earth's journey around the sun
- 2. Physics of very small things
- 3. Endless or limitless
- 5. A moment in time
- 9. The final frontier