Crossword Speed Challenge

123456789101112131415161718192021
Across
  1. 6. A Mars rover launched in 2020
  2. 8. Main gas in Earth's atmosphere
  3. 9. Earth's largest ocean
  4. 10. Rome's famous gladiatorial arena
  5. 13. Chemical element with symbol O
  6. 14. A polygon with five sides
  7. 17. Capital of Japan
  8. 18. One thousand years
  9. 20. Country known for kangaroos
  10. 21. Device that sends email
Down
  1. 1. Author of The Shining
  2. 2. Opposite of "false"
  3. 3. Your future title
  4. 4. Italian city known for canals
  5. 5. Strong metal alloy of iron and carbon
  6. 7. Study of living organisms
  7. 11. Natural satellite of Earth
  8. 12. Coldest continent
  9. 15. Word meaning "before noon"
  10. 16. Opposite of "rare" when referring to steak
  11. 19. Music tempo marking meaning "slow"