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Across 1. I found out that one particular comet comes around ? 6. I am the largest ocean in Earth ? 9. When I release these huge burdens of gas I destroy satellites 10. 97% percent of my atmosphere is made of this ? 11. How long is a day on Mercury ? 12. I am the largest moon in the solar system ? 16. I am the Roman God of War ? 17. I am the largest peak on Earth ? 18. My two moons are captured ? 19. The average on Venus is ? 20. On Mercury how long is a year ? 21. I am the Roman Goddess of Beauty ?

Down 2. I cover one fifth of the Earth surface ? 3. In this process I create Helium which generates energy ? 4. I am the Largest volcano in Our solar System ? 5. I discovered Jupiter's four largest moons ? 7. I was the first probe to go to Mercury ? 8. I am a large volcano in Venus ? 13. I am often called the baby bear planet ? 14. I am the closest planet to the sun ? 15. I contain comets from which Halley's comet came from ?