Across
- 3. Neptune's largest moon, which orbits the planet in a "backward" or retrograde direction.
- 5. Saturn's largest moon, famous for its thick orange atmosphere and lakes of liquid methane.
- 6. The smallest and outermost moon of Mars, named after the Greek personification of terror.
- 8. The collective name for Io, Europa, Ganymede, and Callisto, first observed in 1610.
- 11. The "Grand Canyon of Mars," a massive tectonic crack that would stretch across the entire United States.
- 14. High-speed, narrow bands of wind that create the banded appearances of Jupiter and Saturn.
- 15. The "gas giants" located beyond the asteroid belt, characterized by large sizes and lack of solid surfaces.
- 16. The group of inner, rocky worlds consisting of Mercury, Venus, Earth, and Mars.
- 18. The largest moon in the solar system, even surpassing the planet Mercury in size.
Down
- 1. The process by which sunlight breaks down chemical compounds, such as water vapor in an atmosphere.
- 2. The critical distance from a planet within which a moon will be torn apart by tidal forces.
- 4. Discs of cosmic dust and ice orbiting all four Jovian planets, most notably Saturn.
- 7. A shield volcano on Mars that stands nearly three times the height of Mount Everest.
- 9. A massive impact crater on Mercury that is one of the largest such features in the solar system.
- 10. The larger and closer of the two Martian moons, destined to eventually crash into the planet.
- 12. A cliff-like ridge on Mercury or the Moon, often formed as the planetary body cooled and "shrank."
- 13. An imaging technique used to "see" through the thick clouds of Venus to map its hidden surface.
- 17. One of the two major highland "continents" on Venus, named after a Babylonian goddess.