Across
- 5. The process used by plants to turn sunlight, water, and carbon dioxide into food and oxygen.
- 7. The true shape of Earth and many planets—a sphere that is squashed at the top and bulges at the equator.
- 9. The theory that a planet's outer crust is broken into moving pieces (plates).
- 11. The layer of gases that surrounds a planet or moon.
- 12. The light-colored, heavily cratered, and mountainous regions of the Moon.
- 18. The natural process where unstable atoms break down, releasing heat inside a planet.
- 20. A measure of how tightly packed matter is inside an object (mass divided by volume).
- 22. Primary waves; the fastest earthquake waves that push and pull the ground like an accordion.
- 23. Bowl-shaped holes in the ground caused by space rocks crashing into a planet or moon.
- 24. Secondary waves; slower earthquake waves that shake the ground side-to-side and cannot travel through liquids.
- 25. The thick, hot layer of rock inside a planet located right beneath its outer crust.
Down
- 1. Long, narrow channels or trenches on the Moon that look like dried riverbeds, carved by ancient lava flows.
- 2. The bending of wind and ocean currents caused by a planet’s rotation.
- 3. The circulation of heat where hot material rises and cold material sinks.
- 4. The process where a planet's crust is pulled apart, creating deep cracks or valleys.
- 6. A process where one tectonic plate slides underneath another and sinks into the mantle.
- 8. When a moon spins at the exact same speed it orbits, causing it to always show the same side to its planet.
- 10. When the Moon blocks the Sun, casting a shadow on Earth.
- 13. An ancient supercontinent where all of Earth's landmasses were joined together long ago.
- 14. When the Earth blocks the Sun, casting a shadow on the Moon.
- 15. The dark, smooth, and flat lava plains on the Moon's surface.
- 16. When a planet's atmosphere traps heat from the Sun, making the surface warmer.
- 17. Bright, splash-like streaks of dust shooting out from a young crater.
- 19. Vibrations or shockwaves that travel through a planet during an earthquake or impact.
- 21. Glowing lights in the sky (like the Northern Lights) caused by solar particles hitting a planet's atmosphere.
