Earth and Moon

4. The fastest seismic waves that compress and expand the ground forward and backward like a slinky.
6. An astronomical event where the Earth passes directly between the Sun and Moon, casting Earth's shadow over the Moon.
8. The process used by plants and algae to convert sunlight, water, and carbon dioxide into oxygen and energy.
10. The heavily cratered, light-colored mountainous regions of the Moon's surface.
11. A measure of how tightly packed matter is within a given space (mass divided by volume).
13. An ancient supercontinent that contained almost all of Earth's landmass before breaking apart 200 million years ago.
14. Bright, radial streaks of ejected material blasting outward from young impact craters.
17. When an object takes the same time to rotate on its axis as it does to orbit another body, causing it to always show the same face (like the Moon to Earth).
18. A vibrant natural light display in the sky, caused by charged solar particles colliding with gases in Earth's atmosphere.• Mantle: The thick, mostly solid middle layer of Earth located between the outer crust and the hot core.
20. The geological process where tectonic plates pull apart, creating deep cracks and valleys in the crust.
21. decay The process by which an unstable atomic nucleus loses energy by emitting radiation, generating internal planetary heat.

1. Effect The apparent curving motion of winds and ocean currents caused by the rotation of the Earth.
2. tectonics The scientific theory that Earth's outer shell is divided into large moving pieces (plates) that reshape the surface.
3. An astronomical event where the Moon passes directly between the Sun and Earth, blocking the Sun's light.
5. effect The process where gases in an atmosphere trap solar heat, keeping a planet warmer than it would otherwise be.
7. The large, dark, smooth basaltic plains on the Moon formed by ancient volcanic eruptions.• Craters: Bowl-shaped depressions on a surface caused by the violent impacts of meteoroids.
9. spheroid The true shape of the Earth; a sphere that bulges at the equator and is flattened at the poles due to its rotation.
12. Slower seismic waves that move the ground side-to-side perpendicular to the direction the wave travels.
15. The layer of gases surrounding a planet, held in place by that planet's gravity.• Seismic waves: Vibrations or energy waves that travel through Earth, typically generated by earthquakes or explosions.
16. The transfer of heat through a fluid where hot, less dense material rises and cold, denser material sinks
17. A process where one tectonic plate sinks beneath another into the mantle at a convergent boundary.
19. Long, narrow depressions or trenches on the Moon's surface that resemble collapsed lava tubes or channels.