| A | B |
|---|
| Astronomy | The study of the universe. |
| Crater | Bowl-shaped depression on the surface of a moon or planet, caused by a meteoroid. |
| Gibbous | Phase of the moon which most of the bright half of the moon faces the Earth. |
| Lunar eclipse | When the moon passes into the Earth's shadow preventing sunlight from getting to the moon. |
| Maria | Extensive dark spots on the moon that represent basins and level plains. |
| Mascon | Areas of higher gravity that are over the lunar maria. |
| Meteroids | A rocky or icy fragment that travels through space. |
| Micrometeoroids | Tiny rock fragments no bigger than a piece of sand that travels through space. |
| Penumbra | Area of a partial shadow surrounding the darkest shadow of the moon and Earth. |
| Phases | Daily changes of the moon's appearance, as viewed from Earth. |
| Ray | Bright streak of broken rock and dust that radiates from a lunar crater. |
| Regolith | Grayish brown mixture of small rock pieces and particles that cover the moon (lunar soil). |
| Rilles | Trench like valley running through the bedrock of the lunar maria. |
| Solar eclipse | When the moon passes between the Earth and sun and the moon's shadow hits Earth's surface. |
| Umbra | The darkest part of the shadow cast by the moon or Earth. |
| Waning | The decreasing of the visible amount of the moons surface. |
| Waxing | The increasing of the visible amount of the moons surface. |
