| A | B |
|---|
| sphere | round, three-dimensional object |
| axis | imaginary line around which the Earth spins |
| rotation | spin of Earth, causes day and night |
| revolution | yearly orbit of Earth around the sun |
| ellipse | elongated closed curve, Earth's orbit |
| equinox | equal hours of daytime and nighttime |
| solstice | sun angle at its greatest distance north or south, summer or winter |
| mascon | concentrated mass beheath craters of the moon |
| moon phase | cjanging appearance of the moon from Earth |
| new moon | phase of moon, dark side faces Earth |
| waxing | more and more of the moon's surface becomes visible |
| first quarter | moon phase when 1/4 of surface facing Earth is lit |
| full moon | moon phase, all surface facing Earth is lit |
| waning | after full moon, less and less is lit |
| third quarter | moon phase, half of lit side is visible |
| solar eclipse | moon is between sun and Earth, shadow cast on Earth |
| lunar eclipse | Earth's shadow falls on the moon |
