The Sun-Earth-Moon System Vocabulary

Front

the spin of an object around its axis

Back

rotation

Front

the line on which an object rotates

Back

rotation axis

Front

the path an object follows as it moves around another object.

Back

orbit

Front

the orbit of one object around another object.

Back

revolution

Front

when Earth's rotation axis is tilted directly toward or away from the Sun.

Back

solstice

Front

when Earth's rotation axis is tilted neither toward nor away from the Sun.

Back

equinox

Front

the lit part of the Moon or a planet that can be seen from Earth.

Back

phase

Front

phases of the Moon during which more of the Moon's near side is lit each night.

Back

waxing phase

Front

phases of the Moon during which less of the Moon's near side is lit each night.

Back

waning phase

Front

the central, darker part of a shadow where light is totally blocked.

Back

umbra