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18 terms

Earth Science Moon Vocab

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Rotation
The spinning of a body around its own axis
Revolution
The movement of one body around another in an orbit
ecliptic
The imaginary plane formed by the earth's orbit around the sun of the plane formed by the apparent motion of the sun through the sky
phases
The visible changes that the moon goes through in every lunar month, caused by the changing angle of illumination from the sun. New, crescent,quarter, gibbous and full.
waxing moon
The period in the moon's monthly cycle after the new moon and before the full moon. During this period, the lighted portion of the moon's surface is increasing.
waning moon
The period in the moon's monthly cycle after the new moon and before the full moon. During this period the lighted portion of the moon's surface is decreasing.
synodic month
The moon completes its entire cycle of phases (new moon to new moon) in a 29 1/2 day month.
sidereal month
The moon completes one revolution around the earth in a 27 1/3 day month.
perigee
The point in the moon's orbit when it is closest to the earth.
apogee
The point in the moon's orbit when it is farthest from the earth.
umbra
The darker cone-shaped core of a shadow, surrounded by a lighter penumbral shadow.
penumbra
The lighter part of a shadow.
lunar eclipse
An eclipse creased by the earth coming between the sun and the moon, Lunar eclipses always happen during the full moon phase. The moon passes into earth's umbra.
solar eclipse
An eclipse caused when the moon comes directly between the earth and the sun, temporarily blocking our sun's disk in the sky. Always happens during the new moon phase. Moon's umbra reaches earth's surface.
annular eclipse
Ring eclipse. A solar eclipse when the moon is at apogee. The apparent diameter of the moon is not large enough to completely obscure the sun, so a ring of light is left uncovered around the dark circle produced by the moon.
tides
The cyclical movement of bodies of water on earth caused by the gravitational pull of the earth, moon and sun.
spring tide
The highest tides in a lunar month, occurring near new and full moon phases, when the earth, sun and moon are aligned.
neap tide
The lowest high tide of the lunar month, occurring near the first and last quarter moon phases.