Earth And Space Science Gt Chapter 30 "moons"

Front 1

apogee

Back 1

point in which the orbit of a planet at which the planet is farthest from the sun

Front 2

calendar

Back 2

system used to measure the passage of time.

Front 3

crater

Back 3

bowl-shaped depression on the surface of a planetary body.

Front 4

day

Back 4

time required for the earth to make one rotation on it's axis, about 24 hours.

Front 5

earthshine

Back 5

sunlight reflected off the surface of the earth.

Front 6

eclipse

Back 6

passing of one planetary body through the shadow of another.

Front 7

full moon

Back 7

phase of the moon in which the entire half of the moon facing the earth is visible.

Front 8

Galilean moon

Back 8

any one of the four largest satellites of Jupiter, which were first seen by Galileo.

Front 9

Gregorian calendar

Back 9

revision of the Julian calendar by Pop Gregory XIII; currently used in most of the world.

Front 10

leap year

Back 10

year with an extra day in it, occuring every four years.

Front 11

lunar eclipse

Back 11

passing of the earth between the moon and the sun during which the earth's shadow crosses the lighted half of the moon.

Front 12

maria

Back 12

dark areas of smooth, dry,solidified lava on the moon that reflect little light.

Front 13

month

Back 13

time required for the moon to go through one set of phases as it orbits the earth, about 29.5 days.

Front 14

new moon

Back 14

phase of the moon during which the side of the moon facing the earth is unlighted.

Front 15

penumbra

Back 15

outer part of the shadow cast by the earth or the moon in which sunlight is only partially blocked.

Front 16

Julian calendar

Back 16

calendar designed by Julius Caesar's astronomers consisting of 12 months; 11 with 30 or 31 days, one with 28 days, and an extra day added every four years.

Front 17

perigee

Back 17

point in the orbit of a satellite at which it is closest to the earth.

Front 18

phase

Back 18

varying shape of the visible portion of the moon.

Front 19

ray

Back 19

streak of displaced rock material radiating from a crater.

Front 20

rille

Back 20

long, deep channel that runs through the maria on the moon.

Front 21

solar eclipse

Back 21

passing of the moon between the earth and the sun during which the shadow of the moon falls on the earth.

Front 22

solar year

Back 22

time required for the earth to mkae one orbit around the sun, about 365.24 days.

Front 23

umbra

Back 23

inner, cone-shaped part of the shadow cast by the earth or the moon in which sunlight is completely blocked.

Front 24

waning

Back 24

describing the phase of the moon during which the size of its visible portion is decreasing.

Front 25

waxing

Back 25

describing the phase of the moon during which the size of its visible portion is increasing.