Earth Science Ch. 22

Ellipse

elongated, closed curve that describes Earth's yearlong orbit around the Sun

perihelion

The point at which the earth is closest to the sun.

aphelion

The place in the Earth's orbit where Earth is farthest away from the sun.

rotation

the spinning of Earth on its axis

revolution

Earth's yearlong elliptical orbit around the sun

perigee

point of moon's orbit when it is nearest the earth

apogee

when the moon is farthest from earth

new moon

Moon phase that occurs when the Moon is between Earth and the Sun, at which point the Moon cannot be seen because its lighted half is facing the Sun and its dark side faces Earth.

full moon

occurs when all of the Moon's surface facing Earth reflects light

quarter moon

a phase of the moon in which it looks like a half circle

crescent moon

the phase of the moon in which only a curved edge of the moon's side that faced earth is illuminated

gibbous moon

when the size of the illuminated portion of the moon is greater than half but not a full moon

waxing

describes phases that occur after a new moon, as more of the Moon's lighted side becomes visible

waning

(of the moon) pertaining to the period during which the visible surface of the moon decreases

lunar eclipse

the blocking of sunlight to the moon that occurs when Earth is directly between the sun and the moon

solar eclipse

occurs when the Moon passes directly between the Sun and Earth and casts a shadow over part of Earth