CHAPTER 14:
THE MOTIONS OF
EARTH, THE SUN,
AND THE MOON
14-1: MOTIONS OF EARTH
Revolution
movement of a
planet or other body around
another body
All
planets revolve around the
Sun
Earth revolves around the Sun
every 365 ¼ days or 1 year
14-1: MOTIONS OF EARTH
Rotation
spinning of a planet
or other body on its axis
Earth
rotates west to east
Earth rotates on its axis every
24 hours or 1 day
14-1: MOTIONS OF EARTH
Axis
imaginary line through the
center of a planet or other body
around which it spins
Earth is tilted 23 ½ ° on its axis
14-2 TIME ZONES
Solar
Noon time of day when
the sun is highest in the sky
There are 24 times zones in
the world
Each
time zone is 15° wide
14-2 TIME ZONES
U.S.
has 8 time zones total
4 for the continental U.S.
Pacific,
Eastern
Mountain, Central, &
14-2 TIME ZONES
 As
you go west, you lose time
 As you go east, you gain time
 International Date Line
boundary where each new day
starts
14-3 SEASONS
Seasons
are caused by
Tilt
of the Earth
Movement around the Sun
Angle
which the Sun’s rays strike
Earth’s surface
14-3 SEASONS
Summer
= tilted towards Sun;
more direct rays
Winter = tilted away from Sun;
more indirect rays
Winter
in N. Hemisphere =
Summer in S. Hemisphere
14.4 SOLSTICES & EQUINOXES
Distance
btw Earth & Sun
change throughout the year
Seasons do not depend on
distance from Sun
14.4 SOLSTICES & EQUINOXES
Perihelion
closest point to Sun
(happens in January)
Earth
is 147 million km from Sun
aphelion
farthest point to Sun
(happens in July)
Earth
is 152 million km from Sun
14.4 SOLSTICES & EQUINOXES
Solstice
the beginning of summer
and winter
1
Pole has 24 hours of daylight, the other
Pole has 24 hours of darkness
Summer
Solstice is on or about
June 21; N. Pole light, S. Pole dark
Winter Solstice is on or about
December 21; N. Pole dark, S. Pole light
14.4 SOLSTICES & EQUINOXES
Equinox
the Sun is directly over
the equator at solar noon; the
beginning of spring & fall
12
hrs. of light/12 hrs. of dark
Vernal
(spring) equinox is around
March 21
Autumnal (fall) equinox is around
September 21
14-5 MOTION OF MOON
Moon
revolves around Earth
every 27 1/3 days
Moon
Moon
revolves @ 3,500 km/hr
rotates on its axis every
27 1/3 days
14-5 MOTION OF MOON
Apogee
moon farthest from
Earth
Perigee moon closest to
Earth
14-5 MOTION OF MOON
When
Earth, Moon, Sun line up
in their orbits & all 3 gravities
are working together = really
high tides and really low tides.
This is a Spring Tide.
Happens
twice a month
14-5 MOTION OF MOON
When
Moon & Sun at right
angles & gravities working
against each other = no high or
low tides. This is a Neap Tide.
Happens
twice a month
14-5 MOTION OF MOON
Moon
appears to rise in east
and set in west
Moon comes into view at
moonrise 50 minutes later
each day
14-6 PHASES OF THE MOON
Moon
appears to change shape
because of the way it reflects
light from the Sun
Phases depend on the position
of the Sun, Moon, & Earth
Moon takes 29 ½ days to go
through all phases
14-6 PHASES OF THE MOON
Waxing
New
increasing in light
Moon no light
Waxing Crescent1/4 right side lit
1st Quarter right 1/2 lit
Waxing Gibbous 3/4 right side lit
14-6 PHASES OF THE MOON
Waning
Full
decreasing in light
Moon all light
Waning Gibbous 3/4 left side lit
3rd Quarter left 1/2 lit
Waning Crescent left 1/4 lit
14-7 LUNAR ECLIPSES
Umbra
center, dark part of a
shadow
Penumbra outside, lighter
part of a shadow
14-7 LUNAR ECLIPSES
Lunar
Eclipse when the
moon passes directly through
Earth’s shadow
Can
only occur during a full
moon
14-7 LUNAR ECLIPSES
Total
Lunar Eclipse when the
moon moves entirely into
Earth’s umbra; all sunlight is
blocked = moon entirely dark
Total
lunar eclipse is rare &
don’t happen regularly
14-7 LUNAR ECLIPSES
Partial
Lunar Eclipse only
part of the moon moves into
Earth’s umbra; some sunlight is
blocked = part of moon dark
14-8 SOLAR ECLIPSES
Solar
Eclipse when the moon
passes directly btw Earth & Sun
Most of Sun’s surface is
blacked out & we see the
corona
14-8 SOLAR ECLIPSES
Total
Solar Eclipse entire
face of Sun blocked by moon
seen
in small area of world
Partial
Solar Eclipse only
part of the face of the Sun is
blocked
seen
over a larger area