Download EARTH SCIENCE KEY NOTES

EARTH SCIENCE REGENTS REVIEW
UNIT 4 – MOTIONS OF EARTH, MOON
AND SUN
1) APPARENT MOTION OF CELESTIAL OBJECTS
 Most celestial objects appear to rise in the east and set in the
west. (This is due to Earth’s rotation which rotates from WEST
to EAST – Counterclockwise looking from the north pole).
 All the motion occurs at a rate of 15° per hour due to Earth’s
rotation.
 THEREFORE EVERYTHING APPEARS TO RISE IN
THE EAST AND SET IN THE WEST.
2) APPARENT DAILY MOTION OF THE STARS
 Polaris appears to be stationary due to the fact that it is directly
above the North Pole. Stars that circle Polaris are called
circumpolar stars.
epod.usra.edu
epod.usra.edu
epod.usra.edu
www.gettyimages.
com
epod.usra.edu
3) APPARENT MOTION OF PLANETS
 Over extended periods of time (weeks to months) planets
appear to change position. (Ex. Retrograde motion – appears
like the object is moving backward).
 Both planets move in a direct (eastward) motion around the
Sun, but the planet with the inside (smaller) orbit moves faster
than the planet on the outside (larger) orbit, and when it passes
the slower-moving planet, each sees the other one as apparently
moving backwards relative to its usual motion around the sky.
In this "retrograde" motion, neither planet is actually moving
backwards; it only appears that way, during the time that one
laps the other.
Cseligman.com
ap.smu.ca
THEORIES OF MOTION
 GEOCENTRIC MODEL
Theory that the Earth was the
center of the Universe.by
Ptolemy (proved to be
incorrect).
www.amazing-space.stsci.edu
 HELIOCENTRIC THEORY
Theory that the Sun is the center of
the Universe by Copernicus. This
model truly explained the motion of
the planets. It verified that the
planets orbit the sun in an elliptical
orbit. (proved to be the center of our
solar system).
www.amazing-space.stsci.edu
4) ACTUAL MOTIONS OF THE EARTH
A) Rotation
B) Revolution
A) EVIDENCE OF EARTH’S ROTATION

Foucault Pendulum
Free swinging pendulum that changes
its path. The pendulum swings in a
fixed direction in space, while the
Earth rotates under the pendulum.
sciencephoto.com
 Coriolis Effect
The tendency of all particles of
matter moving at Earth’s
surface to be deflected or
curved. (To the right in the
northern hemisphere and to
the left in the southern
hemisphere).
williamsclass.com
B) EVIDENCE OF EARTH’S REVOLUTION
Seasons change throughout the year.
www.boqueteweather.com
Different constellations are
seen throughout the year. (a
constellation is a group of stars
that form a pattern – ex. (Big
Dipper).
lpi.usra.edu
Changes in apparent
diameter.
addins.kwwl.com
5) LOCAL TIME (Time of Day)
 Every 15ºof longitude = 1 hour. (24 time zones).
 All places on the same longitude line have the same
local time.
 Over the course of a whole year EVERY place on
Earth averages out and receives the same amount of
daylight hours (different intensity due to the angle of
insolation).
physicalgeography.net
6 PM
NYS DEPT OF EDUCATION
 To determine the time of day just rotate the Earth counterclockwise.
 See what section the the point is about to move into.
 Do not move the day and night, just the point. Point “X” is just about
to turn into the night therefore its is 6 PM.
 (This diagram shows that the terminator line (day and night) cuts
through the North Pole. This is a HUGE clue that this is an
EQUINOX !!!)
6) APPARENT MOTION OF THE SUN
 Appears to rise in the east and set in the west.
1. (In N.Y. in the summer the sun rises NORTH OF DUE
EAST AND SETS NORTH OF DUE WEST.
2. In the winter the sun rises SOUTH OF DUE EAST AND
SETS SOUTH OF DUE WEST).

Seasons are caused by the TILT OF THE EARTH.

Distance of the Earth to the Sun has no effect on seasons.
 The Earth is closest to the Sun on Jan.3rd (perihelion) and
furthest on July 4th (aphelion).
 Solar Noon – When the sun reaches its highest position in the
sky.
1. Everyday in New York at solar noon the sun is in the
SOUTH.
 Insolation – Incoming Solar Radiation (sunlight).

Angle of insolation - the angle at which the sunlight is striking
a place. The higher the angle of insolation, the greater the
intensity of the insolation will be.
1) The highest the angle of insolation can be is 90
degrees. This occurs when the sun is directly overhead.
Which can only happen between the tropics.
(23.5 *N (Tropic of Cancer) to 23.5 *S (Tropic of
Capricorn).
 Duration of Insolation – This means how many daylight
hours the sun is out.
 Intensity of Insolation – This means the strength of the
radiation from the sun.
 Zenith - The point directly over your head.
 Shadows (Annually) – Your shadow is longest when the sun is
lowest in the sky (Dec 21st). Your shadow is shortest when the
sun is highest in the sky (June 21st). (This is at the time of solar
noon).
 Shadows (Daily) – Your shadow is shortest at solar noon and
longest at sunrise and sunset.
 Everyday in New York at solar noon the sun is in the
SOUTH, therefore your shadow is always in the NORTH.
CELESTIAL SPHERE KEY POINTS
• CHECK OVER OBSERVERS HEAD - If the sun can be directly
over your head then you MUST be standing at or between the Tropic
of Cancer (23 1/2º North) and the Tropic of Capricorn (23 1/2º South).
• CHECK WHERE SOLAR NOON IS – If the sun at SOLAR
NOON is in the south then you are standing in the northern
hemisphere. If the sun at SOLAR NOON is in the north then you are
standing in the southern hemisphere.
• CHECK YOUR DIRECTIONS – Look at south and north.
Sometimes they both say NORTH (that means you are probably
standing at the SOUTH POLE). Sometimes they both say SOUTH
(that means you are probably standing at the NORTH POLE).
• CHECK SUNRISE AND SUNSET – If the sun never sets that
means you are standing either at the North or South Poles (or actually
above the Arctic Circle 66 ½ degrees north or below the Antarctic
Circle 66 ½ degrees south).
• EQUINOX – If the sun rises directly DUE EAST and sets directly
DUE WEST then it is an Equinox. Everyone on Earth has 12 hours of
daylight and 12 hours of darkness. The sun is directly overhead at the
Equator at solar noon.
EQUINOX = EQUAL DAY AND NIGHT(EVERYBODY) =
EQUATOR.
• EVERYDAY OF THE YEAR THE EQUATOR HAS 12 HOURS
OF DAYLIGHT AND 12 HOURS OF DARKNESS
!!!!!!!!!!!!!!!!!!!!!!!
AFTERNOON
MORNING
regentsearth.com
NEW YORK STATE
SOLAR NOON
EQUINOX
NYS DEPT OF EDUCATION
6) SEASONS
 Astronomical Causes of The Seasons
1. Tilt of the Earth’s Axis
 23 1/2º with respect to a line perpendicular
to the plane of its orbit of the sun.
2. Parallelism of Earth’s Axis
 Earth’s axis always points in the same
direction in space.
3. Revolution of the Earth Around the Sun
 As Earth revolves around the sun, the
direction of the Earth’s axis with respect to
the sun varies because of its tilt and
parallelism.
www.boqueteweather.com
NEW YORK STATE
DATE
(APPROXIM
ATE)
LATITUDE
OF SUN'S
DIRECT
RAYS
DIRECTION
OF SUNRISE
AND
SUNSET
ALTITUDE
OF NOON
SUN
LENGTH OF
DAYLIGHT
Sept. 23
(Autumnal
Equinox)
Equator
(0°)
Rises due
East
Sets due
West
48°
12 hours
December 21
(Winter
Solstice)
Tropic of
Capricorn
(23.5°S)
Rises in
South East
Sets in South
West
24.5°
(lowest)
8 hours
(shortest day)
March 21
(Vernal
Equinox)
Equator
(0°)
Rises due
East
Sets due
West
48°
12 hours
June 21
(Summer
Solstice)
Tropic of
Cancer
(23.5°N)
Rises in
North East
Sets in North
West
71.5°
(highest)
16 hours
( longest day)
12 AND 12
24 HOURS OF
DAYLIGHT
24 HOURS OF
DARKNESS
12 AND 12
NYS DEPT OF EDUACTION
NYS DEPT OF EDUCATION
SEASONS KEY POINTS
1) Seasons are caused by the TILT OF THE EARTH.
2) Distance of the Earth to the Sun has no effect on seasons.
3) EVERYDAY OF THE YEAR THE EQUATOR HAS 12
HOURS OF DAYLIGHT AND 12 HOURS OF
DARKNESS !!
SUMMER
 The first day of summer ( June 21st) in the northern
hemisphere is called the Summer Solstice.
 On the Summer Solstice the direct rays of the sun strike
23.5* N (The Tropic of Cancer).
 The sun rises NORTH of DUE EAST and sets NORTH of
DUE WEST.
 The North Pole has 24 hours of daylight (actually
everything above the arctic circle 66 ½ ° north) (South
Pole has 24 hours of darkness (actually everything below
the antarctic circle 66 ½ ° south).
WINTER
 The first day of winter ( Dec. 21st) in the northern
hemisphere is called the Winter Solstice.
 On the Winter Solstice the direct rays of the sun strike
23.5* S (The Tropic of Capricorn).
 The sun rises SOUTH of DUE EAST and sets SOUTH of
DUE WEST.
 The North Pole has 24 hours of darkness (actually
everything above the arctic circle 66 ½ ° north) (South
Pole has 24 hours of daylight (actually everything below
the antarctic circle 66 ½ ° south).
SPRING AND FALL
 The first day of spring (Mar. 21st) in the northern
hemisphere is called the Spring (Vernal) Equinox. The
first day of fall (Sept. 23rd) is called the Fall (Autumnal)
Equinox.
 On both equinoxes the direct rays of the sun strike the
Equator.
 The sun rises directly DUE EAST and sets directly DUE
WEST.
 Everyone on Earth receives 12 hours of daylight and 12
hours of darkness.
 If the Circle Of Illumination (separating day and night)
passes right through the North and South Poles it is
an Equinox !!!!!
7) MOTION OF THE MOON
MOON PHASES
The varying amounts of lighted moon as seen from earth are known
as the moon’s phases.
 Waxing- means getting brighter. When the moon is in a waxing
phase the light will be on the right side.
 Waning – is when less of the moon is becoming lit up. During
the waning phases the left side of the moon is lit up.
www.astro.virginia.edu
PHASES OF THE MOON KEY POINTS
 We see phases of the moon because the MOON REVOLVES
AROUND THE EARTH.
 The moon is ALWAYS half lit.
 The moon’s rotation (27.3 days ) is equal to the moon’s
revolution around the Earth (27.3 days) (See E.S.R.T). This is
called a sidereal month. They are synchronized. Therefore we
always see the same side of the moon.
 It takes 29.5 days for a complete set of phases to occur (full
moon to full moon). This is called a synodic month. This 2 day
difference is because while the Moon is revolving around the
Earth, the Earth is revolving around the sun.
 APOGEE – When the moon is at its furthest distance.
 PERIGEE – When the moon is at its closest distance.
8) TIDES - (caused primarily by the gravity of the
moon and to a lesser degree the Sun).
 Tides are cyclic events and very predictable.
 There is a high tide approximately every 12 hours
and 25 minutes.
 There is a low tide approximately every 12 hours and 25
minutes.
 There are 2 high tides and 2 low tides approximately
every day (every 24 hours).
 The gravity of the moon pulls on Earth’s waters, creating
a bulge of water on the side of the Earth closest to the
moon. A tidal bulge forms on the opposite side of Earth
as well.
 Spring Tide:
When the Moon and the Sun are in line with the Earth,
the gravitational pull is at its greatest causing very
HIGH tides and very LOW tides. (FULL MOON AND
NEW MOON phases).
 Neap Tide:
When the Moon and the Earth are at 90 degree angles, the
gravitational pull causes very average tides. (FIRST
QUARTER AND THIRD QUARTER phases).
http://www.jochemnet.de/fiu/tide2.jpg
www.atlantickayaktours.com
NOTE:
Look for the MOON to find the high tide !!!
9) ECLIPSES
An eclipse is an astronomical event that occurs when an astronomical
object is temporarily obscured, either by passing into the shadow of
another body or by having another body pass between it and the viewer.
Note : We do not see an eclipse every month because the
moon’s orbit is 5° tilted from Earth’s orbit !!!!!!!!!!
UMBRA - Area where a total eclipse will occur.
PENUMBRA – Area where a partial eclipse will occur.
 Solar Eclipse:
When the Moon passes directly between the Earth and
the Sun (NEW MOON phase).
THREE TYPES:
A. Total – The entire central portion of the Sun is
blacked out.
B. Partial – Only part of the Sun is blacked out.
C. Annular – Only a small ring-like sliver of light is
seen (Moon’s shadow does not reach
the Earth).
astroadventures.net/solar_eclipses.html
 Lunar Eclipse:
When the Earth passes directly between the Moon and the Sun
(FULL MOON phase).
jrscience.wcp.muohio.edu