the moon copyright antonio cidadao. used by permission.antonio cidadao
TRANSCRIPT
Animation Shows:
The complete cycle of phases Apparent size of the Moon's disk changes as
its distance from Earth varies (the closest and farthest points do not always occur at the same phases, however).
One side of the Moon always faces Earth
I. Moon Names
Closest astronomical object to Earth
Earth/Moon forms almost a double planet for no other planet has a satellite as large in comparison to the size of the planet.
Called Luna by the Romans
Selene and Artemis by the Greeks
II. Moon Phases http://www.earth.uni.edu/~morgan/astro/course/java/MoonPhases/moonlocation.htm
Daily changes in the Moon's appearance Occur for 2 reasons:
1. Moon is seen due to reflected sunlight 2. Moon is in orbit around Earth
Waxing- Moon changes from New Moon to Full Moon, increasing in the amount of reflected light seen night after night
Waning - Moon changes from Full Moon to New Moon, decreasing in the amount of reflected light seen night after night
A. New Moon
"Rises at dawn, sets at dusk" The Moon's non-illuminated side is facing
the Earth. The Moon is not visible (except during a
solar eclipse).
B. Waxing Crescent
The Moon appears to be partly but less than one-half illuminated by direct sunlight.
The fraction of the Moon's disk that is illuminated is increasing.
Visible during the day
C. Waxing Quarter (1st quarter) "Rises at noon, sets at midnight" One-half of the Moon appears to
be illuminated by direct sunlight. The fraction of the Moon's disk that is
illuminated is increasing. Can be seen during the day The dividing circle between the
light side and the dark side is called the terminator.
D. Waxing Gibbous
The Moon appears to be more than one-half but not fully illuminated by direct sunlight.
The fraction of the Moon's disk that is illuminated is increasing.
E. Full Moon
"Rises at dusk, sets at dawn“ The Moon's illuminated side is
facing the Earth. The Moon appears to be
completely illuminated by direct sunlight.
F. Waning Gibbous
The Moon appears to be more than one-half but not fully illuminated by direct sunlight.
The fraction of the Moon's disk that is illuminated is decreasing.
G. Waning Quarter (3rd quarter) “Rises at midnight, sets at
noon" One-half of the Moon appears
to be illuminated by direct sunlight.
The fraction of the Moon's disk that is illuminated is decreasing.
H. Waning Crescent
The Moon appears to be partly but less than one-half illuminated by direct sunlight.
The fraction of the Moon's disk that is illuminated is decreasing.
Test your knowledge of Moon Phases with thisShockwave gamehttp://www.spaceday.com/conmgmt/index.php?option=displaypage&Itemid=156&op=page&SubMenu=
Daytime Moon Phases
Moon between Earth & Sun can be seen in the daytime sky
Lit side of Moon faces away from Earth during a New Moon
Nighttime Moon Phases
Moon opposite Earth from the Sun is seen mostly in the nighttime sky
Lit side of Moon faces Earth during Full Moon
III. Motions of the Moon
Revolves around Earth from west to east (counter clockwise) in an elliptical orbit
Revolution rate around Earth 27.3 days
Rotates on axis once every 27.3 days
Same side of Moon always faces Earth because rotation rate = revolution rate
http://jove.geol.niu.edu/faculty/stoddard/JAVA/moonphase.htmlhttp://www.brainpop.com/science/space/moon/index.weml
What moon phase comes after Wanning Gibbous?
A. Last Quarter
B. 1st Quarter
C. Full Moon
D. Waxing Gibbous
How many days does it take the moon to rotate?
A. 29.5 days
B. 30 days
C. 27.3 days
D. 1 days
Which of the following means the amount of reflected light seen is increasing from night to night?
A. Waxing
B. Waning
Lunar Month/Lunation
Complete cycle of phases Ex. Full moon to next full moon Takes 29.5 days Moon takes 2 days to catch up with Earth’s
advance around the sun http://cygnus.colorado.edu/Animations/lunar2.mov
Moon Rise Times
The Moon moves 130 along its orbit each day In 24 hrs the Moon has not returned to the same
spot in our sky because the Earth has been moving in its revolution around the Sun.
Moonrise & Moonset is 50 minutes later each day. a. Perigee - point in the Moon's orbit when it is closest to Earth b. Apogee - point in the Moon's orbit when it is furthest from Earth
IV. Apparent Size Comparison
The Sun is approximately 400 times the size of the Moon
Both appear similar in size in the sky because the sun is 400 times further away.
V. EclipsesThe Causes:
Revolution of the moon causes eclipses Moon doesn’t revolve in the same plane as
Earth Occurs when Earth or the Moon blocks the
sunlight reaching the other Can only occur when the Sun, Moon, &
Earth are perfectly in line http://www.sun-sentinel.com/graphics/science/eclipse.htm Dates of Lunar Eclipses
http://www.earth.uni.edu/~morgan/astro/course/Notes/lunareclipses.html
The angle between the Earth's orbit & the Moon's orbit is 50
Means the Moon is sometimes above the Earth's shadow and sometimes below it by 50
Determines whether a solar or lunar eclipse occurs or a New or Full Moon instead.
A. Solar Eclipse When the moon moves
directly between the sun and Earth Moon casts a shadow on part of the
Earth. Only people within the narrow band
of the umbra see a full Solar Eclipse
Solar Eclipse Cont’
Occurs only at New Moon
1. Umbra – area of total shadow; person within it sees a total eclipse
2. Penumbra – area of partial shadow; person within it sees a partial eclipse
3 Types of Solar Eclipses a. Total b.Partial c. Annular
1. Totality
The short part of an eclipse when the moon entirely blocks the Sun.
Totality usually lasts for just a few minutes (no more than 8 minutes in any one location on Earth).
Total Solar Eclipses (Path of Totality )
Solar Eclipse Cont’
The longest solar eclipses occur when: –Earth is at aphelion (farthest from the
Sun, making the solar disc smaller) –And the Moon is at perigee (closest to the
Earth, making the Moons apparent diameter larger).
2. Partial Solar Eclipse
Moon only covers part of the solar disc.
Annular Eclipse
Animation by Kevin McMahon TR South Class of '05
Moon at apogee, the shadow from the umbra doesn’t reach Earth.
Observers at the center see the sun as a thin, bright ring around the moon.
B. Lunar Eclipse
Earth’s shadow falls on the moon; Moon becomes darker and may appear red in color because the light from the sun is refracted around the Earth
Only the longest wavelengths (red & orange) make it.
Lunar Eclipse Cont’
• Anyone on the nighttime side of Earth can see a Lunar Eclipse.
• Occurs only at Full Moon• Full Moon is usually above or below the
Earth's umbra so no eclipse occurs
VI. Tides
Daily rise & fall of the ocean waters On avg. tides rise 50 minutes later each day. During New moon & Full moon tides are
large During Quarter moon phases tides are small Approximately 6 hrs & 12 minutes between
high & low tide
A. Direct High Tide
Bulge in ocean on the side of the Earth near the moon Reason: –Gravity is stronger when objects are
closer together. –Water on Earth is pulled more than Earth
because it is "closer" to the moon
B. Indirect High Tide
Bulge in ocean on the side of Earth furthest from the moon. –Why? Earth's center is nearer the moon
than the water on the far side of Earth. –Earth is pulling away from the water
causing the bulge. –Low tide occurs in areas that lie in
between the two high tides.
A. Spring Tides
high tides are very high, and low tides are very low
1. Occur during New and Full Moon phase2. Occur twice a month3. Sun, Moon & Earth are in alignment4. Gravitational effects of the Sun & Moon are
added together5. Moon at Perigee- tidal effect is greater especially
during a New or Full Moon
B. Neap Tides
High tides are not very high and low tides are not very low
1. Occur during Quarter Moon phase2. Occur twice a month3. Sun and Moon are at 900 angles to Earth
C. Tidal Range - the difference in lebetween high tide and low tide Ex. Bay of Fundy, Nova Scotia has a range of 20m
D. Hydrographer - scientist who studies tides
Moon Time
New Moon
Waxing Crescent
1st Quarter
3rd Quarter
Waxing Gibbous
Waning CrescentWaning Gibbous
Full Moon
12 PM
3 PM
6 PM
6 AM
9 P
m
9 AM3 AM
12 AM
Set Moon Rise
W Phase E
S