Download File earth, sun, and moon

Earth, Sun, and Moon
Physical Properties of Earth
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Diameter (pole to pole)
Diameter (equator)
Circumference (poles)
Circumference (equator)
Mass
Density
Average distance to sun
Period of Rotation
Period of Revolution
12,714 km
12,756 km
40,008 km
40,075 km
5.98 x 1027 g
5.52 g/cm3
149,600,000 km
23 hr 56 min
365 days 6 hr 9 min
Motions of the Earth
1)
Rotation
1.
2)
Revolution
1)
3)
Turning or spinning on its axis
Earth revolving around the sun in an elliptical orbit
Precession
1)
Slight movement over a period of 26,000
years of Earth’s axis
Rotation
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2 ways of measuring
1) Solar Day – time from one noon
to the next
 2) Sidereal Day- time it takes Earth
to complete one full rotation (360
degrees) with respect to another
star other than our sun
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 Time
required for a star to reappear at
the identical position in the sky where it
was observed the day before
 23 hours 56 minutes
Revolution
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Earth revolves around the sun in an
elliptical orbit at an average speed
of 107,000 kilometers/hour
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Average distance from the sun is 150
million kilometers
Perihelion- Earth is closest to the
sun 147 million kilometers away
(January)
 Aphelion- Earth is farthest from the
sun about 152 million kilometers
away (July)
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Precession
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Earth wobbles on its 23.5o axis and North
pole points to different stars in 26,000 year
period
Now points towards Polaris
 In 14,000 will point to Vega
 By 28,000 will point to Polaris again
 Has a slight affect on seasons
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Seasons
The northern hemisphere experiences
summer when Earth is farthest from the
sun.
 It experiences winter when Earth is closest
to the sun.
 The seasons are a result of the Earth’s tilt
on its axis.
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Remember Earth’s axis is at a 23.5o tilt.
Equinox
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Equinox is the time when the sun is
directly on Earth’s equator.
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Number of daytime hours = Number of
nighttime hours
Northern and Southern Hemispheres are
not tilted toward the sun.
 Spring Equinox – Around March 20, 21
 Fall Equinox – September 22, 23
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Solstice
The point when the sun reaches its
greatest distance north or south of the
equator.
 Summer Solstice – June 21, 22
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Long days, shorter nights
Winter Solstice – December 21, 22
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Short days, longer nights
http://esminfo.prenhall.com/science/geoanimati
ons/animations/01_EarthSun_E2.html
Earth-Sun Motion
Earth, Sun, and solar system speeds in
the direction of the bright star Vega at 20
Kilometers per second
 Also- Sun revolves around the galaxy
 Galaxies themselves are also in motion
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We are approaching Andromeda
Earth’s Moon (Luna)
Earth’s only natural satellite (objects that
are in Earth’s orbit)
 Density is 3.3X greater than mantle rocks
of Earth
 Gravitational attraction is 1/6 of that on
Earth- 150lb on Earth = 25 lb on the moon
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Earth’s Moon
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The moon rotates on its axis, and revolves
around the earth.
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Moon’s rotations = 1 rotation every 27.3 days
Moon’s revolution = 1 rev. every 27.3 days
Because the revolution and rotation times are
the same, we always see the same side of the
moon.
The moon shines because of light being
reflected from the sun.
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Moon phases are the changing appearances of the
moon as seen from Earth.
Phases of the Moon
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New Moon – the lighted half of the moon is
facing the sun and dark side faces the earth.
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Occurs when the moon is between Earth and the sun.
Waxing – Shortly after the new moon, more and
more of the moon’s lighted side becomes visible
(about 24 hours after new moon)
Waxing occurs until we see the full moon
Waning Phases
Happens after the full moon, when the
moon’s lighted side becomes smaller.
 Waning gibbous occurs after the full moon.
 Then third quarter phase occurs
 Next comes waning crescent
 Finally the waning phase ends with a new
moon.
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New Moon
Waxing Crescent
(Anything small than a quarter)
First Quarter
Waxing Gibbous
(More than one-quarter is visible)
Full Moon
Names for the Full Moon
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January: Wolf or Hunger moon. During this month the wolves once
roamed the countryside, thus suggesting the name wolf moon. In
cold and temperate climates of the Northern Hemisphere, it was
difficult to find food during January, thus the name hunger moon.
February: Snow Moon. In certain parts of the world, snow is usually
the deepest in this month, thus the name snow moon.
March: Sap or Worm Moon. Because sap rises in March, this full
moon is called the sap moon. The ground softens during this month,
and worms begin to burrow out of the ground, thus the name worm
moon.
April: Pink Moon. Many flowers turn pink and bloom in April, thus the
name pink moon.
May: Flower Moon. Because many flowers bloom in May, after the
April downpours, May's moon is called the flower moon.
June: Strawberry or Rose Moon. Because strawberries bloom in
June, this month's moon is the strawberry moon. Also, the French
call this moon la lune rose, which translates into English as "the rose
moon."
Names for the Full Moon Continued
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July: Buck Moon. Male deer, or bucks, grow their first antlers during
this month, thus the name buck moon.
August: Sturgeon Moon. Because it is sturgeon season in certain
parts of the world in August, its moon is called the sturgeon moon
September: Harvest or Corn Moon. Native Americans began to
harvest their crops during this month every year. (If this full moon
occurs late in August it is called the harvest moon.). If the full moon
occurs earlier in September, it is called the corn moon because the
corn crop is ready for picking at that time.
October: Hunter's Moon. The hunting season begins in October,
thus the name hunter's moon.
November: Beaver Moon. Beaver traps were once set in this month
to catch enough beaver to make warm clothing for the upcoming
winter.
December: Cold Moon. The approach of cold weather in the
Northern Hemisphere gives this month's full moon its name.
Compton's Interactive Encyclopedia
Waning Gibbous
Third (Last) Quarter
Waning Crescent
New Moon
(Cycle starts over again!!!)
Eclipses
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Shadow effects
When the moon moves in a line directly
between Earth and the Sun it casts a shadow
on Earth- Solar Eclipse
 When the moon moves within Earth’s shadowLunar Eclipse
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The revolution of the moon causes eclipses
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What does the moon revolve around?
Solar Eclipses
Umbra – Darkest portion of the moon’s
shadow (Total Eclipse)
 Penumbra – Surrounds the umbra and is
lighter shadow on Earth’s surface (Partial
Eclipse)
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Caution: Regardless of where you are standing, never
look directly at a solar eclipse. The light will permanently
damage your eyes.
Lunar Eclipse
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Happens when the shadow of Earth falls
on the moon.
Moon moves into Earth’s penumbra.
 Continues to move, enters the umbra, and
you see a curved shadow on the moon’s
surface.
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Partial Lunar Eclipse
Only a portion of the moon moves
into Earth’s umbra
Total Lunar Eclipse
(January 2000)
Structure of the Moon
Don’t believe everything you read.
 Discovery of life on the Moon was
announced to the American public by the
New York Sun in 1835. This fanciful
illustration is supposed to have shown
what astronomers were seeing with new
and more powerful telescopes.
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Structures of the Moon
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Maria are dark-colored, relatively flat
regions on the moon.
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Formed when ancient lava flows from the moon’s
interior filled large basins on the moon’s surface.
Some are 3 to 4 Billion years old and are the youngest
rocks on the moon
Highlands- densely pitted light-colored
areas
 Regolith- soil-like layer composted of
igneous rock, glass beads, and fine lunar
dust
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Maria
Maria
Craters
Most obvious features on the moon
 Depression formed by meteorites,
asteroids, and comets, which struck the
moon.
 Cracks have formed in the moon, during
impacts
 Many more than Earth because the moon
has no atmosphere to burn up debris and
no destruction by tectonic forces
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South Pole of the Moon
Surface seen by
Apollo 11 on its
decent to the moon
Apollo 11
Moon Interior
Core
Mantle
Crust
Moon’s Interior
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Earthquakes allow scientists to map the
moon’s interior.
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Seismographs were left by Apollo astronauts
Crust:
60 km thick on the side facing Earth
 150 km thick on the far side
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Mantle: solid mantle, maybe 1000 km thick
 Core: May be a solid iron-rich core
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False Color Mosaic
Taken by Galileo in 1992
Red = Lunar Highland
Blue & Orange = ancient
lava flows
Blue regions contain more
titanium than orange
Purple = regions that
formed during large volcanic
eruptions
Moon dust under microscope
Mostly titanium
and iron
oxides
Origins of the Moon
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Three popular theories, prior to the
Apollo missions:
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Moon was captured by Earth’s gravity
Moon condensed from loose material
surrounding Earth during the formation of
the solar system.
Blob of molten material was ejected from
Earth while Earth was still in its early stage.
Impact Theory
Impact Theory
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Moon formed around 4.6 billion years ago when
a Mars-sized object collided with Earth
Melted part of Earth’s Mantle and the impacting
object. Material ejected into space
Debris started orbiting the Earth, some debris
fell back to Earth
Material formed a ring of hot dust and gas
around Earth
In about 100 years, the particles in the ring
joined together forming the moon
Future Moon Missions
Will there be future missions to the moon?
 Will there be colonies on the moon?
 How can we sustain life on the moon?
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Please take a few moments to think about
these questions.