The position of the Earth, Sun, and moon affect us daily
Seasons change, day turns to night, tides rise & fall
The Earth’s Shape
The Earth was once believed to be flat (YES, it is roundish)
Aristotle reasoned that the Earth was round because it cast a round shadow (Not flat) on the Moon during eclipses
Sailors used line of sight to show the Earth was curved
Pgs. 613 - 622
Earth the Oblique spheroid
Today we know the Earth is almost round
It is a slightly flattened sphere (Oblique Spheroid)
Sphere: round three dimensional object
Slightly bulged at the Equator, Flatter at the poles
The axis runs through the poles
Axis: line around which the Earth spins (Rotation)
Rotation causes day and night
The Equator: line bisecting the Earth (90 O from Poles)
Only known planet to have liquid water
Made up of 70% water.
97% of all water is salted.
Only known planet to have life
Earth Data (the Specifics)
Diameter: (Pole to Pole) = 7,901 mi.
Diameter: (at Equator) = 7,926 mi
Earth rotates at about 1000 mi/hr.
Mass: 5.98 x 10 27 g = 5.98 x 10 23 kg
Density: 5.52 g/cm 3
Average distance from the Sun = 149,600,000 km
Period of Rotation (1 day) = 23hr. 56 min.
Pd. of Revolution (1 year) = 365 days 6 hr. 9 min.
Polar tilt: 23.5 0 from vertical
Average Temperature is 60 o F
Hottest Temperature: 134 o F in Death Valley California (1913)
Coldest Temperature: -129 o F in Vostok, Antartica (1983)
This means the earth is constantly moving around the sun.
Earth’s Rotation
The Earth rotates, the sun appears to move across the sky (from East to West)
Night is caused by ½ the Earth being in shadow
Earth’s Magnetic Field
The Earth acts as a giant magnet
It produces a magnetic field just like a bar magnet
The Magnetic field is produced from under the surface
It radiates out into space
It is affected by energy from the sun (causes distortion)
Magnetic North
Earth’s magnetic axis, does not line up with it’s polar axis
A compass points to magnetic North (not North Pole)
Difference is 11.5 0 from polar North
Earth’s Orbit
REVOLUTION – Yearly orbit around the sun.
Just like the Moon is a satellite of the Earth, the Earth is a satellite of the sun.
The Earth revolves around the sun
Earth’s orbit is an ellipse
Ellipse: off center oval (elongated closed curve)
Distance from the sun changes during the year
Closest to the sun = Perihelion Jan 3 rd and is about 91,500,000 miles from the sun.
Farthest from the sun = Aphelion July 4 th and is about 94,500,000 miles from the sun.
The Seasons
Seasons: Annual change in climate
Due to the Earth’s tilt on it’s axis 23.5 0
Seasons are opposite between hemispheres
Daylight hrs are longer for the pole pointed toward the sun
More solar energy = warmer temperatures
Equinoxes
Equinox: Equal amounts of sunlight
Daylight = 12 hrs; Night = 12 hrs.
Sunlight hits directly on the Equator
Northern Hemisphere:
Spring (VERNAL) Equinox (Marks beginning of Spring) March 20 th or 21 st
Autumn Equinox (Beginning of Fall) September 22 nd or 23 rd
Reversed for the Southern Hemisphere
Solstices
Solstice: “longest” of the year
Sun reaches its farthest point North or South
Summer Solstice: (Northern Hemisphere)
Occurs on June 21 st or 22 nd (Beginning of Summer)
Sunlight reaches the Tropic of Cancer
“ Longest day of the year” = 16 hrs. of sunlight
North Pole = 24 hrs of daylight
South Pole = 24 hrs of night
Winter Solstices
Sun directly on Tropic of Capricorn
Occurs on December 21 st or 22 nd
Northern Hemisphere = Beginning of Winter
“ Longest night of the Year” (16 hrs. of night)
North Pole: 24 hrs. of night
South Pole: 24 hrs. of daylight
22.2 Earth’s Moon
You know the moon looks different over the month
You see different amounts visible
It rises at different times (sometimes even during the day)
The Moon’s Rotation & Revolution
The moon rotates on its axis (27.3 days = 1 rotation)
It revolves around the Earth (27.3 days = 1 revolution)
Unique situation: We always see the same side of the moon
Pgs. 623 - 631
Why the Moon Shines
The moon is not like the sun
It does not create it’s own light
It reflects sunlight = Moon light
Only the side of the moon facing the sun can be seen
Other side in shadow
Moon Phases
Phases: Daily change in the moon’s appearance
Occur because the moon reflects sunlight & orbiting Earth
Our view point & Moon’s position determines what we see
Waxing: More & more of the moon becomes visible
Occurs between New moon and Full moon
Waning: Less & less of the moon is visible
Occurs between Full moon and New Moon
There are Eight Main Phases:
1.) New Moon 5.) Full Moon
2.) Waxing Crescent 6.) Waning Gibbous
3.) First Quarter 7.) Last Quarter
4.) Waxing Gibbous 8.) Waning Crescent
Phases of the Moon
1.) NEW MOON – When the moon is completely in shadow
2.) WAXING CRESCENT – Right side of moon begins to become visible, Left side in shadow.
3.)FIRST QUARTER – Right half is visible, left half in shadow.
4.)WAXING GIBBOUS – More than half of the lit side is visible, moon takes on an egg shape
5.)FULL MOON – When all of the moon’s surface facing earth is lit up and visible.
6.)WANING GIBBOUS – Moon begins to appear less lit up, takes on an egg shape again (Left side still shines, Right side in shadow)
7)THIRD (LAST) QUARTER – Left half of moon visible
8) WANING CRESCENT – only a sliver of the left side is visible.
NEW MOON
WAXING CRESCENT
FIRST QUARTER
WAXING GIBBOUS
FULL MOON
WANING GIBBOUS
THIRD QUARTER
WANING CRESCENT
Phases of the Moon
Average Distance from the Earth to the Moon: 238,857 miles
The Harvest Moon is the FULL MOON nearest to the AUTUMNAL EQUINOX , which occurs (in the NORTHERN HEMISPHERE) on or about SEPT. 23rd
The Harvest Moon is also known as the Wine Moon, the Singing Moon and the Elk Call Moon. In MYTH and FOLKLORE the full moon of each month is given a name. There are many variations but the following list gives the most widely known names:
January – Wolf Moon July – Hay Moon
February – Ice Moon August – Corn Moon
March – Storm Moon Sept. – HARVEST MOON
April – Growing Moon Oct. – Hunter’s Moon
May – Hare Moon Nov. Snow Moon
June – Mead Moon Dec. – Winter Moon
When there are 2 full moons in a month the second is called a BLUE MOON .
Eclipses:
Eclipses occur when the sun, Earth, & Moon align
Caused by the position of the moon
The moon’s orbit is not on the same plane as Earth’s
Can only occur when orbits cross
Shadows are the reason for the phenomena
The Moon’s orbit is tilted about 5 degrees from the Earth’s
Parts of a Shadow:
Shadows have 2 parts:
Umbra: Darkest part (center)
Penumbra: Lighter part (outside)
Solar Eclipses
Solar Eclipse: Moon’s shadow covers part of the Earth
Blocks view of the sun
Only occur during New Moon
Occur every year, only seen in specific areas
Total Solar Eclipse:
The moon blocks out the sun
Only the Corona is seen glowing
Partial Solar Eclipse:
Moon’s penumbra shades part of sun
Total Solar Eclipse Partial Solar Eclipse
Lunar Eclipses
When the moon passes into the Earth’s Shadow
Partial eclipse occur when the moon is in the Penumbra
Total eclipse occur when the moon is in the Umbra
Total Eclipse must occur during Full moons (about once a year)
Moon turns blood red in color
Stages of a Lunar Eclipse
Moon’s Surface Tycho Mare Imbrium Copernicus Mare Serenitatis Mare Tranquillitatus Notice the rays from Tycho Kepler
Moon Surface Features
We can see light and dark parts with our eyes
Maria- Dark colored lava plains with circular basins
Highlands- Areas of light colored crust
Lunar Highlands- made up of mountain chains
Found around maria edges, and extinct volcanoes
The Moon is riddled with craters
Lunar Dirt: Called Regolith (rock particles and dust)
Not soil- contains no water or organic material
The Moon’s Interior
Apollo Missions left instruments to study the moon
Learned about what is below the moon’s surface
Surface:
35 miles thick facing the Earth
90 miles on other side
Solid Mantle: Lies below the surface (600 miles deep)
Partially molten zone: Lies below solid mantle
Core: Iron-rich & solid
The Moon is prone to Moonquakes due to structure
Origin of the Moon
Impact theory:
A Mars sized object collided with the Earth (6.4 b.y.a.)
Vaporized material thrown into space
Material condensed & formed the moon
22.3 Exploration of the Moon
No manned missions to the moon since Apollo
None scheduled missions either
In 1994, one spacecraft was placed in lunar orbit
Clementine: two month mission to survey the moon
Clementine the Spacecraft
Carried & tested sensors to track cold objects in space
Cold objects include satellites, warheads & Asteroids
Also compiled detailed maps of the moon’s surface
Pgs. 632-633
Moon’s average day time temperature is 214 o F
Moon’s average night time temperature is -300 o F
Moon’s Gravity is 6x lighter than the Earths.
Moon has not atmosphere so it is always black there.
Moon’s diameter is 2160 miles
Moon Missions
12 Americans landed on the moon between 1969-1972 during the Apollo Program
July 20,1969 – Apollo 11 first manned lunar landing. Neil Armstrong and Buzz Aldrin walked on the moon.
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