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Earth Science Notes
The Earth, Moon, and Sun
Properties of the Earth
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Rotation refers to the spinning of
earth on its axis
When Earth spins on axis it causes
day and night
Properties of the Earth
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Revolution refers to the orbiting of
earth around the sun
Earth’s orbit is an ellipse
Properties of the Earth

Change in seasons are caused by the
tilt of the earths axis as it revolves
around the sun
– The hemisphere that is tilted toward the
sun received more sunlight (has longer
days)
The Seasons
Properties of the Earth

Solstice is the day the sun reaches its
greatest distance north or south of the
equator
– Winter solstice and summer solstice
Properties of the Earth
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Equinoxes occur when the sun is
directly above the Earth’s equator
– Sunlight hours are equal during this time
– Fall and Spring Equinox
Properties of the Earth

The earth bulges slightly at the
equator
– Gravity contracts earth into sphere
– Rotation cause Earth’s sphere to bulge
– Pull of moon creates tidal bulge
Properties of the Earth
Earth has a magnetic poles
 Moving material inside the earth as
well as Earth’s rotation may generate
the magnetic field
 The poles change over time
– Recall magnetic reversals as evidence of
seafloor spreading
The Moon
Moon phases
 Different forms that the moon takes in
appearance
The Moon
Moon Phases - depend on the relative
position of the Earth, Moon, and Sun.
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New Moon  Moon is between earth and
the sun – no light is reflected
Waxing Crescent  first thumbnail
shaped portion of the moon seen
First Quarter  one quarter of the moon
is reflecting the sun light
Waxing Gibbous  means more of the
illuminated half can be seen each night
Moon Phases
Moon Phases (cont.)
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Full Moon  moon surface that faces
earth reflects all light from sun
Waning Gibbous  means less of
the illuminated half can be seen each
night
Third Quarter  one quarter of the
moon is reflecting the sun light
Waning Crescent  last thumbnail
shaped portion of the moon seen
Moon Phases
The Moon

Solar eclipse occurs when the moon
moves directly between the sun and
the earth.
Solar Eclipse
The Moon

Lunar eclipse occurs when the earth
falls directly between the sun and the
moon
The Moon
Structure of the moon
 Models for moon’s
interior derived from
seismic activity (i.e.
moonquakes)
 The moon is made up
of crust, upper mantle,
lower mantle, and core.
The Moon
Origin of the Moon
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Various theories had been
proposed for the formation of
the Moon.
Fission Theory – moon
somehow separated from the
earth
– Location – pacific basin
– Evidence – moon is made of
materials similar to Earth’s mantle
– Problem – cast off of moon would
be do to rapid spinning of Earth –
no fossil evidence of this
The Moon
Origin of the Moon

Capture Theory: Moon was formed
somewhere else in the solar system, and
was later captured by the gravitational field
of the Earth
The Moon
Origin of the Moon
• The Condensation Theory:
the Moon and the Earth condensed
individually from the nebula that
formed the solar system.
• Problem – if the Moon formed
near Earth it should have nearly
the same composition.
Specifically, it should possess a
significant iron core, and it does
not.
The Moon
Origin of the Moon

The Giant Impactor Theory: proposes that a small planet
the size of Mars struck the Earth just after the formation of the solar
system, ejecting large volumes of heated material from the outer layers
of both objects. A disk of orbiting material was formed, and this matter
eventually stuck together to form the Moon in orbit around the Earth.
–This theory can
explain why the Moon
is made mostly of
rock and how the rock
was excessively
heated. Furthermore,
we see evidence in
many places in the
solar system that
such collisions were
common late in the
formative stages of
the solar system.
Giant Impactor Theory
Trips to the Moon
Click the link to learn more about these missions
http://www.lpi.usra.edu/expmoon/apollo_landings.html
The Sun
Structure of the Sun
The Sun
Structure of the Sun

Corona – largest layer of the sun’s atmosphere, extends millions of
km out into space
Chromosphere –
transition zone
between the
photosphere and the
corona
Photosphere –
lowest layer of the
sun’s atmosphere,
where light is given
off, 6000 K.
The Sun

Convention layer – heat energy rises and
falls in this layer as gases rise, cool, and then
fall
Radiation zone –
energy from the suns
core is transferred to
the conduction zone
Core – source of
suns energy, where
nuclear fusion takes
place
The Sun
Surface Features of Sun
 Sunspots – spots on the
sun that are darker
because they are cooler
The Sun
Surface Features of Sun
 Prominences – arching
columns of gas
– Maybe caused by Sun’s
magnetic field
The Sun
Auroras

Created as a result of electrically charged particles from
the sun’s corona hitting the earth’s atmosphere and
ionizing gases there.
The Sun

The sun is an average star. It emits
average heat and light energy
Summary
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How does rotation and revolution differ?
What are the effects of each?
Explain why we have seasons.
What are the phases of the moon?
What is the difference between solar and
lunar eclipses?
Explain different theories regarding the
origin of the moon.
Describe the Sun’s structures and its
features.