1. Unit 2: Astronomy Earth Science- Ms. Gill Note Packet #3C
UNIT 2: ASTRONOMY

PACKET 3C: FROM EARTH’S PERSPECTIVE
When you change
the way you look at
things, the things you
look at change
P.S. I’m Theodore
HONORS EARTH SCIENCE
MS. GILL
NOTE PACKET #3C
NAME:_______________________ PER:____ DATE: ________
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2. Unit 2: Astronomy Earth Science- Ms. Gill Note Packet #3C
Name: ___________________________ Period: _____ Date:__________________
Astronomy from Earth’s Perspective:
Before the invention of technology that enable humans to leave earth’s perspective,
astronomers relied solely on their observations of the heavens to make inferences about
earth’s motions.
Models of the Solar System
 Based upon observations of the apparent motion of
celestial objects.
 Before our current understanding that the planets
revolve around the sun, people actually believe that
the sun and other planets revolved around earth.
___________________________ ___________________________
– The Sun is at the center, and the
– Earth is the center of the solar planets revolve around it
system, and all objects revolve around
it.
-Used epicycles (small sub-orbits) to
explain retrograde (backward) motion
of planets
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3. Unit 2: Astronomy Earth Science- Ms. Gill Note Packet #3C
Coordinates in the Sky…
On earth we use latitude and longitude to locate places. In astronomy we use
_______________ and __________________.
Altitude is the angle above the horizon in degrees. (Horizon: imaginary boundary between
the sky and the ground)
The highest angle of altitude is ______ and that is the point directly over the observers
head. The 90° point is called the ________________.
Azimuth is direction broken down into degrees from ________ to _______
Altitude and azimuth together form a coordinate grid for locating objects in the sky.
We draw this grid on a model of the sky on a dome called a ___________________.
Earth’s Shape
Rather than a perfect sphere Earth is an
_____________________________________
Meaning that the equatorial circumference is just
slightly bigger than the polar circumference.
(bulges at the equator) This difference is small
and can not be seen with the naked eye.
Proof that the earth is round:
-Ships appear to sink GRADUALLY below the
horizon as they travel away from observer
-Polaris (North Star) changes altitude (angle
measured in degrees above earth’s surface)
directly with your latitude
-Lunar Eclipses - Earth’s shadow on the moon
-Satellite Imagery (pictures) – absolute proof
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4. Unit 2: Astronomy Earth Science- Ms. Gill Note Packet #3C
Celestial observations
___________________________: any object in space (outside of earth’s
atmosphere) examples: Moon, planet, stars, sun
The apparent daily motion of celestial objects (like stars) have enabled scientist to
create theories about earth’s motions: _________________ &
__________________
Earth’s Motions:
Rotation:
The apparent daily motions of the
celestial objects in our sky are due to
Earth’s Rotation or spin on its axis
How long is one rotation? ________
Rotation is responsible for:
-Day and Night
-Rising and Setting of our Sun
-Rising and Setting of our Moon
-Movement of stars through the sky
-Seasons
- Changing Constellations
Rotational Facts
Earth’s axis is tilted ________ from the line perpendicular to earth’s orbit. Earth’s axis
is always tilted in the same direction, this is called ____________________.
___________– the imaginary line through Earth from the North Pole to the South Pole
The earth rotates _________________ when looking from down at the North Pole
from ______ to __________ when looking at a side view of earth
How many degrees per hour does the earth rotate? Show calculation:
________ degrees per hour ________ degrees per day
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5. Unit 2: Astronomy Earth Science- Ms. Gill Note Packet #3C
Our North Star: Polaris
• Polaris is the star that lies in space practically over the _________________
North Pole of the earth.
• Since Polaris is located above our axis of rotation it is a __________________ in
our sky above the North Pole.
• Any one in the Northern Hemisphere can see Polaris but where it appears on the
celestial sphere depends on the observer’s _____________________
• An observer on the North Pole would find that Polaris is at the observer’s
______________________ (directly over head)
• An observer on the equator would find Polaris along the ________________.
• Any observer in between would find Polaris has an altitude equal to their latitude.
So for NYS, Polaris will have an altitude of approximately ___________.
Altitude of Polaris = Your latitude!
If you can spot Polaris in the sky, you can always tell which way is north. Because of this,
Polaris was the most important star for navigating at sea.
Finding Polaris:
• To find Polaris, look for the Big
Dipper.
• Draw an imaginary line from the two
end ‘pointer’ stars.
• They will point approximately to the
last star in the handle of the Little
Dipper… Polaris!
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6. Unit 2: Astronomy Earth Science- Ms. Gill Note Packet #3C
Apparent Daily Motion
An apparent motion is a motion an object
appears to make, it can be real or an
illusion.
Celestial objects appear to move in the
sky through out the night.
This is due to the
__________________________
Celestial Objects appear to move
______________, because Earth
rotates 360° in ______ hours.
The apparent daily motions of stars
changes when the observer’s
_________________ on earth changes.
Therefore, at the poles (90° N or S)
stars do not rise or set but at the Apparent daily motion of the Big
equator (0° ) all stars rise and set Dipper, a ___________________
constellation (never sets)
At 41° N (New York state) some stars,
like the sun appear to rise in the east and
set in the west making an arc across the
celestial sphere. Other stars such as
ones part of circumpolar constellations
never set but instead trace out giant
circles daily around the poles.
Using a time-lapse camera we can
document this phenomenon. We call these
images _________________
Stars are so far away they appear
stationary (not moving). Why do they
have this pattern?
_____________________
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7. Unit 2: Astronomy Earth Science- Ms. Gill Note Packet #3C
Since earth is spherical as it rotates greater distances are covered at the equator than
at the poles for every degree the earth turns.
Rotational speed at Poles _____________________
Rotational speed at Equator ____________________
The Earth is moving ________________ at the equator than at the ____________
How many degrees did the stars move from diagram 1 to diagram 2? ____________
How can you find Polaris?
_________________________________________________________________
What hemisphere must you be in if you can see these constellations? Why?
_________________________________________________________________
What direction must you be looking? ______________________________
Do the stars appear to move clockwise or counterclockwise? ___________________
What causes them to appear to move at all?
__________________________________________________________________
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8. Unit 2: Astronomy Earth Science- Ms. Gill Note Packet #3C
Evidence of Earth’s Rotation
1. ____________________________________
2. ___________________________________
Foucault’s Pendulum Coriolis Effect
As the pendulum swings back and A projectile fired northward from
forth, the Earth rotates underneath the equator appears to veer
it so that the direction of the eastward because it retains the
pendulum's swing appears to change. eastward speed of the equator,
which is greater than the eastward
Since there is NO force that makes speeds north or south of the
pendulum rotate – must be earth that equator.
is rotating!!!
Because of the Coriolis effect,
The ground moves under the freely projectiles and currents of air and
swinging pendulum. water veer to the right in the
northern hemisphere, and to the
The Pendulum appears to move but is left in the southern hemisphere
actually swing in the same initial
direction
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9. Unit 2: Astronomy Earth Science- Ms. Gill Note Packet #3C
Determining Time of Day: Since the earth rotate at a predictable rate (15 °per
hour) we can easily determine the time of day when looking at an aerial image of earth
on the equinoxes. Start by indicating the direction of rotation. Then label your
diagram with 12 AM, 12 PM, 6 AM and 6 PM. Draw in the lines of longitude, all
locations on this line will have the same time.
Remember
12pm (noon)
will be in the middle of the day
or lit portion of the earth.
12 am (midnight)
will be in the middle of the night,
or dark side of the earth.
Revolution:
The apparent yearly change in position of all celestial objects is due to the Earth’s
Revolution around the sun.
Period of revolution: the length of time for one orbit around the sun = 1 year
How many days are in 1 year ? ________
To account for the .26, Every leap year we add February 29 to our calendar to account
for the four quarter days we accumulated over the last four years.
How many degrees does the earth travel in its orbit around the sun in one day?
_____________ Show calculation below:
Revolution is responsible for:
-Sun’s Path across the sky
-Angle of Insolation
-Seasons (combined with Earth’s tilt)
-Changing Constellations
-Rising and setting of the moon
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10. Unit 2: Astronomy Earth Science- Ms. Gill Note Packet #3C
Seasons:
Name the four seasons and their starting dates:
Season Starting date
How many days are in each season on average? _______
What causes the seasons?
_________________________________________________
_________________________________________________
_________________________________________________
As earth revolves around the sun– the tilt of Earth’s axis does not change producing a
cyclical change of seasons…. Earth’s axis is always tilted __________.
Label the seasons on the
aerial views of earth…
Note the position of the
shadow
Label perihelion and
aphelion…
Is distance important to seasonal change? ________ because earth’s orbit is a
___________________________________
Earth is farthest away from the sun on ________ this is called _____________
Earth is closest on to the sun on ________ this is called _______________
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11. Unit 2: Astronomy Earth Science- Ms. Gill Note Packet #3C
What changes do we observe during seasons in NY?
1. ________________________ changes
-The sun is highest on June 21 (summer)
-The sun is lowest on Dec. 21 (winter
- _________________________ at our latitude.
2. ___________________________________ also change with the season.
-On the equinoxes, the sun always rise due east and sets due west.
-The rises and sets South of east and west in __________ and _____________.
-The Sun rises and sets North of East and West in ___________ and ____________.
3. __________________________( Duration of Insolation) changes with the season.
- ___________ hours of day light: Shortest on Winter Solstice, Dec. 21
- ___________ hours of day light: Longest on Summer Solstice, June 21
-12 hours on Equinox for all locations on Earth
Important facts about the solstices and equinoxes in the Northern Hemisphere
Summer Solstice Winter Solstice Both Equinoxes
1.June 21, longest day of the 1.Dec. 21, shortest day of 1.Sept. 21 and March 21.
year. the year. 2. Equal day/night 12 hrs of
2.Sun at highest altitude at 2.Sun at lowest altitude at daylight, 12 hrs of night.
noon. noon. 3.Direct sun ray at Equator.
3.24 hrs of daylight at North 3.24 hrs. of darkness at 4.Sun rise – E, Sun set – W.
Pole. North Pole.
4.Direct sun ray at 23.5° 4.Direct sun ray at 23.5°
north latitude. south latitude.
5.Sun rise – NE, Sun set - 5.Sun rise – SE , Sun set –
NW SW
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12. Unit 2: Astronomy Earth Science- Ms. Gill Note Packet #3C
Apparent Solar Motion
Rotation cause Sun’s apparent daily path from sunrise to sunset has the shape of an arc
moving l5° per hour. However, the sun’s arc changes both its position and its length with
the seasons due to the earth’s Revolution.
The sun appears to move across the sky, like all celestial objects due to earth’s rotation.
But sun’s apparent path in the sky varies by _______________ and _______________.
How does the location of the sun change through
out the year?
-No matter where you are on the globe, on the
equinoxes, the sun will always rise due east and set due
west. The path depends on your latitude.
-Changes in the altitude of the path and horizon
position of sunrise and sunset are due to
_______________________________
Date Sun Rise Sun Set Altitude of Solar Noon is…
Equinoxes
(Spring/ Fall)
Summer
Solstice
Winter
Solstice
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13. Unit 2: Astronomy Earth Science- Ms. Gill Note Packet #3C
Directions:
On the diagrams
below, draw and
label the path of
the sun for each
location during
the equinox, the
spring solstice
and the winter
solstice.
.
Long Island, New York
Latitude = approximately 40°
Summer max altitude of noon sun is ____
Winter is ______
Spring/Autumn: _______
A location along the Equator
Latitude = 0
Summer max altitude of noon sun is ____
Winter is ______
Spring/Autumn: _______
A location along the arctic circle
Latitude = approximately 6°
Summer max altitude of noon sun is ____
Winter is ______
Spring/Autumn: _______
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14. Unit 2: Astronomy Earth Science- Ms. Gill Note Packet #3C
Insolation:
a. “IN”-coming “SOL”-ar radi-“ATION”
b. The ____________the Sun is in the sky, the
stronger (more intense) the sunlight is.
c. Places near the ____________________ receive
the most intense insolation.
d. At places near the _________, the Sun never rises
high in the sky, so the sunlight is always weak. The
Polar Regions receive the least intense insolation.
e. During the summer months, the duration, angle, and
intensity of insolation are _________________
f. Day=hot; Night= cold (no insolation)
g. Summer=hot; Winter = cold
Angle of Insolation:
h. ___________________ - found at the altitude where the sun is at its zenith (altitude
of sun 90° overhead) so sun’s rays are perpendicular to earth’s surface. (No shadow)
i. Angle of Insolation and earth’s surface = _______________________. (depends on
latitude and time of day)
j. As the angle of Insolation increases, the intensity of insolation increases (it’s hotter).
k. The intensity of Insolation increases as the as the sun’s altitude ______________.
L. Solstice - when the direct ray is at a maximum distance from the equator (Tropics) .
m. Equinox - when the duration of insolation equals __________at every location on earth.
Direct ray is at the equator
n. Due to the tilt of the Earth’s axis, the sun’s rays are only perpendicular (directly
overhead) at noon, between 23.5° N and 23.5° S during the year
o. Because of the earth’s spherical shape, on any particular date, there is just 1 place where
insolation is at an angle of 90°. All other places are less than 90°.
Question: Does the 90° ever reach the United States? _____________________
Directions: Draw in the rays of the sun. Remember thay are parallel to each other.
Label the with an arrow the latitudes that receive direct rays with the
Date they receive the direct rays.
________________
________________
________________
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15. Unit 2: Astronomy Earth Science- Ms. Gill Note Packet #3C
Your shadow!
-In NY, the noon sun will always be in the South
Sky! So which way will your shadow fall? ________
-Your shadow always changes with the altitude of
the sun and time of day!
-The length and direction of a shadow depends on
the ____________________ and the observers
____________________. Both variables effect
the sun’s altitude and the angle of insolation.
-Your shadow will always be opposite of the sun, if
the sun is just rising in the east, your shadow will
fall west. If the sun is high in altitude, your shadow
is small, when it is low in altitude your shadow is
long.
-Five different shadows, A', B', C', D', and E', are
cast on a certain day by the post when the Sun is in
positions A, B, C, D, and E, respectively.
Length of Day
The tilt of the Earth on its axis is also responsible for the day and night length
EQUINOX (MEANS EQUAL NIGHTS) =12 HOURS OF DAY AND 12 HOURS OF NIGHT
1) If Earth’s axis were tilted less than 23.5○, which seasonal average temperature
change would occur in New York State?____________________________________
2) Which position of Earth represents the first day of summer in the Northern
Hemisphere? _________
3) How many degrees will the Sun’s vertical rays shift on Earth’s surface as Earth
travels from position C to position D? ________________________
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16. Unit 2: Astronomy Earth Science- Ms. Gill Note Packet #3C
Constellations:
Constellations are groupings of stars that make an
imaginary image in the night sky. They have been named
after mythological characters, people, animals and
objects. In different parts of the world, people have
made up different shapes out of the same groups of
bright stars. It is like a game of connecting the dots. In
the past constellations have became useful for navigating
at night and for keeping track of the seasons.
Stars in constellations are often very far from one
another but we see them in the same direction in the sky
Evidence of Earth’s Revolution around the Sun
-Seasonal Constellations: Because of the Sun’s annual motion, some constellations are
visible at night only during certain seasons.
-Constellations are visible when the dark side of Earth (away from sun) faces toward the
constellation.
-The 13 constellations the sun appears to travel through during the year
Position Season Constellation Visible
A
B
C
D
Directions:
Draw label the positions of the
big dipper during the yearly cycle
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17. Unit 2: Astronomy Earth Science- Ms. Gill Note Packet #3C
The Moon
 The __________ is Earth’s only natural
satellite
 It is estimated to be about
____________________ years old
Features
 The Moon’s interior is thought to have
_________, similar to earth
 The Moon’s surface is covered with
_________, caused by
________________ impacts.
The Moon’s Surface
 Dark areas called _________ (from Latin mare, meaning sea). These are ancient
lava flows.
 Light areas are ___________________, which are mountain ranges made of
lighter color rocks.
Moon Rocks
 Rocks on the Moon are made of ______________ similar to those on Earth.
Rotation and Revolution
 The Moon’s periods of rotation and
revolution are both _________ days.
The result is that the same side of the
Moon always faces Earth (the near side).
 However, it takes 29.5 days for the
Moon to completely revolve around the
Earth
 Moon has to revolve for 2 more days to
get back to the new moon phase
This occurs because the Earth is
revolving around the Sun.
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18. Unit 2: Astronomy Earth Science- Ms. Gill Note Packet #3C
Phases Of The Moon :
 Moon Phases are apparent changes in shape due to the
position of the Moon in its orbit.
 Phase names:
– New
– Crescent
– Quarter
– Gibbous
– Full
 Waxing – becoming more visible
 Waning – becoming less visible
What causes the phase of the moon?
________________________________________
Why does the moon rise later and later each day?
_________________________________________
How many hours is the moon visible each day? _____
The phase of the moon are a ____________ event.
Moon’s Effect on Tides
 ________ are the periodic rise and fall of the ocean surface
 Tides are caused by the _________________________ of the Moon and the Sun on
ocean water
 High tide will occur when the __________ is overhead, as well as on the opposite side of
the Earth.
 How many tides a day? ______
 Why are there not exactly 12 hours between tides? ___________________________
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19. Unit 2: Astronomy Earth Science- Ms. Gill Note Packet #3C
Phases and Tides
* The alignment of the Moon with
the Sun affect tides.
* At the full and new moon phase,
both are in line, causing a higher
high tide and a lower low tide.
This is called the
________________________.
* At the quarter phases, the Sun
and Moon work against each
other, resulting in weaker tides,
called
_______________________.
Eclipses
 ________________________ occurs
when the Sun’s light is blocked from
either the Earth or the Moon.
 We do NOT have solar and lunar
eclipse every month because the orbit
of the Earth and the Moon are along
different planes, the moon orbit is
tilted _________________.
Solar Eclipse Lunar Eclipse
 ___________________ – (moon goes into
 _________________ – (Earth earth’s shadow) occurs when the Earth blocks
goes into moon’s shadow) occurs the Sun’s rays from reaching the Moon.
when the Moon blocks the Sun’s  Only occurs at full moon phase.
rays from reaching Earth. Earth blocks light to the moon.
 It occurs only at new moon phase. Moon must be in Umbra for a Total Lunar
 Only a few people see it. Eclipse.
 Moon blocks light to the Earth. Does not occur that often, moon orbit is tilted.
Occur less often than lunar.
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