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Unit 2: Astronomy Earth Science- Ms. Gill Note Packet #3C
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UNIT 2: ASTRONOMY
PACKET 3C: FROM EARTH’S PERSPECTIVE
HONORS EARTH SCIENCE MS. GILL
NOTE PACKET #3C
NAME:_______________________ PER:____ DATE: ________
When you change the way you look at
things, the things you look at change
P.S. I’m Theodore
Unit 2: Astronomy Earth Science- Ms. Gill Note Packet #3C
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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
planets revolve around it
___________________________ – Earth is the center of the solar system, and all objects revolve around it. -Used epicycles (small sub-orbits) to explain retrograde (backward) motion of planets
Unit 2: Astronomy Earth Science- Ms. Gill Note Packet #3C
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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
Unit 2: Astronomy Earth Science- Ms. Gill Note Packet #3C
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Earth’s Motions:
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: _________________ & __________________ 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
Unit 2: Astronomy Earth Science- Ms. Gill Note Packet #3C
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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!
Unit 2: Astronomy Earth Science- Ms. Gill Note Packet #3C
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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 equator (0° ) all stars rise and set 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? _____________________
Apparent daily motion of the Big Dipper, a ___________________
constellation (never sets)
Unit 2: Astronomy Earth Science- Ms. Gill Note Packet #3C
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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? __________________________________________________________________
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 ____________
Unit 2: Astronomy Earth Science- Ms. Gill Note Packet #3C
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Evidence of Earth’s Rotation
1. ____________________________________ 2. ___________________________________
Foucault’s Pendulum As the pendulum swings back and forth, the Earth rotates underneath it so that the direction of the pendulum's swing appears to change. Since there is NO force that makes pendulum rotate – must be earth that is rotating!!! The ground moves under the freely swinging pendulum. The Pendulum appears to move but is actually swing in the same initial direction
Coriolis Effect A projectile fired northward from the equator appears to veer eastward because it retains the eastward speed of the equator, which is greater than the eastward speeds north or south of the equator. Because of the Coriolis effect, projectiles and currents of air and water veer to the right in the northern hemisphere, and to the left in the southern hemisphere
Unit 2: Astronomy Earth Science- Ms. Gill Note Packet #3C
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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
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.
Unit 2: Astronomy Earth Science- Ms. Gill Note Packet #3C
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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 __________.
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 _______________
Label the seasons on the aerial views of earth… Note the position of the shadow Label perihelion and aphelion…
Unit 2: Astronomy Earth Science- Ms. Gill Note Packet #3C
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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 year. 2.Sun at highest altitude at noon. 3.24 hrs of daylight at North Pole. 4.Direct sun ray at 23.5° north latitude. 5.Sun rise – NE, Sun set - NW
1.Dec. 21, shortest day of the year. 2.Sun at lowest altitude at noon. 3.24 hrs. of darkness at North Pole. 4.Direct sun ray at 23.5° south latitude. 5.Sun rise – SE , Sun set – SW
1.Sept. 21 and March 21. 2. Equal day/night 12 hrs of daylight, 12 hrs of night. 3.Direct sun ray at Equator. 4.Sun rise – E, Sun set – W.
Unit 2: Astronomy Earth Science- Ms. Gill Note Packet #3C
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Date Sun Rise Sun Set Altitude of Solar Noon is… Equinoxes (Spring/ Fall)
Summer Solstice
Winter Solstice
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 _______________________________
Unit 2: Astronomy Earth Science- Ms. Gill Note Packet #3C
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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: _______
Unit 2: Astronomy Earth Science- Ms. Gill Note Packet #3C
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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. ________________
________________
________________
Unit 2: Astronomy Earth Science- Ms. Gill Note Packet #3C
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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? ________________________
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.
Unit 2: Astronomy Earth Science- Ms. Gill Note Packet #3C
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Position Season Constellation Visible A B C D
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
Directions: Draw label the positions of the big dipper during the yearly cycle
Unit 2: Astronomy Earth Science- Ms. Gill Note Packet #3C
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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.
Unit 2: Astronomy Earth Science- Ms. Gill Note Packet #3C
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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? ___________________________
Unit 2: Astronomy Earth Science- Ms. Gill Note Packet #3C
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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 _________________ – (Earth
goes into moon’s shadow) occurs when the Moon blocks the Sun’s rays from reaching Earth.
It occurs only at new moon phase. Only a few people see it. Moon blocks light to the Earth.
Occur less often than lunar.
Lunar Eclipse ___________________ – (moon goes into
earth’s shadow) occurs when the Earth blocks the Sun’s rays from reaching the Moon.
Only occurs at full moon phase. Earth blocks light to the moon. Moon must be in Umbra for a Total Lunar Eclipse. Does not occur that often, moon orbit is tilted.