Name:______________________
Period:____
Unit 7
Astronomy
Focus Questions
___1. How and why do stars move through our sky?
___2. Explain the apparent motion of the Sun through our sky? How does the path of the Sun change
throughout the year?
___3. Why do we have seasons?
___4. How does latitude and the angle of the Sun affect daylight hours?
___5. Explain why we see the Moon’s phases?
___6. Explain what happens during a lunar and solar eclipse?
___7. Why do we have tides?
___8. What is the true shape of an orbit and what are the parts of an orbit?
What is the equation to measure an orbit’s eccentricity?
___9. Explain what the HR diagram is used for? Explain our Sun’s properties
by using the HR diagram.
___10. Describe galaxies and what theory is used to describe the formation of
the universe? How can we tell if celestial objects are moving towards or away
from us?
A. Celestial Observations
celestial
1. The objects in the sky collectively are called ____________________
_____________________
objects
The Sun, planets, moons, stars, etc.
--They include ____________________________________
From East to West
--They appear to move in the sky ______________________
An arc
--The path they appear to take is in the shape of _______________
2
2. All objects in the night sky appear to travel in a set
path around ____________which
is located almost
Polaris
directly over the North Pole of Earth.
Many of the stars form specific patterns, or
constellations Some of these never go below the
________________.
horizon in New York State. Instead, they appear to circle
Polaris over the course of a night.
This is about a ten hour time exposure of the northern sky. The
arcs are the paths of the stars circling the North Star (Polaris) in
the center.
These stars can be seen year-round in the northern sky although
their exact location each night will vary throughout the year.
Orion
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Other stars appear to move throughout the night from east
to west.
These are trails of stars that are
further to the south in our night
sky. Their trails appear almost
straight.
The constellations and the stars
that make them up also appear
in different locations
throughout the year.
All celestial objects appear to move at a rate of 15
degrees per hour. (From horizon to horizon is about
180 degrees.) Why do these objects appear to move
at a rate of 15 degrees per hour?
Because Earth rotates 15 degrees per hour
_______________________________________________________
We call this motion the
Apparent daily motion
_________________________________
3. Apparent Solar Day:
_________________________________
How long it takes the Sun to move
_______________________________________
through our sky.
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B.
Terrestrial Observations
1. There are two main motions of Earth:
motion of one object around another
a. Revolution: The
___________________________________________
____________________________________________
object. The planets revolve around the Sun. Moons
and satellites revolve around planets.
Evidence: Different constellations appear in our night sky at different
times of the year.
b.
The spinning of an object on its axis. Earth
Rotation: __________________________________________
rotates
once every 24hrs.
____________________
Evidence:
(1) Foucault’s Pendulum:
A
mass suspended from a
_____________________________
wire
at a single
_____________________________
point.
When set in motion,
_____________________________
its
apparent change in
_____________________________
position
is the result
of the
_______________________
______
rotation of the Earth.
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(2) Coriolis Effect:
The deflection of
______________________________
a an object that is moving
above
the Earth’s surface. In the Northern
______________________________
Hemisphere,
the Coriolis effect causes moving
______________________________
______________________________
objects
to be deflected to their right, while in the
______________________________
Southern
Hemisphere, the deflection is to the object's
left.
2. Apparent Motion of the Sun: It changes with the
seasons and latitude due to:
________________________
Earth does not lie directly
Earth’s
Tilt
23 ½ degrees
straight up and down, it is tilted _____________
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The Sun rises N of
Summer: __________________
due
East and sets N of due
__________________________
West.
The noon Sun is highest
__________________________
in
the sky
but the sun
___________
is NEVER directly
overhead for us! Because
the path of the sun is
longest in the summer,
days are longest.
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Occurs approx. on June
Summer Solstice: _____________________________
___________________________________________
21st
The Sun rises S of due East and sets S of
Winter: _____________________________________
due West. The noon Sun is lowest in the sky
___________________________________________
Occurs approx. on
Winter Solstice: ______________________________
December 22nd.
___________________________________________
Spring and Fall:
The Sun rises due East and
______________
______________
sets
due West. The noon Sun
______________
is
at approx. 48 degrees.
Vernal Equinox:
Approx. March 21st
______________
Autumnal Equinox:
______________
Approx. September 22nd
At the _______________,
day and night are 12 hours long everywhere
Equinoxes
on Earth.
Latitude: The closer you are to the poles, the lower the noon time sun
and the greater the difference between the winter and summer length of
daylight. At the equator, day and night are 12 hours long all year.
Important Note: We do not have summer in June because we are closer
to the sun. We are actually closest to the sun in December, the beginning
of winter.
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Tropics of Cancer and Capricorn: 23.5o north and south latitude. Mark
the furthest north and south travel of the direct rays of the sun. Sun is
directly over the Tropic of Cancer on June 21st and the Tropic of
Capricorn on December 21st.
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Sun’s apparent path for four different observers on June
21st. Notice how the path and position of the noontime
sun change for each location.
Because the sun is
higher in the sky in
the summer, the rays
of the sun shine
down at a more direct
angle.
The length of shadows cast by a stick are also
affected by the height of the sun. In the
summer, the sun is high in the sky, so the
short
shadows it casts are ______.
Shadows cast in
longer
spring and fall are __________.
In the winter,
the sun is very low in the sky, so the shadow it
long
casts is very ____.
C. Geometry of Orbits
I.
Terms
The motion of one object around another
A. Revolution: __________________________
object.
Path of movement of a satellite around its primary body.
B. Orbit:_______________________________
1. Example: __________________________
The moon around the Earth.
Shape of planet’s orbits around the Sun
2. Ellipse: ___________________________
(flattened or squashed circle).
__________________________________________
3. Focus (foci): _______________________
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Ratio of focal length to length of
4. Eccentricity: ___________________________
major axis of an ellipse. (How flat an ellipse is)
_________________________________________
a. Formula:
____________
E=d/
____________
L
____________
____________
____________
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II.
Force and Energy
force that keeps all satellites
A. Gravity: The
__________________________
moving inward in their curved orbits.
________________________________________
The tendency of an object in
B. Inertia: ___________________________
motion to continue in motion in a straight
________________________________________
path.
C. Energy and Orbits
Earth is closest to the Sun;
1. At perihelion: ____________________
pull of gravity is greatest
________________________________________
________________________________________
Earth is furthest from the
2. At aphelion: _____________________
Sun; pull of gravity is weaker
________________________________________
________________________________________
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III. Orbits and Johannes Kepler
A. Orbital Velocity: _____________________
Speed of orbiting object
B. Earth’s Orbit
1. perihelion: ________________________
Earth is moving the
_________________________________________
fastest
Earth is moving the
2. aphelion: _________________________
slowest
_________________________________________
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C. Kepler’s Laws of Planetary Motion
-Johannes Kepler, a German astronomer during the late 1500’s to
early 1600’s, developed three laws of motion of objects in the sky
to help better explain and predict their motions. Before Kepler,
most astronomers agreed that planetary orbits were circular.
1. Elliptical Orbits: ______________________
The orbits of the planets are
_________________________________________
ellipses, with the Sun at one focus of the ellipse.
The line joining the planet to the
2. Equal Areas: _________________________
Sun sweeps out equal areas in equal times as the
_________________________________________
planet travels around the ellipse.
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________
Inertia
Gravity
_________
Orbit
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Note that as the orbiting
body gets closer to the
object it is orbiting, the pull
of gravity becomes stronger.
Therefore, its forward speed
must also be greater to
compensate.
3. Harmonic Motion: the period for a planet to orbit
the Sun increases rapidly with the radius of its orbit
The distance between the
a. Astronomical Unit: ____________________
Earth and the Sun; 93 million miles.
_________________________________________
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D. Satellite Motions
Earth’s natural satellite
The Moon: ____________________________
The moon revolves in its orbit
A. Orbit _____________________________
at the same rate that it rotates
_________________________________________
I.
1. Sidereal month: ___________________
_________________________________________
The moon takes 27 days to complete
_________________________________________
one revolution around Earth.
2. Synodic (lunar) month: _____________
The moon’s phases take about 29 ½
_________________________________________
days to go through one cylce.
_________________________________________
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(27 1/3 days)
One synodic month later
(29 ½ days)
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The apparent change in the shape of the
B. Phases: ________________________________
moon caused by the changing positions
__________________________________________
of Earth, the Sun, and the Moon.
__________________________________________
C. Phases change from: ____________
Waxing to Waning
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New Moon
New Gibbous
Third Quarter
New Crescent
Full Moon
Old Crescent
First Quarter
Old Gibbous
D. Because of the moon orbiting Earth, each day the moon rises over the
in a different spot
eastern horizon ______________
___________.
E. As a result, if you look at the moon two consecutive nights, the moon
East
is farther ________
the second night and each night thereafter.
Day 1
C. Tides: _________________________________
The twice-daily rise and fall of the
__________________________________________
oceans due to the gravitational
__________________________________________
attraction of the moon and the Sun.
2 highs and 2 lows per day,
1. High and Low: ________________________
every 6 hours
__________________________________________
Normal tidal change is less
2. Normal: ______________________________
than 3 feet
__________________________________________
NOTE: Even though the sun is much larger, the
moon is much closer so the primary force pulling on
the tides is the moon.
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Highest high tides and lowest low
3. Spring:_________________________________
tides, moon phase is near full and new.
__________________________________________
Smallest change between high and low
4. Neap: __________________________________
tides, moon is in the quarter phases.
__________________________________________
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The partial or complete obscuring
D. Eclipses: ________________________________
(hiding) of one celestial body by another.
__________________________________________
1. Shadow Geometry
Inner, darker part
a. umbra: ____________________________
Outer, lighter part
b. penumbra: _________________________
__________________________________________
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when sun "gets dark" because the
2. Solar Eclipse: __________________________
moon blocks sunlight from reaching the Earth.
________________________________________
Solar Eclipses happen during a New Moon.
When the entire Sun is blocked out by the moon
a. total: ______________________________
some of the Sun is blocked out
b. partial:When
____________________________
c. annular: ___________________________
When the moon is further away from the
_______________________________________
Earth and you see an orange ring around the moon.
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3. Lunar: _________________________________
When the full moon moves into Earth’s
__________________________________________
shadow.
a. total: ________________________________
When the moon is closer to Earth and the Earth’s
__________________________________________
shadow completely covers it.
b. partial: ______________________________
When the moon is further from Earth and the Earth’s
__________________________________________
shadow partially covers it.
NOTE: Lunar eclipse does not occur
during every full moon because the
plane of the moon’s orbit is slightly off
from Earth’s.
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E. The Solar System
I.
A star and it’s surrounding planets.
Solar System: __________________________
A. Models
Model of the solar system with the
1. Geocentric: _________________________
Earth at the center.
_________________________________________
The planets revolve around the Sun
epicycle: ___________________________
in circular orbits called epicycles.
_________________________________________
Retrograde Motion: ___________________
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Geocentric Model of the Solar System
Problem:_____________________________
Did not explain the Focault
____________________________________
Pendulum and the Coriolis Effect
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2. First Heliocentric: _______________________
Had circular orbits.
_________________________________________
Did not explain the changing size
Problem: __________________________________
of the Sun.
_________________________________________
Planets move in ellipses.
3. Revised Heliocentric: _____________________
_________________________________________
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B. Objects
A star that is the basis of the solar system
1. Sun: __________________________________
and that sustains life on Earth, being the source of
____________________________________________
heat and light.
Dark, irregular spots that are cooler than
a. sunspots: ___________________________
the surrounding areas on the Sun.
___________________________________________
brief powerful eruption of
b. flares/prominences: a___________________
particles and intense electromagnetic
____________________________________________
radiation from the sun's surface
10,000-27 mil.
Degrees F
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A celestial body moving in an
2. Planets: _______________________________
elliptical orbit around a star.
a. Terrestrial: __________________________
Small, inner planets made up of
____________________________________________
mostly solid rock; high density
b. Jovian: _____________________________
Large, outer planets made up of
____________________________________________
mostly gases; low density.
3. Asteroids: ______________________________
A small rocky body orbiting the
____________________________________________
sun. Large numbers of these are found between
the orbits of Mars and Jupiter
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B. Objects (cont.)
A meteoroid is a sand- to boulder-sized particle of
4. Meteors: ____________________________
debris in the Solar System. The visible path of a meteoroid that enter
_________________________________________
Earth's atmosphere is called a meteor, or a shooting star. If a
_________________________________________
meteoroid reaches the ground then it is called a meteorite.
_________________________________________
5. Comets:
They are a mixture of ices (both water
_________________________________________
and frozen gases) and dust,
_________________________________________
Earth
“dirty snowballs”
_________________________________________
Sun
Comet
F. The Universe
I.
Parts of the Universe
Objects in space that emit
A. Stars: ______________________________
__________________________________________
their own light.
create their energy through
1. Energy: Stars
__________________________
_________________________________________
the process of nuclear fusion.
stars are big exploding balls of
2. Composition: _____________________
_________________________________________
gas, mostly hydrogen and helium.
of lines that show the
a. spectrum: Pattern
_______________________
chemical makeup of a star.
_________________________________________
breaks down the light emitted or
b. spectroscope: ____________________
__________________________________________
absorbed
by chemical elements into specific lines of color.
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Cloud of gas and dust where new stars
Nebula: ______________________________________
are born.
_____________________________________________
Star Life Cycle: Stars are like humans. They are born, live and
then die.:
new, just forming
Protostar: _____________
star; baby star
_____________________
Mature star:___________
pre-teen
Stage
____________
a star with a
Red Giant:__________
mass like our Sun that is
___________________
in the last phase of its life
_____________
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White Dwarf: ______
an old
star
that has used up
_________________
all of its hydrogen.
_________________
Very dense.
_________________
Supernova: ______
The explosive death
________________
of a massive star whose
________________
energy
output causes its
expanding
gases to glow
________________
brightly
________________
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The life cycle of stars depends on their mass.
Small and medium stars become black dwarves once they die.
Neutron Stars
Larger stars become novae and die as: ____________
Black Holes
The most massive stars become supernovae and die as: ______________
Star with density so great that a teaspoon of
Neutron Star: ______________________________
material weighs several thousand tons.
_________________________________________
Body of infinite density and gravity so great that
Black Hole: _____________________________
not even light can escape.
_______________________________________
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3. Classifying: _____________________________
__________________________________________
__________________________________________
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B. Galaxies: _______________________________
Large systems of stars,
__________________________________________
gas, and dust.
1. Composition: _________________________
Millions of stars revolving
__________________________________________
around the center of the galaxy
Light years wide
2. Size: ________________________________
Our Galaxy, a spiral
3. The Milky Way: ______________________
galaxy( 120,000 Light
_________________________________________
years wide)
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These are galaxy clusters and separate galaxies taken by long-range
telescope. The area of the sky covered is less than the diameter of
the moon.
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Contain millions of
C. Clusters: ____________________________
__________________________________________
galaxies
II.
Distance in the Universe
A. The speed of light: ___________________
186,000 miles/sec.
_________________________________________
long it takes light to
B. The Light Year:How
_____________________
_________________________________________
travel in one year
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III. The Expanding Universe
A. The Big Bang Theory: ________________
_________________________________________
_________________________________________
B. Doppler Shift
Shows a change in a star's spectrum; evidence that the
universe is expanding
1. red shift: ___objects are moving away from
us_______________________
__________________________________________
2. blue shift: __objects are moving towards
us_______________________
__________________________________________
Since the spectrum for all galaxies show a _______
from Earth, we assume the universe is __________
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