Download Earth`s Motion and Seasons

Galaxies & Objects in
the Universe
State Correlation 4e and 4f
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Part A:
The Earth’s Motion and
Seasons
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Earth’s Motion and Seasons
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A. Motions of the Earth
–1. Axis- the imaginary line
drawn from the north
geographic pole through the
Earth to the south geographic
pole
–2. Rotation- the spinning
of the Earth on its Axis;
Causes day and night.
–What do you think: What
would happen if the earth
stopped rotating?
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Earth’s Motion and Seasons
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3. Revolution- the motion of Earth traveling around
the sun
a. Earth’s revolution causes seasons.
 b. Earth’s elliptical path around the sun is called an
orbit.
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Earth’s Motion and Seasons
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4. Solstices and Equinoxes
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a. Because the Earth’s axis forms a 23.5 degree angle,
the Sun’s position relative to the equator constantly
changes.
 Because of this daylight hours are longer for the
hemisphere that is tilted towards the sun, and the
sun is higher in the sky for longer periods of time.
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Earth’s Motion and Seasons
 B.
Summer and winter
solstices- the longest and
shortest days of the year;
when the sun reaches its
greatest distance north or
south of the equator.
 Directly above the
Tropic of Cancer or
the Tropic of
Capricorn.
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Earth’s Motion and SeasonsSummer Solstice
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Earth’s Motion and SeasonsWinter Solstice
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Earth’s Motion and Seasons
 Summer
Solstice (Longest Day) for the northern
hemisphere is June 21 or 22 and December 21 or
22 for Southern Hemisphere
 The opposite of this is Winter Solstice (Shortest
Day)
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Earth’s Motion and Seasons
 c.
Equinox- when the sun is directly
above the equator
 Length of day equals length of
night all over the world.
 In the northern hemisphere –
 Spring (vernal) equinox is
March 21 or 22
 Fall (autumnal) equinox is
September 21 or 22
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Earth’s Motion and SeasonsEquinox
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Copy and Answer this Question

When you watch a sunset are you observing
an effect of the Earth’s rotation or the
Earth’s revolution?
Draw this
diagram in
your notes
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Click on the link below to view a video
discussing how ancient cultures used the
position of the sun to determine seasons,
planting times, and other events.
http://sunearthday.nasa.gov/2011/multimedia/
ancient_observatories.php
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Part B:
Stars, Galaxies, and The
Universe
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What do You Already Know?
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Using a Circle Map: round – table what you
know about the universe and galaxies
Share what you know in order to make a class
circle map
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Telescopes
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Telescopes are instruments that allow us to view
distant objects.
They use forms of energy in the electromagnetic
spectrum to view these objects.
The electromagnetic spectrum includes radio waves,
infrared waves, visible light, ultraviolet rays, X-rays
and gamma rays.
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How the Electromagnetic Spectrum
Determines Celestial Bodies
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Refracting Telescopes
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Refracting telescopes use curved lens to gather
and focus light.
This convex lens is a piece of transparent glass,
curved so the middle is thicker than the edges.
See fig. 2 page 710
Draw and label the refracting telescope.
Use a bubble map to describe a refracting
telescope.
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Reflecting Telescopes
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The first reflecting telescope was built by
Isaac Newton in 1668,
A reflecting telescope uses a curved mirror to
collect and focus light
The larger the mirror, the more light the
telescope can collect.
The largest telescopes are reflecting telescopes.
Draw and label the reflecting telescope in fig. 2
page 710.
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Radio Telescopes
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Devices used to detect radio waves from objects
in space.
Most have curved, reflective surfaces that focus
radio waves the way reflecting telescopes focus
light.
The larger the radio telescope the more radio
waves it can collect.
Other types of telescopes collect the shorter
waves such as gamma rays, X-rays, and
ultraviolet rays.
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Group Time
Mexico City at Night

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The light from street lights, businesses, and signs
make it difficult to objects in the night sky. This
is known as light pollution.
Round table brainstorm how our community
could develop a plan to reduce light pollution.
Owachomo Bridge in Utah's Natural Bridges
National Monumentone of the few clear night views left
New York City skyline
What can we do within our
own communities to help?
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Observatories
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A building that contains one
or more telescopes.
However, some observatories
are located in space.
One of the best observatory
sites on Earth is on the top of
Mauna Kea, a dormant
volcano, on the Island of
Hawaii.
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Advanced Telescopes
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Many large optical telescopes are equipped with
systems that improve the quality of their images.
Some are equipped with computers for
automatic adjustments, and lasers
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Telescopes in Space
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The Hubble Telescope is a reflecting telescope with a
mirror 2.4 meters in diameter.
Because it orbits Earth above the atmosphere, it can
produce very detailed images.
Hubble images have changed how astronomers view the
universe.
The most recent addition to NASA’s lineup of telescopes
in space is the Spritzer Space Telescope launched in 2003.
It produces images in the infrared portion of the
spectrum.
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Images from the Hubble Telescope
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Measurement in Space

Parallax: apparent shift in the position of an
object when view from two different locations
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measures the distance of stars from earth that are
relatively close
Light Years: Unit of measurement for large
distances in space
Distance light travels in 1 year
 Light travels 300,000 km/s or 9.5 trillion km /year
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Proxima Centauri: closest star to earth
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(4.3 light years away – 40 trillion km)
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Size of the Planets
and Stars
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Click on the link below to see a
comparison of the Sizes of the
Planets, the Stars, and the
Galaxies
http://www.cleanvideosearch.co
m/media/action/yt/watch?v=H
Eheh1BH34Q
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Proxima Centauri Video
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Nebulae
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Large cloud of gas, plasma & dust within a galaxy
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Typically a few light-years wide
Two types:
Diffuse nebulae
 Planetary Nebulae
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Diffuse nebula
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Gas & dust particles are spread out and irregular
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Provides the raw materials that will form new stars
A
star is born by fusion of hydrogen at 10 million K
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Planetary Nebula
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Forms when a star dies
and throws off some of
its outer material to
form a cloud of gas,
dust, & plasma
Does not contain
enough material to
create a new star.
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Group Time
Use a double-bubble map to compare and
contrast planetary & diffuse nebulae
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Life Cycle of Stars Video
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Life Cycle of a Star
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Main Sequence Star: hydrogen fueled star
Makes up about 90% of stars
 Our sun is a main sequence
 Two types
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Low mass – remains a main sequence star longer and are
smaller in size
 High mass – goes through main sequence much faster and
are much larger in size
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Life Cycle of a Low mass Star
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Giants: fueled by helium from a low mass star
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Outer layers Cool & expands with a carbon core
Planetary nebula: occurs as the core collapses
on itself & shells of gas are thrown outward
White dwarf: outer layer of gases escapes into
space, core contracts leaving a hot dense small
star
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Life Cycle of a High mass Star
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Super Giant: Fueled by helium from a high mass star
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Outer layers cool & expands with an iron core
Super Nova: iron core collapses and the star
explodes
Neutron star: collapsed core of super giant with
extremely high density
 Black Hole: tremendously big supernova that collapses to
a point of no volume
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Neutron Stars and Black Holes
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Relative size of stars
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The Color of Stars
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Show Video
“The Color
of Stars”
Hertzsprung-Russell
diagram (H-R):
1. Which Star has a hotter
Surface: Rigel or Aldebran?
2. Identify these Stars:
A. 18,000 C, Low Brightness
____________________
B. 3,5000 C, High Brightness
______________________
C. 5,800 C, Middle Range
_______________________
3. Which Star is most Likely
to be red: Rigel, Sirius B, or
Betelgeuse?
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Brightness of StarsApparent Brightness
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Apparent Brightness- How bright a star seems
as seen from Earth.
But can’t be used to tell how much light a star
actually gives off.
Just as a flashlight looks brighter the closer it is
to you- a star will look brighter the closer it is to
Earth.
Our sun looks bright just because it is close
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Brightness of StarsAbsolute Brightness
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Absolute Brightness- the brightness the star
would have if it were a standard distance from
Earth
The brightness of stars can vary tremendously.
The brightest stars are more than a billion times
brighter than the dimmest stars!
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Use a flow chart to show the
cycle of a star linguistically and
non-linguistically based on the
information in the notes.
Round-table
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Galaxies
Huge collection of stars, gas,
& dust
Galactic Cluster is a group
of gravitationally bound
galaxies--They are the largest
gravitationally bound
celestial bodies in the
universe
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Three Types of Galaxies
 Elliptical
 Spiral
 Irregular
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Elliptical
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Range from spherical to elliptical
No typical size or brightness
 Contains old cool red stars & small amounts of gas
& dust, so no new stars are forming
 Most common type
 Ex. Maffei 1 Follow this Link
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Spiral
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Spiral: stars arranged in two or more
spiral arms
 Ex.
Milky Way & Andromeda
New blue stars form in arms
 Center is often bulging disk of older red stars
 Barred Spiral: sub-group with a vast straight bar of
stars lying across the center with a spiral arm at the
end of each bar
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Irregular
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lack regular pattern & shape, and are small
& faint
Two types: colliding & gravitational interaction
distorting the shape
 Mixture of young & old stars with lots of gas & dust
for new star formation
 Ex. Clouds of Magellan
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Group Time
Use a tree map to categorize types of
galaxies
Round Table
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Galaxies
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Milky Way
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Our Galaxy - The Milky Way
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Normal Spiral
About 100,000 light-years in diameter
Contains between 200 billion & 400 billion stars
About 14 billion years old
3 basic parts:
Bulge
 Disk
 Halo
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Central Bulge
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Core of galaxy made mostly of older stars
Small amounts of gas and dust
Very little star formation
Why do you think there is little star formation
here?
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Disk
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Flattened area containing the spiral arms that are pinwheeled shaped
Contains lots of gas and dust with younger stars
Our solar system is located on the Orion Arm 25,000
light-years away from the central bulge
Open Clusters: vast cloud of dust & gas that forms a
loose grouping of stars
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Contains a few dozen to thousands of stars
Interstellar matter is thin but widespread
Bound together with gravity by a common origin
Believed to be what forms the spiral arms
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Halo
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Sphere of gas & stars surrounding the central bulge & disk
Thought to be 100’s of thousands of light-years across
Oldest stars in the galaxy
Globular Clusters: tight gravitationally bound concentration
of approximately 10 thousand to one million stars that do
not break apart
Dark Matter: does not produce or reflect light
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Has a gravitational effect that can be detected
Believed to be the most common material in the Milky Way
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Dark Matter Video
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Group Time
Use a brace map to linguistically & nonlinguistically show parts of the Milky
way Galaxy
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What is the Big Bang
Theory?
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Astronomers theorize the universe began
billions of years ago.
At that time, the part of the universe we can see
was no larger than a period at the end of
sentence.
According to the big bang theory, the universe
formed in an instant, in an enormous explosion.
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Moving Galaxies
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In 1920, Edwin Hubble studied the spectrums
of many galaxies and determined they were
moving away from us indicating the universe is
expanding.
Hubble found a relationship between the
distance to a galaxy and its speed.
Hubble’s Law states the farther away a galaxy is
the faster it is moving away from us.
Hubble’s law strongly supports the big bang.
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Cosmic Background
Radiation
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In 1965, two American physicist, accidently detected
faint radiation, on their radio telescope.
Scientists later determined this was left over thermal
radiation from the big bang.
This would have been distributed in all directions at the
big bang.
Astronomers can approximate how fast the universe is
expanding they can infer how old the universe is.
Astronomers estimate the universe to be about 14 to 17
billion years old.
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