Transcript Stars

Our Universe
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Universe
TEKS
(8.13) Science concepts. The student knows
characteristics of the universe. The
student is expected to:
(8.13A) describe characteristics of the
universe such as stars and galaxies.
(8.13B) explain the use of light years to
describe distances in the universe.
(8.13C) research and describe historical
scientific theories of the origin of the
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Universe
TAKS Objectives
Objective 5: The student will demonstrate
an understanding of earth and space
systems.
Components in the universe may also be
included, such as stars, nebulae, and
comets.
Characteristics of the universe such as stars
and galaxies may be integrated with all
grade 8 objectives to make them more
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relevant.
Once Upon a Time…..
12- 15 Billion Years ago all the
contents of the Universe were
gathered into a small area under
extreme heat and pressure.
THEN
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The Big Bang
The Big Bang Theory is one
theory of the formation of the
Universe. It states that the
universe began with a
tremendous explosion
http://hrw.com
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Evidence to Support the Big Bang
Theory
1. The even Spread of Radiation
Thermal energy from the original
explosion was distributed in every
direction.
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Even Spread of Background
Radiation
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Evidence to Support the Big Bang
Theory
2. The Red Shift of Galaxies
The spectrum of the distant
galaxies is shifted to the red
end.
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Red Shift Of a Galaxies Spectrum
Galaxies moving away from us would have their light waves
stretched out and the spectrum would shift to the red end.
Galaxies moving toward us would have their light waves
compressed and the spectrum would shift to the blue end.
All distant Galaxies have a red shift.
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Doppler Effect
 Just like light waves, sound waves will also be
compressed as an object moves toward you
and they will be stretched as the object moves
away.

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Universe
contains:
1.
2.
3.
4.
5.
Galaxies
Stars
Nebulae
Quasars
Comets
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Galaxies
 There are three main types of
Galaxies
–Spiral
–Elliptical
–Irregular
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Spiral
Galaxies
– Characterized by a bulge at the center and
spiral arms
– Spiral shape is caused by the rotation of the
galaxy
http://hrw.com
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Elliptical
Galaxies
– Characterized by a very bright centers and
very little dust and gas
– Appear elongated or spherical and are
basically massive blobs of stars
– Composed of mostly old stars
http://hrw.com
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Irregular
Galaxies
– Galaxies that do not fit into any other
class
– As their name indicates they have
irregular shapes
http://hrw.com
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Stars
 Composition
 Brightness
 Temperature
 Mass
 Life Cycle
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Stars
Composition
–Made up of different elements in the
form of gasses
–When viewed through a spectrograph
the specific gasses can be identified
through an absorption spectrum
which is a continuous spectrum with
dark lines where less light gets
through.
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Stars
Composition
http://hrw.com
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Stars
Brightness
–Apparent Magnitude – how bright a
star looks from Earth
–Absolute Magnitude – how bright a
star actually is
(How bright the star would appear to the
human eye if it were at a distance of 10
parsecs from the earth)
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Stars
Temperature
 Determined by the color of a star
 Classified by the following letter
categories (O, B, A, F, G, K, M)
http://hrw.com
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Stars
http://hrw.com
The Hertzsprung Russell Diagram (H-R) is a graph
showing the relationship between a star’s surface
temperature and its absolute magnitude
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Stars
Illustrating the relationship between temperature
and brightness
http://hrw.com
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Stars
Mass
 Single most important determiner of a
stars life cycle
 High Mass
 Low Mass
http://www.enchantedlearning.com/subjects/astronomy/stars/lifecycle 23
Stars
Illustrating the relationship between
mass and star life time
http://hrw.com
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Stars
Illustrating the relationship between mass and brightness
http://hrw.com
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Nebula
Latin for “Cloud”



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Giant clouds of gas and dust
Where new stars are formed
Found in spiral galaxies
Not found in elliptical galaxies
http://nssdc.gsfc.nasa.gov/photo_gallery/photogallery-astro-nebula.html
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Quasars
 The most powerful energy source in the
universe
 May be the core of young galaxies forming
 Among the most distant objects in space from
Earth
http://hubblesite.org/newscenter/newsdesk/archive/releases/category/galaxy/quasar_active%20nucleus/
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Comets
 A comet is made of dirty ice, dust, and gas.
 When a comet gets close to the Sun, part of the
ice starts to melt. This lets the dust and gas out.
 Solar winds then push them away from the
comet. This makes the comet's tail.
 Every time a comet comes close to the Sun, a
part of it melts. Over time, it will completely
disappear.
 A comet does not give off any light of its own. Ice
in the comet acts just like a mirror. What we see
is sunlight bouncing off the comet.
http://www.nasa.gov/audience/forkids/home/F_SC_comet.html 28
Comets
Halebopp Comet
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http://www.nashttp://deepimpact.jpl.nasa.gov/science/comets.html
Looking through the center of the Milky Way
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http://www.nashttp://deepimpact.jpl.nasa.gov/science/comets.html
Questions and Discussion
1. Which characteristics are used to
classify stars?
A. temperature
B. brightness (magnitude)
C. mass
D. All of the above
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Questions and Discussion
1. Which characteristics are used to
classify stars?
A. temperature
B. brightness (magnitude)
C. mass
D. All of the above
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Questions and Discussion
1. Temperature and brightness are both used to
classify stars as seen on the HR diagram, but
mass is also important because it determines
a stars temperature and brightness.
http://hrw.com
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Questions and Discussion
2. If a star becomes a black hole at the
end of its life, it is a?
A. high mass star
B. nebula
C. low mass star
D. All of the above
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Questions and Discussion
2. If a star becomes a black hole at the
end of its life, it is a?
A. high mass star
B. nebula
C. low mass star
D. All of the above
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Questions and Discussion
2. Becoming a black hole would mean that the
star was a high mass star, giant actually as
seen in the following illustration.
http://www.enchantedlearning.com/subjects/astronomy/stars/lifecycle 36
Questions and Discussion
3. Galaxies are classified based on
their?
A. composition
B. color
C. shape
D. All of the above
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Questions and Discussion
3. Galaxies are classified based on
their?
A. composition
B. color
C. shape
D. All of the above
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Questions and Discussion
3. Galaxies are classified based on their
shape. This is evident because of their
name categories. The categories of
galaxies are spiral, elliptical and
irregular.
http://hrw.com
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Questions and Discussion
4. Scientist believe that quasars give
off as much light as 10 trillion suns
because of their?
A. composition
B. distance and brightness
C. shape
D. color
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Questions and Discussion
4. Scientist believe that quasars give
off as much light as 10 trillion suns
because of their?
A. name
B. distance and brightness
C. shape
D. color
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Questions and Discussion
4. Scientist know the absolute brightness of
a quasar known as PKS 0637-152, and
they know that it gives off as much light as
10 trillion suns because of its calculated
distance using parallax.
http://hrw.com
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