Chapter 8, Astronomy
Lesson 5, Galaxies and Beyond
Objectives __________________________________________________________
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Main Idea __________________________________________________________
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Vocabulary
galaxy ______________________________________________________________
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Milky Way __________________________________________________________
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spectrum ___________________________________________________________
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expansion redshift ____________________________________________________
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big bang ____________________________________________________________
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background radiation _________________________________________________
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What are galaxies?
Is a constellation a natural grouping of stars? ______________________________
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In what way are stars naturally grouped? _________________________________
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The Milky Way Galaxy
What is the name of the galaxy in which Earth is located? What type of galaxy is
it? _________________________________________________________________
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How can you tell that Earth is in one of the Milky Way’s spiral arms and not in its
center? _____________________________________________________________
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Quick Check
Fact and Opinion
“The Milky Way is a spiral galaxy.” Is this statement a fact or an opinion? Why? __
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Critical Thinking
How are the three types of galaxies similar? How are they different? __________
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What was the big bang?
If all of the galaxies are moving away from one another, how would their positions
now compare with their positions in a hundred years? _______________________
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How would their positions a hundred years ago compare with their positions now?
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What about a thousand years ago? ______________________________________
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As you look further and further back in time, what do you see happening to the
universe? ___________________________________________________________
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Can we see everything there is? _________________________________________
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Formation of the Solar System
Read a Diagram
Star Formation
How does this region of galaxy M33 resemble “starburst” galaxies? ____________
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Quick Check
Fact and Opinion
“Scientists theorize that the universe was very hot and dense in its first moments.”
Is this a fact or opinion? Why? _________________________________________
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Critical Thinking
What do astronomers think caused the background radiation found in space? ____
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How did Earth form?
Of what are the inner planets mostly made? Of what are the outer planets mostly
made? _____________________________________________________________
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What keeps the rock in the planets and the gas in the Sun from flying out into
space? _____________________________________________________________
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What formed the atmosphere that surrounds Earth today? ___________________
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Read a Diagram
How Our Solar System Formed
What part did gravity play in the formation of the solar system? _______________
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Quick Check
Fact and Opinion
“Plants did not exist on Earth in its first years, because the atmosphere lacked
oxygen.” Is this statement a fact or an opinion? Why? ______________________
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Critical Thinking
How did Earth’s original atmosphere evolve into its present one? ______________
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