Chapter 8, Astronomy
Lesson 5, Galaxies and Beyond
Objectives __________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
Main Idea __________________________________________________________
___________________________________________________________________
___________________________________________________________________
Vocabulary galaxy ______________________________________________________________
_______________________________________________________________
Milky Way __________________________________________________________
_______________________________________________________________ spectrum ___________________________________________________________
_______________________________________________________________ expansion redshift ____________________________________________________
_______________________________________________________________ big bang ____________________________________________________________
_______________________________________________________________ background radiation _________________________________________________
_______________________________________________________________

What are galaxies?
Is a constellation a natural grouping of stars? ______________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
In what way are stars naturally grouped? _________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
The Milky Way Galaxy
What is the name of the galaxy in which Earth is located? What type of galaxy is it? _________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
How can you tell that Earth is in one of the Milky Way’s spiral arms and not in its center? _____________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
Quick Check
Fact and Opinion
“The Milky Way is a spiral galaxy.” Is this statement a fact or an opinion? Why? __
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________

Critical Thinking
How are the three types of galaxies similar? How are they different? __________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
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? _______________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
How would their positions a hundred years ago compare with their positions now?
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
What about a thousand years ago? ______________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
As you look further and further back in time, what do you see happening to the universe? ___________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
Can we see everything there is? _________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________

Formation of the Solar System
Read a Diagram
Star Formation
How does this region of galaxy M33 resemble “starburst” galaxies? ____________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
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? _________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
Critical Thinking
What do astronomers think caused the background radiation found in space? ____
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
How did Earth form?
Of what are the inner planets mostly made? Of what are the outer planets mostly made? _____________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________

What keeps the rock in the planets and the gas in the Sun from flying out into space? _____________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
What formed the atmosphere that surrounds Earth today? ___________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
Read a Diagram
How Our Solar System Formed
What part did gravity play in the formation of the solar system? _______________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
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? ______________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
Critical Thinking
How did Earth’s original atmosphere evolve into its present one? ______________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________