Test 1, 2013.05.01<br>
Astronomy 123</br>
Spring 2013<br>
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I will finish the review sheet after the conclusion of class on Monday.
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Details:<p>
INTRODUCTION<p>
1. Define cosmology. How has cosmology (as a science) evolved
from the time of the Greeks to current times? 
2. What makes a <i>model</i> scientific? Contrast science and philosophy.
3.Compare the terms (and use of the terms) Universe and universe. 

4. List the basic observtions which led to the Big Bang Theory. Explain how
each piece of data supports the Big Bang theory.
5. Briefly describe the Big Bang theory. 
Is the Big Bang theory on secure ground. What why or why not.
6. Describe Hubble's Law. How was Hubble's Law discovered?
7. Compare and contrast the Doppler shift and cosmological redshift.
8. Describe the <i>naive</i> interpretation
of Hubble's Law. How does the Principle of Mediocrity influence our
interpretation of Hubble's Law? Describe the currently accepted notion for
Hubble's Law.
9. For Homework 1, your determination of the distances to the given galaxies
relied on the assumption that our Universe is flat among other assumptions.
How would your results change if the Universe is open (saddle-shaped)?
10. Describe the horizon problem. Describe why the CMBR's properties lead to 
the horizon problem.
11. Describe the makeup of the Universe. Be sure to consider both matter and
dark energy. 
12. Describe the principle of mediocrity.
Give and describe examples of how the principle of mediocrity seemed to
be violated at different times during history. Be sure to mention how 
different experimental results (that pertain to the principle of 
mediocrity) were misinterpreted in the past. 
13. Describe the cosmological principle. 
Describe the meanings of homogeneity
and isotropy. Give simple examples that illustrate each concept. 
14. The Universe is clearly not bland and uniform, in what sense is
the cosmological principle valid? 
15. Describe the Perfect Cosmological Principle. Is it currently considered by
astronomers when they model the Universe? It is not, what are some reasons why
the Perfect Cosmological Principle is not in favor? 
16. What is the Cosmological
Constant? It was first proposed by Einstein, why? Why did Einstein withdraw his 
suggestion? Has this idea returned to favor today? 
17. Describe the Anthropic Principle.
Does Jim like the Anthropic Principle? Why does
Jim like (or dislike) the Anthropic Principle?
18. Briefly describe the Big Bang Theory.
Upon what observations is the Big Bang Theory based? Is the Big Bang on a 
firm observational footing?
19. Describe Olbers's Paradox and the resolution of the
paradox. That is, what are the assumptions which underlie Olbers's Paradox
and must they be modified to resolve the paradox?
How can the Big Bang resolve Olbers' Paradox?
<li>Describe the Friedman models for the Universe. What assumption did 
Friedman make when finding his models for the Universe? Was this assumption
valid? 
<li>What is meant by spacetime? In terms of spacetime, describe each of
Friedman's models for the Universe.
<li>In which type of Friedman universe are we thought to live? Which universe
is a closed universe (and what does this mean)? Which universe is an open
universe (and what does this mean)?
<li>How can we distinguish open, closed, and flat universes? Describe the tests
and the results of the tests described in class. Describe the behavior of 
parallel lines, triangles in the different Friedman models.
<li>Interpret and explain the Hubble Law in the context of an expanding
Universe. What is meant by cosmological redshift? Describe cosmological 
redshift. How does the cosmological redshift fit in with the Hubble Law?
What is meant by scale factor [R(t)]? How does the scale factor behave for
each type of Friedman universe?
<li>Describe Hubble's law and how it changes for distant galaxies. Explain how
Hubble's law as determined by distant galaxies can show us ultimate evolution
of the Universe.
<li>What is the Cosmological Constant? What is the Horizon Problem? What is
the Flatness Problem?
<li>How can we distinguish open, closed, and flat universes? Describe the tests
and the results of the tests described in class. Describe the behavior of 
parallel lines, triangles in the different Friedman models.
<li>Interpret and explain the Hubble Law in the context of an expanding
Universe. Describe cosmological 
redshift. How does the cosmological redshift fit in with the Hubble Law?
<li>What is the Horizon Problem? What is
the Flatness Problem? What is the Matter/Anti-Matter Asymmetry Problem?
How does inflation address each of these problems?
<li>Carefully describe
<i>Inflation</i> and describe the <i>mysteries</i> of the Universe 
that <i>Inflation</i> solves and explain how <i>Inflation</i> solves
the problems.
<li>What are the four known forces of the current Universe? Have there always
been only four distinct forces (four distinct ways in which things
interact) in the Universe? If not, how has the situation evolved?
<li>What forces play dominant roles in
the evolution of the Universe? How does the changing number of forces 
as the Universe evolves lead to <i>inflation</i>?  
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History of the Universe
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<li>How old is the Universe? How do we arrive at this age estimate? 
How old are the oldest
stars in the galaxy? Is there a problem with this age for the oldest stars?
<li>What is the correct order for the radiation era, the matter era, and the
dark energy era? When did the transitions from era to era occur? What is 
meant by radiation era, matter era, and dark energy era?
<li>Describe how the Universe evolved starting from the Planck Era (what is
meant by the Planck Era) to GUT Era to the Quark Era to Nuclear
(Nucleosynthesis) Era and to the formation of the CMBR. 
<li>How long did the Planck era last? Why did the Planck era
end? 
<li>What is meant by symmetry breaking? What were the various 
symmetry breakings which occurred in the evolution of the Universe? 
What are GUTs?
<li>What is meant by 
annihilation? 
<li>Physicaly, what is the meaning of
E = mc<sup>2</sup>? What is the conundrum of 
Matter/Anti-Matter
Asymmetry? 
<li>Cosmological Constant. What is meant by the  
Cosmological Constant? Who first proposed the Cosmological Constant and 
why? 
<li> How does a matter 
particle differ from its anti-matter twin? 
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Weighing the Universe and Determining the Expansion Rate for the Universe
<ul>
<li>Describe how the following method used to determine the ultimate fate 
of the Universe works:
<ul>
<li>Examination of the behavior of the Hubble Law at large z. How is the 
<i>Hubble Law</i> at large z determined? What standard candles are used for
this exercise? What is the fate of the Universe implied by these results?
<li>What is current best model for the Universe? Of what 
is the Universe composed
in the best current model of the Universe?
<li>How is the expansion rate of the Universe determined? What is the most
difficult aspect in the determination of the expansion rate of the Universe?
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