Topic: history of universe exam

1. What is dark matter? What is the evidence for dark matter?
Explain.
2. Describe each of the three major questions left unanswered by
the Big Bang theory without inflation, and explain how inflation
3. Make a list of the major eras in the history of the universe,
summarizing the important events thought to have occurred
during each era.
4. Based on the results from the Planck satellite, describe in
percentages the overall composition of the universe. How is this
data measured?
5. (Problem Solving): From laboratory measurements, we know that a particular
spectral line formed by hydrogen appears at rest wavelength of 121.6nm. The
spectrum of a particular star shows the same hydrogen line appearing at a
wavelength of 120.5nm. Calculate the radial velocity. V= (λmeasured – λreference/λreference )
x c, where c = 3.0 x 108 m/s (speed of light)
6. This graph below shows how the average distances between galaxies changes
with time in the four models for the universe, and also shows data points measured
from white dwarf supernovae. What was the data telling us about each of the
models? Which model fits our current understanding of the expansion rate of the
Universe?
7. What defines the habitable zone around a star? Which worlds in
our solar system seems to be potentially habitable, and why?
8. (Problem Solving): What is Hubble’s Law? If you were given a value of Ho=
55.4 km/s/Mpc, what would the estimated age of the Universe be? (Hint: Hubble’s
Law Lab, page 417, TSBT textbook).
Use this diagram to answer question 9 below.
9. These diagrams represent four possible models for the universe. Each model
shows how the size of the observable universe changes with time, with the
Recollapsing Universe having the youngest age. Describe the difference between
the Recollapsing, Critical, and Coasting Universe in terms of the amount of dark
matter, matter density vs. the critical density and the geometrical shape of the
universe with each model. What is the fate of our Universe?
Use this diagram to answer question 10 below.
10. The formulas below are to be used for the following problem.
Stefan-Boltzmann Law: Emitted power = σT4 watt/m2
σ = 5.7 x 10-8 w/m2 x K4
Wein’s Law: λmax ~ 2,900,000/T nm
(Problem Solving): Consider that the Cosmic Background Radiation has a
temperature of 2.735 K, what is its wavelength of peak intensity? (Units:mm).
This is evidence that the CMB exist. What do the little squares represent in the
CMB?
11. At what wavelengths do Earth’s atmosphere completely absorb
visible light? What would then happen to the surface
temperature if all the visible light was absorbed? Would life be

Use this diagram to answer question 12 below.

1. Explain why current theories can’t describe what happened
during the Planck era. What does the head of the snake in the
Cosmic Uroboros swallowing its tail represent?
2. (Problem Solving): Calculate the mass, in Msun, of a galaxy
cluster that has an average galactic speed of 970 km/s and a
diameter of 8.5 Mpc using the Orbital Velocity Law.
3. (Short answer): What wrong with this picture?
Many science fiction stories have imagined the galaxy divided
into a series of empires, each having arisen from a different
civilization on a different world, that hold each other at bay
because they are all at about the same level of military
technology. Is this a realistic scenario? Explain
4. What is the cosmological Principle? Use the New Universe and
5. Earth is an unusually suitable planet for complex life vs.
extrasolar planets, why? (ref. chapter 8 of your online textbook)
6. What is dark energy? How do we know of its existence?
7. What is the Drake equation? Define each of its factors, and
describe the current state of understanding about the potential
values of each factor.
8. (Problem Solving): Using the long version of the Drake
Equation: N = RfsfpneflfifcL, calculate the number of civilizations
with whom we could potentially communicate given the variables
below. What does the Drake Equation tell us?
• R = 10 stars/year
• fs = 0.1
• fp = 0.1
• ne= 5
• fl = 1
• fi = 10-2
• fc = 1
• L = 106 yrs
9. What are Dr. J’s favorite beverages?
a) beer
b) soda
c) coffee
d) French Martinis and Canvas Chardonnay from the Napa
Valley
Please attach your essay. This represents a possibility of a total of 30 points
All corrections made to the final essay will receive half of the points back. If
you do not make corrections, you will receive the grade on the original draft
returned to you.