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Einstein's Universe: Exam 4



True/False
Indicate whether the sentence or statement is true or false.
 

 1. 

During its early history, the universe was dominated by matter.
 

 2. 

Light travels 1 light year in 1 year of time. If the universe is 13.7 billion years old, the the most distant object we have ever observed is  currently 13.7 billion light years away
 

 3. 

The night sky is dark because the universe is neither static nor infinitely old.
 

 4. 

The cosmological principle states that any observer, in any galaxy, will see the same general features of the universe.
 

 5. 

The red shifts of the galaxies imply that the universe is expanding, and that we are at the center.
 

 6. 

Scientists have been able to determine the  physical conditions of the universe at the instant of the Big Bang.
 

 7. 

The inflationary theory of the universe may explain why the background radiation is so isotropic.
 

 8. 

Homogeneity is the assumption that the universe looks the same in all directions.
 

 9. 

Most of the elements heavier than helium were made during the first few minutes after the big bang.
 

Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
 

 10. 

For entire spiral galaxies the M/L ratio can be as high as
a.
It has no M/L value
b.
5 M/L
c.
15 M/L
d.
50 M/L
 

 11. 

The steady state theory, which says that the universe has always existed, was abandoned primarily due to the discovery of
a.
the primordial background radiation.
b.
a super massive black hole at the center of the Milky Way.
c.
dark matter in clusters of galaxies.
d.
the Hubble law.
e.
quasars as very distant and luminous active galaxies.
 

 12. 

What evidence supports an acceleration in the expansion rate of the universe?
a.
The discovery of MACHOs
b.
The discovery of the grand unified theory
c.
The discovery of super massive black holes at the center of quasars
d.
The discovery that type Ia supernova in distant galaxies are 25 percent fainter than expected.
e.
none of the above
 

 13. 

Galaxy seeds around which galaxies, clusters and walls grew may be
a.
baryons.
b.
caused by hot dark matter.
c.
defects in space-time.
d.
the result of the separation of the electromagnetic and weak forces.
e.
the result of freezing water molecules shortly after the universe became transparent to photons.
 

 14. 

If galaxy A is four times more distant than galaxy B, then according to the Hubble Law, galaxy A will recede _______________ than galaxy B.
a.
2 times faster
b.
16 times faster
c.
1.2 times faster
d.
0.25 times faster
e.
4 times faster
 

 15. 

If the universe is flat and not accelerating,
a.
dark energy accounts for a small fraction of the critical density of the universe.
b.
the density of the universe is greater than the critical density.
c.
the universe it not isotropic.
d.
the universe's age will be equal to 1/H.
e.
the universe's age will be equal two-thirds of 1/H.
 

 16. 

If the Hubble constant, H, is smaller for extremely distant galaxies than it is for nearby galaxies, then
a.
we must be located near the center of the universe.
b.
dark matter cannot exist between galaxies.
c.
we must be located near the edge of the universe.
d.
the expansion is accelerating.
e.
the universe is closed.
 

 17. 

The cosmic background radiation comes from the time in the evolution of the universe
a.
known as the inflationary period.
b.
when protons and neutrons were first formed.
c.
when gamma rays had enough energy to destroy nuclei.
d.
when electrons began to recombine with nuclei to form atoms.
e.
when the big bang first began to expand.
 

 18. 

If the Hubble constant has a value of 50 km/s/Mpc, determine the age of the universe
a.
2.7 billion years
b.
200 billion years
c.
2 billion years
d.
20 billion years
 

 19. 

During the first moments of the big bang, nuclear fusion reactions made few heavy elements because
a.
no nuclei heavier than helium could form since there weren't any electrons formed.
b.
no stable nuclei exist with masses of 5 or 8 hydrogen masses.
c.
the temperature and density were too low.
d.
all heavy nuclei are unstable.
e.
the helium nucleus was unstable
 

 20. 

The resolution of Olbers' paradox suggests that it gets dark at night because
a.
the universe is isotropic
b.
the universe is accelerating.
c.
the universe is flat.
d.
the universe is not infinite in age.
e.
the universe is closed.
 

 21. 

If the universe is closed, then its age will be
a.
equal to the square-root of H.
b.
equal to 1/H
c.
less than two-thirds of 1/H.
d.
equal to H squared.
e.
more than two-thirds of 1/H.
 

 22. 

The age of the universe can be determined if
a.
the temperature of the cosmic background radiation can be accurately determined.
b.
the amount of dark matter in the universe can be accurately determined.
c.
the rate of recession of the galaxies in the Local Group can be accurately determined.
d.
the universe is flat.
e.
the Hubble constant and density of the universe can be accurately determined.
 

 23. 

If  the age of the universe is 18 billion years, determine the value of the Hubble constant
a.
5.6 km/s/Mpc
b.
12 km/s/Mpc
c.
73 km/s/Mpc
d.
56 km/s/Mpc
 

 24. 

The flatness problem is that
a.
the density of the universe is very close to the critical density.
b.
the flat universe would expand forever and we could never measure the density of the universe
c.
the density of the universe is much larger than the critical density.
d.
the laws of physics may not be different at different times in the history of the universe.
e.
the red shift of a distant galaxy is caused by the curvature of space-time.
 

 25. 

For galaxy clusters the M/L ratio can be as high as
a.
100 M/L
b.
50 M/L
c.
25 M/L
d.
It has no M/L value
 

 26. 

If the total mass of the universe is greater than the critical density, rho(c),  the universe will
a.
Expand, but slow down
b.
Expand but at an ever increasing rate
c.
Expand forever
d.
Stop expanding, then contract
 

 27. 

The flatness problem and horizon problem
a.
imply that the inflationary theory is incorrect.
b.
show that dark matter must be a small fraction of the total mass of the universe.
c.
show that the universe cannot be described by the steady state theory.
d.
are solved if there was a sudden inflation of the universe at a very early time.
e.
imply that the universe was once much hotter than it is now.
 

 28. 

The best determination of the Hubble constant, using Cepheid variables found in distant galaxies by the Hubble telescope, suggests that the
a.
dark matter in the universe must be composed primarily of baryonic matter.
b.
age of the universe is between 8 and 14 billion years.
c.
Hubble constant is less than 50 km/sec/Mpc
d.
Hubble constant is greater than 100 km/sec/Mpc.
e.
age of the universe is greater than 20 billion years.
 

 29. 

The assumption of isotropy states that
a.
the universe looks the same at all epochs.
b.
the universe looks the same in all directions.
c.
the universe looks the same in all locations.
d.
all of the above
e.
none of the above.
 

 30. 

The best scientific data and models suggest that the universe is
a.
closed, expanding, and accelerating.
b.
flat, expanding, and accelerating.
c.
open, expanding, but decelerating.
d.
closed, expanding, but decelerating.
e.
open, expanding, and accelerating.
 

 31. 

If a galaxy is located at a distance of 18 Mpc, and it is found to have recessional velocity of 1170 km/sec, what is Hubble's constant based only on this galaxy?
a.
55 km/sec/Mpc
b.
85 km/sec/Mpc
c.
75 km/sec/Mpc
d.
95 km/sec/Mpc
e.
65 km/sec/Mpc
 

 32. 

If the total mass of the universe is less than the critical density, rho(c),  the universe will
a.
Expand, but slow down
b.
Expand but at an ever increasing rate
c.
Expand forever
d.
Stop expanding, then contract
 

 33. 

Baryonic matter includes

I.
protons
II.
neutrons
III.
WIMPs
IV.
neutrinos
V.
MACHOs
a.
I, II, & V
b.
I, II, III, IV, & V
c.
III & IV
d.
I & II
e.
I, II & III
 

 34. 

_______________ cause sudden brightening of distant stars by gravitationally lensing the light from those stars. This processes causes the distant stars to grow brighter over a period of a few tens of days.
a.
WIMPs
b.
neutrinos
c.
globular clusters
d.
MACHOs
e.
none of the above
 

Completion
Complete each sentence or statement.
 

 35. 

The _____________ Era is the closest we can get to the instant of the Big Bang
 

 

 36. 

The _______________ states that the universe is both isotropic and homogeneous.
 

 

 37. 

_______________ are a form of dark matter that consists of very low mass stars and planets too faint to be seen.
 

 

 38. 

The _______________ are theories that unify the electromagnetic, weak and strong forces at extremely high energies
 

 

 39. 

The Cosmic acceleration can be explained with the _______________.
 

 

 40. 

COBE and WMAP measured the temperature of the cosmic background radiation to be _______________.
 

 



 
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