This document appears to be a final exam for an astronomy course. It consists of 50 multiple choice questions testing concepts covered in the course, followed by open response sections. The multiple choice questions cover topics such as the scientific method, theories of the solar system, properties of stars and galaxies, and the age and expansion of the universe. The open response sections ask students to apply formulas to calculate distances and ages, compare star properties, and analyze hypothetical planetary systems and star cluster diagrams.

1. ASTR 100
Final Exam – Spring 2015
University of Maryland University College
Dr. Hunt
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Section-1
Check the letter that represents the best answer to each of the
multiple choice questions. Answer all questions in this section.
Each question is worth 1 point.
This section is worth 50 points.
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[1] In the scientific method, a hypothesis is _____.
A ) is a statement of fact
B ) makes a prediction that can be tested
C ) is usually proven to be correct
D ) can only be tested once
E ) all of these
[2] Which of the following can be considered a definition of
"theory?"

2. A ) A theory can be an explanation of scientific laws.
B ) A theory is an integrated explanation of numerous
hypotheses, each supported by a large body of observations and
experiments.
C ) A theory is a condensation and simplification of many data
that previously appeared unrelated.
D ) A theory is a prediction for new data suggesting new
relationships among a range of natural phenomena.
E ) All of the above.
[3] An integrated explanation of numerous hypotheses is known
as a _____.
A ) fact
B ) law
C ) control
D ) theory
E ) guess
[4] What is the correct sequence of steps in the scientific
method?
I. State a problem
II. Analyze and interpret data
III. Develop a hypothesis
IV. Share the results with other scientists

3. V. Design and perform experiment to test the hypothesis
A ) I – II - III - IV – V
B ) III – I - V – II – IV
C ) V – IV – III – II – I
D ) I – III – V – II – IV
E ) V – II – I – III - IV
[5] Ptolemy's model sought to explain retrograde motion by
_____.
A) adding circles to epicycle orbits
B) adding circles to elliptical orbits
C) adding epicycles to elliptical orbits
D) adding epicycles to circular orbits
[6] Which of the following is correctly ordered from shortest to
longest lifetime?
A) Sun, very high mass star, very low mass star
B) very low mass star, Sun, very high mass star
C) very high mass star, Sun, very low mass star
D) Sun, very low mass star, very high mass star
[7] Which of the following is correctly ordered from smallest to
largest size?
A) Moon, neutron star, white dwarf, galaxy

4. B) white dwarf, neutron star, Moon, galaxy
C) planet, neutron star, white dwarf, galaxy
D) neutron star, Moon, white dwarf, galaxy
[8] Inner planets have _____ than outer planets.
A) lower densities
B) higher densities
C) thicker atmospheres
D) higher masses
[9] A star’s energy is normally generated by ____ reactions.
A) chemical
B) biological
C) fusion
D) fission
[10] Measurements indicate that a certain star has a very high
intrinsic brightness (100,000 times as bright as the Sun) and yet
is relatively cool (3500 K). How can this be?
A) The star must be in the upper part of the main sequence.
B) The star must be very large.
C) The star must be quite small.

5. D) There must be an error in observation, because no star can
have these properties.
[11] Population II stars ____ than population I stars.
A) have higher percentages of hydrogen and helium
B) sparkle more
C) give off more blue light.
D) are younger
[12] The average temperature at the surface of Venus is
SUBSTANTIALLY greater than the average temperature at the
surface of Earth because ____.
A) it is closer to the Sun
B) it rotates more slowly
C) of the amount of carbon dioxide in its atmosphere
D) clouds in its atmosphere reflect sunlight back into space
[13] Which of the following is NOT explained by the Solar
Nebula theory?
A) common rotation of most of the planets
B) the number of moons each planet has
C) common age of Solar System objects
D) different composition of inner and outer planets
[14] Suppose that in 2012 NASA's Kepler Mission discovers a
series of planets with the following characteristics moving

6. around a star that resembles our Sun: spherical, solid surfaces;
mean densities about 4 times that of H2O; radii about 4000 km;
low-density atmospheres. What would these planets be
classified as, in comparison to our Solar System?
A) Cometary nuclei
B) Asteroids
C) Terrestrial planets
D) Jovian planets
[15] A typical ____ galaxy has ____ than a typical ____ galaxy
and therefore has ____ active star formation.
A) elliptical, more gas and dust, spiral, more
B) spiral, more gas and dust, elliptical, more
C) elliptical, more gas and dust, spiral, less
D) spiral, less gas and dust, elliptical, more
[16] Newton's _____ provides an explanation for Kepler's laws
of planetary motion.
A) second law of motion
B) first law of motion
C) law of gravity
D) third law of motion
[17] Scientists estimate the Universe is about _____ old.

7. A) 6,000 years
B) 14 million years
C) 14 billion years
D) infinitely
[18] The Milky Way galaxy is no more than a couple of hundred
thousand _____ in diameter.
A) miles
B) astronomical units
C) light years
D) solar diameters
[19] The closest star to the Sun is a few ____ away.
A) miles
B) million light-years
C) astronomical units
D) light-years
[20] The size of our Solar System is about a few dozen _____.
A) light years
B) solar diameters

8. C) parsecs
D) astronomical units
[21] The lifetime of a typical star is a few _____ years.
A) thousand
B) billion
C) million
D) hundred
[22] Galaxies throughout the Universe appear to be distributed:
A) mostly in a single spherical shell surrounding a void in
space, presumed to have been caused by a vast explosion at the
time of the Big Bang.
B) uniformly throughout space.
C) in groups and surfaces surrounding vast voids, much like the
surfaces of giant bubbles.
D) around a single point in space, the presumed location of the
original Big Bang that created the Universe.
[23] Current evidence indicates the Universe’s expansion ____.
A) is speeding up
B) is slowing down
C) has stopped
D) is constant
[24] Where are we?

9. A) At the exact center of an expanding Universe, as shown by
the universal expansion away from us in all directions.
B) Near, although probably not right at, the center of the
Universe, as shown by the fact that the edge is so far away.
C) Somewhere in an expanding Universe, but not in any special
part of it.
D) Near the edge of an expanding Universe, as shown by the
microwave radiation coming to us from the edge.
[25] Which of the following does not play a role in creating the
elements needed for life as we know it?
A) high mass stars
B) heavy element fusion
C) supernovae
D) neutron stars
[26] A successful theory of Solar System formation must be
able to primarily explain:
A) The origin of life.
B) The fact that Pluto’s orbit is very elliptical.
C) The fact that the planetary orbits lie approximately in the
same plane.
D) The fact that Mars has satellites.
[27] Scientists can determine what a distant star is made of by
looking at ____.

10. A) its continuous spectrum
B) its absorption spectrum
C) similar stars
D) samples obtained from the star
[28] The name of Milky Way’s Galaxy cluster is
a.
the Magellanic cloud.
b.
the Hydra cluster.
c.
the primordial direball.
d.
the Ursa Major cluster.
e.
the Local Group.
[29] Which of the following statements about our Galaxy is
incorrect?
a.
It is a spiral galaxy.
b.
There is probably a supermassive black hole in its center.
c.
Stars form from the interstellar matter in the spiral arms.

11. d.
There is evidence, from how the speed of rotation of matter in
the diskdepends on its distance form the Galactic center, that
there is a large
amount of dark matter in our Galaxy.
e.
Correction: all of the above are true
[30]
Globular clusters are found in what part of the galaxy?
a.
Nucleus
b.
Disk
c.
Halo
d.
Corona
e.
They are not found in galaxies.
[31] Which of the following used to be considered a planet?
a.
Pluto
b.

12. The Sun
c.
The Moon
d.
Ceres
e.
all of the above
[32] A moon crossing the Roche Limit for its planet will
a.
do nothing; there is no such thing as a “Roche Limit”
b.
crash into the planet
c.
exit the solar system
d.
be ripped apart by tidal stresses
[33] If the planets’ inertia suddenly disappeared, what would
happen to them?
a.
The would fly off in straight lines at constant speed.
b.
They would fly off away from the sun at a constantly increasing
rate.

13. c.
They would fall into the sun due to the sun’s gravity.
d.
They would come to rest and stay that way forever.
[34] Which of the following planets would it be impossible to
see from Venus at midnight (Venus time)?
a.
Mercury
b.
Venus
c.
Earth
d.
Mars
e.
All of the above
[35] If you were standing on the South Pole, where would
Polaris be relative to you?
a.
At the zenith
b.
At your nadir
c.
On the north point on your horizon

14. d.
On the south point on your horizon
e.
None of the above
[36] The point at which the Earth is closest to the Sun is called
a.
Perihelion
b.
Aphelion
c.
Focus
d.
Zenith
e.
Nadir
[37] Think about the Earth's precession. The star Vega was the
North Star in about 11,000 B.C.E. About when will it next be
the North Star?
a.
Never
b.
It is the North Star now
c.
In the year 15,000 BCE

15. d.
In the year 37,000 BCE
e.
In the year 15, 000 CE
[38] A blue spaceship is moving TOWARD you at an extremely
fast rate. It would appear
a.,
red
b.
orange
c.
yellow
d.
blue
e.
violet
[39] About how many times will the solar system have orbited
the center of the galaxy?
a.
0
b.
1
c.
20

16. d.
240 million
e.
4.6 billion
[40] The spiral structure of our Milky Way galaxy is thought to
be caused by
a.
magnetic fields.
b.
density waves.
c.
rapid rotation.
d.
interaction of stars with interstellar gas.
e.
expansion of the galactic disk.
[41] The astronomer put on trial for advocating the heliocentric
model was
a.
Ptolemy
b.
Copernicus
c.
Galileo
d.
Kepler
e.
Newton
[42] The planet that was once erroneously thought to have a

17. vast network of canals on it was
a.
Mercury
b.
Venus
c.
Mars
d.
Jupiter
e.
Saturn
[43] Dark Energy
a.
Makes up over 70% of the contents of the universe
b.
Is responsible for the acceleration of the universe’s expansion
c.
Is likely due to a property of the vacuum of space
d.
All of the above
[44] Galactic collisions
a.
Happen routinely
b.
involve few things actually colliding, and are instead more of a
merger of forms
c.
Are cataclysmic events involving the smashing together of many
individual objects
d.
a and b
[45] The cores of the HEAVIEST supernovae become
a.
white dwarfs
b.

18. neutron stars
c.
quark stars
d.
black holes
[46] A rotating neutron star is referred to as a
a.
quasar
b.
pulsar
c.
black hole
d.
gravitational lens
[47] The planet with the most prominent rings is
a.
Jupiter
b.
Saturn
c.
Uranus
d.
Neptune
[48] The Great Red Spot is a ________ on ________
a.
storm; Jupiter
b.
crater; Jupiter
c.
storm; Mars
d.
crater; Mars
[49] Olympus Mons and Valles Marineris are features on
a.
Venus
b.

19. Mars
c.
Earth
d.
Mercury
[50] The most volcanically active world in the solar system is
a.
Venus
b.
Mars
c.
Earth
d.
Titan
e.
Io
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Section-2
Answer FOUR of the FIVE questions in this section. To get full
credit for a question you must show your work and explain your
reasoning in detail. Each question is worth 5 points. This
section is worth 20 points total. Please do not answer the
questions out of order, and please do not answer more than four.
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[1] Comet Halley has an orbital period of about 75 years.
(a). Using one of the formulas from the formula sheet,
determine the average distance of Comet Halley from the sun in
AU.
(b). Sometimes, Comet Halley can be found just about past the
orbit of Neptune, which is (on average) about 30 AU from the
sun. Explain how this is possible given the average distance you
found from its orbital period.

20. [2] (a). If the measured parallax shift of star A is 0.1 arcsecs
and the parallax shift of star B is 0.05 arcsecs, which star is
farther away from the Earth, why?
(b). Using one of the formulas from the formula sheet, what is
the distance of the farther star in parsecs?
(c). What is the distance of the farther star in light-years?
[3] Two stars have the same radius but have very different
temperatures. The red star has a surface temperature of 3000 K
and the blue star has a surface temperature of 15,000 K. Using
one of the formulas from the formula sheet , by what factor is
the blue star more (or less) luminous compared to the red star?
(for example, 2 times, 10 times, 100 times?)
(a). The blue star is _____ times (b). _____ (more/less)
luminous.
[4] There was a great debate concerning the value of the Hubble
constant. (NOTE: The presently accepted value of the Hubble
constant is 72 km/s/Mpc as listed in your formula sheet.)
One party believed the Hubble constant (Ho) was closer to 50
km/s/Mpc and the other party believed the Hubble constant was
closer to 100 km/s/Mpc. Assuming you measure a recessional
velocity of a galaxy of 10,000 km/s, using one of the formulas
from the formula sheet, what is the distance to that galaxy given
the two different Hubble constants?
(a). Distance to galaxy using 100 km/s/Mpc = _____ Mpc
(b). Distance to galaxy using 50 km/s/Mpc = _____ Mpc
(c). How do the different Hubble constants affect the calculated
age of the universe?
[5] If you triple the distance between two celestial objects,

21. using one of the formulas from the formula sheet, how does the
resultant gravitational force between the two objects compare to
the original force? (for example, 2 times, 10 times, 100 times?)
(a). The force is _____ times (b). _____ (greater/weaker).
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Section-3
Answer SIX of the questions in this section. Explain in detail to
get full credit. Each question is worth 5 points. This section is
worth 30 points total. Please do not answer the questions out of
order, and please do not answer more than six.
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[1] Below are HR diagrams taken of 4 star clusters. Identify the
ages of the star cluster from YOUNGEST to OLDEST and
describe in detail how you can determine the relative age of
each cluster. Use the HR diagram provided at the end of this
exam as a guide in your decision making process.
[2] Assume that the four planets listed in the table below are all
terrestrial-type worlds, they formed at the same time, they orbit
the same star, and each has nearly circular orbits.
(a) Which of the four planets should show the most seasonal
variations over its orbit? Explain your reasoning.
(b) Which of the four planets is the most likely still to be
geologically active? Explain your reasoning.
Planet
Tilt (Deg)
Radius (km)
Density (g/cm3)
Average Distance from Star (AU)
A

22. 1.0
1,111
5.90
1.1
B
23.5
4,051
4.25
2.0
C
47.0
6,950
4.52
3.5
D
0.0
3,397
3.10
5.4
[3] Below are images of two moons in the outer solar system.
Describe in detail which moon has the younger surface and
WHY.
[4] The Big Bang theory of Cosmology is accepted by nearly all
astronomers. Please list, and describe, three major observations
that support this theory.
[5] Use your textbook and the internet to research the issues
involved with human space travel within, and ouside of, the
solar system. List some of the issues that make human space
travel within the Solar System difficult. What are the factors
that make human interstellar space travel unlikely - even in the
distant future?
If they exist, what implications does this have for contact
between advanced civilizations in the Universe?

23. [6] Of the various astronomers we’ve discussed in the course,
please choose one that you think is the most influential and
write a short paragraph about him/her. Include specific
contributions.
[7] Exoplanets or extrasolar planets are planets that orbit stars
other than the Sun. Do a web search for Exoplanets. How many
of these planets are thought to have been detected? How were
they detected? Do any of these planets orbit stars similar to the
Sun? Are any of these planets similar to the Earth in terms of
size and mass?
[8] Please refer to the H-R Diagram posted elsewhere in this
conference for this question.
a. Where on the diagram would one find stars most like our
Sun?
b. Where would one find objects of the smallest size (radius)?
c. Where would one find stars has of the largest size (radius)?
d. Where would one find stars that will burn out the fastest?
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1
Constants & Formulas
c = 300,000,000 m/s
c = 300,000 km/s

24. 1 pc = 3.26 Ly
1 Mpc = 1,000,000 pc
1 Ly = 9.46 x 1015 m
1 nm = 10−9 m
1 AU = 1.50 x 1011 m
1 AU = 1.50 x 108 km
H = 72 km/s/Mpc
σ = 5.67 x 10−8 W/m2/K4
G = 6.673 x 10−11 m3/kg/s2
Tsun = 5780 K
Lsun = 3.83 x 10
26 W
Msun = 2.00 x 10
30 kg
Rsun = 6.96 x 10
8 m
MEarth = 5.97 x 10
24 kg
REarth = 6,378,000 m
d = ct(1)

25. P 2 = a3(2)
Vescape =
√√√√2 GM
R
(3)
c = λf(4)
Vr = H d(5)
T =
3.00 x 106
λm
(6)
V =
λ0
)2
− 1
λ0

26. )2
+ 1
c(7)
B =
L
4πd2
(8)
L = 4π R2 σ T 4(9)
R
RSun
=
(
TSun
T
)2 √√√√ L
LSun
(10)
dpc =
1
p
(11)
M1 + M2 =

27. a3
P 2
(12)
M = (L)
1
3(13)
RS =
2 GM
c2
(14)
L =
2 π D A
360
(15)
Fgravity =
GM1 M2
R2
(16)
19
Bobby

28. Super Giant
Bobby
Giant
Bobby
Main Sequence
Bobby
White Dwarf
Bobby
Text Box
University of Maryland University CollegeSHORT ANSWER
QUESTIONS – 6 short answer questions @ 5 points = 30
POINTS TOTAL: Each Short Answer question is worth 5
points. The full number of points will be awarded for accurate,
correct, full, complete, and thorough answers. Partial credit
will be awarded for less than accurate, correct, full, complete,
and thorough answers so it is to your advantage to attempt an
answer.PROBLEMS – 4 problems @ 5 points = 20 POINTS
TOTAL: Each Problem is worth 5 points. The full number of
points will be awarded for accurate, correct, full, complete, and
thorough answers. Partial credit will be awarded for less than
accurate, correct, full, complete, and thorough answers so it is
to your advantage to attempt an answer.