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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?"
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
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
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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
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.
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
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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 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.
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
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[20] The size of our Solar System is about a few dozen _____.
A) light years
B) solar diameters
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?
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.
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[27] Scientists can determine what a distant star is made of by looking at ____.
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.
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]
a.
b.
c.
d.
e.
Globular clusters are found in what part of the galaxy?
Nucleus
Disk
Halo
Corona
They are not found in galaxies.
[31] Which of the following used to be considered a planet?
a.
Pluto
b.
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.
c.
They would fall into the sun due to the sun’s gravity.
d.
They would come to rest and stay that way forever.
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[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
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
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
d.
240 million
e.
4.6 billion
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[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 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.
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
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[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.
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.
[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?
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(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, 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.
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[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
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.
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[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?
[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)?
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d. Where would one find stars that will burn out the fastest?
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