NAME
________________________________________
Astronomy 121
Test 2
July 5, 2018
Multiple Choice Questions -- Select and circle the best answer
from the choices given.
1. Tycho Brahe showed conclusively that
____________________
.
a. the Earth orbited the Sun by being the first to observe annual
trigonometric parallax
b. the heliocentric theory of Copernicus was correct
c. the geocentric theory of Ptolemy was correct
d. neither the geocentric and heliocentric theories of the day were
correct
e. gravity was able to explain why the planets moved as they did
2. Kepler's third law of planetary motion says that
____________________
.
a. a planet moves more rapidly in its orbit when near the Sun than when it is far from the Sun
b. the Sun sits at the center of planetary orbits
c. slow moving planets are closer to the Sun than are fast moving planets
d. planets close to the Sun have shorter orbital periods than those far from the Sun
e. retrograde episodes occur every sidereal revolution period
3. The Terrestrial planets are
____________________
.
a. Mercury, Jupiter, and Uranus
b. Jupiter, Uranus, Neptune, and Pluto
c. Mercury, Earth, Venus, and Mars
d. Jupiter, Saturn, Neptune, and Uranus
e. Saturn, Pluto, Jupiter, Uranus, and Neptune
4. The best theory for the origin of our Moon is
____________________
.
a. the collision and coalescence of dust particles, just as happened
for the Earth
b. that the young Earth spun rapidly and ejected the Moon from its surface
c. that the Moon formed outside of the Solar System
and was captured by the Sun and then by the Earth
d. that the young Earth was struck by a Mars-sized object which ejected
material into a disk around the Earth which led to the formation of the Moon
e. the Earth and the Moon formed independently at different
locations in the Solar Nebula; the Moon was subsequently captured
by the Earth after its formation
5. The Greek credited with taking the Geocentric
model to its pinnacle is
____________________
.
a. Aristotle
b. Aristarchus
c. Erastosthenes
d. Ptolemy
e. Hipparcos
6. The recent discovery and study of thousands of extra-Solar planets
and planetary systems
____________________
.
a. shows us that planetary systems are common in the Milky Way galaxy
b. allows us to test our understanding of how our Solar System formed
c. shows us that our Solar System may not be typical
d. helps us to understand planetary physics
e. All of the above are true.
7. The Earth travels fastest in its orbit in January, when it is the
closest to the Sun. This can be understood through an application of
____________________
.
a. Kepler's law of ellipses
b. Kepler's law of equal areas
c. Kepler's harmonic law
d. a combination of Kepler's law of ellipses and the harmonic law
e. a combination of Kepler's harmonic law and law of equal areas
8. The key to understanding the large difference between
the Jovian planets and the Terrestrial planets is
____________________
.
a. noting that water was able to exist in solid form (ice) starting
between the orbits of Mars and the Jovian planets
b. noting that the outer Solar System contains more hydrogen than does the
inner Solar System starting around Jupiter
c. the ability of rocky material to be in solid form only around the orbits
of the Jovian planets
d. that there was no gas in the inner Solar System
e. We do not understand why the Jovian planets are so different from the
Terrestrial planets.
9. Which concept is not a part of Kepler's Laws of Planetary Motion?
a. All planetary orbits are ellipses.
b. The square of the planet's orbital period is equal to the cube of
its average distance from the Sun.
c. A planet moves fastest in its orbit when it is at its closest point to
the Sun.
d. Epicycles are used to explain the varying brightnesses of the planets.
e. The line that connects the planet and the Sun sweeps out equal areas in
equal times.
10. When first proposed, the Copernican model was not accepted by the
scientific community because
____________________
.
a. there was strong and arbitrary opposition by the scientific establishment to
his model
b. there was strong opposition by the religious establishment
c. it did not agree with the data of the day any better than did geocentric
models
d. of the slow variation of the seasons over the course of one year
e. the Earth was large, it had a measured circumference of over 25,000 miles
11. Based on recent studies of extra-Solar planets,
____________________
.
a. it is found that most planetary systems show properties similar to our Solar System
b. it is surmised that Jovian planets are the most common type of planet
c. it is surmised that our Solar System is an anomaly and cannot be used as a model for other systems
d. it is found that the most common type of planet is a Super-Earth, a type of planet not found in our Solar System
e. it is concluded that our current model for the formation of planetary systems is wrong and needs nearly a complete overhaul
12. The chemical composition of Jupiter and Saturn is
most similar
____________________
.
a. to that of the Sun
b. to that of Venus
c. to that of the Earth
d. to that of Mars
e. to that of Mercury
13. The Terrestrial planets did not capture gas from the Solar Nebula because
____________________
.
a. of the large spin (angular momentum) of the forming
planets prevented capture of gas
b. their masses were too small and the gas was too hot
c. the gas was too hot and waterice was not able to form
d. the Terrestrials have solid surfaces
e. None of the above
14. According to Copernicus, retrograde motion
____________________
.
a. could only be understood if the stars were very close to the Earth
b. was due to the epicyclic motion of the planet
c. would occur when a faster moving inner planet caught up and passed a
slower moving outer planet
d. occurred because of the slow drift of the Earth's rotation axis caused by
precession
e. could not be easily understood in a heliocentric model
15. Of the following which are considered Universal in the sense discussed in class?
a. Newton's Law of Gravity
b. Kepler's Laws
c. Titius-Bode relation
d. only a and b
e. a, b, and c
16. The density of a planet gives strong clues to the
____________________
.
a. age of the planet
b. sidereal day of the planet
c. chemical composition of the interior of the planet
d. chemical composition and mass of the atmosphere of the planet
e. existence of tides on the planet
17. What important event occurred when the Sun turned-on and
developed an intense Solar Wind and high luminosity?
a. Jupiter collided with a large Mars-like planetesimal producing Venus.
b. The Earth developed free oxygen in its atmosphere.
c. Dust rapidly formed signaling the start of planet formation.
d. The gas was swept out of the region of planet formation
e. Protoplanets started to coalesce from planetesimals
18. The initial phase in the formation of planets
____________________
.
a. is the collision and coalescence of dust particles
b. is the collision and merging of planetesimals
c. is the capture of hydrogen and helium gas by dust particles
d. is the capture of hydrogen and helium gas of by asteroid-like objects
e. occurs after the young Sun ignites and clears out the hydrogen and
helium gas from the planet forming region
19. If two objects with differing masses are dropped, the more massive
object
____________________
.
a. feels a stronger gravitational force due to the Earth than does
the less massive object`
b. strikes the ground at the same time as the less massive object if both
are released from the same height and from rest
c. hits the ground after the less massive object if it initially has some
horizontal motion while the less massive object is released from rest
d. Only a and b are true.
e. a, b, and c are all true.
20. The Titius-Bode relation
____________________
.
a. led to the discovery of Pluto in the 1920s
b. explains why more massive objects are harder to move than less massive
obejcts
c. explains why Kepler's laws are valid, even in other planetary systems
d. led to the recent discovery of Planet X
e. led to the discovery of the asteroids in the 1800s
SHORT ANSWER QUESTIONS
Answer two of the three following questions.
Question 1:
Dynamical and physical properties of the planets
a. Complete the following Table.
Compare and contrast their distances from Sun, masses, diameters, densities,
and chemical compositions. If you know of other important properties to
compare, incude them in the Table as well. Be as quantitative as possible, but
if you do not know numbers, say greater than, less than, or the same
as, for your comparisons.
Property |
Terrestrials | Jovians |
Rock/Ice |
| | | |
| | | |
| | | |
| | | |
| | | |
| | | |
b. List the three dynamical regularities exhibited by the Solar System planets
which any theory of planetary formation must explain.
Question 2:
Development of modern physics
a. What were the major contributons, in one or two sentences, of
- Tycho Brahe
- Johannes Kepler
- Issac Newton
b. In your opinion, who of the above was the most influential? Support
your answer with a reasoned argument.
Question 3:
Formation of the Solar System
a. Our Solar System formed from the collapse of a large interstellar
gas cloud. The initial cloud was nearly spherical in shape, slowly
spinning, had size on the order of light years across.
The Solar System is much smaller with size on the order of light days
across. Briefly describe how the flattened, spinning disk of
gas and dust out of
which the planets formed is explained
in our current model for the formation of the Solar System.
b. What is the snow line and what is the signficance of the snow line?
c. What are Hot Jupiters? How do we understand Hot Jupiters?