NAME
________________________________________
Astronomy 121
Test 3
July 12, 2018
Multiple Choice Questions -- Select and circle the best answer
from the choices given.
1. A comparison of the atmospheric pressures of Venus and the Earth tells us
____________________
.
a. the relative densities of the cores of the planets
b. the relative ages of the planet
c. the relative masses of the planets
d. the temperatures of the gas molecules in the atmospheres of the planets
e. the relative masses of the atmospheres
2. Magnetic fields are produced by
____________________
.
a. the decay of radioactive nuclei
b. electrical currents
c. chemical differentiation
d. the convective motions in the asthenosphere
e. volcanic activity
3. The asthenosphere is
____________________
.
a. the plastic layer beneath the solid surface of the Earth
b. the iron-nickel cores of the Earth
c. the region at the very center of a planet
d. the least dense region of the lithosphere
e. the molten layer beneath the solid surface of the Earth
4. On the Earth, the oceanic plates
____________________
.
a. are the oldest portions of the lithosphere
b. are the plastic portions of the lithosphere
c. are denser than the Continental plates
d. are thought to be molten iron
e. are ancient, some were formed as long as 4.1 billion years ago
5. Which of the following statements about the surface of Venus is correct?
a. The surface of Venus is thought to be young, less than 1 billion years old
b. There is an overabundance of craters with diameters less than 30
km on Venus
c. Most of the surface of Venus is old, more than 3.6 billion
years old
d. The surface of Venus is covered primarily by continental-type
regions
e. Venus's lithosphere is anomalous in that it is composed primarily of iron
6. The majority of the surface features on Mercury were formed through
____________________
.
a. plate tectonic activity
b. wind and water erosion
c. volcanism
d. impacts
e. uplifts
7. Near subduction zones, we expect
____________________
.
a. to find large changes in the level of the oceans
b. to find active volcanism
c. to see the formation of island chains (like Hawaii)
d. to observe the creation of new continental crustal material
e. to see sea-floor spreading
8. Because crustal material is continuously created,
____________________
.
a. the Earth is growing in diameter by around 2 - 3 cm per year
b. the landmasses (continents) are continuously destroyed
c. the Earth is getting more massive as time goes by
d. the ocean basins are replaced every few hundred million years
e. the sea level is rising by around 2 - 4 cm per year
9. The mountains on the Moon are
____________________
.
a. strong evidence for the recent collision of continental plates
b. caused by hot-spots in the mantle of the Moon
c. created by the impacts of large objects on the Moon
d. evidence of extensive volcanism in the early history of the Moon
e. evidence that the Moon was once part of the Earth
10. We know that the maria formed after the Lunar highlands because
____________________
.
a. the highlands are more heavily cratered than are the maria
b. the maria are at lower elevations than are the highlands
c. there is a lack of maria on the far side of the Moon
d. the highlands are darker in color than are the maria
e. most of the Moon is covered by highland regions
11. The lunar maria
____________________
.
a. are the result of the flooding of large impact basins
b. have much higher crater densities than the surrounding
regions
c. are spread uniformly over the surface of the Moon
d. are unique to the Moon; they have no counterparts on
other planets
e. All of the above are correct statements about the lunar
maria
12. The interior of the young Earth was heated by
____________________
.
a. solar energy and the solar wind
b. the energy released in its formation
c. the decay of radioactive isotopes
d. a and b
e. b and c
13. The light-colored regions on the Moon are known as the
____________________
.
a. highlands and are thought to be the youngest features on
the Moon
b. highlands and are heavily cratered
c. maria and are thought to be old; ages up to 4.6 billion
years
d. maria and are thought to be around 3.2 - 3.8 billion years
old
e. weird terrain
14. The study of the Moon's surface has revealed that
____________________
.
a. the rate of impacts has been roughly constant since the
Solar System was born
b. the rate of impacts has been slowly declining since the
Solar System was born
c. the rate of impacts was very high 4 billion years ago but
then dropped
d. the Moon has had an anomalously low impact rate over its
lifetime probably because it has been shielded by the Earth
15. Active geology on a planet
____________________
.
a. is due to the existence of a lithosphere
b. is due to the existence of a differentiated interior
c. requires an outward flow of heat
d. requires that the planet have a moon
e. occurs in smaller planets, in general
16. On the Earth, the oceanic plates
____________________
.
a. are denser than the continental plates
b. are re-cycled roughly every 2 billion years
c. make up less than half of the surface of the Earth
d. contain the oldest rocks found on the Earth
e. play the crucial role of providing the energy to move
around the continental plates
17. Convective motions in the
____________________
.
a. lithosphere are thought to drive plate tectonics
b. asthenosphere are thought to drive plate tectonics
c. mesosphere are thought to lead to differentiation
d. Earth's outer core are thought to drive plate tectonics
e. lithosphere are thought to produce differentiation
18. Which of the following statements about the surface of Venus is
correct?
a. The surface of Venus is thought to be ancient; 4.6
billion years old
b. There is an overabundance of craters with diameters
less than 30 km on Venus
c. The surface of Venus is fairly young; less 1 billion years
d. The surface of Venus is primarily highland regions
e. The largest volcanos in the Solar System are found on Venus
19. The surface of Venus is best characterized as
____________________
.
a. rolling plains covering 65 % of the planet
b. rugged, highland-type regions covering over 75 % of the
planet
c. maria (lowland) regions covering about 95 % of the planet
d. rolling plains covering less than 10 % of the planet
e. oceanic basins covering 55 % of the the planet
20. Compared with the side of the Moon facing the Earth, the lunar backside
has
____________________
.
a. more maria
b. substantially fewer craters
c. substantially fewer mountain ranges
d. a thicker crust
e. one active volcano while the nearby side has none
SHORT ANSWER Questions -- Answer four of the short answer questions. Each
answer is worth 5 points.
1. Radioactive age dating is used to determine the age of rocks. Suppose I
have a Moon rock, how do I determine its age using radioactive age
dating?
2. List the ways astronomers probe the interiors of Terrestrial planets. What
has been the best method for the Earth? What has been the best
method for Venus?
3. Why do large planets like the Earth have active geologies while small
planets like Mercury and the Moon do not? Explain your answer.
4. What are plumes? Describe how the Hawaiian islands were formed.
5. How Magellan map the surface of Venus? (This was done
despite the fact that Venus is heavily enshrouded by clouds.)
How could Magellan show that Venus was geologically active today?
Did Magellan present evidence that Venus is still volcanically active?
6. What features of the Moon suggest that it was formed via the Giant Impact
mechanism? What is the Giant Impact mechanism?