Test 4: Review Sheet
Sample Short Answer Questions and Points Disccussed in Lecture
1. Describe how one uses radioactive age dating to determine the age
of a rock.
2. Describe the surface features on the Moon. What are the oldest
regions? What are the youngest regions? How are the relative ages
of the various features determined? How are their absolute ages determined?
The period of late heavy bombardment on the Moon occurred ~3.8-4.2
billion years ago. What is the
period of late heavy bombardment?
What has been proposed as a cause for the late heavy bombardment?
3. What are the signatures of Plate Tectonic activity? What drives plate
tectonic activity? Roughly, how many plates are on the surface of the Earth?
What drives geology on any planet? What evidence and
facts led Wegener to propose the theory of plate tectonics? Why was the
theory not immeditately accepted? What eventually led to the acceptance
of the theory of plate tectonics? What are oceanic plates? What are continental
plates? How do they differ? What are rift zones, subduction zones? Describe
what occurs at the places where different plates collide and the locations
where different slide along each other.
4. What is the Juan de Fuca plate? Why is the Juan de Fuca plate
of significance to us in Oregon? What geological activity is associated with
the plate interactions in the Plate Tectonic theory? What are shield volcanoes?
What makes the Hawaiian islands a chain of islands? What are plumes? Why don't
the Hawaiian island volcanos fall near plate boundaries?
5. Do we believe that Plate Tectonic activity occured
on Mars? Cite evidence that supports
your answer. What about Venus?
6. What are maria? How were they formed? Where are they
found? When were they formed? On what objects are they found?
7. What is the rate at which large craters (D > 100 km) are formed on
the Earth (the rate at which the purported dinsoaur killer
events occur)?
8. How are the ages of the surface
features on the Moon determined? How are the ages of surface features
on Mercury estimated? How do the ages of the surace features on the Earth,
Venus, Mar, Moon, and Mercury compare? If different, why are they different?
9. What are the ways in which energy is transported (given in class)?
Describe convection?
What is conduction? What is radiation transport? Near a campfire, explain
why you feel heated if you are above the flames, on the ground away from
the flames, and why your hand feels warm if you hold an iron poker placed
into the fire.
10. How does radar ranging work (on Venus by Magellan)?
What information can be obtained from
radar ranging? What is its significance for Venus and why was it used on
Venus? What is
Magellan?
11. What is meant by primary atmosphere? By secondary atmosphere?
12. What are the possible sources for the atmospheres of the Terrestrial
planets? Which is the most likely for the Earth?
13. Describe the Faint Young Sun Paradox. What is the resolution of the
Faint Young Sun Paradox? What is meant by equilibrium temperature? What is
meant by albedo? What is the rough albedo for the Terrestrial planets?
14. Describe the Greenhouse Effect. What are the most important Greenhouse
gases on the Earth?
15. What are the layers of the Earth's atmosphere? Where is the ozone layer
and roles does it play for us? What is the water trap? Why is the water trap
important?
16. Venus, Earth, and Mars likely started out under similar conditions.
Describe the current thinking as to why each planet wound up so radically
different from each other (in terms of the atmospheres).
17. If all of the water on the Earth were in liquid form and spread over the
Earth, to what depth would the Earth be covered? If the same was done on Venus,
to what depth would Venus be covered? What happened to Venus's water?
18. Are there liquid oceans on Mars today? If not, is there water on Mars? If
there is water on Mars, where is the water?
19. The largest volcano in the Solar System is Olympus Mons on Mars. Suggest
reasons why the largest volcanoes are found on Mars and not on the Earth or
Venus.
20. Briefly, contrast the surface features on Venus and Mars. Do either Venus or
Mars show plate tectonic activity? If not, does this mean Venus and Mars do
not show signs of geology?
1. Write the Drake Equation and describe the terms in the Drake Equation.
The Drake Equation is the product of a series of prbabilities, which
probabilities are known, can be be found (astronomically), and which are
likely going to be difficult to tdetermine? Which are the ones that were
addressed in Astr 121 and, roughly, what are the values of those
probabilities?
2. What is the Fermi Paradox? What are von Neumann machines? What are the
plausible takeaways from the Fermi Paradox? Where do you fall on the issue?
Give a cogent response to the question with concrete arguments for your
position.
3. Carefully describe why Mars is considered the best site for searches for
extra-Terrestrial life in our Solar System. Cite the reaonse with the
observations of mars that support your answer.
4. the primary experiments (Viking and ALH8401)
that address the question of life on Mars? Carefully describe the VIking
mission and the life search experiments
performed by Viking, the general results of the experiments, whether the
experiments showed or did not show life on Mars. Currently where do we stand
on the question of life on Mars based on Viking? What are the properties of
ALH 84001? Why is ALH 84001 considered a Martian meteorite? What features of
ALH 84001 suggested that life existed on Mars? Describe the evidence that life
exited on Mars based on ALH 84001. Which pieces of evidence remain strong to
this day? Which pieces of evidence are not considered to be strong today?
What the reaseons? What is the final take on the ALH 84001 (today)?
5. Some of the inner moons of Jupiter (which)
are targets for searches for life.
These are moons, however, and so why are they targets for searches for life?
Give some of the features of Europa, Enceladus, Callisto that make them
targets? Which of the moons of the Jupiter show volcanos and jets and explain
these moons can show apparent geologic activity. Why is Titan, the
largest moon of Saturn considered a prime target as well. What is a large
concern about all of these targets as locations where could develop.
6. What is LAWKI and is it a reasonable guideline for
seaches for extra-Terrestrial
life? Support your with a cogent arugement supported by more than supposition
and feelings, that is give as factually based argument as possible.
7. Describe the structure of the Earth's atmopshere. How does the structure
of Venus's atmosphere compare to the Earth's atmosphere?
6. The chemical composition of the atmosphere of Mars is most similar to the atmosphere of
a. Jupiter * b. Venus c. the Earth d. the Moon e. Mercury
7. The plastic region in the interior of the Earth where energy is transported by convective motions is the
a. core b. mantle * c. asthenosphere d. lithosphere e. crust
12. The light-colored regions on the Moon are
a. the highlands and are thought to be the youngest features on the Moon * b. the highlands and are heavily cratered c. the maria and are thought to be old; ages up to 4.6 billion years d. the maria and are thought to be around 3.2 - 3.8 billion years old e. wind-swept plains formed early in the Moon's history
13. The study of the Moon's surface and rocks has revealed that
a. a short period of intense bombardment occured around 1 billion years ago b. the cratering history of the Moon is anomalous in that it is different from what we know about the cratering rates of the other planets * c. the rate of impacts was very high 4 billion years ago but then precipitously to its current levels d. the far side of the Moon has never been struck by objects as large as the ones which struck the near side of the Moon (and formed the maria)
14. The relative ages of the regions on Mars can be inferred from
a. the heights of their volcanos b. the lengths of their canyons (e.g., Valles Marineris) * c. the number of craters d. the sizes of their largest craters e. the number of volcanos they contain
15. Active geology on a planet
a. requires the existence of a lithosphere b. requires an extensive and thick atmosphere c. only occurs when the planet has a sizable moon * d. will only occur if the planet has a hot interior e. will only occur on smaller planets, in general
16. On the Earth, the oceanic plates
a. are less dense than the continental plates * b. are re-cycled roughly every 100 - 200 million years c. contain some of the oldest surface features found on the Earth d. are thought to be composed mainly of iron and nickel e. tend to float on top of the continental plates
17. Continental drift (plate tectonic activity) may be driven by
a. strong winds b. ocean currents c. earthquakes d. volcanism * e. convection
18. The Tharsis region on Mars
a. shows some of the oldest surface features on Mars b. lies for the most part below the sea level on Mars * c. is a region of very recent volcanism d. contains both heavily cratered and relatively uncratered regions e. is strong evidence that, in the past, Mars showed extensive plate tectontic activity
19. The Martian surface shows a striking asymmetry between its northern and southern hemispheres. The differences show up
a. in the composition of the atmosphere above each region * b. in the elevations of the regions c. in the number of continents each contains d. in the amount of plate tectonic activity each exhibits e. All of the above are examples of the striking differences between the two hemispheres
20. 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. Most of the surface of Venus is fairly young, only 3 billion years old d. The surface of Venus is covered primarily by continental-type regions * e. Venus's lithosphere is thought to be weaker and more pliable than the Earth's lithosphere
21. The surface of Mercury is more like that of _____ while its interior is more like that of _____ .
a. the Moon; Jupiter b. Mars; Venus * c. the Moon; the Earth d. Mars; Jupiter e. Mars; the Earth
26. 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. an active volcano!
28. The Solar System is thought to be
a. 100 - 200 million years old b. 46 million years old * c. 4.6 billion years old d. 10 billion years old e. 300 - 800 million years old
29. Which of the following Terrestrial planets shows strong evidence for past or present plate tectonic activity?
a. Venus * b. Earth c. Mars d. only the Earth and Venus e. Venus, Earth, and Mars
30. The majority of the surface features on Mercury were formed via
a. plate tectonic activity b. erosion c. volcanism * d. impacts e. a few very large impacts due to asteroid-sized objects
31. What explains the lack of small impact craters (less than 1.4 km) on Venus?
a. objects of the size needed to produce such craters never reach the surface of Venus due to Venus's strong magnetic field * b. the thick atmosphere burns up most objects which produce craters of this size c. small impact craters have been eroded by water and wind d. the statement is incorrect -- there are many such small craters on Venus
32. A measurement of the density of a planet can tell us
* a. the rough composition of the planet b. the age of the planet c. the mass of the planet d. the size (diameter) of the planet e. All of the above can be deduced from only the density of a planet.
34. Based on the composition of the Earth, we define the following regions in the interior of the Earth (in order of increasing distance from the center of the Earth)
a. troposphere, mesosphere, stratosphere * b. core, mantle, crust c. mantle, core, crust d. lithosphere, hydropshere, asthenosphere e. core, asthenosphere, lithosphere
35. 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
36. Due to the continuous creation of crustal material
a. the Earth is growing in diameter by around 2 - 3 cm per year. b. the land masses (continents) are being continuosly 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
37. 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
38. We know that the Lunar 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
39. Of the following planets, which has the largest iron core relative to its overall mass?
* a. Mercury b. Venus c. Earth d. Moon e. Mars
44. The surface of Venus is around
a. 4.6 million years old b. several trillion years old c. 4.6 billion years old * d. 300 - 800 million years old e. 100 - 200 million years old
45. Which of the following statements best describes the formation of the Lunar maria?
a. melting and crust solidification followed by impacts b. massive volcanism and the subsequent cooling of the crust * c. large impacts followed by volcanism d. massive volcanism followed by large impacts e. uplifts and subsequent collapses of the lunar crust
46. Modern data indicates that Venus
a. has extensive, rapid, and current continental drift b. has never had volcanic activity c. is covered mainly by continent-like regions (highlands) * d. may have had recent volcanic activity e. is covered by a layer of water to a depth of roughly 2 -3 kilometers
47. A major reason for the large size of the volcanos on Mars is
* a. the probable lack of continental drift on Mars b. the rapid motion of continental plates on Mars c. the large number of volcanos on Mars d. the small size of Mars
48. Based on the appearances of the Moon, Mercury, and the Earth, plus knowledge of their interiors, we might conclude that
* a. Mercury and the Moon have changed little in the last 3 billion years while the Earth is evolving continuously b. both Mercury and the Earth are still evolving, while the Moon is dead c. All three of the objects are geologically active today d. The surface on all three of the objects may be considered permanent, that is, they are unchanging
49. Large quantities of rock (new crustal material) are emerging from the mantle a. along the tops of continental mountain ranges (such as the Himalayas) b. along the boundaries between continental and oceanic plates c. along the major continental rivers (such as the Mississippi) where the crustal plates are the thinnest * d. along the rifts found between oceanic plates