NAME _______________________________________________

Astronomy 121

Test 4

Multiple Choice Questions, 20 questions--1 point per question. Select the best answer.

1. Comparative planetology _ .

a. helps us to understand the physics of the Earth
b. helps us to understand how the Solar System formed
c. helps us to learn which planets are suitable for life as we know it
d. helps us to understand planetary physics
e. All of the above are true.

5. The conditions in the current atmosphere of Mars are _ .

a. such that water cannot exist in any form on the surface of Mars
b. such that one expects a substantial stratosphere to form
c. such that liquid water cannot exist on the surface of Mars
d. such that one expects that life could exist near the equator on Mars during the summer months

6. When Mars was young, its climate was believed to be similar to the current climate of the Earth. Its atmosphere then evolved to what it is today. The current wisdom says that this was because of ___ .

a. the impact of a large object which caused the Martian atmosphere to boil-off
b. the lack of large-scale plate tectonics on Mars
c. a stage of intense volcanism, as has also been postulated for the Moon
d. the rapid cooling of the interior of Mars
e. the depletion of the Martian ozone layer

8. Of the following, which suggests that Mars has a permafrost layer?
a. Valles Marineris
b. splosh craters
c. seasonal polar ice caps
d. sinuous dried riverbeds
e. the residual northern polar ice cap

9. In the Greenhouse Effect on Earth, carbon dioxide traps _ in the atmosphere.

a. x-rays
b. ultra-violet radiation
c. infrared radiation
d. visible light
e. microwaves

12. The Greenhouse Effect _ .

a. explains why Venus's surface temperature is 800-900 F
b. explains why the Earth has an average temperature of 70 F and not -4 F
c. helps us to understand why the Earth was warmer in the past when the Sun was less bright
d. only a & b are true
e. a, b, & c are all true

13. The current atmospheres of the Terrestrial planets are _ .

a. the result of volcanic outgassing
b. the result of the capture of many comets
c. gases captured directly from the cloud that formed the Solar System
d. A combination of a & b
e. The combination of a, b, & c

14. The majority of the Moon's surface is best described as _ .

a. rolling plains
b. highland regions
c. lowlands
d. maria
e. lava plains and shield volcanos

15. Continental plates on the Earth _.

a. are much younger than oceanic plates
b. make up the plastic portion of the lithosphere
c. are less dense than oceanic plates
d. flow easily because they are molten iron
e. are found only near the poles of the Earth

16. The Tharsis region on Mars _ .

a. is a large impact basin that lies, for the most part, below sea level on Mars
b. is the oldest region on Mars
c. was formed by a large impact, similar to the one that formed our Moon
d. contains both heavily cratered and relatively uncratered regions
e. was likely formed by an uplift of Mars's crust

17. Uranium 235 decays to lead 207 with a half-life of around 700,000 years. A rock contains one-eighth of its original uranium. How old is the rock?

a. 700,000 years
b. 1,400,000 years
c. 2,100,000 years
d. 2,800,000 years
e. 5,600,000 years

18. The reason the atmospheres of Venus and Earth have followed such different evolutionary paths is _ .

a. at birth, Venus was rich in carbon dioxide while the Earth was not
b. the Earth is more massive than Venus
c. Venus is closer to the Sun than is the Earth
d. the day is longer on Venus than it is on the Earth
e. Venus does not exhibit active plate tectonics

19. Of the following, which best describes the planet most likely to have an atmosphere?

a. large mass, small radius, low temperature
b. low mass, small radius, low temperature
c. large mass, large radius, high temperature
d. low mass, large radius, high temperature
e. large mass, large radius, low temperature

20. The early atmosphere of Venus may have been as hot as 2,700 F because _ .

a. of an anomalously large amount of carbon dioxide present in its atmosphere when it was young
b. the Sun was much brighter 4.5 billion years ago
c. there was a large amount of water vapor in Venus's early atmosphere
d. it is believed that Venus developed a technologically advanced civilization in its early history
e. Venus had an extensive Ozone layer when it was born

22. Near a subduction zone, we expect _ .

a. to find large changes in the level of the oceans
b. to find active volcanism
c. to see the formation of volcanic island chains (like Hawaii)
d. to observe the creation of new continental crustal material
e. to see sea-floor spreading

24. The bulk of the carbon dioxide initially present in the atmosphere of the young Earth _ .

a. has been lost to space
b. is now contained in green plants and plankton
c. is now tied up in the crust of the Earth
d. is now contained in the oceans of the Earth
e. is now contained in the polar caps

25. Of the following statements about Venus, which is NOT correct?

a. The surface of Venus is young, less than 1 billion years old
b. There is an underabundance of craters with diameter less than 30 km on Venus
c. The surface of Venus is covered primarily by rolling plains
d. The surface of Venus may show signs of recent geological activity
e. Maxwell Montes, the largest shield volcanos on Venus, is also the largest volcano in the Solar System

26. The Valles Marineris _ .

a. was likely formed by water erosion, similar to how the Grand Canyon formed
b. was likely formed by the impact of a protoplanet that cracked Mars's lithosphere
c. is likely the remains of a large rift zone
d. is likely the remains of ancient subduction zone formed by Mars's only oceanic plate
e. was formed by cracking that occurred during the formation of the Tharsis Bulge

27. Lunar maria _ .

a. resulted from the flooding of large impact basins by lava flows
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

28. Strong evidence that the Moon was geologically active in the past comes from the .

a. mountains in the highland regions
b. existence of the continent-like highland regions
c. light color of the highland regions
d. maria
e. All of the above

29. The Ozone layer on the Earth .

a. helps to protect the surface from Solar ultraviolet radiation
b. helps to trap water vapor in the lower atmosphere
c. supplies the heat that drives the convection that produces our weather
d. only a & b
e. a, b, & c

30. The Hawaiian island chain _ .

a. is strong evidence for the recent collision of continental plates
b. was caused by a hot-spot in the mantle of the Earth and crustal motion
c. was created by a series of impacts of large objects
d. is evidence that the Moon was once part of the Earth
e. was formed in a manner similar to the Andes in South America

32. The oldest rocks on the Earth are around _ old, according to radioactive age dating.

a. 46,000 years
b. 200,000 years
c. 200 million years
d. 4.4 billion years
e. 460 billion years

33. Compared to the side of the Moon facing the Earth, the Lunar backside has _ .

a. more mountains
b. substantially fewer craters
c. substantially fewer mountain ranges
d. fewer maria
e. one active volcano, while the near side has none

34. The surface of Mercury bears the strongest resemblance to _ .

a. that of the Earth
b. that of Venus
c. that of the Moon
d. that of Mars

35. The cratering density in the Lunar highlands and maria tells us that _ .

a. the Moon was geologically active in the past
b. the highlands are older than the maria
c. the cratering rate on the Moon has slowed down in the last billion years
d. large impacts like the dinosaur killer on the Earth, occur every 10 million years or so on the Moon
e. plate tectonic activity on the Moon continued until the last billion years

36. Earth and Venus are often called sister planets. In what ways are Venus and the Earth most alike? Earth and Venus have similar _ .

a. atmospheric composition and density
b. size, density, and escape speed
c. surface temperature and atmospheric pressure
d. size, density, and atmospheric pressure
e. interior composition and atmospheric composition

37. A large difference between Mars's northern hemisphere and its southern hemisphere is _ .

a. the southern hemisphere appears to be older than the northern hemisphere
b. the northern hemisphere is, on average, at higher elevation than the southern hemisphere
c. the southern hemisphere contains nearly all the volcanos and also contains the largest volcano on Mars, Olympus Mons
d. the southern hemisphere is dominated by maria-like regions while the northern hemisphere is more highland-like in character
e. the northern hemisphere is strong evidence of on-going plate tectonic activity on Mars

39. Outflow Channels .

a. are evidence for the existence of an early tropical climate on Mars
b. are evidence for sudden catastrophic floods on Mars
c. are evidence for active volcanism in the northern hemisphere of Mars
d. are evidence for high mountain lakes on Mars
e. are evidence for ancient canals on Mars

40. The troposphere is __ in the Earth's atmosphere.

a. where we find the ionosphere
b. where the weather is generated
c. where the Ozone layer is located
d. one of the layers where the temperature increases as you move up in altitude
e. the outermost layer

41. Oceanic crustal plates _ .

a. are the youngest part of the surface of the Earth
b. cover about 55 % of the surface of the Earth
c. are subducted when they collide with a continental plate
d. can be created near rift zones
e. All of the above are correct

42. A comparison of the atmospheric pressures of Venus and the Earth tells you _.

a. the chemical compositions of the planets
b. the depth of the oceans on the planet
c. the escape velocities of the planets
d. the masses of the atmospheres of the planets
e. whether an ozone layer exists around the planet

43. The majority of Venus's surface is best described as _ .

a. maria-like basins
b. highland regions
c. weird terrain
d. oceanic basins
e. rolling plains

47. The light-colored regions on the Moon are ___ .

a. highlands, the oldest and most heavily cratered regions on the Moon
b. ancient Lunar ocean basins
c. maria, lava-filled impact basins
d. large dust covered Lunar plains
e. mountain ranges produced during the era when plate tectonics was active on the Moon

48. Which of the following statements about the surface of Venus is NOT correct?

a. The surface of Venus is young, less than 1 billion years old
b. There is an underabundance of craters with diameter less than 30 km on Venus
c. The surface of Venus is covered primarily by rolling plains
d. The surface of Venus may show signs of recent geological activity
e. All of the above are correct statements about Venus.

49. Venus is very dry today with no liquid water on its surface. What happened to Venus's oceans (liquid water)?

a. The water exists as water vapor in the upper atmosphere of Venus.
b. The water escaped to space after Venus was struck by a Mars-sized object that caused the oceans to boil
c. Venus was not born with any water; it was always dry.
d. The water vapor rose to high altitudes where it was broken into hydrogen and oxygen; the hydrogen escaped to space and the oxygen formed other molecules and compounds
e. The water slowly seeped into the crust of Venus, where it formed a permafrost layer and/or was incorporated into rocks in the mantle of Venus

51. The Earth's atmosphere is composed _ .

a. primarily of carbon dioxide and water
b. primarily of water with trace amounts of carbon dioxide
c. primarily of nitrogen but with a significant amount of oxygen
d. primarily of oxygen with trace amounts of carbon dioxide
e. primarily of oxygen with significant amounts of carbon dioxide and water

52. The portion of the northern Martian polar cap that remains in the summer is composed of _ while the seasonably variable portion of the cap is composed of _.

a. water ice, water ice
b. carbon dioxide ice, carbon dioxide ice
c. water ice, carbon dioxide ice
d. carbon dioxide ice, water ice
e. water ice and frozen hydrogen, water ice

53. If the Ozone layer around the Earth was to disappear, then _ .

a. the water vapor in our atmosphere would be slowly lost
b. the amount of ultraviolet radiation at the Earth's surface would strongly increase
c. the thermosphere would also likely disappear
d. only a & b
e. a, b, & c

54. The cratering density in the Lunar highlands and maria tells us that _ .

a. the Moon was geologically active in the past
b. the highlands are older than the maria
c. the cratering rate on the Moon has slowed down in the last billion years
d. large impacts like the dinosaur killer on the Earth, occur every 10 million years or so on the Moon
e. plate tectonic activity on the Moon continued until the last billion years

55. The current atmospheres of the Terrestrial planets are most likely _ .

a. the result of outgassing of materials trapped during the formation of the planets
b. the capture of many comets over the lifetime of the planets
c. the initial gases captured directly from the Solar Nebula 4.6 billion years ago
d. probably a combination of a & b
e. probably a combination of a, b, & c

56. The Gaia Hypothesis says _ .

a. Venus is uninhabitable because of the Greenhouse Effect
b. the Earth is habitable because of the ionosphere and mesosphere
c. tidal forces led to the development of life on the Earth
d. the Earth is habitable because of life
e. life is possible because the Earth is habitable

57. Of the following, which best describes the formation of 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 lava flows
d. massive volcanism followed by large impacts
e. uplifts and subsequent collapses of the lunar crust

58. Of the following statements about Mars, which is correct?

a. there has never been liquid water on Mars
b. space probes have found pools of water beneath the Martian surface
c. there are large lakes near the North pole of Mars
d. water ice probably exists in a permafrost layer below the surface of Mars
e. It appears that Mars never had water in any form over its entire history