Test 2

LAST NAME __

FIRST NAME _

Test 2
Astronomy 121

Sign the test form and the Scantron form. Include your student identification number on the Scantron form and bubble-in the appropriate circles on the Scantron form. When you are finished with the exam, hand in both the Test form and the Scantron form at the front desk.

50 Multiple Choice Questions at 2 points per question. Select the best answer

1. Astronomers have discovered ____ .

a. more than one-hundred and fifty planets outside our Solar System
b. that almost all planetary systems contain planets hospitable for life
c. many Terrestrial-like and Jupiter-like planets
d. that planetary systems are rare in our galaxy
e. that all of the new planetary systems have Kuiper belts

2. Listed below are properties exhibited by the planets in our Solar System. Of these, which is clearly NOT true for the newly discovered planets?

a. Planets orbit about their star in the counter-clockwise sense, as viewed from the North Celestial Pole
b. Terrestrial-like planets form close to their stars, within 3 to 4 A.U.
c. Planets generally rotate on their axes in the counter-clockwise sense, as viewed from the North Celestial Pole
d. Jovian planets are found beyond where water is first able to freeze
e. Planets revolve about the Sun in roughly the same plane, the ecliptic plane

3. For the current atmospheric conditions on Mars, _ .

a. Mars's Equilibrium Temperature and its surface temperature are nearly the same
b. an extensive Ozone layer should form in the Martian stratosphere
c. water cannot exist on the surface of Mars, in any form
d. one expects that life could exist on the nightside of the planet
e. one expects that there will be an underabundance of small craters on Mars

4. When Mars was young, its climate was believed to be similar to the current climate of the Earth. Its atmosphere subsequently evolved to its current inhospitable state. Current wisdom says that this change occurred because _ .

a. a large object struck Mars that caused its atmosphere to boil-off
b. Mars lacks large-scale plate tectonics
c. intense volcanism boiled-off its atmosphere
d. rapid cooling of the interior of Mars froze the oceans
e. of the depletion of the Martian ozone layer

5. The Greenhouse Effect on the young Venus was _ .

a. intensified by the presence of technologically advanced life forms
b. weakened by the presence of a thick Ozone layer
c. intensified by water vapor
d. intensified by an overabundance of CO₂ compared to the Earth
e. very mild because of its thick cloud layer

6. Outflow Channels are evidence for __ .

a. the existence of an early tropical climate on Mars
b. current single-cell life on Mars
c. active volcanism in the northern hemisphere of Mars
d. active plate tectonics in the soutern hemisphere of Mars
e. a permafrost layer on Mars

7. The most successful searches for extra-Solar planets are based on the fact that _ .

a. planets exhibit annual trigonometric parallax
b. planets and their star orbit about the center-of-mass of the planetary system
c. all planets undergo epicyclic motions
d. stars produce gravitational micro-lensing
e. planets may transit across their stars

8. 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

9. The discovery of extra-Solar planets _ .

a. has occured primarily over the last ten years
b. has been going on for the last forty years; the discoveries were triggered by the space program
c. has taken place slowly but steadily over the last 2,000 years
d. was first made by Galileo and has continued smoothly since then
e. started with Aristarchus, but then stopped until the 18th century when the first large telescopes were constructed

10. The continental land masses on the Earth _ .

a. are the youngest part of the surface of the Earth
b. cover about 60 % of the surface of the Earth
c. are subducted when they collide with an oceanic plate
d. formed one large supercontinent around 200 million years ago
e. All of the above are correct

11. When we say that the Earth has "differentiated", we mean that _ .

a. the density of the Earth gets smaller as you move inward toward the core
b. the Earth evolved differently than did Venus and Mars
c. the iron and nickel core of the Earth is denser than the silicate mantle and crust of the Earth
d. the current rate of radioactive heating is smaller than when the Earth was young
e. the current magnetic field of the Earth is larger than when the Earth was young

12. 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

13. S waves .

a. can only travel through solid material
b. are examples of longitudinal waves
c. are detected by Doppler shifts
d. can travel through liquid and solid materials
e. can only travel along the surface of the Earth

14. The majority of the surface features on the Moon were formed through _ .

a. plate tectonic activity
b. wind and water erosion
c. volcanism
d. impacts
e. uplifts

15. Near subduction zones, we expect _ .

a. to find rift valleys
b. to find active volcanos
c. to see the formation of island chains (like Hawaii)
d. to observe the creation of new continental crustal material
e. to find the oldest crustal rocks on the Earth

16. Mars does not have a strong magnetic field. This is expected because .

a. Mars does not have a thick atmosphere
b. Mars has the lowest density for a Terrestrial planet
c. of Mars's permafrost layer
d. of the lack of plates tectonics on Mars
e. of Mars's relatively small size (small diameter)

17. The asthenosphere is ___.

a. the layer in the Earth where heat is transported by convection
b. the layer just below the stratosphere in our atmosphere
c. the molten part of the iron core of the Earth
d. the densest region in the interior of the Earth
e. the layer that drives the weather on the Earth

18. The large impact basins that became the maria _ .

a. were formed shortly after the Moon was born, roughly 4.5 billion years ago
b. were produced when a comet broke apart; the comet debris then struck the Moon
c. were produced fairly recently, within the last billion years
d. were produced during the period of the final heavy bombardment
e. were produced around the time the crust of the Earth formed

19. A transform fault is _ .

a. where a plate slides along another plate
b. a region where crust is created
c. a region where crust is destroyed
d. an uplift, like the coronae and arachnoids on Venus
e. the liquid part of a planet's core

20. The largest volcano in the Solar System _ and is found on _ .

a. is Maxwell Montes -- Venus
b. is Sif Mons -- Venus
c. are the Hawaiian islands -- Earth
d. is Olympus Mons -- Mars
e. is Krakatoa -- Earth

21. The most useful probe of the interior of Mercury that has been used is _ .

a. Mercury's density
b. the rotation period of Mercury
c. seismology
d. the magnetic field of Mercury
e. gravitational lensing

22. Of the following, which has the largest effect on producing the great heights of the Martian shield volcanos?

a. The low temperature of the Martian atmosphere
b. The low mass (and hence low gravity) of Mars
c. The thin atmosphere of Mars
d. The thin crust of Mars
e. The large distance of Mars from the Sun

23. The present atmospheres of the Terrestrial planets _ .

a. are the result of outgassing and cometary impacts
b. are the result of the capture of the Solar wind during the T Tauri phase
c. are the result of the gases captured originally from the Solar Nebula
d. A combination of only a & b
e. The combination of a, b, & c

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

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

25. Oceanic plates on the Earth ___.

a. make up the plastic portions of the lithosphere
b. are less dense than the continental plates
c. are moved around by the convection motions in the athenosphere
d. flow easily because they are molten iron
e. are found only near the poles of the Earth

26. If no Greenhouse Effect operated in our atmosphere, _ .

a. this would explain why the Earth was warmer in the past, when the Sun was actually fainter
b. plate tectonic activity would slowly cease
c. we would have an average surface temperature of -4 F
d. the ice at the North Pole would melt
e. we would quickly evolve to conditions like those found on Venus

27. Ocean formation allowed the Earth to remove much of the _ from our atmosphere.

a. hydrogen
b. carbon dioxide
c. oxygen
d. nitrogen
e. helium

28. Which of the following is not a product of plate tectonics?

a. the Himalayas
b. the mid-Atlantic ridge
c. the San Andreas fault (in California)
d. the Grand Canyon
e. All of the above are products of Plate Tectonics

29. Which atmospheric component of the Earth's atmosphere is chiefly a byproduct of life?

a. carbon dioxide
b. nitrogen
c. water vapor
d. oxygen
e. sulfur dioxide

30. Which of the following features suggests that Mars's atmosphere was thicker in the past?

a. outflow channels
b. splosh craters
c. the permafrost layer
d. the sinuous dried riverbeds
e. the northern residual polar cap

31. The Tharsis Bulge _ .

a. is a large impact basin that subsequently filled with lava
b. is the oldest region on Mars
c. was formed by a collision with a large object, an object similar in size to the one that formed our Moon
d. contains both heavily cratered and relatively uncratered regions
e. was likely formed by an uplift in Mars's crust

32. Uranium, U²³⁵, decays to lead, Pb²⁰⁷, with half-life of around 700,000 years. A rock now contains one-fourth of its original amount of 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. We cannot tell from the information given.

33. The dark-colored regions on the Moon are _ .

a. the 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 time when plate tectonics was active on the Moon

34. 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.

35. 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

36. The appearance of Mercury is most similar to _ .

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

37. We do not expect Mercury to have an atmosphere because _ .

a. of its closeness to the Sun and its small mass
b. the Sun turned on before it could capture an atmosphere
c. of its unusual chemical composition
d. of its small mass and its lack of plate tectonics
e. liquid oceans cannot form on the surface of Mercury

38. Because Lunar maria are chiefly on the side of the Moon facing the Earth, we can conclude that _ .

a. the Moon's interior is not chemically differentiated
b. the crust of the Moon on the side facing the Earth is thinner than the crust on the far-side of the Moon
c. the core of the Moon sits closer to the crust on the far-side of the Moon
d. the heat from the radioactivity of the Earth heated the near side of the Moon, melting it around 3 billion years ago

39. The property of a Terrestrial planet that determines whether it will have active geology today is _ .

a. whether its interior is hot or cold
b. whether its equilibrium temperature is larger than or smaller than 32 F
c. whether it has a segmented lithosphere or whether its lithosphere is one solid plate
d. the mass of its atmsophere
e. the amount of water on the planet

40. 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 that which formed the Valles Marineris

41. A significant source of the heat that melts the interior of a Terrestrial planet is _ .

a. radioactive decay
b. absorption of Solar ultraviolet radiation
c. the spin of the planet
d. the convective motions in the interior of the planet
e. All of the above.

42. The key to understanding why Venus's current atmosphere is so different from the current atmosphere of the Earth is _ .

a. that liquid oceans could not form on Venus
b. that a large comet struck the Earth 4 billion years ago; the comet carried in the Earth's oceans
c. that the lithosphere on Venus is very thin compared to the Earth's lithosphere
d. the apparent lack of plate tectonics on Venus
e. the heat supplied by Venus's large number of active volcanos

43. 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

44. Several observations suggest on-going (current) volcanic activity on Venus. Which of the following is NOT evidence of on-going (current) volcanic activity?
a. The lava flows detected by Magellan
b. The changing levels of Sulfur Dioxide found in the atmosphere of Venus
c. The radio outbursts seen in the atomosphere of Venus
d. All of the above are evidence of on-going volcanic activity

45. Impacts that produce craters similar to the Chicxulub crater found off the Yucatan peninsula, are thought to occur _ .

a. every few thousand years
b. every fifty thousand years or so
c. every million years or so
d. every hundred million years or so
e. only once per 4.5 billion years
46. Evidence that the Moon showed geological activity in the past comes from the .

a. mountains in the highland regions
b. lack of maria on the farside of the Moon
c. existence of the continent-like highland regions
d. light color of the highland regions
e. maria seen on the Moon

47. The current atmosphere of Venus is very dry. If all of the water on Venus were turned to liquid, the water would form an ocean that covered Venus to a depth of _ .

a. around 1 kilometer
b. around 3.6 kilometers
c. a couple of inches
d. around 150 meters
e. about 1 meter

48. Large earthquakes hit the Northwest every three or four hundred years. They are the result of the _ formed where the _ .

a. subduction zone -- Juan de Fuca and North American plates collide
b. subduction zone -- Pacific and North American plates collide
c. rift zone -- Juan de Fuca and North American plates collide
d. rift zone -- Pacific and North American plates separate
e. transform fault -- North American and Pacific plates collide

49. The surface of the northern hemisphere of Mars is believed to be much younger than the surface in the southern hemisphere of Mars because ___ .

a. the north is less heavily cratered than is the south
b. the north is at lower average elevation than is the south
c. there is a lack of maria in the northern hemisphere of Mars
d. the Tharis Bulge has an average elevation of 10 km
e. the southern hemisphere shows ancient dried-up riverbeds

50. 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