Exam 2
Friday, June 21
This is a closed book, closed note exam worth 100 points (15% of your final grade) and which ends promptly at 10:50 AM. There are 20 multiple choice questions worth 2 points each, 15 short answer questions worth 3 points each, and 3 long answer questions worth 5 points each. Put your name and ID number on the test sheet. Please read each question carefully. Good luck!
Multiple Choice (2 points each)
1. Venus is about _______ AUs from the Sun.
A) 10
B) 1.5
C) 1
D) 3/4
E) 1/5
2. The atmosphere of Venus is mostly:
A) oxygen
B) nitrogen
C) carbon dioxide
D) argon
E) sulfuric acid
3. Rocks found on Hawaii and the Lunar Maria are both:
A) carbonate
B) granite
C) basalt
D) stony-iron
E) none of these
4. The Jovian planets (Jupiter and Saturn) are mostly made of:
A) hydrogen and helium
B) ice
C) rock
D) hemp
E) water, methane and ammonia
5. The first successful Mars landing was:
A) Voyager 2 in 1979
B) Mariner 2 in 1961
C) Apollo 11 in 1969
D) Viking 1 in 1976
E) Magellan in 1980
6. A seasonal change observed on Mars is:
A) shifting patterns of wind-blown dust
B) shrinking and expanding polar caps
C) global dust-storms, some years
D) changing atmospheric pressure
E) all of the above
7. The reddish color of Mars is caused by:
A) scattering of blue light in the thick Martian atmosphere
B) Martians who are badly sun-burned due to the lack of an ozone layer
C) iron oxide minerals which reflect red light more than blue light
D) carbon dioxide in the atmosphere
E) dust particles
8. Which of the following is NOT found on Mars:
A) dried up ancient rivers
B) giant shield volcanoes
C) a planet-wide system of plate tectonics
D) polar caps of "dry ice"
E) Ancient, heavily cratered highlands
9. Jovian planets are so much larger than terrestrial planets because:
A) Ices could form at these great distances from the sun, so there was more solid mass to form planets.
B) They are farther apart, so each could sweep up stuff from a larger volume of space.
C) They reached a critical mass so they could directly accrete gas from the nebula.
D) All of the above.
E) None of the above. In fact Jovian planets are quite tiny.
10. The clouds of Venus are composed of droplets of:
A) water
B) nitrogen
C) carbon dioxide
D) salt
E) sulfuric acid
11. Impact craters on the Earth:
A) do not occur because of the thick atmosphere
B) are rare compared to the other terrestrial planets because of erosion
C) do not occur because of plate tectonics
D) are rare because of plate tectonics
E) both B and D.
12. The canals of Mars:
A) were carved by liquid water which has mysteriously disappeared
B) were probably created by an ancient civilization there
C) were a historical misconception
D) may have been formed by some liquid other than water
E) are probably still under construction
13. The building blocks of proteins are:
A) genes
B) nucleotides
C) amino acids
D) DNA molecules
E) none of the above
14. The Urey-Miller experiment:
A) Showed that the primitive molecules necessary for life can be created quite easily.
B) Proved that life formed on Earth from ultraviolet energy and methane.
C) Created life in the laboratory for the first time.
D) Has been shown to be completely irrelevant for the origin of life question.
E) Proved that life is made out of organic molecules.
15. Water on Mars:
A) apparently flowed on the surface at one time
B) is partially hidden now as permafrost beneath the surface
C) is frozen in the polar caps
D) in frozen form was responsible for the lobate ejecta seen around some impact craters
E) all of the above
16. Asteroids are:
A) small icy bodies which mostly exist far outside the orbit of Neptune.
B) large, slow moving objects in the outer solar system, mostly composed of gas
C) small bodies, most of whose orbits lie near the plane of the ecliptic between the orbits of Jupiter and Mars.
D) hypothetical objects which may explain some of the craters on the Moon.
E) the most distant objects ever detected.
17. Comets are :
A) small icy bodies which mostly exist far outside the orbit of Neptune.
B) large, slow moving objects in the outer solar system, mostly composed of gas
C) small bodies, most of whose orbits lie near the plane of the ecliptic between the orbits of Jupiter and Mars.
D) hypothetical objects which may explain some of the craters on the Moon.
E) the most distant objects ever detected.
18. Saturn's rings are made out of:
A) gaseous hydrogen and helium
B) large rocky boulders
C) liquid hydrogen
D) bzillions of orbiting "Barney" dolls
E) small icy particles
19. The Roche limit is:
A) the closest distance that an artificial satellite can approach the Earth without being burned up by the atmosphere
B) the maximum size a planet can be before its own tidal forces would destroy it
C) The shortest distance a natural satellite of any size can be from a planet without being destroyed by tidal forces
D) the minimal precessional period a planet can have
E) none of these
20. The Magellan spacecraft:
A) successfully mapped the surface of Mercury
B) went to Mars and discovered ancient riverbeds
C) was the first spacecraft to successfully go to Venus
D) mapped almost the entire surface of Venus, using radar
E) will go to Saturn in the year 2000 and drop a probe into Titan
Short Answer (3 points each)
21. What is meant by the phrase "geologically young"?
22. What is zodiacal light? Where do you see it? What causes it?
23. If you were on Jupiter instead of Earth, some things in the sky would look different - circle True or False for each of the following statements:
T / F A) The Sun would look brighter to you than it does from Earth.
T / F B) Your year (the time it takes to orbit around the Sun once) would be shorter than Earth's year.
T / F C) You would be able to see retrograde motion of planets inferior to you (Mars, Earth, Venus, Mercury)
24. Why is Olympus Mons so much larger than the volcanoes on the Earth?
25. Why do planetary astronomers think that Venus underwent catastrophic resurfacing?
26. What is a corona? Which planet has coronae?
27. Where is the Oort cloud and where is the Kuiper belt? Where were the comets that inhabit each of them formed?
28. What is a proplyd?
29. Describe the differences between a meteorite, meteoroid, and meteor.
30. Why do we see no small craters on Venus' surface?
31. Where would you find an endolithic organism?
32. What is meant by the phrase, "The impact frustration of life"?
33. What is "genetic takeover"?
34. Why are the atmospheres of the Jovian planets different from the atmospheres of the terrestrial planets?
35. What causes shooting stars? How big an object causes an average shooting star? How are meteor showers related to comets?
Long Answer (5 points each)
36. Today is summer solstice. For about how long is the Sun in the sky today? When is it at its highest? Is it due S, E, W, N or directly overhead at this time? For about how long will the Sun be in the sky today at the equator? Draw a picture of the Earth in its orbit around the Sun, with the axis and northern and southern hemispheres correctly labeled. Show the correct orientation of the Earth's axis with respect to the Sun.
37. Give an overview of the composition and structure of the terrestrial (inner) planets versus the Jovian (Jupiter, Saturn) planets. Use drawings to explain your answer. What processes in the early history of the solar system do you think gave rise to these differences?
38. Describe the formation of the solar system. Use all of the following words correctly in your sentences: solar nebula, accretion, planetesimals, condensation sequence, metals, silicates, ice and frozen gases.
6/27/96