Midterm 3 (4/12/2007)

Transcription

1 Midterm 3 (4/12/2007) Instructions A. Answer ALL questions on the optical scan page provided, using a #2 pencil. B. Make sure to include your NAME and STUDENT ID. The computer identifies you by your student ID; do not forget to include it. C. Do NOT mark your date of birth. Instead, use the first column of the day of the date of birth, to mark the VERSION NUMBER(0 or 1) as indicated above. This is VERY IMPORTANT, since different versions have different answers. D. The exam is CLOSED BOOK. You should not use any books or notes. E. Time: 1 HOUR AND 15 MINUTES. 1. Which kind of robotic space mission enables us to take a quick look at a planet? A) sample return B) flyby C) orbiter D) lander/probe 2. The first person to claim to see linear features on the surface of Mars was A) Angelo Secchi B) Percival Lowell C) Giovanni Schiaparelli D) William Herschel 3. If we allow for a simple runaway greenhouse effect, the inner boundary of the Sun s habitable zone would be A) roughly halfway between the orbits of Venus and Mercury B) just outside the orbit of the planet Mercury C) roughly half way between the orbits of the Earth and Venus D) just inside the orbit of the Earth 4. Which of the following is the most convincing observation that suggests that like Europa, Ganymede may also have a subsurface ocean? A) the detection of salts on the surface that may have been brought up from below the crust B) the presence of young grooved terrain that may be the result of cryovolcanism C) the fact that it is the largest moon in the solar system and, hence, should have plenty of internal heat to maintain liquid water beneath its surface D) in addition to its internal magnetic field, Ganymede has a magnetic field induced by Jupiter which is consistent with a salty ocean beneath its crust - 1 -

2 5. Why must lander probes on Mars be sterilized before launch? A) to prevent terrestrial microbes hitching a ride on the probe and contaminating the Martian surface B) to prevent terrestrial microbes destroying the electronics in the probe during its passage to Mars C) to prevent Martian dust from building up on the probe on the surface D) to prevent Martian microbes from contaminating the lander probe 6. A star more luminous than our Sun will have a habitable zone that is A) narrower and farther from the star than the habitable zone of the Sun B) narrower and closer to the star than the habitable zone of the Sun C) wider and farther from the star than the habitable zone of the Sun D) wider and closer to the star than the habitable zone of the Sun 7. The Earth s axis tilt has changed little over its history due to A) the stabilizing effects of Jupiter s gravity B) the stabilizing effects of the Sun s gravity C) the stabilizing effects of the Moon s gravity D) its rapid rotation 8. If life does indeed exist elsewhere in our solar system it will most likely take the form of A) human beings B) plants C) birds D) microbes or other simple life 9. During summer, the northern polar cap of Mars is made of A) carbon dioxide ice overlaying water ice B) a layer of carbon dioxide ice C) a layer of water ice D) water ice overlaying carbon dioxide ice 10. What is the origin of the nitrogen in Titan s atmosphere? A) gas captured from the solar nebula B) breakdown of ammonia (NH 3 ) by ultraviolet light from the Sun C) outgassing from Titan s interior D) impacts from comets 11. A common way a robotic spacecraft can be accelerated and have its trajectory changed without the use of any fuel is via A) a gravitational assist from another spacecraft B) radiation pressure from the Sun C) the ejection of mass from the probe D) a gravitational assist from another planet - 2 -

3 12. As the average surface temperature of the Earth rises, the Northern hemisphere of the Earth is warming more rapidly than the Southern hemisphere because A) the Northern hemisphere contains more landmass which more readily absorbs solar radiation B) during summer in the Northern hemisphere, the Earth is closer to the Sun C) there is less ice in Arctic regions compared to the Antarctic regions so less radiation is reflected out into space D) there are more clouds in the Southern hemisphere to reflect solar radiation out into space 13. Which of the following is NOT a basic requirement for chemically based life? A) a liquid medium to transport biological molecules B) a source of molecules from which to build living cells C) oxygen from photosynthesis D) a source of energy to fuel metabolism 14. When the Sun runs out of nuclear fuel and expands to become a red giant, A) the Earth s oceans will freeze solid B) the Earth will be ejected from the solar system C) the Earth will be destroyed D) the Earth will experience a runaway greenhouse effect followed by the total loss of its atmosphere 15. The most important geological process that has removed craters from the Martian surface in the past is A) plate tectonics B) wind erosion C) volcanism D) water erosion 16. The largest Jovian moon that appears to have been captured is A) Titania, the moon of Uranus B) Io, the moon of Jupiter C) Triton, the moon of Neptune D) Titan, the moon of Saturn 17. What is the origin of Martian meteorites? A) they are rocks brought to Earth by Martians B) they are rocks brought back to Earth by sample return missions C) they are rocks blasted from the surface of Mars by volcanoes; these rocks then floated around in interplanetary space before falling to Earth D) they are rocks blasted from the surface of Mars by impacts; these rocks then floated around in interplanetary space before falling to Earth - 3 -

4 18. The Mars Exploration Rovers, Spirit and Opportunity, landed on the surface of Mars using A) balloons B) rockets C) jet engines D) airbags 19. Most of the carbon dioxide on the Earth A) is locked up in carbonate rocks in its crust or is dissolved in the oceans B) is trapped beneath the surface of the planet in gaseous form C) has escaped into space D) is located in its atmosphere 20. Where is probably the best place to find life on Mars today? A) inside craters that used to be filled with water B) in the Mariner Valley C) in the residual polar caps D) in geologically active areas like Tharsis where subsurface water may exist 21. Typically, what color is the Martian sky during the daytime? A) green B) yellow-brown C) red D) blue 22. The lack of large impact craters on the surface of Europa is consistent with A) active volcanism that is constantly resurfacing the crust B) the surface being covered with an ocean of liquid water C) the crust being so thick and hard that impacts leave no marks on the surface D) a subsurface ocean of water because large impacts will break the thin crust causing water and slushy ice below to flood out and resurface the crust 23. Molecules like water in which electrons are distributed unevenly within the molecule are referred to as A) bipolar B) ionic C) charged D) polar 24. Which of the following statements best describes the idea behind the Carbon Assimilation Experiment on board the Viking landers? A) living organisms in the soil should incorporate carbon from atmospheric gases B) radioactive gases should be produced when radioactive nutrients are added to a soil sample C) soil with living organisms in it should contain organic molecules D) living organisms in the soil should give off gases when they metabolize nutrients - 4 -

5 25. When the Huygens probe touched down on Titan, it landed A) in a vast ocean of liquid methane B) on a solid surface of frozen water and methane ices that resembled a streambed C) in a shallow pool of liquid methane D) on the slopes of an icy volcano covered with water and methane ice 26. The biggest obstacle to life being present in the atmospheres of Jupiter and Saturn is the A) absence of liquid water in their atmospheres B) high levels of solar radiation that would destroy any biological molecules C) strong vertical wind speeds that would rapidly carry organisms into the hot interior where they would be destroyed D) very low temperatures at the tops of the clouds where water would not be liquid 27. What is the most likely origin of the Valles Marineris on Mars? A) it is a fissure in the surface carved out by a giant impact B) it is a tectonic fracture associated with the formation of the adjacent Tharsis bulge C) it is a huge canyon system formed by water erosion D) it was formed from the separation of two tectonic plates 28. What is the definition of a star s habitable zone? A) the range of distances from the star where planets with life have been detected B) the range of distances from the star where rocky planets can form C) the range of distances from the star where organic molecules can be stable on the surface of a suitable planet D) the range of distances from the star where liquid water can be stable on the surface of a suitable planet 29. If Triton has a subsurface ocean, it will most likely consist of A) water mixed with ammonia, methane, or other melted ices B) liquid nitrogen C) liquid ammonia and methane D) liquid water 30. The Huygens probe is an example of which kind of spacecraft? A) orbiter B) sample return C) lander D) flyby 31. The positive result from the Labeled Release experiment was inconsistent with the results from which other biology experiment or experiments? A) Carbon Assimilation B) Gas Exchange C) Gas Chromatograph/Mass Spectrometer D) it was inconsistent with all of them - 5 -

6 32. Most of the carbon dioxide on Venus A) has frozen out in the polar regions B) is dissolved in oceans of liquid water, forming carbonate rocks C) is still present in the atmosphere D) has escaped into space 33. From a chemical energy standpoint, the basic requirement for life is a situation in which chemicals naturally exist in a state of A) instability B) disequilibrium C) equilibrium D) stability 34. Due to its elliptical orbit, Mars is farther from the Sun on average during summer in the Northern Hemisphere. This means Northern Summer on Mars will be A) long and mild B) short and hot C) long and hot D) short and mild 35. Mercury and the Moon do not have atmospheres because A) their surfaces are so cold that any atmospheric gases freeze out onto their surfaces B) charged particles from the Sun have stripped away their atmospheres C) they are rotating too rapidly, causing their atmospheres to be thrown out into space D) their gravities are too weak to prevent atmospheric gases escaping into space 36. If the Earth were to be moved to where Venus is today, A) the oceans would evaporate, blocking light from the Sun and causing global temperatures to fall B) carbon dioxide would be released from the oceans leading to higher temperatures but liquid water could still exist on the surface C) the oceans would evaporate slightly producing a slightly warmer, more humid planet D) the oceans would evaporate and carbonate rocks would decompose producing a runaway greenhouse effect much more severe than the one that exists on Venus today 37. The most recent time that water appears to have flowed on Mars, if only briefly, is during the A) Amazonian Era B) Hadean Era C) Noachian Era D) Hesperian Era - 6 -

7 38. Europa may have a subsurface ocean of liquid water due to A) the insulating properties of its icy surface B) tidal heating from Jupiter and the other Galilean moons C) internal heat left over from its formation D) tidal heating from the Sun 39. Life beneath the surface of Europa would most likely obtain energy from A) the Sun B) Jupiter C) radioactivity D) tidal heating 40. The first Jovian moons were discovered by A) Galileo B) Tycho C) Huygens D) Cassini 41. Seasonal variations on Mars are due A) only to its changing distance from the Sun B) only to its axis tilt C) to changes in the amounts of energy emitted by the Sun D) both to its axis tilt and its changing distance from the Sun 42. Why does the Sun brighten with time? A) as time progresses, helium starts to fuse in the core, in addition to hydrogen, leading to an increase in brightness B) as hydrogen is converted into helium in the core, the number of hydrogen nuclei decreases, decreasing the fusion rate. To maintain the balance with gravity pressing inward, the core compensates by shrinking and heating up C) as time progresses, more and more heat is trapped inside the core, leading to an increase in brightness D) as hydrogen is converted into helium in the core, the number of hydrogen nuclei decreases, decreasing the fusion rate. To maintain the balance with gravity pressing inward, the core compensates by expanding and cooling 43. Gusev Crater was chosen at the landing site for the Mars Exploration Rover Spirit because A) of its proximity to the Tharsis region B) remote sensing measurements from the Mars Odyssey orbiter indicate that larger than average deposits of water ice are present beneath the surface C) we believe this region was once filled with water D) remote sensing measurements from the Mars Odyssey orbiter indicate that deposits of the mineral hematite (which commonly forms in water) are present - 7 -

8 44. The surface of Venus is much hotter than the Earth because it A) has no magnetic field B) has a very thick atmosphere of carbon dioxide C) has a much higher rate of volcanic activity D) is closer to the Sun 45. As global warming progresses, the A) landmasses will warm the most B) equatorial regions will warm the most C) polar regions will warm the most D) oceans will warm the most 46. Mars currently lacks surface habitability mostly because of A) the chemical composition of its atmosphere B) its distance from the Sun C) its small size D) the chemical composition of its surface 47. What did the Martian surface look like from the Viking lander sites? A) a dry, dusty, boulder-strewn desert B) a huge canyon stretching out to the horizon C) flat, dark volcanic rocks out to the horizon D) very mountainous with huge volcanoes in the distance 48. The fact that the strength of gravity decreases with distance means the force of gravity exerted by one object on another (e.g., the Earth and Moon) is greater on the near side than the far side. This effect is commonly referred to as a A) tidal force B) differential force C) distortive force D) tractive force 49. In addition to being the second-largest moon in the solar system, Saturn s moon Titan, is A) the only moon to have its own internal magnetic field B) the only moon to have its own atmosphere C) more geologically active than the Earth D) the only moon to show evidence for a subsurface ocean of water - 8 -

9 50. The Moon is in the habitable zone of the Sun at the same distance as the Earth but is not habitable. How can this be? A) the Moon did have water on its surface in the past, but it was destroyed by highenergy particles from the Sun B) the Moon has never had water on its surface at any time C) the Moon is too small to retain an atmosphere necessary for liquid water to be stable D) the Moon did have water on its surface in the past, but it was blasted off the surface by impacts - 9 -