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PH109 Exploring the Universe, TEST #2, Fall 2001
Please indicate the best answer to the following questions on the answer sheet provided.
1. What is (are) the major source(s) of tides on Earth?
a) Moon, b) Moon and Sun, c) Moon, Sun, and Jupiter, d) Moon and other planets
2. What are the two major greenhouse gases in Earth's atmosphere?
a) oxygen and nitrogen, b) nitrogen and carbon dioxide
c) carbon dioxide and methane, d) water vapor and carbon dioxide
3. One of the following factors, along with temperature, determines whether a body will retain an atmosphere of
a given composition.
a) size, b) distance from the sun, c) escape speed, d) rate of rotation
4. Name two places on Earth where convection is operating on a large scale, creating natural phenomena that
are important features for life on Earth.
a) In the atmosphere and the mantle., b) In the two Van Allen belts.
c) In the crust and the exosphere d) all of the above,
5. The Moon's atmosphere is composed of:
a) Nitrogen and oxygen., b) Carbon dioxide.,
c) Hydrogen and helium., d) it has none,
6. The rate of cratering on the lunar highlands helps to show that:
a) They are younger than the maria., b) They are older than the maria.
c) They are about 1 billion years old., d) They are about 2 billion years old.
7. What theory of the Moon's origin is favored by most astronomers today?
a) The Moon formed as a separate object near Earth and at about the same time.
b) The Moon formed far from Earth and was captured by its gravity.
c) The Moon originated as material torn from the young molten Earth by centrifugal or tidal forces.
d) The Moon originated as material torn from Earth by the collision of a large Mars-sized body.
8. What causes a meteor shower?
a) Earth crosses the orbit of a comet
b) Earth intercepts a stray swarm of asteroids.
c) Earth encounters the asteroid belt.
d) A small constellation of dying stars disintegrates.
9. The Oort Cloud is thought to be:
a) The cloud of gas and dust from which our solar system formed.
b) A cloud of debris that occasionally encounters the Earth, causing a meteor shower.
c) A cloud of comets surrounding the solar system.
d) A cloud of asteroids moving between the orbits of Mars and Jupiter.
10. The orbits of most asteroids:
a) Lie beyond the orbit of Mars., b) Cross the orbit of Mars.
c) Cross the orbit of Earth., d) Bring them near the Sun; these asteroids are called Sungrazers.
11. What causes the bright flash of light as a meteor plunges through the atmosphere?
a) The meteor glows white hot., b) Lightning sparked by the meteor's passage.
c) Air molecules ionized by the friction of the meteor's passage. d) All of the above
12. Which of the following has an icy composition?
a) asteroids, b) meteors, c) comets, d) meteoroids
13. How do the densities of the terrestrial and jovian planets compare?
a) They all have similar densities.
b) The Jovian planets generally have higher densities than terrestrial planets.
c) Comparisons are useless because the jovian planets are so much larger than terrestrial planets.
d) The terrestrial planets have higher densities than the jovian planets.
14. In light of modern solar system theory, why do the orbits of the planets all lie in nearly the same plane?
a) The Sun's gravity forced them into these orbits.
b) The angular momentum of the solar system was kept to a minimum this way.
c) The early solar nebula flattened into a disk.
d) This happened purely by chance.
15. What factor caused different planets to form out of different types of material?
a) The angular momentum of the forming planet.
b) The quantity of dust particles in the solar nebula.
c) The variation in temperature throughout the solar nebula.
d) The age of the Sun when the planets formed
16. What is the process of accretion?
a) Growth of an object by the accumulation of matter.
b) The breakup of large objects by violent collisions with other similar-sized objects.
c) The period of time during which the Sun swept away all the excess material in the solar nebula.
d) It is the process by which the solar nebula became heated during its collapse.
17. Mercury's surface resembles that of what other world?
a) Earth., b) The Moon., c) Mars., d) Venus.,
18. Mercury experiences extreme highs and lows in temperature between day and night because:
a) Mercury is so close to the sun.
b) Mercury lacks a blanket of atmosphere.
c) The planet's surface is undergoing a runaway greenhouse effect.
d) Mercury has a low inclination.
19. The presence of a magnetic field on Mercury is surprising because:
a) The planet is low in iron., b) The planet rotates so slowly.
c) Planets rarely have magnetic fields., d) The planet is so close to the sun.
20. What is the main constituent of the atmosphere of Venus?
a) Oxygen., b) Nitrogen., c) Hydrogen., d) Carbon dioxide.
21. The lack of a magnetic field on Venus probably stems from the planet's:
a) Nearness to the Sun., b) Extremely thick atmosphere.
c) Slow rotation., d) High surface temperatures.
22. What effect does the Greenhouse effect have on the surface environment of Venus?
a) Little or no effect.,
b) About the same as on Earth.
c) It has reduced the surface temperature by about 30 degrees Celsius.
d) It has raised the surface temperature by hundreds of degrees Celsius.
23. How long is a day on Mars?
a) About equal to one Earth day., b) Three Earth days.
c) Mars rotates once for each revolution around the Sun., d) About 10 hours.
24. Why is one hemisphere of Mars believed to be older than the other?
a) One hemisphere is darker., b) One hemisphere is more heavily cratered.
c) One hemisphere is lower., d) One hemisphere leans more away from the Sun.
25. Why does Mars have seasons?
a) Its orbit is circular.
b) It rotates only a few times during each orbit around the Sun.
c) Mars' orbit brings it closer to the Sun during summer and farther from the Sun during winter.
d) Its axis is tilted relative to its orbital plane.
26. Why is Mars red?
a) Dust storms on the planet have blasted the planet so fiercely that the rocks have reddened.
b) The planet's surface undergoes a process by which rust forms.
c) Sulfuric acid rain etched a reddish color into surface rocks.
d) The ancient volcanoes poured out vast plains of molten red lava which has now solidified.
27. Venus and Mars probably evolved differently from Earth because:
a) They are slightly bigger than Earth., b) They are more massive than Earth.
c) They formed sooner than Earth., d) They orbit at different distances from the Sun.
28. Who discovered Uranus?
a) Galileo, b) William Herschel, c) Johann Galle, d) John Adams and Urbain Leverrier
29. Which of the following planets deviates most from the temperature it would have if it were in thermal
equilibrium with the radiation form the Sun?
a) Mercury, b) Mars, c) Venus, d) Earth
30. How often does a location on the Earth experience a "High" tide
a) once per day, b) twice per day, c) once per month, d) twice per month
31. The Roche limit is
a) distance from the Sun where life cannot exist
b) distance from a planet where moons cannot exist
c) the boundary layer between the solar system and the rest of the galaxy
d) the maximum distance a spacecraft can be sent from Earth
32. Cassini's division is
a) a new form of math
b) imaginary line which divides a planet into Eastern and Western hemispheres
c) a gap in Saturn's rings
d) the space between Mars and Jupiter where there is no planet
33. Approximately how fast is continental drift moving the continents about with respect to each other?
a) cm per day, b) cm per year, c) cm per century, d) cm per million years
34. What produces aurorae?
a) chemical reactions in the upper atmosphere, b) meteors
c) collisions of high energy particles with atmospheric gas, d) reflection of Sunlight by clouds
35. Which of the following is a consequence of the fact that the rotation and revolution periods of the moon
are the same?
a) the moon keeps the same face turned toward the Earth
b) the moon can never be seen from one hemisphere of the Earth
c) all lunar phases can be seen from the Earth
d) there are about 12 months per year
36. What accounts for the seasonal changes in the coloration of certain regions on Mars?
a) the covering and uncovering of the regions by dust, b) melting and refreezing of permafrost
c) changes in cloud cover, d) migration of large herds of quadrupeds
37. In which part of Saturn's rings do the ring particles move the fastest?
a) the innermost part of the rings, b) the outermost part of the rings
c) in Casssini's division, d) they all move at the same speed
38. Which of the following planets was discovered due to its gravitational effect on other planets?
a) Jupiter, b) Saturn, c) Uranus, d) Neptune
39. Why are no impact craters seen on Io?
a) it does not have a solid surface, b) it has extensive volcanic activity
c) it was very recently captured by the solar system, d) its icy surface heals very rapidly
40. The heat that keeps the interior of Io molten is due to
a) tides, b) radioactive materials, c) frequent meteoroid impacts, d) a large greenhouse effect