Name __________________________

INSTRUCTIONS: Fill in your Student ID# and the FORM NUMBER of your
exam on the answer sheet. Choose the BEST answer for each question and
mark your choice on the answer sheet. Use a #2 pencil only.

1. The atmosphere that we are now breathing is
*a. the third atmosphere that the Earth has had.
 b. the second atmosphere that the Earth has had.
 c. the first atmosphere that the Earth has had.
 d. the seventh atmosphere that the Earth has had.

2. How is interferometry used in radio astronomy?
 a. Signals from different places around the dish of a radio
    telescope are combined to produce interference and increase the
    angular resolution of the telescope.
 b. Signals from a radio source are combined with a time delay that
    causes interference and increases the angular resolution of the
    telescope.
*c. Signals from two different radio telescopes are combined to
    produce a single image of greater angular resolution than from
    either telescope alone.
 d. Signals from different parts of a radio source are combined to
    increase the angular resolution of the telescope.

3. What future awaits Triton, the largest satellite of Neptune?
*a. Tidal break-up as it spirals closer to Neptune
 b. Escape from Neptune after billions of years, as Triton gradually
    spirals outward
 c. Gravitational capture by Pluto
 d. Probable destruction from impact by Pluto

4. Most surface rocks on the Earth are younger than a few million years
   old, whereas ages of lunar rocks have been measured in billions of
   years. Why is this?
 a. The ages of Earth and Moon are fundamentally different, the Moon
    being an old object captured from space by a younger Earth.
 b. Most early surface rocks on Earth have been washed into the sea
    by weathering and rainwater, and this does not happen on the
    Moon.
*c. Much of the Earth's surface is continually recycled (created and
    subducted) by the underlying mantle because of plate tectonic
    activity, and this does not occur on the Moon.
 d. The complete surface of the Earth has been covered periodically
    by younger material from intense volcanic eruptions in the last
    few million years. No such activity occurred on the Moon.

5. To what does "planetary differentiation" refer?
*a. The sinking of heavier elements towards the center of a planet
    and the rising of lighter elements towards the surface.
 b. The formation of rocky planets in the hotter, inner solar system
    and gas giants in the colder, outer regions.
 c. The large-scale convection of rock in the mantle of a planet,
    which on the Earth causes continental drift.
 d. The circulation of iron in the core of a planet, resulting in the
    generation of a magnetic field.

6. What is the overall composition of Jupiter, excluding its rocky
   core?
*a. 86% hydrogen, 13% helium, 1% everything else.
 b. 75% hydrogen, 15% helium, 10% everything else.
 c. Pure hydrogen.
 d. Hydrogen and helium only, nothing else.

7. It is difficult to improve the angular resolution of optical
   telescopes on the surface of the Earth because
 a. large telescopes are always reflecting telescopes and these
    suffer from too much chromatic aberration.
 b. we would need to build large telescopes and this is very
    expensive.
 c. spherical mirrors suffer from too much aberration.
*d. air turbulence distorts the star images more than the telescopes
    do.

8. Scientists have now examined rocks that came from Mars in their
   laboratories on Earth because
 a. a large impact that occurred on the Martian surface early in its
    history created a vast dust cloud through which Earth passes once
    per year and samples of this dust have now been collected by the
    Space Shuttle.
 b. an orbiting spacecraft scooped up Martian dust during its passage
    by Mars and then returned to Earth.
*c. several meteorites found in Antarctica are now thought to have
    been knocked off Mars and fallen to Earth.
 d. spacecraft have been to the surface of Mars and have returned
    with samples of Martian rocks and soil.

9. How is the Earth's magnetic field generated?
*a. By electric currents in the Earth's core.
 b. By electric currents in the Earth's mantle.
 c. By electrons and ions in the Earth's magnetosphere.
 d. By permanent magnetism in the Earth's crustal rocks.

10. Why was adaptive optics developed?
 a. To compensate for spherical aberration.
*b. To compensate for distortion caused by the Earth's atmosphere.
 c. To prevent distortion by sagging in very thin, light-weight
    mirrors.
 d. To prevent distortion of mirrors by the vacuum of space.

11. The pressures of the atmospheres at the surfaces of Mercury, Venus,
    and Mars, in terms of the pressure at the surface of the Earth,
    (known as 1 atmosphere) are
 a. 0.01 atmosphere; almost 100 atmospheres; 1/10 atmosphere.
 b. 0; about 10 atmospheres; 0.1 atmosphere.
*c. 0; almost 100 atmospheres; 0.01 atmosphere.
 d. 0.1 atmosphere; almost 100 atmospheres; 1/10 atmosphere.

12. Which of the following characteristics of an astronomical telescope
    is the most important for determining the angular resolution?
*a. The diameter of the objective lens or mirror.
 b. The focal length of the objective lens or mirror.
 c. The magnifying power of the telescope.
 d. The focal length of the eyepiece.

13. In a single photograph of a comet and its tail, the only direction
    that one can determine with certainty is
 a. the direction in which the comet is moving, from the trailing
    tail.
 b. the direction towards Jupiter, since the gravity of this giant
    planet pulls the tail material towards it.
*c. the direction away from the Sun, since the tail is pushed in this
    direction by the solar wind.
 d. the direction towards the Sun indicated by the tail direction,
    since gas and dust in the tail is attracted towards the Sun by
    its gravity.

14. In telescopes, the angular resolution is worse for
 a. larger diameter lenses or mirrors and longer wavelength light (of
    other electromagnetic radiation).
*b. smaller diameter lenses or mirrors and longer wavelength light
    (or other electromagnetic radiation).
 c. smaller diameter lenses or mirrors and shorter wavelength light
    (of other electromagnetic radiation).
 d. larger diameter lenses or mirrors and shorter wavelength light
    (or other electromagnetic radiation).

15. The main reason for the very high temperature (750 K) on the surface
    of Venus is thought to be
 a. chemical reactions between constituents of the atmosphere,
    particularly sulfuric acid.
 b. the radiation from hot lava, produced by intense and continuous
    volcanic action.
 c. the continuous bombardment of the surface by solar wind particles
    and meteoroids.
*d. the absorption of visible radiation by Venus's surface and the
    subsequent trapping by the atmosphere and clouds of infrared
    radiation emitted by the surface.

16. Chromatic aberration is the failure of a telescope objective to
    bring all colors of light to the same focus, and appears
 a. in all telescopes, since it is a basic property of light.
 b. only in a reflecting telescope.
 c. in both reflecting and refracting telescopes.
*d. only in a refracting telescope.

17. How did Comet Shoemaker-Levy 9 achieve lasting fame?
*a. It crashed into Jupiter.
 b. It just missed the Earth, passing closer than the Moon.
 c. It exploded after passing too close to the Sun.
 d. It became the first comet to be visited by spacecraft.

18. What is the mass of Jupiter compared to other objects in the solar
    system?
*a. Twice the mass of all other planets combined.
 b. Twenty times the mass of all other planets combined.
 c. As large as the mass of Saturn and Neptune combined.
 d. Half the mass of the Sun.

19. Cassini's division in the rings of Saturn are thought to be due to
    tidal gravitational forces from the moon, Mimas. If the revolution
    period of Mimas is 22.6 hours, what would be the orbital period of
    any particles that exist within Cassini's division?
*a. 11.3 hours, or 1/2 of Mimas' period.
 b. 45.2 hours, or 2 x Mimas' period.
 c. 7.5 hours, or 1/3 of Mimas' period.
 d. 22.6 hours, since Mimas moves within Cassini's division.

20. Which of the following statements is NOT true for asteroids?
 a. Some asteroids have orbits that carry them inside the Earth's
    orbit.
*b. Only a minority of all asteroids are in the asteroid belt.
 c. Some asteroids occupy the same orbit as Jupiter.
 d. The total mass of all asteroids is much smaller than the mass of
    the Earth.

21. The surface features and overall topology of Venus have been
    determined primarily by
*a. radar methods from Venus-orbiting spacecraft, measuring radio
    echoes from the surface.
 b. balloon-borne spacecraft, launched into Venus's atmosphere by
    spacecraft.
 c. surface landing vehicles that have explored the surface
    thoroughly.
 d. visible and UV photography from the Space Shuttle.

22. What method do geologists and geophysicists use to probe the
    structure of the Earth's core and mantle?
*a. Studying the deflection of seismic waves from earthquakes.
 b. Direct sampling of interior rock by deep drilling through the
    ocean floor.
 c. X-ray analysis from satellites.
 d. Extrapolation of surface features (e.g., mountain chains) into
    the deep interior.

23. One of the most important sources of heat in the interiors of moons
    that orbit close to giant planets is
*a. continuous tidal distortion from the planet and other moons.
 b. re-radiation of thermal energy received from the planet.
 c. decay of radioactive elements within the moons.
 d. reflection of sunlight from the planet's surface.

24. The Earth's stratosphere is warmer than the layers above and below
    it because
*a. ozone in the stratosphere absorbs ultraviolet radiation from the
    Sun.
 b. CO_2 in the stratosphere absorbs infrared light radiated outward
    by the ground.
 c. the methane released when we burn fossil fuel collects in this
    layer and absorbs infrared light.
 d. warm air heated by contact with the ground rises into the
    stratosphere and heats it.

25. The metal that is relatively abundant in meteorites but that is
    generally rare upon Earth has been found in specific layers of clay
    throughout the world, and its study is helping to evaluate the
    effect of meteor impacts upon the Earth's climate and its
    inhabitants in recent geological time (e.g., dinosaurs). This metal
    is
 a. cobalt.
 b. iron.
 c. nickel.
*d. iridium.

26. An Earth-based telescopic view of Venus shows
 a. evidence of ice-covered polar caps and huge dust storms.
 b. a crater-covered surface of reddish color.
 c. a smooth, dark surface with few mountain ranges.
*d. a completely cloud-shrouded planet with high atmospheric wind
    speeds.

27. Many amateur astronomers have telescopes with mirrors 20 cm (1/5 m)
    in diameter. In comparison, the largest astronomical telescope in
    the world is the Keck telescope, with a diameter of 10 m. How many
    times larger is the light-gathering power of the Keck telescope
    than a 20-cm telescope?
 a. 125,000 times larger
 b. 7 times larger
 c. 50 times larger
*d. 2,500 times larger

28. If astronauts were to set up a permanent settlement at Tranquility
    Base on the Moon, how many times each year would the Earth rise and
    set as seen by a resident of this base?
*a. Never - the Earth would remain essentially motionless in the sky.
 b. Once each year.
 c. 12 times each year.
 d. 13 times each year.

29. Which is the only satellite in the solar system known to possess a
    permanent, dense, atmosphere?
*a. Titan
 b. Ganymede
 c. Callisto
 d. Charon

30. What are the characteristic features on the visible surface of
    Jupiter?
*a. Light and dark bands of clouds parallel to the equator.
 b. Large volcanoes and a long, deep rift valley.
 c. A greenish, almost featureless cloud layer.
 d. A bluish tint with high, white clouds and dark storms.

31. Billions of years ago, the Earth's atmosphere was composed primarily
    of carbon dioxide. Where might you go to find a large fraction of
    this carbon dioxide today?
*a. To the Rocky Mountains, which are composed largely of limestone.
 b. Anywhere, most of the carbon dioxide is still in the atmosphere,
    but nitrogen and oxygen have since been added to it.
 c. Nowhere, most of the carbon dioxide escaped into space.
 d. To extinct volcanoes like Mt. Edziza, British Columbia, which are
    composed of rock from the Earth's interior.

32. When electromagnetic radiation (e.g., light) is Doppler-shifted by
    motion of the source away from the detector,
*a. the measured wavelength is longer than the emitted wavelength.
 b. the measured frequency is higher than the emitted frequency.
 c. the speed of the radiation is less than the emitted speed.
 d. the measured frequency of the radiation remains the same, but its
    wavelength is shortened, compared to the emitted radiation.