1)  Planet X, which (due to a collosal oversight) has just been discovered,
    orbits the Sun in 60 Earth years.  Where is planet X's orbit?
    (a) Between the orbits of Venus and Earth.
    (b) Between the orbits of Mars and Jupiter.
    (c) Between the orbits of Saturn and Uranus.
    (d) Outside the orbit of Pluto.
Answer


2)  What would you expect the average density of planet X to be?
    (a) About 1 gram per cubic centimeter.
    (b) About 3 grams per cubic centimeter.
    (c) About 5 grams per cubic centimeter.
    (d) About 7 grams per cubic centimeter.
Answer


3)  Which of the following are caused primarily by gravity?
    (a) The temperature of Mercury.
    (b) The retrograde rotation of Venus.
    (c) The weather on Mars.
    (d) The temperature of Io.
    (e) The colors of Jupiter.
    (f) The gaps in Saturn's rings.
Answer


4)  Before radar was invented, astronomers measured the distance
    to the Moon by a method similar to that used to measure the
    distance to a star.  It involved measuring the position of
    the Moon relative to the stars ... (which ONE is correct?)
    (a) at two times, six months apart.
    (b) at two times, two weeks apart.
    (c) from two observatories, 1000 km apart.
    (d) from two telescopes, 10 m apart.
Answer


5)  What is the evidence that Neptune has an internal heat source?
Answer


6)  Pluto was originally believed to be considerably larger and
    more massive than Earth.  How did we find out that this was
    not correct?
Answer


7)  Explain why the moons of the outer planets are made of rock and
    ice while their parent planets are mostly hydrogen and helium.
Answer