Version A

Write your name at the top of this quiz as well as on your answer sheet. WRITE YOUR VERSION ON YOUR ANSWER SHEET. Feel free to write or draw on the quiz.

PICK THE BEST ANSWER FOR EACH PROBLEM.

1. Comets:
a) Mostly orbit the Sun in the plane of the ecliptic.
b) Mostly orbit the Sun between the orbits of Earth and Mars.
c) Are balls of mostly metal.
d) Are rocky objects.
e) Are made up of ice plus rock.

e) Are made up of ice plus rock.

2. Which of the following objects has the largest atmospheric pressure on its surface?
a) Mars.
b) Triton.
c) Earth.
d) Venus.
e) Europa.

d) Venus.

3. The primary constituent of the atmosphere of Jupiter is:
a) hydrogen.
b) CO₂.
c) O₂
d) N₂.
e) sodium.

a) hydrogen.

4. How much bigger is the light gathering power of the 5 meter Palomar telescope, compared to a 1 meter telescope?
a) five times larger.
b) twenty-five times larger.
c) 1/5 as large.
d) 1/25th as large.
e) the same.

b) twenty-five times larger.

5. Titan:
a) Is the largest moon in the solar system.
b) Has the thickest atmosphere of any moon in the solar system.
c) Is considered a dwarf planet, according to the new IAU definition.
d) Orbits its planet in an opposite direction compared to the other moons in the solar system.
e) Is a moon of Uranus.

b) Has the thickest atmosphere of any moon in the solar system.

6. Which of the following is a Galilean Moon?
a) Callisto.
b) Triton.
c) Phobos.
d) Titan.
e) The Moon.

a) Callisto.

7. As a spinning interstellar cloud gravitationally collapses to form a solar system, what happens to its spin rate?
a) it gradually slows down.
b) it stops spinning.
c) it speeds up.
d) it keeps spinning at the same rate.
e) it depends upon its mass; a high mass cloud slows down, while a low mass cloud spins up.

c) it speeds up.

8. According to the recent IAU definition, a dwarf planet is:
a) an object larger than Pluto, but that orbits a planet rather than the Sun.
b) an asteroid.
c) a spherical object that orbits the Sun, but that has not cleared the neighborhood around its orbit.
d) a non-spherical object that orbits the Sun.
e) a terrestrial planet, like Mercury, Earth, Venus, or Mars.

c) a spherical object that orbits the Sun, but that has not cleared the neighborhood around its orbit.

9. Most of the extrasolar planets found so far have been found using which technique?
a) imaging with ultraviolet telescopes.
b) imaging with optical telescopes.
c) imaging with infrared telescopes.
d) measuring the `wobble' in the position in a star on the sky due to the planet orbiting around it.
e) measuring the alternating redshift/blueshift of a star, due to a planet orbiting around it.

e) measuring the alternating redshift/blueshift of a star, due to a planet orbiting around it.

10. Which planet is spinning backwards, compared to the other planets?
a) Mercury.
b) Venus.
c) Mars.
d) Jupiter.
e) Saturn.

b) Venus.

11. What do astronomers call a collection of telescopes that all act together, and so provide much better spatial resolution than each individual telescope alone?
a) a gathering telescope.
b) a diffraction telescope.
c) an interferometer.
d) an extramirror telescope.
e) a Galilean telescope.

c) an interferometer.

12. Io is very geologically active. Its atmosphere is rich in:
a) CO₂.
b) H₂.
c) sulfur compounds.
d) O₂.
e) N₂.

c) sulfur compounds.

13. Ganymede:
a) Is bigger than Mercury.
b) Is bigger than Pluto, but smaller than Mercury.
c) Is bigger than Mars.
d) Is slightly smaller than the Earth's Moon.
e) Is the smallest of the Galilean Moons.

a) Is bigger than Mercury.

14. Ceres:
a) Is a dwarf planet, according to the recent IAU definition.
b) Is an asteroid.
c) Is approximately spherical.
d) Orbits the Sun, rather than a planet.
e) All of the above.

e) All of the above.

15. The main constituent of the atmospheres of both Mars and Venus is:
a) CO₂.
b) O₂.
c) H₂O vapor.
d) H₂.
e) sodium and helium.

a) CO₂.

16. The most recent spacecraft to Mercury is:
a) Voyager 1.
b) Voyager 2.
c) Galileo.
d) Cassini.
e) Messenger.

e) Messenger.

17. The density of Pluto is:
a) Larger than that of any of the eight major planets.
b) Less than any of the eight major planets.
c) Larger than that of rocks alone, meaning it contains a lot of metals as well.
d) Between that of ice and that of rock, suggesting it contains both rock and ice.
e) Unknown.

d) Between that of ice and that of rock, suggesting it contains both rock and ice.

18. In an X-ray telescope, to reflect the X-rays and bring them to a focus:
a) The light must hit the mirror nearly head-on.
b) The light must hit the mirror at a very large angle, relative to the normal.
c) X-rays can never be reflected; they are too high energy.
d) No X-ray telescopes exist yet; we do not yet have the technology to build one.
e) There is no point in building an X-ray telescope, since no astronomical objects produce that high energy light.

b) The light must hit the mirror at a very large angle, relative to the normal.

19. Voyager 2 visited:
a) Jupiter.
b) Saturn.
c) Uranus.
d) Neptune.
e) All of the above.

e) All of the above.

20. The density of water is 1 g/cm³, while the density of rock is 2-3 g/cm³, and metals have densities of about 8 - 10 g/cm³. What is the average density of the Earth?
a) 0.7 g/cm³.
b) 1.0 g/cm³.
c) 2.0 g/cm³.
d) 5.5 g/cm³.
e) 15 g/cm³.

d) 5.5 g/cm³.