PART I: MULTIPLE CHOICE QUESTIONS (50 Pts s1

5. The Earth's Moon is said to be in synchronous rotation. Which of the following is a consequence of this property? A. The same side of the Moon always faces Earth. B. The Moon orbits the Earth once every 24 hours. C. The motion of the Moon is synchronized with the motions of the moons of the other planets. D. The phases of the Moon are synchronized with Earth's year. E. The far side of the Moon is always dark.

6. An observer at the equator would see A. only circumpolar stars. B. no circumpolar stars. C. a midnight Sun on January 1. D. the Sun at the zenith on the Winter Solstice. E. the Sun at the zenith on the Summer Solstice.

7. From College Park, which of the following planets can never be at opposition? A. Mars B. Jupiter C. Venus D. Saturn E. all of the planets above can be at opposition

8. In 13,000 years Vega will be the north star and the newspaper horoscopes will be off by six signs due to A. leap years. B. precession. C. elongation. D. stellar parallax. E. retrograde motion.

9. According to the solar nebula theory, the planets in our Solar System formed A. in outer space and were captured by the Sun. B. out of a flattened, rotating disk of gas and dust. C. as another star collided with our Sun. D. a few million years ago. E. closer to the Sun but were flung outward by a passing star.

10. During lunar eclipses, Greek astronomers in Aristotle’s time observed A. stellar parallax. B. the retrograde motion of the Moon. C. an annular eclipse. D. a curved shadow of the Earth on the Moon. E. the phases of Venus. 11. When you stop suddenly in your car, the grocery bag next to you tips over. Why? A. Its inertial motion continued to carry it forward. B. Gravitational acceleration is independent of mass. C. It reached escape velocity momentarily. D. It was weightless for an instant. E. It had angular momentum.

12. In the “Powers of Ten” video and in the introductory chapter of the textbook, our galaxy is depicted as a giant spiral shaped collection of stars with the Solar System A. exactly at the center. B. near the center. C. outside the spiral. D. above the spiral. E. in the spiral, but about 2/3 of the way out from center.

13. During a phone conversation with my friend in London, England, he mentions that the full moon looks beautiful tonight. It is midnight in London and 7 PM in College Park. It is clear so I look out my east window and see A. the full moon. B. a quarter moon. C. a gibbous moon. D. a crescent moon. E. no moon at all.

14. Mercury is difficult to observe from Earth because A. it emits only radar. B. it rotates very rapidly. C. it reflects sunlight. D. its surface is hidden by clouds. E. it is never very far away from the Sun in the sky.

15. Your latitude on Earth is also the altitude of A. the zenith. B. the nadir. C. the celestial pole. D. the celestial equator. E. the ecliptic.

16. Which of the following represents the oldest material dated using the radioisotopic dating method? A. dinosaur bones B. material brought back from the lunar maria C. rocks from Venus brought back by the Magellan probe D. meteorites E. rocks from the floor of the Atlantic Ocean 17. The planet that is currently visible in the southeast during early evening is A. Mercury. B. Venus. C. Mars. D. Jupiter. E. Saturn.

2 18. You know that F = G m1 m2 / r On the Earth, Mrs. Deming's cat, Skyler, weighs 10 lbs. What would Skyler weigh on a planet 5 times as massive as Earth and whose radius is 5 times larger than Earth's radius? A. 2 lbs. B. 5 lbs. C. 10 lbs. D. 50 lbs. E. 250 lbs.

19. According to Kepler’s laws, planets A. formed from a rotating cloud of gas and dust. B. move on epicycles. C. rotate slower with increasing distance from the Sun. D. do not show phases. E. move fastest in their orbits when closest to the Sun.

20. The most abundant gas in the Earth’s atmosphere is A. hydrogen. B. nitrogen. C. oxygen. D. water vapor. E. carbon dioxide.

21. The Moon's orbit is slightly inclined to the Earth's orbit. This explains A. why the Sun moves along the ecliptic. B. why we never see the lunar "far side." C. why we see the Moon sometimes during the day. D. why earthshine occurs. E. why a solar eclipse doesn't occur every month.

22. If the Moon were midway between first quarter and full phases, when would the Moon rise? A. noon B. 3 PM C. 6 PM D. 9 PM E. midnight 23. The surface features on Venus have been mapped extensively using A. optical telescopes on Earth. B. optical telescopes orbiting Earth. C. radar imaging from spacecraft orbiting Venus. D. landing spacecraft on Venus. E. infrared sensors from Earth.

24. Studies of seismic waves have revealed that A. Venus is differentiated. B. Earth has a liquid region inside. C. the Moon has a strong magnetic field. D. Mercury has a wrinkled surface. E. plate tectonics have modified the lunar surface.

25. The Giant Impact theory that used a collision between the young Earth and a Mars- sized object to explain lunar formation accounts for A. the Moon’s retrograde orbit. B. the Moon’s highly inclined orbit. C. the large average density differences between Earth and Moon. D. the Moon’s lack of rotation. E. the heavily cratered lunar surface. PART II. SHORT ANSWER QUESTIONS (50 pts.) Answer all of these questions as completely as you can using what you have learned in ASTR 101. Write your answers directly on these pages. After you have finished answering a question, be sure to re-read the question.

26. a) Describe the two main processes by which an impact crater can be destroyed on Earth. (4 pts.)

b) Explain why these processes occur on Earth but not currently on the Moon. (3 pts.)

c) Explain what prevents the mutual gravitational attraction between the Moon and Earth from pulling the two together into one object. (2 pts.)

29. a) Make a sketch showing the positions of the Sun and the Earth in its orbit on the date of the Solstice (June 21). Label the N and S poles on Earth. Indicate any important orientations. (4 pts.)

b) Which season does each hemisphere (northern and southern) experience at this time? Explain why there is a warm-up or cool-down here in College Park, Maryland. (6 pts.)

EXTRA CREDIT (2 pts.) You are lost in the woods. It is dark and very clear. You think you recognize a pattern of bright stars Mrs. Deming told you about in ASTR 101 that could help you find Polaris, the North Star. How would you use these stars to find Polaris? 30. a) Aristotle's geocentric theory gained support due to the inability of the Greek scientists to detect stellar parallax. What is stellar parallax? (3 pts.)

b) How did the work of Tycho Brahe and Johannes Kepler support the heliocentric theory? What did they do and why was it significant? (4 pts.)

c) Describe one telescopic observation that Galileo made and explain why it challenged the geocentric model. (3 pts.)