The Solar System – ASTR 121
First Midterm – October 12, 2012, 9:00-9:50
Instructions: Print your name and student identification number at the top of this page. Answer each of the questions A through J in the space provided. Be clear and thorough in your answers using sentences, sketches, and formulas where appropriate. Each question is worth two points.
A. Why do we see phases of the Moon when half the Moon is always illuminated?
B. What was Galileo's observation which most convincingly supported the Copernican model? Explain.
C. State Kepler’s first law of planetary motion.
D. How did Earth's position in the Solar nebula affect its composition? Explain.
E. Do observations of exoplanets imply that Earth-like planets are rare? Explain.
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F. Name the Jovian planets in order of their distance from the Sun.
G. What is the key ingredient of condensation theory which is missing from nebular theory? Explain.
H. What is precession (of the equinoxes), and what causes it?
I. In what sense does a baseball fall to Earth rather than the Earth fall on the baseball? Explain.
J. How far away is an object whose angular position differs by about 1 minute of arc when observed from different sides of the Earth (about 104 kilometers)?