The Solar System – ASTR 121

First Midterm – January 27, 2016, 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, labeled diagrams, and formulas with symbols defined, where appropriate.  Each question is worth two points.

A.  Define an astronomical unit.

B.  What is an arcminute?

C.  Suppose the Earth's axis had no tilt.  Would we still have seasons?  Explain.

D.  How did an inability to detect stellar parallax support an Earth-centered universe?

E.  State Kepler's second law of planetary motion.

F.  How did the Copernican revolution change the human view of the universe?

G.  What is Occam's razor?

H.  Give an example illustrating conservation of energy in astronomy.

I.  State Newton's universal law of gravitation..

J.  Use Newton's version of Kepler's third law to determine the mass of a star (in solar masses) which has a planet 1 AU from the star, with an orbital period of two years.