The Solar System – ASTR 121

First Midterm – April 19, 2013, 10:00-10:50

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.  Explain why there are there seasons on the Earth.

B.  Describe two contributions made by Islamic astronomers during the Dark Ages in Europe?

C.  What was Tycho Brahe's main contribution to the advancement of astronomy and why was it so important?

D.  Describe two properties of the Solar System a theory of its formation must explain.

E.  What happened to the outer planets as icy (carbonaceous) planetesimals disappeared?  Explain.

F.  Describe two ways astronomers detect extrasolar planets.

G.  Describe two important differences between Terrestrial and Jovian planets.

H.  Explain how space scientists use gravity to propel spacecraft to the outer parts of the Solar System.

I.  What is the key ingredient of the condensation theory of the Solar System not present in the nebular theory?  Explain.

J.  During radar ranging of Venus, a signal was found to return in 600 seconds.  How far from Earth was Venus when this measurement was made?  (Radar pulses travel at about 3x10⁸ m/s.)