20071024

Astronomy midterm question: cooler Uranus

Astronomy 10 Midterm 2, Fall Semester 2007
Cuesta College, San Luis Obispo, CA

Astronomy 10 learning goal Q2.2

[15 points.] Discuss the evidence that supports the theory that the interior of Uranus is cooler than the interior of Neptune.

Solution and grading rubric:
  • p = 15/15: Correct. The lack of belt-zone and cyclonic weather patterns on Uranus, which are generated by convection from core heat is evidence that the interior of Uranus is cooler than the interior of Neptune. The tilted axis of Uranus is evidence that may explain how a large impact may have caused a "Cooper Cooler(TM) Effect" (stirred fluids cool off faster than static fluids).
  • r = 12/15:
    Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. Points out tilted axis of Uranus, but argues that sideways spin results in cooler interior temperatures for Uranus, and not how the tilted axis may have been the result of a large impact that would have disrupted and stirred its interior.
  • t = 9/15:
    Contains right ideas, but discussion is unclear/incomplete or contains major errors. Explains how the "Cooper Cooler(TM) Effect" works, but does not discuss evidence that this may have occurred for Uranus.
  • v = 6/15:
    Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. May appeal to the "Turkey/Cornish Hen Effect" (smaller objects cool off faster than larger objects).
  • x = 3/15:
    Implementation/application of ideas, but credit given for effort rather than merit.
  • y = 1.5/15:
    Irrelevant discussion/effectively blank.
  • z = 0/15:
    Blank.
Grading distributions:
Section 0135
p: 15 students
r: 6 students
t: 5 students
v: 9 students
x: 3 students
y: 0 student
z: 0 students

Section 1073
p: 30 students
r: 3 students
t: 6 students
v: 5 students
x: 2 students
y: 0 students
z: 1 student

A sample of a "p" response (from student 5150) is shown below:

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