Astronomy final exam question: IAU classification of Earth's moon fragments in Oblivion (2013)

Astronomy 210 Final Exam, spring semester 2013
Cuesta College, San Luis Obispo, CA

In the movie Oblivion (Universal Pictures, 2013), Earth's moon is broken into a large irregular-shaped fragment surrounded by much smaller debris, presumably all of which orbit Earth. Classify the large irregular-shaped fragment, using the International Astronomical Union classification scheme.

Solution and grading rubric:

• p:
  Correct. Of the three IAU requirements (orbits the sun, has a rounded shape, cleared/dominates its orbit) this large fragment fails all three, but failing the first requirement classifies it as a satellite/moon of Earth.
• r:
  Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. Understands which IAU requirements this large fragment satisfies or does not satisfy, but misclassifies typically as solar system debris.
• t:
  Contains right ideas, but discussion is unclear/incomplete or contains major errors. Problematic discussion of IAU requirements.
• v:
  Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. Discussion only tangentially related to the IAU requirements.
• x:
  Implementation/application of ideas, but credit given for effort rather than merit. Discussion unrelated to the IAU requirements.
• y:
  Irrelevant discussion/effectively blank.
• z:
  Blank.

Grading distribution:
Section 30674
Exam code: finalnNz2
p: 12 students
r: 6 students
t: 6 students
v: 0 students
x: 1 student
y: 1 student
z: 1 student

Section 30676
Exam code: finals56G
p: 8 students
r: 16 students
t: 2 students
v: 7 students
x: 4 students
y: 1 student
z: 1 student

A sample "p" response (from student 8387):
Another sample "p" response (from student 1019):
A whimsical sample "y" response (from student 9999):