Cuesta College, San Luis Obispo, CA
In the movie Star Wars (20th Century Fox, 1977), the Death Star was a giant spherical traveling space station that was initially mistaken as a "small moon." In the webcomic panel at right[*] it is further argued that the Death Star is "too small to be a moon." Discuss why the Death Star cannot be considered a moon, despite its small size. Explain using the International Astronomical Union classification scheme.
[*] Randall Munroe, "Small Moon," xkcd.com/1458/.
Solution and grading rubric:
- p:
Correct. Of the three IAU requirements (orbits the sun directly, has a rounded shape, cleared/dominates its orbit), if an object does not orbit the sun (or presumably any star) directly, but orbits a planet, then it is classified as a moon/satellite. Since the Death Star can travel through space, then it would not be a moon/satellite while it is not in orbit around a planet. - r:
Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. May argue that the Death Star is not a moon because it does not orbit the sun (when the IAU classification scheme asks whether the object directly orbits the sun, or is in orbit around another object such as a planet), but understands the importance of the first classification question. - t:
Contains right ideas, but discussion is unclear/incomplete or contains major errors. May also involve the shape of the Death Star and/or its ability to gravitationally dominate other objects as important, other than its orbiting another object in orbit around the sun (or any star). - 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 classification scheme. - x:
Implementation/application of ideas, but credit given for effort rather than merit. Discussion unrelated to the IAU classification scheme. - y:
Irrelevant discussion/effectively blank. - z:
Blank.
Section 70160
Exam code: midterm02n1N0
p: 16 students
r: 9 students
t: 5 students
v: 1 student
x: 0 students
y: 0 students
z: 0 students
A sample "p" response (from student 7063), also sharing tangentially personal opinions on Star Wars:
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