Astronomy final exam question: countering Drake equation pessimism

Astronomy 10 Final Exam, Spring Semester 2008
Cuesta College, San Luis Obispo, CA

Astronomy 10 learning goal F.2

[15 points.] The Drake equation can be used to show that Earth is the only advanced technological civilizations in the Milky Way. Discuss a plausible argument against this unreasonably pessimistic result.

Solution and grading rubric:

• p = 15/15:
  Correct. Discusses in some form how a null result cannot disprove a hypothesis, the Mediocrity Principle/Copernicanism, the Scale Argument, or any sound, principled, reasonable argument against overly pessimistic results from the Drake equation.
  
• r = 12/15:
  Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors.
  
• t = 9/15:
  Contains right ideas, but discussion is unclear/incomplete or contains major errors. Argues uncertain, unproven characteristics ("SWAG") of Drake equation components, or instead cites arguments against unreasonably optimisitic results.
  
• v = 6/15:
  Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner.
  
• 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 distribution:
Section 4160
p: 19 students
r: 0 students
t: 13 students
v: 2 students
x: 0 students
y: 1 student
z: 0 students

Section 5166
p: 30 students
r: 2 students
t: 6 students
v: 1 student
x: 0 students
y: 1 student
z: 0 students

A sample "p" response (from student 4024):
Another "p" response (from student 1337):
A "p" response (from student 1379) with a nice afterword:
Yet another "p" response (from student 1886) with a nice afterword:
Student 3635 goes for the "y" response: