Astronomy midterm question: radio telescope locations

Astronomy 210 Midterm 1, Fall Semester 2009
Cuesta College, San Luis Obispo, CA

[20 points.] Decide whether a proposed radio telescope should be placed on the ground or in outer space in order to be most cost-effective and be able to most efficiently gather astronomical data. Explain the reasoning behind your decision, in terms of relevant criteria discussed in this class.

Solution and grading rubric:

• p = 20/20:
  Correct. In general, the atmosphere is relatively transparent to radio waves, such that a ground-based telescope would be cheaper and just as effective as a space-based radio telescope. May argue for high-altitude or space-based radio telescopes for specific wavelengths that the atmosphere is relatively opaque for (e.g., FM/AM).
  
• r = 16/20:
  Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors.
  
• t = 12/20:
  Contains right ideas, but discussion is unclear/incomplete or contains major errors. Does not specifically discuss the relative transparency of Earth's atmosphere to radio waves, but only in general terms such as disruption, inteference, distortion.
  
• v = 8/20:
  Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner.
  
• x = 4/20:
  Implementation/application of ideas, but credit given for effort rather than merit.
  
• y = 2/20:
  Irrelevant discussion/effectively blank.
  
• z = 0/20:
  Blank.
  

Grading distribution:
Section 70160
p: 37 students
r: 0 students
t: 5 students
v: 0 students
x: 0 students
y: 0 students
z: 0 students

A sample "p" response (from student 7144), using toys made of solid gold as an analogy:
Another "p" response sample (from student 6363), narrowing the discussion of radio waves to the FM/AM band:
Yet another "p" response (from student 1022) discussing the criteria posed by the different types of radio waves: