Astronomy midterm question: simultaneous total lunar and total solar eclipses?

Astronomy 210 Midterm 1, Spring Semester 2010
Cuesta College, San Luis Obispo, CA

[20 points.] Consider the following excerpt regarding viewing total lunar and solar eclipses:

On July 6, 1982, a woman telephoned a radio show that had invited people to give their impressions of the total lunar eclipse then in progress. She said: 'We're seeing this total eclipse of the moon right now on our side of the world. Does that mean that at this same moment the people on the other side of the world are seeing a total eclipse of the sun?'"
—Guy Ottewell, Astronomical Calendar 2010, Universal Workshop, Raynham, MA, 2009, p. 43.

Decide whether seeing a total eclipse of the sun "at this same moment" is plausible or implausible. Support your answer using a diagram showing the positions of the sun, moon, and Earth.

Solution and grading rubric:

• p = 20/20:
  Correct. Draws a correct diagram of a total lunar eclipse, where the moon is on the other side of Earth than the sun; and since the moon must be on the same side of Earth as the sun for there to be a total solar eclipse, it is implausible that observers anywhere on Earth can observe a total solar eclipse simultaneously with a total lunar eclipse. May also illustrate and argue the converse argument, when a total solar eclipse is occuring a total lunar eclipse cannot be simultaneously observed.
  
• r = 16/20:
  Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. Diagram is problematic (misalignment of sun-Earth-moon line), but essential argument that the moon cannot be at two different locations on either side of Earth correct.
  
• t = 12/20:
  Contains right ideas, but discussion is unclear/incomplete or contains major errors. Diagram missing, but essential argument correct, or vice versa.
  
• v = 8/20:
  Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. Argument based on timing of time zones, size of moon's umbral spot, or improbable sun-Earth-moon diagrams.
  
• 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 30674
p: 36 students
r: 1 student
t: 1 student
v: 6 students
x: 0 students
y: 0 students
z: 0 students

Section 30676
p: 62 students
r: 6 students
t: 23 students
v: 13 students
x: 13 students
y: 1 student
z: 3 students

A sample "p" response (from student 1802):

Another sample "p" response (from student 7129), lamenting the fact that Earth does not have two moons:

Another sample "p" response (from student 2425):

A sample "v" response (from student 9696), with two Earths?