Cuesta College, San Luis Obispo, CA
Astronomy 10 learning goal Q12.1
[15 points.] Sir Martin Rees, Astronomer Royal of Great Britain remarked that, "we in astronomy have an advantage in studying the universe, in that we can actually see the past." Explain what makes this is possible.
Solution and grading rubric:
- p = 15/15:
Correct. Due to the finite speed of light, it takes one year of time for light to travel one light year, and thus observing distant objects means that they appear as they did in the past.
- 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.
- 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:
p: 24 students
r: 4 students
t: 0 students
v: 0 students
x: 0 students
y: 1 student
z: 1 student
Students were for the most part successful in answering this question, particularly expressed in a number of different ways. A sample of a "p" response (from student 1929) is shown below:A "p" response (from student 1524) is somewhat more poetic: A whimsical "p" response (from student 1985):
One more "p" response (from student 9389) with an illustration of how the finite speed of light affects observations: