20141011

Astronomy midterm question: airplane swerves to avoid collision with Venus?

Astronomy 210 Midterm 1, fall semester 2014
Cuesta College, San Luis Obispo, CA

According to Transportation Safety Board of Canada (TSB) Aviation Investigation Report A11F0012,[*] Air Canada flight 878 swerved in order to avoid colliding with Venus:
The Air Canada Boeing 767–333 was flying eastward. At 1:55 AM the first officer initially mistook an unidentified bright light in the sky for an aircraft.
Discuss why the unidentified object the first officer spotted could not have been Venus, and how you know this. Support your answer using a diagram showing the positions of the sun, Venus, Earth, and an observer on the airplane.

[*] Adapted from http://www.tsb.gc.ca/eng/rapports-reports/aviation/2011/a11f0012/a11f0012.asp.

Solution and grading rubric:
  • p = 20/20:
    Correct. Complete diagram (with the sun, Venus, and observer on Earth), and discusses/demonstrates:
    1. observer at/or near 1:55 AM on Earth, and indicates the visible sky above the east to west horizon that can be seen by this observer;
    2. Venus cannot be seen no matter where it is in its orbit inside of Earth's orbit, such that it is impossible for Venus to be the unidentified bright light.
  • r = 16/20:
    Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. Diagram and/or explanation has minor errors. May explicitly discuss that Venus must be located in its orbit such that it was visible as an evening star earlier, and this is the reason why it is not possible for Venus to be visible later at 1:55 AM, when in fact any location for Venus in its orbit makes it impossible to be seen at that time.
  • t = 12/20:
    Contains right ideas, but discussion is unclear/incomplete or contains major errors. At least has diagram clearly showing observer on Earth, and Venus on an inner orbit.
  • v = 8/20:
    Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. Diagram and discussion problematic.
  • x = 4/20:
    Implementation/application of ideas, but credit given for effort rather than merit. Misconceptions or non-relevant concepts.
  • y = 2/20:
    Irrelevant discussion/effectively blank.
  • z = 0/20:
    Blank.
Grading distribution:
Section 70160
Exam code: midterm01neVs
p: 21 students
r: 4 student
t: 5 students
v: 5 students
x: 1 student
y: 0 students
z: 0 students

A sample "p" response (from student 1248):

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