20150315

Astronomy midterm question: "evening stars" visible as "morning stars?"

Astronomy 210 Midterm 1, spring semester 2015
Cuesta College, San Luis Obispo, CA

A view of the San Luis Obispo, CA sky is shown below for June 10, 2017 with the planets Jupiter and Mars.


Discuss which of these planets will be visible at sunrise the next day. If neither planet will be visible, then explain why. Support your answer using a diagram showing the positions of the sun, Jupiter, Mars, Earth, and an observer on Earth.

Solution and grading rubric:
  • p:
    Correct. Complete diagram (with the sun, Jupiter, Mars, and an observer on Earth), and discusses/demonstrates:
    1. places Jupiter somewhere in an outer orbit such that it is visible high overhead at sunrise, and Mars somewhere in an outer orbit to be low over the western horizon of the observer at sunset;
    2. at sunrise 12 hours later, Jupiter and Mars will both essentially be in their same locations in their orbits;
    3. thus both Jupiter and Mars would be below the horizon for an observer on Earth at sunrise, and thus not be visible.
  • r:
    Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. Two of three points (1)-(3) correct, one is problematic/incomplete.
  • t:
    Contains right ideas, but discussion is unclear/incomplete or contains major errors. Problems with either diagram or discussion. One of three points (1)-(3) correct.
  • v:
    Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. Diagram and discussion problematic.
  • x:
    Implementation/application of ideas, but credit given for effort rather than merit. Misconceptions or non-relevant concepts.
  • y:
    Irrelevant discussion/effectively blank.
  • z:
    Blank.
Grading distribution:
Section 30676
Exam code: midterm01sh3P
p: 13 students
r: 11 students
t: 14 students
v: 9 students
x: 5 students
y: 0 students
z: 0 students

A sample "p" response (from student 1212), with an observer lying prone on the ground:

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