SKY FAMILIARIZATION WITH THE SC001 STAR CHART
NAME
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LAB PARTNER ________________________________
DATE
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PHYS XXXXXXXXXXRETROGRADE MOTION LAB
In this lab, you will observe the motion of a planet as it makes one complete trip around the Sun. Attached, you will find a chart showing the motion of the planet from March 1, 1970 to March 1, 1972. During this time period, the planet’s o
it exhibited retrograde motion. Using the chart of the o
it of the mystery planet, answer the following questions:
1. Does the o
it of the planet ever stray out of the zodiacal band? Why? Hint: Remember that the zodiacal band is an 18o wide centered on the ecliptic.
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2. Does the planet always move through the sky at the same rate? Why?
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3. How many months did it take for this planet to complete one o
it around the Sun? Hint: How long did it take for the planet to get back in the same part of the sky?
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4. How many (Earth) years did it take for this planet to complete one o
it around the Sun? Hint: Take what your answer from question 3 and divide by 12.
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5. Now that you know how long it takes for the planet to go around the sun, you can use Kepler’s 3rd Law (P2=a3), to calculate the average distance between the planet and the Sun.
“P” is the period which is the length of the time to complete the o
it in years (your answer to question 4). So, you will solve the equation for “a” which is the average distance between the sun and the planet. The answer you get will be in astronomical units.
The planet’s average distance from the sun is ______________ astronomical units.
6. Most of the time, the planet’s position shifted which direction (East or West) on the chart?
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7. Between which months did the planet’s position shift towards the west (this is when it exhibits retrograde motion)?
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8. In what constellation did the planet’s position go through retrograde?
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9. In what constellation would you find the planet on the following dates?
Date
Constellation
March 1, 1970
September 1, 1970
January 1, 1971
September 1, 1971
Fe
uary 1, 1972
10. In the space below, explain in great detail why some planets, as viewed from Earth, exhibit retrograde motion in the sky (Hint - This one you can look up).
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This Signature Assignment addresses the following core competencies:
1. Problem Solving
2. Analytical Skills
3. Team Work
4. Communication Skills