Astronomy 1000
Worksheet 1
Motion of the Sun in the Sky
The
northern hemisphere
analemma, below, shows the Sun photographed at the same time each
day producing a lopsided figure-eight.
Use what you learned last week to answer the following
questions.
1.
Is the lower, larger lobe taken in winter or in summer?
Winter
2.
How do you know that?
When the earth is closer to the sun, it moves more rapidly near the sun causing the path to
change more quickly. When the planet is farther from the sun, it moves slower.
3.
If the time intervals between snapshots are equal, is Earth moving faster or slower in the
lower lobe?
It’s moving slower.
4.
What is the reason for your answer?
Since the earth is further from the sun, it moves slower and causes the sun’s path to change
slower.
5.
Would an analemma photographed from the southern hemisphere look differently?
If so,
how?
If not, why not?
It would look inverted because the southern hemisphere gets more exposure to the sun and so it
changes the data.
Answer:
Since the Sun is lower in the sky, the lower lobe is taken in the northern winter. The
Sun points are farther apart, so Earth is traveling faster (as it is closer to the Sun). The southern
hemisphere analemma looks the same, but is inverted to the horizon due to the inverted
perspective of the southern hemisphere, and oriented to the north.
