In the images you have analyzed you are looking at Jupiter and its
moons from the side. Luckily, there is a slight tilt of Jupiter and its
moons to our line of site or it would be very difficult to see the the
orbits clearly. In this activity, we are going to use the information
from our images to draw a model of Jupiter and its moons as though we
were looking down on the orbits instead of from the side.
Make a Prediction
In a paint program or on a piece of paper, make a drawing of what
your combined image would look like if you were looking down on it.
Save this drawing.
Constructing a New Picture
Have a protractor and compass handy before you begin.
- Print out the combined image you made in Activity 2.
- Use a compass to make a circle on the paper that has the same diameter as the distance to the farthest position of Io.
- Label the center of this circle "Jupiter's Center"
- Using this same center, draw a smaller circle the size of the planet Jupiter.
- Draw a line from the Jupiter's Center to the farthest position of Io. This is your radius line.
- For the first Io on your combined image draw a perpendicular line up to the circle from the radius line.
- Draw a perpendicular line from the radius line down to the circle through each of the moon positions.
- When you are finished you should see the position that Io would be
at each time an image was taken if you could have been viewing it from
You can follow the same steps for the two remaining moons. You may
want each on their own sheet so that your work is a little easier to
use in the next activity.