Jupiter

©1995 The Regents of the University of California

Introduction

• As you might recall, (depending on how much you pay attention to the news) 1994 was a sensational year for astronomers and for the planet Jupiter. The comet Shoemaker-Levy 9 was caught in Jupiter's enormous gravitational field. Jupiter pulled the comet off its solar orbit and attracted it toward itself. While the comet was getting hijacked, it was broken apart by the difference between the pull of Jupiter's gravity from one side of the comet to the other. The comet collided spectacularly with the giant planet in July 1994.
• You will use images of the collisions taken by astronomers using ground-based and space-based telescopes to determine the rotation rate of Jupiter. If you find two pictures taken at different times, you can use the comet impact crater (or use any other area) as your landmark.
• You will need to make a template for your pictures.
• You will measure how many degrees the crater (or any other landmark) has turned by using a template for any two images.
• You can figure out the time between the two pictures from the captions.
• If you want, before you start, to look at a really cool image of a fireball created by the comet fragment impacting Jupiter, click on the buttons below. (It won't help you find rotation rates, but it's o.k. to look at truly cool images while you discover the rotation rates.)

Image and text of comet impacting Jupiter (image taken in infrared part of the spectrum).

Internet Information

These are the best images of Jupiter we found that can be used in calculations of the rotation rate of the planet:

• Impact site G at 04:56 UT 19 July, 1994
• Impact site G at 05:48 UT 19 July, 1994
• Textual information about impact images

Strategy

1. Click on two first buttons above, observe both images of the same impact, and try to find the difference in the locations of the same spot
2. Read textual information about this imact and observe images taken at different times
3. Trace both images using transparent paper
4. Prepare a transparent templet having the same size as the images of Jupiter you are working with (do you remember the portable angle measurer mentioned earlier)
5. Measure the angle of rotation of the landmark
6. Calculate the angular velocity of Jupiter
7. Calculate the period of rotation of Jupiter (you have all the necessary data)
8. Discuss your results with other members of your group and make a conclusion.

Questions

• Does the famous Red Spot rotate? If it does, is it at the same rate as the comet spots?
• Does Jupiter spin faster or slower than Earth?
• Do other big planets spin at that speed?

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