29:52 Homework Set #4

Assigned: March 29, 2004

Due: April 7, 2004

Confused? Don’t go around miserable and despondent! Ask for help and explanation from me. Even better, work on these problems with one or two of your classmates.

1. Look at the appendix in your book on the property of planetary satellites. (Appendix 7). Note that the moon Thebe of Jupiter is about the same distance from Jupiter as the moon Enceladus is from Saturn. In spite of the fact that these two moon are about the same distance from their planets, the orbital periods are substantially different (0.68 days for Thebe), (1.37 days for Enceladus). Why are the orbital periods different?
2. It is possible that you could observe Venus closer to the Sun on the sky (i.e. a smaller angular separation) than the planet Mercury? Support your answer with a diagram showing the orbits of the two planets.
3. Based on information presented in lecture notes or the textbook, compare the Ishtar region on Venus with the continent of Africa.
4. Explain why a comparison of Ishtar and Africa makes sense scientifically.
5. Use the “solar system simulator” at http://space.jpl.nasa.gov to find the current distance to Saturn. In this problem, I want a precise distance good to about three significant figures.
6. If you were to send a radio signal to a spacecraft at Saturn, and it was to immediately respond, how long would you have to wait between transmission and reception of the reply?
7. With the exception of Titan, no moon in the solar system has an atmosphere. What kind of measurement or observation would you propose to show this?