29:52 Homework Set #5

Assigned: December 2, 2004

Due: December 9, 2004

Here’s the last of the homework sets. It should get you in shape for the last exam. If you have questions about these problems, contact me for clarification or help. You should also communicate with your classmates via the bulletin board.

1. Draw an ellipse which has an eccentricity of 0.95. The drawing doesn’t have to be at the same level as a professional draftsman, but should be clearly and carefully done with a ruler and some control over your hand (or diagram-drawing program). Clearly indicate on your drawing, or say in attached text, what you are doing to insure that it is an ellipse with an eccentricity of this value. Remember that an eccentricity of 0.95 would be low for most comets.

2. Look at the diagram of the orbit of Halley’s comet presented in the on-line lecture notes. Describe where Halley’s comet is right now. Say where it is relative to the orbits of the planets, and say how you came to this conclusion.

3. Most asteroids are located in the asteroid belt that lies between 2.1 and 3.3 astronomical units from the Sun. What orbital periods correspond to the inside and outside of the asteroid belt? (Hint: remember back to Kepler’s Laws earlier in the semester).

4. Here’s a subtle one. If you look at the pictures of asteroids in the online notes, you will notice that all of them look like irregularly-shaped big rocks except for Vesta, which appears roughly spherical, like the other solar system objects we have discussed this semester. Why do you think that is true? What is causing Vesta to be nearly spherical, while the other ones are randomly shaped? Hint: Appendix 8 might provide some food for thought.

5. This year on the evening of December 13-14 we will see the annual Geminid meteor shower. Based on what you have learned in the class, do you expect that the meteors are pieces from a main belt asteroid, or from a comet? Give your reason.

6. Estimate the year of the next time the Sun is at solar maximum. Describe what information and ideas you are using to obtain this number. That year will be a good time to watch for auroras, and would be a bad time to send people out in spaceships in interplanetary space.

7. Use Figure 17.33 to find the sunspot number at the highest sunspot maximum of the 19^th century, and the highest sunspot maximum of the 20^th century. Compare that with the same number at the last solar maximum.