Characteristics and Origins of the Solar System

Third Sample Examination

November 14, 2000

This sample exam in intended to be helpful to you in studying for the exam, not to be a scourge. You can do as much or as little as you wish with this document. I am not going to collect answers. My intention is that the questions on the real exam should resemble these, and I may even use one or two of them.

1. The Leonid meteors, which are always most prominent between midnight and dawn, move across the sky much more rapidly than meteors in showers which are most prominent between sundown and midnight. Why do you think this is so?
2. Warning: Take your time with this one. The rate at which an atmosphereless object radiates energy to space (and thus cools itself) is proportional to the fourth power of the temperature. That is, the power radiated, in Watts/square meter can be written as P=AT⁴ . Given this, how much colder should an object at the orbit of Neptune be than one in the orbit of Jupiter? By “how much colder”, I mean what is the ratio of temperatures. Hint: The power input, which warms the object, is furnished by sunlight.
3. Describe the chemical composition of the Jovian planets, and give scientific reasons (as well as you can) why we know this.
4. Compare the interior of Jupiter with the interior of the Earth.
5. Discuss some of the issues brought up in deciding whether Pluto should be considered a planet. What is your opinion on this?
6. Describe how the “geology” differs from one Galilean satellite to another.
7. Let us assume that the density of some moon of an outer planet has a density of 1.2 grams / cubic centimeter. What conclusions would you draw about the moon from this single fact?
8. Describe and discuss a physical process responsible for the differences between the Galilean satellites.
9. Where in the solar system would an object be that was in a 2:1 resonance with Jupiter? Show your arguments. Citing authority or scripture won’t do it!
10. How close to Uranus would you expect to find a small, spherical moon with a density of approximately 1 gram/cubic centimeter? By “how close” , I mean what is the minimum possible distance for such an object from Uranus. Be sure and describe what concepts and physical principles you are using.
11. Describe a weird similarity between the Earth and Saturn’s moon Titan.
12. Describe how and why Saturn’s ring came into existence.
13. What role do Saturn’s moons play in determining the nature of Saturn’s ring?
14. In what way is Saturn’s moon Titan unique among the moons of the solar system?
15. Describe what we know about the surface of Titan.
16. Describe some notable features of Triton, the largest moon of Neptune.
17. Comets frightened people in antiquity because they would “suddenly” appear and disappear (read Plutarch, biography of Julius Caesar) and seemed to not follow the predictable laws of the other planets. Within the context of our current astronomical understanding of these objects, explain why comets appeared as they did do ancient observers.
18. Compare the mass of a comet to that of the Earth.
19. Comet Hale Bopp has a period of 4500 years and an eccentricity greater than 0.999. How far out in space is it at perihelion?