Astronomy 201 Practice Final

Short answer questions(5 marks each)

You are kidnapped, drugged and flown somewhere. After an indefinite time in a dark cell, you escape and try to determine from the sky where you are. What could you say about your location on the Earth if you find Polaris and estimate its altitude to be 70 degrees above the northern horizon?

Which planet has most of the orbital angular momentum in the solar system? Why?

What is the major reason why summers are warmer than winters?

What phase will Venus, which is closer to the Sun than Earth, have when it is at its closest to the Earth?

Briefly explain why the fact that all planets orbit in the same direction and almost the same plane is evidence that the solar system was formed from a single collapsing cloud.

Why are most asteroids found orbiting between Mars and Jupiter?

Why were many communications and other satellites either turned off or turned away during the recent Leonid meteor shower?

Why does nuclear fusion only happen in very dense, high-pressure environments like the core of the Sun?

Where do the long-period comets spend most of their time? Can they be directly observed there? Why or why not?

What is the difference between a solar and a sidereal day? Which is longer? If the Earth rotated in a retrograde direction (ie opposite to its orbital direction) how would this be different?

Why do the two smallest terrestrial bodies in the Solar System (the Moon and Mercury) have no atmosphere? Briefly describe the physical process at work here.

Longer questions (20 marks each)

The Greeks estimated distances to the planets by assuming that the farther away a planet is, the more slowly it will move across the sky. Taking into account Kepler's Laws and what we now know about the solar system, discuss why it might work for some planets, and which planets would give right and which wrong answers using this method.

Recently, a giant planet was discovered around a star which is smaller and cooler than the Sun. Discuss the method that was used to find this planet, in the context of how much we can infer about its properties. Using the condensation theory as a guide, would you expect the planet to be in a similar place to the Solar System's giant planets, closer, or further away? What is another important factor which affects our interpretation of its distance from its star?

Discuss Kuhn's philosophy of science, and the important differences from earlier philosophies of science. Give an example of how an existing paradigm in a certain field might make certain questions seem not worth asking, and how this might affect the progress in this field. How could scientists get around this problem?

Describe the observations that you have made of the sky this semester, and how they related to what you have learned about the solar system and the motions of the Earth and planets