ASTR 103 - Wagner

Homework 1

Instructions: Answer each question below completely. All answers must show your reasoning

and explanations. Any questions that involve a calculation must show your work. Incomplete

answers will not receive full credit! Remember, homework assignments are primarily graded on

effort, so make your attempt on each question. If you dont answer a question, you get no

credit for it!

1. Discuss some of the largest dimensions that you have personal knowledge of. For

example: running a mile, hiking 10km, running a marathon, etc.

2. Why are light-years more convenient than miles, kilometers, or astronomical units for

measuring certain distances in astronomy? Explain.

3. Explain why it is a difficult process to detect planets orbiting other stars.

4. Explain what the size of a star image in a photograph tells you.

5. Light from the sun takes 8 minutes to reach Earth. How long will it take light to reach

Mars?

6. If the speed of light is 3x105 km/sec, how long would it take for light to travel across the

diameter of our galaxy.

7. The nearest large galaxy to us is the Andromeda Galaxy which is 2 million light years

away. Use the information in your text to calculate how long it will take light to reach us

from the Andromeda Galaxy.

8. How many galaxies like our own would have to be laid edge to edge to reach the

Andromeda Galaxy? Explain your reasoning/calculation.

9. Explain how scientists use the scientific method to test their ideas.

10. How is a statement in a political campaign speech different from a statement in a

scientific argument? Explain