Homework Assignment #3
This assignment is due at the beginning of class on Friday, September 26. Late homework will not be accepted, including homework turned in at the end of class.
You must do the first three problems. Each of those problems will be worth 10 points. If you make a sincere, honest effort to answer each question, you will receive at least 5 points of credit. Do not abuse this, or I will stop doing it later in the term!
Staple your homework! If you require more than one page to complete the homework, fasten the multiple pages together with a staple; folding the corner won't cut it. If your homework has multiple pages but you fail to staple, you will be docked 3 points.
The last three problems are given to you as additional review problems. You do not need to turn them in, and they will not be graded when you do. However, solutions to them will be posted along with the solutions to the first three problems. You may want to do them if you think you need extra review in the class.
Please write out the problem statement at the top of your solution. (This is for two reasons; it is so I can know which problem you answered, and that you answered the right problem from the book. It also will make your graded homework more useful as a study aid later.)
In class, I told you that if the Sun were a grain of sand and Proxima Centauri (the closest star to the Sun) were another grain of sand, they would be something 20 miles apart. Create a similar analogy for the Milky Way and Andromeda galaxies, only using frisbees or dinner plates to represent the disks of these Galaxies. Comment on what this says about how often you might expect to see galaxy/galaxy collisions in the Universe compared to star/star collisions in our Galaxy. (For the size of our Galaxy and the distance to the Andromeda Galaxy, refer to the Reading Assignment from September 17.)
Chapter Four, Question 14 in the text (page 126).
An astronomer detects two yellowish stars which she believes have identical luminosities. Star A has a measured parallax of 0.125". Star B is detected to be 400.0 times dimmer than Star A. What is the distance to star B?
Chapter Four, Question 11 in the text (page 126). Skip part (b), as we have not talked in class about what you need to do this.
Chapter Four, Question 12 in the text (page 126).
(The problems below will not be graded, and need not be turned in.)