Astronomy 115: Homework Assignment #1


Due:Tuesday, Sept. 12

For all homework assignments, write neatly, staple multiple pages, and show your work. You may not receive full credit for simply providing answers without showing work. If you are having trouble with a problem, read it again carefully--it often helps to read it out loud. Office hours and help sessions are also available...but plan ahead!
Do not return this page with your homework.

The Size & Scope of the Universe (Ch. 1)

  1. The following important terms will be used throughout the course. First, write down what the term means to you or how you've heard it before. Then look up the words in your textbook's glossary and give their astronomical definitions, if different. Optional: Draw a picture of each!

  2. The speed of the Earth in its orbit is 30,000 meters per second (m/s).
    A.) Express this number in kilometers per second (km/s).
    B.) Use a conversion factor (1 km = 0.6 miles) to find how many miles the Earth (and everyone on it) moves in one second.

  3. How many months are there in three light-years? Explain your answer.

  4. Chapter 1, Review Question 9.
    What is the ecliptic, and why is it tilted with respect to the celestial equator?

  5. Describe in your own words what must happen for you to witness a total solar eclipse. On August 21, 2017, a total solar eclipse was seen in the United States. Did you see it? Was it total?

  6. Suppose you had a young niece or nephew who asked "Why do we have seasons?" Explain in one paragraph, including a diagram, how you would answer.

    Getting Experience with Very Large Numbers

  7. A.) What, astronomically speaking, happens once between your last birthday and your next birthday?
    B.) How many seconds does it take for this to happen? Express your answer in scientific notation. (NOTE: Remember this number, you'll be using it again and again.)

  8. The "National Debt" is the total amount of money which the United States has borrowed, and spent in various ways and not yet payed back. Look up the current national debt, in dollars, and write this number in both long form and scientific notation (OK to round the number off).

    Optional:Ask your friends if they know the approximate size of the national debt, and write down their responses!

  9. The largest Lottery Jackpot ever won in the US was the $1.5 billion Powerball jackpot won in Jan. 2016. If you won the lottery 1000 times, would you have enough money to pay off the national debt? (Note that 1 Trillion = 1,000 Billion, and 1 Billion = 1,000 Million.)

  10. In addition to paying back the money it borrows, the U.S. must also pay interest on the money borrowed. In 2016, the U.S. payed out about $250 billion just in interest payments on the National Debt. Meanwhile, the amount we spent on science, through the National Science Foundation (NSF), in 2016, was about $7.5 billion. Use these two figures to complete this sentence:

    "The United States spends _______ times more (or _____ times less) on interest on the national debt than it does on science at the NSF."

  11. Optional, Extra Credit Download software for your computer or cell phone that lets you see which objects are in the sky right now. (Search for "Planetarium Software") Run the software while outside at night and try to identify some stars an planets. Write a brief (1 paragraph) review of the software, and describe how you used it. Did it work well?