Astronomy 115-06, Fall 2007

Homework #1

Due September 14, 2007

SHOW YOUR WORK TO GET FULL CREDIT!

Chapter 1: Problems (pg. 9)

#4. Venus orbits 0.7 AU from the sun. What is that distance in kilometers?

#8. How long does it take light to cross the diameter of our Milky Way Galaxy?

#9. The nearest galaxy to our own is about 2 million light-years away. How many meters is that?

Chapter 2: Review Question (pg. 21)

#6. Why do some people say the magnitude system is backwards? How did that arise?

Chapter 2: Problems (pg. 21)

#1. If light from one star is 40 times more intense than light from another star, what is their difference in magnitudes?

#2. If two stars differ by 8.6 magnitudes, what is their intensity ratio?

National Debt Problem: The “National Debt” is the total amount of money that the United States has borrowed and must pay back.

a) Look up the national debt online, with a reference and a date (like September 1, 2007).

b) Write this number in scientific notation and long-form (feel free to round it off).

c) The largest lottery jackpot ever won was $325 million. If you won the lottery with this jackpot 1,000 times, would you have enough money to pay off the national debt? How many times would you have to win the lottery to pay off the debt? {Note: 1 trillion is 1,000 billion; 1 billion is 1,000 million}