1. My friends say it is too hot to be closer than 80 million kilometers to the Sun. They also say that it is too cold to be more than 240 million kilometers away from the Sun. My doctor says I should avoid extremes of cold and heat. Which planets (not Earth, for goodness sake) would be within those distances and how are the temperatures on those planets?

2. I have seen how the astronauts carry their own Oxygen around. I don't want to carry Oxygen tanks on my back all the time. Do any of the planets have breathable Oxygen in their atmosphere? Which ones if any?

3. I can't get all my work done in 24 hours each day. Which planets would give me a longer day than the Earth, and which one would give me the longest?

4. I told your ticket agent I would buy passage if she could send me to a place whose day is longer than its year. She said she could, but she did not say to which planet. Where is she sending me?

5. I am twenty years old and anxious to live on Mars. Your agent tells me I will have to change my age into Mars years. What is my Mars age? (Hint: find out how many Earth days this person has lived and use that to find out their Mars age)

6. By careful dieting I have kept my weight to 100 pounds. Your agent said I would be heavier on Jupiter. What will be my weight there?

7. Your ticket agent mentioned that some of the planets have such cold temperatures that the atmosphere is in a liquid state and the solid planet surface is many miles below. Could you please give me a list of those planets; I get very seasick on rafts or boats and would like to avoid those planets.

8. I asked in my last letter how fast your spaceships are. You replied that they could travel up to 40,000 Km per hour. How long will it take to get to Neptune?

9. My ticket is marked "to the land of many moons, one way only". Which planet has the most moons? I guess that is where I am going.

10. Why won't your ticket agent sell me a ticket to one of Mercury's moons?

11. My husband wants to send me to Nereid on a separate vacation. How big is Nereid compared to Earth? About how far is Nereid from the Sun? How far is Nereid from Earth? At a speed of 40,000 Km per hour, how long will my trip take, one way? At six cents per Kilometer, what is this going to cost me?

12. I would like to use some real estate as an investment. I am planning to buy a large moon. Which moon is the largest in our Solar System and where is it located? How does it compare in size to the smaller planets? How much would a 100 Lb. person weigh on that moon? (Hint: compare the mass of a 100 Lb. person on a planet of similar size)
CAN WE MOVE TO OTHER PLANETS?

After writing answers to these questions, you should be ready to describe a planet or satellite that would be suitable for human habitation. Please answer questions 13 through 15 on your paper after the answers to the letters. Here are two specifications of a planet that would be suitable for human life:

A. To be habitable, any planet or satellite must have liquid water (not ice or vapor alone). Let's assume that throughout the universe, water freezes at 0 0C and vaporizes at 100 0C. Therefore any planet we want to live on must have temperatures within this range.

B. To be habitable, any planet or satellite must have enough gravity to hold gasses so there will be an atmosphere. Among these gasses, there must be Oxygen. Gases like Methane and Ammonia are poisonous to humans.

13. Which planet, other than Earth, has free Oxygen in its atmosphere? Could we, by changing the atmosphere or the planet, make it more livable? Which planet would be the easiest to "Terra-form"? How could you do it?

With this information, you should see that your assignment may not be carried out. There is no place in our Solar System that will support populations of humans unless you provide them with an artificial environment.

Wait! Do not close down your operations! Maybe you can send emigrants to planets belonging to other solar systems. The nearest star (beside the Sun) is 4.3 light-years away. You may remember that a light-year is the distance that light would travel in one year (6 trillion miles or 9 trillion Km).

14. Since our present spaceships travel about 9 Km per second, it would take about 4 trillion seconds to reach the nearest star, Proxima Centauri. That is how many years, approximately? Do you believe moving people to other planetary systems will be the answer to the world's population problem?

Let's be very optimistic as we look at the problem from another standpoint. Suppose the space shuttle could carry 100 people to one of the planets for the same cost as that of carrying these people to the Moon. Assuming no change in the growth rate, we would have to export about 70,000,000 people per year in order to hold the present world population constant.

15. How many people would have to leave Earth daily? How many 100-passenger spaceships would have to leave Earth daily?

The cost would exceed $300,000,000,000 daily, not counting any expenses involved in training the migrants or in preparing a new home for them. It appears that you will have to resign your job. On the basis of what you now know, you cannot move people to new homes on some other planet. Your job is impossible. If your boss does not believe your job is impossible, ask her/him to do this