Homework 2, Astr 305V, Fall 2009

Due: Tu, Sep 15.

1. (Question 39b. from the text book, chapter 2). Suppose you could travel back in time and show the Greeks ONE observation from modern times. If your goal was to convince the Greeks to accept the sun-centered model (=helio centric model), what observation would you choose? Explain your choice of observation, so why does it prove beyond a doubt that the heliocentric model is correct? Do you think they would be convinced? (Note that you can find the answer to this in the textbook provided you read the material carefully. If you have any questions about this, come see us).

2. Light takes 8 minutes to cross the distance from the sun to the earth. If we picture the distance between earth and sun as 1 foot, how far away (in feet) is the nearest star from us? Note that the nearest star is about 4 light years away.

Given this, if a space ship could travel the distance between us and the sun in 1 month, how long would it take us to get to the nearest star, assuming we would be traveling at the same speed?

3. Describe 3 major differences between "terrestrial planets" and "jovian planets".