The following problems are form The Cosmic Perspective (make sure you're using the second edition!). Make sure you do the problems under "Problems" in the end of each chapter!!
Should humans try to travel to, colonize and (if necessary) terraform other planets? Things you might want to think about: costs, time needed, ethics of forcing your children to live on another planet, ethics of terraforming another planet. (There are more things to consider, and — as always — you're welcome to use these other considerations.)