I had to pick this post for two reasons: 1) I love space, all things space, or solar system, space travel, the universe etc. 2) I love Neil DeGrasse Tyson. But after picking this post for those two reasons I found what a fun activity this would be. I really like the idea of using predictions to set up problems, it think students can learn so much when they have to try and figure something out with out much help/knowledge. It also gives the kids something to think back on after the math is done, it gives them instant feedback to how their thinking and knowledge of the problem has changed. This lesson could be so much more though, I was thinking it could be done as an in-class project. The students would be told they have a 5m diameter sun and they have the rest of the class to make a planet that is the correct size (proportionally), they would also have to say how far from the 5m sun it would be. This lesson could teach several skills and it could be a lot of fun.