1. The problem statement, all variables and given/known data The problem is page 5 on: http://www.physics.ox.ac.uk/olympiad/Downloads/PastPapers/Paper3_2010_.pdf [Broken] I will just summarise the question: The refractive index of space,n, at a distance r from the sun is given by √(1+5920/r). The light from a distant star is deflected by a small angle θ. Using a simple model, calculate θ. 2. Relevant equations Snell's law? 3. The attempt at a solution I have no idea of how to get started with this question. I think that the model will involve some discrete layers but I still wouldn't know how to do the problem. Any help would really be appreciated.