There is a debate going on regarding this subject, and many different physics professors, who have a PhD in optical physics, are providing different answers. It looks like they are getting destroyed in the debate which is rather silly. I have been watching and I am very curious about the correct answer. The question is a child like (why is the sky blue) but all the answers are completely different. I was wondering if anyone else would take a crack at it. If you could provide the math that would also be helpful. I am just a stay at home mom with an insatiable curiosity. Here is the question. Why do the colors of the spectrum reverse in order when you look at the light source through a prism? When the light shines through and hits the wall or paper the blue is towards the base of the prism but when you look through the prism at the light the red appears where the blue should be. I know that there is displacement of the object or light source but how would the displacement cause the spectrum to reverse? Why would the virtual image be reversed? The only reason I can think of is that our eyes trace it back in a straight path and it crosses over but this doesn’t seem like a sufficient answer. A few professors have agreed with my answer but it is getting destroyed in the debate. Any other ideas would be greatly appreciated.