It's official the universe is freaking massive!!! But explaining and understanding just how big it is to students can be just as large of a dilemma and could possibly cause headaches for all involved. Luckily some creative individual out here has created a really cool interactive site that allows you to use a slider through hundreds of relative objects that give you a genuine understanding of just how big space is.
It both looks amazing and is highly informative at the same time and would be an ideal interactive white board resource.
It has some real links to both maths and science you can enxplore with your students or you can simply look at it and go wow!