The universe is expanding. We know this because light from distant stars is red shifted indicating that they are moving away from us. Here is the nugget that just occurred to me. Lower frequency light carries less energy so if all the light emanating from a star shifts further down in frequency the further it travels then energy is not conserved as a direct result of space expanding. From this I can surmise that there should be a relationship between space and light. Perhaps the relationship is more general, between space and energy. perhaps this relationship is similar to the relationship between energy and mater. If space, energy, and matter can be shown to be equivalent or interchangeable that would be a paradigm altering idea, at least to me. Does anyone know of any work done along this line of thought?