> If the concept of energy conservation does not apply to the entire Universe, then we must ask where the additional energy created comes from or is removed. N

> If the concept of energy conservation does not apply to the entire Universe, then we must ask where the additional energy created comes from or is removed. No, we musn't, because the reason why the concept of energy conservation does not apply to the entire universe is that there is no well-defined concept of "energy of the universe as a whole" to begin with. So you can't even frame a well-defined question about whether this thing that doesn't exist is conserved or not. > the collapsing Universe followed by the expanding Universe loop ties everything up nicely (cyclic model [1]). This is a speculative model which at present has no evidence that favors it over our best current model. Of course we might discover more evidence in the future that would change that. If that did happen in future, then yes, we would have to reassess the "energy of the universe as a whole" question as well. I am not familiar enough with the details of cyclic models to know whether there is a well-defined "energy of the universe as a whole" in them or not.