I'm imagining a hypothetical scenario based on the Big Rip theory of the end of the universe (https://en.wikipedia.org/wiki/Big_Rip), where eventually the expansion of the universe causes everything to fly apart from each other. In my framework, humans harness a kind of magic which affects the rate of expansion, and use it to power their civilization. Unbeknownst to them however, is that they are radically increasing the rate of expansion, to the point where over the span of say a century, their local galaxy unbinds and a night sky previously lit by millions of stars goes dark over the course of say a century. At this point I am going to have a sort of magical collapse which ends the use of that magic and slows the rate of increase of the universe back to the original level.
I haven't decided yet if there is a moon present or not, I am thinking yes because I want to make this as earthlike a place as possible, but I am trying to figure out what effects the disappearance of all stars over an approx 50-100 year period would have on human civilization, ecology, wildlife, etc.
For instance, I'm imagining huge effects in human culture regarding religion and superstition (new cults formed, prophets prophesying the end times, mass unrest, etc). But I'm not sure what would happen to the ecology of the world. Would the disappearance of the stars have any effect on weather, climate, animal/plant life? Also, I am imagining the night would be much darker when the moon is low or new moon phase...what effects might this have on human or animal behaviors?
Finally, same as all of the above questions, but sans moon, which I assume would be a much more drastic change, as without a moon in the sky the stars provide the only light there is, whereas without the stars at least you still have a moon when it's visible.