TLDR: Because of the finely tuned nature of the our universe many believe their aren’t “aliens” in the Multiverse. Ethan Siegel explains that dark energy isn’t as important to planet formation as many physicists believe.
What I don’t understand is why any other universe would have any different physical constants. Why wouldn’t they all be the same? What determines what universe gets what laws of physics? It makes me think there must be an underlying set of physical laws for all these universes. Well, that and there is no evidence (as far as I know) that there is more then one universe.. other then the fact that there “must be” since there is the one we are in.