I am not familiar with the physics involved, but from my limited understanding, we can only measure time as it exists in our universe, because it's the only metric we have. How then, if we were somehow able to detect other universes (and how would that work, if the ways in which we measure things have no meaning um . . . between universes?) how would we be able to tell when they came into existence in relation to our own? Or would "when" not really apply?

I have also wondered about intelligent extra-terrestrial life and the time between the Big Bang and the present. For example, how long did it take for the universe to be able to host life as we know it, or life at all? What if we are the first intelligent species? What if we are the last? What if we haven't found any aliens because we do not exist at the same time that other intelligent species existed/will exist? Also, imagine if in the future, human scientists were to find the remains of some kind of interplanetary (or larger) civilization. What might that look like?

Lastly, what if reality does not appear to be the same throughout the universe? For example, what if time runs differently in other sectors, for whatever reason?

I understand that my lines of thinking are running into science fiction, but the more I read about the universe, the stranger it seems.