I get that, and I get there's stuff that we haven't yet, "seen" that could exist that we don't know about yet... But I'm saying could there have been "big bangs" from other large masses we also don't know about (because we can't see it) and therefore a 'multiverse' in the sense that there are even larger distances between universe clusters.

Let's think about time for a second (well, more than a second):

1. Second = house
2. Minute = city
3. Hour = state/territory
4. Day = country
5. Week = continent
6. Month = planet
7. Year = solar system
8. Decade = galaxy
9. Century = supercluster
10. Millennium = universe

OK so with that comparison, we see scale. But what's beyond a millennium or universe? I've found 1m years is called a megannum or aeon. So what's the equivalent in space? Beyond the megannum (million) I've found gigannum (billion years) and terannum (trillion)...

My point is we often refer to the known universe as whatever we know or have seen to exist, but that's a sort of dynamic or organic designation vs a unit of measurement. We should have units beyond the universe for all the hypothetical existence beyond what we know. To continue the scale:

11. Megannum = (Name for cluster of universes)
12. Gigannum = ? 13 . Ternnum = ?? (Even necessary?)

Edit: I know I'm going down a rabbit hole, but should universe refer to 1 (being uni) and then megaverse match megannum? Then gigaverse refer to a cluster of megaverses? Just.... Time consuming to think about how big those could actually be.

Should we also call a new measurement of light travel time to extend light years to light decade or light century to get a gist of even greater distances? I know. To fathom is mind boggling. I've wasted so much time at work today already on this comment 😅😅