If so, does that mean that there has always been an infinite number of them?
It would be weird to have exactly 59 universes - the choices that seem possible to me are: 1, infinity - or zero (with the last excluded by fairly reliable evidence).
What does “always” mean in this context? Since time is a characteristic of the universe, each universe has its own time and, if universes don’t intersect, then neither do times. So another universe can’t be said to exist before, or after, or contemporaneously with, or for as long as, or longer than, or shorter than, our own universe; it exists within its own time, which is nothing to us.
Or two.
There is the option of “all possible universes”, with there being some constraints of possibility which mean that the number of possible universes is very large, but infinite.
True: 10^500 is a number I’ve seen kicked around - but I don’t quite trust it
Did you mean finite?
Check out the Wikipedia article Many-worlds interpretation - Wikipedia
My layman’s explanation of this is that the many worlds hypothesis deals with the uncertain outcomes of quantum events by accepting that every outcome can happen, but each outcome “creates” a new universe. In popular interpretations of this (e.g the movie “Everything Everywhere All at Once”) the events are anthropomorphic, but this is not accurate.
So, to try to answer the question, yes there probably are an infinite number of universes, and the number of them is always increasing. As to whether there was ever just one universe way back when the big bang happened, I don’t know.
Yeah, I don’t know what there being more than one universe “means” exactly. Like WHERE do they exist? The popular sci-fi trope from the MCU to The Flash to Everything Everywhere All At Once and so on is that they all sort of exist on top of each other without interacting, but you can travel to them by traveling through a wormhole or changing some resonance frequency or some other pseudo-scientific bullshit.
There is another school of thought that even in a single infinite universe like ours, there are actually a finite number of ways to organize a bazillion trillion molecules. So if you travel in the same direction long enough, you should encounter another version of Earth, or a version or Earth where the Brooklyn Bridge is blue, so on and so forth. But that’s more like the same universe endlessly repeating (which it can do because it’s infinite).
But other than some sort of abstract mathematical construct or sci-fi film setting, it’s difficult for me to conceive of how a parallel universe or alternate reality might actually work.
Did you meann to say finite?
There are probably two versions of lots of universes.
Many worlds - which is our own universe but splitting into separate versions.
Many universes, each possibly with different physics, and maybe some even touching in some weird way.
Infinite is a difficult word. It isn’t just a very large number. Just what is meant by infinity has to be a bit clearer. Many worlds isn’t infinite.
Many universes can be anything you like. It isn’t science so you can make up pretty much any number you want.
Many worlds is not really science either, but provided a way of thinking about implications of quantum physics. One that is significantly at variance to the popular version of it, which is mostly just a stupid plot device.
So nothing here is definitely impossible. But whether that makes is possible is another matter. Within scientific understanding as we have it, all of them as just as fanciful as any other fairy story.
Yes. Well spotted.
Where, perhaps, it might fit. But time itself has an element of locality, such that the idea that we can take a snapshot of this very instant in the entire universe is nonsensical. What is happening on Tau Ceti e at this very moment is not a meaningful question, because, on the scale of the universe, “now” is non-cartesian.
In other words, the possibility of divergnce creating a vast variety of universal permutations does not comport with the actual reality of time. There could be a sort of fine, dense foam of localized permutations, but what would one do with that?
Indeed. Unless it makes testable predictions not much. Write popular books and build YouTube channels peddling quantum woo seems about the best use case.
Is that allowed (by the Mathists)? Having an infinite set and then increasing it?
Sure. Haven’t you heard of the Infinite Hotel?
Indeed. It isn’t an infinite number. It is just very very big.
There are schools if thought suggesting that even our current single universe is infinite in extent. This isn’t necessarily in opposition to the Big Bang either.
But like all of the other questions, if it cannot provide a testable result, it is just navel gazing. There is no actual science.
Then we will get ourselves into the usual discussion of kinds of infinity. That doesn’t get us any further, but is fun in it’s own way.
My method for visualising an infinite multiverse is by imagining that it all happens inside a five-dimensional space. We are accustomed to thinking of our own universe as occupying a four-dimensional volume (three dimensions of space and one of time); it turns out you could accommodate an infinite number of infinite four dimensional volumes inside a single five-dimensional volume, with an arbitrary distance between them. Like in Hilbert’s Hotel, you could even increase the number of such spaces in an arbitrary manner, without any fear of these spaces colliding or intersecting.
Of course I’ve got no evidence for such a 5-dimensional space, but that doesn’t matter; it is just a visualization tool, not a useful or testable theory. It just shows that you could easily fit an infinite number of different universes within a simply visualised mathematical structure; you don’t need an infinite number of separate dimensions to accommodate an infinite number of worlds or timelines, just one extra degree of freedom.
Infinity can get larger and larger?
Yes, see posts #15 and #16.