Exploring the Possibility of a Multiverse

[cdux]

How can there be a concept of it expanding when there is no realm existing for it to expand into?
Unless, there is that realm and space is only another new medium our Universe can exist in.

 

[HallsofIvy]

No one has said "space" is expanding. It is the distance between stars that is expanding.

 

[cdux]

That's news to me. I thought it was consensus that space and time were created at the Big Bang and expanded from there on.

 

[ImaLooser]

How can there be a concept of it expanding when there is no realm existing for it to expand into?
.

I don't mean to be snide, but my answer is: why not? True, it is a kind of weird concept.

 

[cdux]

I don't mean to be snide, but my answer is: why not? True, it is a kind of weird concept.

Yes, why not, indeed, but my point is that even if the medium of what we're talking about is expanding (even if it's not the consesus opinion apparently, let's assume it is) then its expansion should have a medium to expand into.

Consider this:

You reach the end of the Universe and you hit a wall.

What is holding the wall?

What is that force behind that wall?

Or do you fall into some kind of destructive event horizon? Why? What is there?

It's either another medium or an incomplete collapsing theory in that sense.

 

[Number Nine]

Yes, why not, indeed, but my point is that even if the medium of what we're talking about is expanding (even if it's not the consesus opinion apparently, let's assume it is) then its expansion should have a medium to expand into.

Consider this:

You reach the end of the Universe and you hit a wall.

What is holding the wall?

What is that force behind that wall?

Or do you fall into some kind of destructive event horizon? Why? What is there?

It's either another medium or an incomplete collapsing theory in that sense.

There is no evidence that the Universe has any such "wall", so there's no problem.

 

[cdux]

There is no evidence that the Universe has any such "wall", so there's no problem.

I guess my point is that at the end of the day any finite universe theory has the problem of explaining what limits its infinity. Where does your universe end and what stops it and what happens when I reach that end?

Because if I reach that end and something stops me or something puts me into a loop, or anything actually, it means another universal medium is holding me back. i.e. your universe is not finite. It has boundaries. And the boundaries require an external universal medium.

Only an infinite universe would explain it.

 

[Mordred]

Not necessarily the term nothing does not reside in quantum mechanics. Quantum fluctuations pervade nothing lol. this article may have some of the answers you seek.
PS its not the best article I've seen but at least it provides some direction for answers.

http://wiki.answers.com/Q/Where_did_the_material_for_the_Big_Bang_come_from

 

[Drakkith]

I guess my point is that at the end of the day any finite universe theory has the problem of explaining what limits its infinity. Where does your universe end and what stops it and what happens when I reach that end?

Because if I reach that end and something stops me or something puts me into a loop, or anything actually, it means another universal medium is holding me back. i.e. your universe is not finite. It has boundaries. And the boundaries require an external universal medium.

Only an infinite universe would explain it.

Or a finite universe that loops back on itself. There is no wall, no boundary. Things just keep expanding. And perhaps a key point here is that the standard model of cosmology does NOT require that the universe be expanding into anything. Per the math it simply doesn't matter. There may or may not be anything else outside our universe, and there may not even be any way to ever tell if there is. But the math that the model is based on doesn't care.

 

[bcrowell]

No one has said "space" is expanding. It is the distance between stars that is expanding.

Either interpretation is OK. They're not empirically distinguishable statements.

 

[cdux]

Or a finite universe that loops back on itself.

If it's looped, what defines the boundaries of its shape? There must be something there that defines the "non part of the universe". How could there be nothing if to have nothing you have to have the absence of non nothing?

 

[Drakkith]

If it's looped, what defines the boundaries of its shape? There must be something there that defines the "non part of the universe". How could there be nothing if to have nothing you have to have the absence of non nothing?

What's outside the universe? I could tell you nothing, or I could say that such a question may not even make sense. Like asking what flavor is blue. Or asking what the volume of 1 second is. Just because there may not be a boundary to the universe, or we may be expanding without expanding INTO anything does not mean that "something" exists "outside" of the universe. To the very best of our knowledge the universe, quite literally, is everything that exists. Asking what exists outside of the universe...is simply nonsensical.

The universe does NOT need to obey our logic. It has proven so time and time again in the past and it will probably continue to do so.

 

[skydivephil]

Surely the phrase outside requires there to be some space. If I am outside my house I I am in a location in space that is beyond the boundary of my house. So therefore isn't it right to say the very phrase "outside" implies a location in space? hence its hard to see how the phrase "outside of space" makes any sense.

 

[Mordred]

I like that analogy skydive nice simple and self explainitary

 

[cdux]

What's outside the universe? I could tell you nothing, or I could say that such a question may not even make sense. Like asking what flavor is blue. Or asking what the volume of 1 second is. Just because there may not be a boundary to the universe, or we may be expanding without expanding INTO anything does not mean that "something" exists "outside" of the universe. To the very best of our knowledge the universe, quite literally, is everything that exists. Asking what exists outside of the universe...is simply nonsensical.

The universe does NOT need to obey our logic. It has proven so time and time again in the past and it will probably continue to do so.

I'm not asking what flavour is blue. I'm asking what color is non-white.

Which come to think of it, I just made your argument, since black could be considered the absence of light and color just a mundane human concept.

However, "color" (universe) would have to pass through a medium to be a color. Is that exotic medium nothing?

For which one could return to me and say "But you just said color is a mundane concept", ah, yes, but here's a catch, we accept that "color"(universe) in consensus physics hence is it not of substance? And if not, is reality nothing?

 

[Mordred]

The simple fact is there is no evidence of a multiverse scenario. We simply do not know if we are one spacetime universe or one of several or an infinite number. There are countless multi verse theorem literature on the web several are posted. Truthfully we don't even know of our own universe is finite or infinite. These are concepts still being studied to determine an answer. Mathematically many of the proposed models make sense however they all have various problems. The big bang best describes the expansion of our own universe. Until we can find evidence outside of our own the question you asked is one that cannot be resolved, only theorized

 

[cdux]

The simple fact is there is no evidence of a multiverse scenario. We simply do not know if we are one spacetime universe or one of several or an infinite number. There are countless multi verse theorem literature on the web several are posted. Truthfully we don't even know of our own universe is finite or infinite. These are concepts still being studied to determine an answer. Mathematically many of the proposed models make sense however they all have various problems. The big bang best describes the expansion of our own universe. Until we can find evidence outside of our own the question you asked is one that cannot be resolved, only theorized

A good theoretical reasoning is that if we can't find an actual reason governing the nature of fundamental properties, then it's logical to assume there may be an infinite or very large number of different sets of laws and it just happens to be in one that works this way.

On the other hand though, it gets tricky when one has to assume the properties of the medium it holds them together. Doesn't it have fundamental properties?

And then what do we get, infinite multiverses?

And then infinite multi-multi-verses?

Perhaps.Then we'd have to explain "why is there infinity?".

Is the actual (whole)universe just the existence of infinity?

But again, "why?".

Or, "How?".

 

[julcab12]

A good theoretical reasoning is that if we can't find an actual reason governing the nature of fundamental properties, then it's logical to assume there may be an infinite or very large number of different sets of laws and it just happens to be in one that works this way.

On the other hand though, it gets tricky when one has to assume the properties of the medium it holds them together. Doesn't it have fundamental properties?

And then what do we get, infinite multiverses?

And then infinite multi-multi-verses?

Perhaps.


Then we'd have to explain "why is there infinity?".

Is the actual (whole)universe just the existence of infinity?

But again, "why?".

Or, "How?".

It's 'ugly' (to me). "Why is there infinity?". It is an idea where (1) equation can be insufficient or (2) unreachable/undefined depending on how you approached it (3)("How") Our limitation(technology) to put value(s)('steps' of larger value on bounds until it tends toward 0) to make sense out of it. BUT it'll end up infinite still. So it boils down to your 'liking' if you are willing to accept emergent(redundant ) infinity OR continue to find some new intuitive solutions to equation OR new model perhaps...

 

[Whovian]

Okay, imagine a one-dimensional Universe consisting of a circle. Not the interior of the circle, just the circular arc surrounding a circular region. This is clearly a finite Universe with no edge.

Now, there are definitely flaws in this analogy, most notably that an outside (the rest of the plane) exists. Try to imagine a circle with no plane to reside in. Nonsensical, but it works. Trying to define a point not on the circle would yield nonsense (Oh, hey! There's a point on this plane I said didn't exist!), and so asking what's outside this Universe would also yield nonsense.

Note that, as people said, trying to apply logic to cosmology can also yield nonsense.

Asking why things happen is, by the nature of science, outside the realm of science. Science is ugly in some ways (like this.) Such questions are probably in the realm of philosophy.

 

[cdux]

Okay, imagine a one-dimensional Universe consisting of a circle. Not the interior of the circle, just the circular arc surrounding a circular region. This is clearly a finite Universe with no edge.

Now, there are definitely flaws in this analogy, most notably that an outside (the rest of the plane) exists. Try to imagine a circle with no plane to reside in. Nonsensical, but it works. Trying to define a point not on the circle would yield nonsense (Oh, hey! There's a point on this plane I said didn't exist!), and so asking what's outside this Universe would also yield nonsense.

Note that, as people said, trying to apply logic to cosmology can also yield nonsense.

Asking why things happen is, by the nature of science, outside the realm of science. Science is ugly in some ways (like this.) Such questions are probably in the realm of philosophy.

Ah, but what you haven't determined is if it's nonsense to reach undefined regions of understanding to begin with. Is it actually nonsense or a lack of a more complete model? In fact, some popular examples of new science concerning cosmology deal with a variation of this very concept, since cases of the appearance of a singularity are rarely accepted as the end of it.

At a basic level one could argue whenever our understanding yields nonsense instead of a clear answer given a certain input then it might mean the understanding might be incomplete. And I don't mean non sense in the sense of probabilistic results since those are a defined answer, even if of course there are ideas interpreting them as subsets of a more complete idea yet to be determined or accepted.

 

[marcus]

...
Note that, as people said, trying to apply logic to cosmology can also yield nonsense.

... Science is ugly in some ways (like this.) ...

We both realize the same objective facts. Distances can increase without any change in the relative position of things----the angles of a triangle do not need to add up to 180, sometimes they don't and the presence of matter affects that. and so on.

I don't see a anything "illogical" or "ugly" about this. So we both are aware of the same realities but we simply adopt different attitudes towards them, which is normal for people to do.

The thing the OP fellow does not seem to grasp is, I would say, that geometry is something we experience and it is NOT something you imagine being viewed by some bizarre creature outside the universe.

We might for instance have the experience of living in a 3D space with a slight positive curvature. this means that with very large triangles we notice a pattern of them adding up to slightly more than 180.

And it means that 3D space is ANALOGOUS to the 2D surface of a ball (where that also happens with triangles.) But it does not mean that our 3D space is automatically the "surface" of some 4D "ball" and that there is something "inside" it and "outside" it. It does not mean that some 4D creature "outside" our 3D space can look at it and see something "round". that is a fantasy that carries the analogy way too far!

All we have then (if we measure a slight positive curvature) is the EXPERIENCE of living in a certain geometry and making measurements in that geometric context. We have no indication or need to imagine, or believe in, anything "outside" of the space we know.

My attitude is that this is not nonsense (your word). Instead it is commonsense---don't pretend to know what you have no evidence for. What we deal with in cosmology is the geometry of the space we live in and which our stars evolved in. We have no indication of any space "outside" of space. So we avoid overextended analogies and stay focused on what we see and know, which is a lot.

My perception of this is it's definitely not illogical, or ugly.

Maybe you were just being funny

 

[Whovian]

Ah, but what you haven't determined is if it's nonsense to reach undefined regions of understanding to begin with. Is it actually nonsense or a lack of a more complete model?

The point was that it's possible to design a reality which seems to conform to the known laws of physics with a finite Universe where "outside" the Universe is meaningless, not that it's te only case.

 

[cepheid]

I think this thread has run its course. The OP's question regarding whether the universe requires something to expand "into" has been addressed: it doesn't. Many other posters have emphasized the experimental nature of science and the fact that it, by necessity, deals only with what is observable and testable. Anything else is wild speculation and/or philosophy, and these things are not permitted in the Cosmology forum. Thread locked.