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## Main Question or Discussion Point

If wormholes connect two areas in spacetime, wouldn't that require 5 dimensions? (an extra dimension past 4d spacetime.)

- Thread starter Jonnyb42
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If wormholes connect two areas in spacetime, wouldn't that require 5 dimensions? (an extra dimension past 4d spacetime.)

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Bill_K

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Well you never can tell, there might be other dimensions. It certainly seems like a popular idea these days, for several reasons. However, are they required to explain General Relativity? Frankly, no. Even in a situation like a wormhole, where spacetime has to bend back and connect to itself, only the curved four-dimensional world we live in has any reality. It may look like extra dimensions are needed to embed that world in some higher dimensional Euclidean space. But since we are confined to our four dimensions, there is no way to detect anything outside that, and it's perfectly consistent to do physics without assuming that anything else exists.

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It is my understanding that wormholes are a theoretical possibilty yet, currently, WITHOUT direct evidence.

Not saying they can't exist, but keep in mind that their existance is currently purely mathematically related.

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Nabeshin

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This bears repeating. Although human minds may require an extra dimension to visualize what's going on here (To use the lower dimensional analogy, if you imagine a wormhole connecting two points on a piece of paper, we extend the "throat" of the hole into the 3rd dimension. You're assuming something similar for 4d spacetime with wormholes), the mathematicsIt may look like extra dimensions are needed to embed that world in some higher dimensional Euclidean space. But since we are confined to our four dimensions, there is no way to detect anything outside that, and it's perfectly consistent to do physics without assuming that anything else exists.

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Ok well, I find that to be crazy.you do not need extra dimensions to curve spacetime.

So can it then be thought of as, scaling?

For instance instead of imagining the x axis bend into the y direction in some regions, can by the same way imagine the x axis

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I am a proponent of "extra-dimensions"

Yet, I find it difficult to find any authoritative/experimental evidence to support this notion.

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I have heard that actually we have more than 10 dimension.. would that be possible?

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I thought wormholes folded space to connect two points.

A simply analogy, if I draw to points on a piece of paper and then fold it in half so they touch, have I used an extra dimension? Of course not.

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If there didn't exist a 3rd dimension you would not be able to fold them and connect the points.A simply analogy, if I draw to points on a piece of paper and then fold it in half so they touch, have I used an extra dimension? Of course not.

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But it does exist, it is already there. There's no need to invoke another dimension.If there didn't exist a 3rd dimension you would not be able to fold them and connect the points.

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But your example is connecting two points in 2d spacetime isn't it, there is not 3rd dimension supposedly, yet you used it to connect the two points.But it does exist, it is already there. There's no need to invoke another dimension.

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The world is 3D last time I checked. The third dimension is there, even if you're not immediately using it (well, actually you are using it because you can't have only 2D in reality).But your example is connecting two points in 2d spacetime isn't it, there is not 3rd dimension supposedly, yet you used it to connect the two points.

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your analogy doesn't have the same dimensions as reality, if it did why would u call it an analogy?The world is 3D last time I checked. The third dimension is there, even if you're not immediately using it (well, actually you are using it because you can't have only 2D in reality).

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Of course it does. To be an analogy it has to be similar, that's all.your analogy doesn't have the same dimensions as reality, if it did why would u call it an analogy?

http://dictionary.reference.com/browse/analogy

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dude, 2d spacetime connecting 2 points through 3rd dimension.Of course it does. To be an analogy it has to be similar, that's all.

http://dictionary.reference.com/browse/analogy

There isn't a 3rd dimension in 2d spacetime...

Are you saying there is 5th dimension in our 4d spacetime?

I'm asking if that's the case.

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What are you taking about?dude, 2d spacetime connecting 2 points through 3rd dimension.

There isn't a 3rd dimension in 2d spacetime...

Are you saying there is 5th dimension in our 4d spacetime?

I'm asking if that's the case.

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My original question is:

How can there be imaginable wormholes connecting two points in our 4d spacetime without an extra 5th dimension.

The paper analogy is a 2d spacetime, connected were imagining a 3rd dimension to bend the paper into. If your saying that we never introduced a third dimension in the 2d spacetime analogy, then your saying, "yes we have a 5th dimension, it's always there."

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Well the way I'm looking at it is that the paper exists within the three dimensions (ignoring others at the moment for simplicity), but we can fold it within those dimensions to join the points.

Think of a balloon, with a piece of string running through the middle. You can 'fold' the balloon so that the ends touch and you never invoke an additional dimension.

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Okay.

- #21

Ryan_m_b

Staff Emeritus

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It's not hard to understand! He's using a 3d piece of paper and folding it to put two distant coordinates next to each other, no extra dimension theredude, 2d spacetime connecting 2 points through 3rd dimension.

There isn't a 3rd dimension in 2d spacetime...

Are you saying there is 5th dimension in our 4d spacetime?

I'm asking if that's the case.

EDIT: He=Jaredandjames

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The paper is supposed to be 2d, that is the point. The real fact that it is 3d, (has thickness) is irrelevant. Then your saying our spacetime has thickness in some 5 dimensions??It's not hard to understand! He's using a 3d piece of paper and folding it to put two distant coordinates next to each other, no extra dimension there

EDIT: He=Jaredandjames

EDIT: I should say, the fact that a real piece of paper is 3d is irrelevant, because it's not really a piece of paper that were using, it's a hypothetical 2d spacetime, that has no 3rd dimension.

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Nabeshin

Science Advisor

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[Note: The piece of paper in what follows is to be thought of a two-dimensional surface, i.e. no thickness]

A simply analogy, if I draw to points on a piece of paper and then fold it in half so they touch, have I used an extra dimension? Of course not.

This is irrelevant, jared. If you want to make your analogy correct, you need to think of it differently. The curvature induced on the piece of paper is a property of the piece of paper and the piece of paper alone. It can be described completely adequately by referring only two two-dimensional coordinates labeled on the paper.

Specifically, you do NOT need a 3rd coordinate to describe the curvature. So while it is true that in every day life to impose this curvature we bend the paper through the third dimension, one does not need to extend this to the universe (as OP would like). That is, the curvature of our universe can be described by referring only to our four dimensions, without any need for invoking a fifth.

The act of "visualizing" a surface necessarily involves an extra dimension. But that

- #24

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Jared Nathan James = my whole name.EDIT: He=Jaredandjames

My point with the 3 dimensions is that we must have them, there is no real object that only exists with 2 dimensions. So we're folding with the three and not needing to invoke another, as per your explanation, if you only use the two to explain you don't need to invoke a third.[Note: The piece of paper in what follows is to be thought of a two-dimensional surface, i.e. no thickness]

This is irrelevant, jared. If you want to make your analogy correct, you need to think of it differently. The curvature induced on the piece of paper is a property of the piece of paper and the piece of paper alone. It can be described completely adequately by referring only two two-dimensional coordinates labeled on the paper.

Specifically, you do NOT need a 3rd coordinate to describe the curvature. So while it is true that in every day life to impose this curvature we bend the paper through the third dimension, one does not need to extend this to the universe (as OP would like). That is, the curvature of our universe can be described by referring only to our four dimensions, without any need for invoking a fifth.

The act of "visualizing" a surface necessarily involves an extra dimension. But thatmeans absolutely nothingabout the existence of such extra dimensions, only that if we wanted to visualize them, we would need them.

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Nabeshin, that is what I understood from the first couple of posts and I realize I just need to study General Relativity to understand curvature fully.

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