On 26/07/2013 05:16 AM, clipka wrote:
> String theory postulates that there are indeed - AFAIR - about half a
> dozen extra dimensions, and it is suggested that they may indeed all be
> curled up in this manner, with sizes roughly on the scale of sub-atomic
> particles.

More fully: Some formulations of string theory suggest that the universe 
has as many as 11 spatial dimensions. The obvious question is then "so 
why can't I see any of them?", and the only answer anybody has come up 
with is "well, maybe they're really tiny..."

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Nekar Xenos <nek### [at] gmailcom> wrote:
> I have heard it mentioned in scientific news that scientists have found  
> the fourth dimension and measured it.

You are probably confusing it with something else.

-- 
                                                          - Warp

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On Fri, 26 Jul 2013 09:36:45 +0200, Orchid Win7 v1 <voi### [at] devnull> wrote:

> On 26/07/2013 05:16 AM, clipka wrote:
>> String theory postulates that there are indeed - AFAIR - about half a
>> dozen extra dimensions, and it is suggested that they may indeed all be
>> curled up in this manner, with sizes roughly on the scale of sub-atomic
>> particles.
>
> More fully: Some formulations of string theory suggest that the universe  
> has as many as 11 spatial dimensions. The obvious question is then "so  
> why can't I see any of them?", and the only answer anybody has come up  
> with is "well, maybe they're really tiny..."

That one is easy. Simply because our eyes can only see in 2d. We can  
perceive 3d images because of the stereoscopic effect of having 2 eyes.

I think it is possible that this universe itself may be 4d or even more  
dimensions, but we can only perceive a 3d slice of it.

If a 4d being has only 2d and 3d "perceptors", how will it know that it is  
4d?

-- 
-Nekar Xenos-

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On Fri, 26 Jul 2013 06:16:05 +0200, clipka <ano### [at] anonymousorg> wrote:

> Am 25.07.2013 19:24, schrieb Nekar Xenos:
>> Now for the part that I don't understand at all:
>>
>> I have heard it mentioned in scientific news that scientists have found
>> the fourth dimension and measured it.
>> How can you measure a dimension? I don't understand that. If the 4th
>> dimension has a "thickness", what then is the thickness of the 3rd
>> dimension. It makes absolutely no sense to me at all.
>
> Those news actually make no sense for yet another reason: Scientists  
> around the world should know better than to call a newly discovered  
> dimension the "4th dimension", as the term is already firmly associated  
> with time.
>
> But yes, there is some sense to measuring a dimension: Imagine the  
> universe was made up of only one spacetime dimension, and one additional  
> dimension curled up in a small loop; the universe would then have the  
> shape of a cylinder surface stretching into infinity(*) along the  
> spacetime dimension. But the other dimension would be finite, and could  
> probably be measured.
>
> (*Alternatively, spacetime might also be finite, but on a much larger  
> scale, in which case we'd get a torus surface.)
>
> String theory postulates that there are indeed - AFAIR - about half a  
> dozen extra dimensions, and it is suggested that they may indeed all be  
> curled up in this manner, with sizes roughly on the scale of sub-atomic  
> particles.
>

It still doesn't make sense to me ...

-- 
-Nekar Xenos-

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On Fri, 26 Jul 2013 12:35:45 +0200, Warp <war### [at] tagpovrayorg> wrote:

> Nekar Xenos <nek### [at] gmailcom> wrote:
>> I have heard it mentioned in scientific news that scientists have found
>> the fourth dimension and measured it.
>
> You are probably confusing it with something else.
>
It may be more dimensions and not just the 4th dimension.

-- 
-Nekar Xenos-

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>> More fully: Some formulations of string theory suggest that the
>> universe has as many as 11 spatial dimensions. The obvious question is
>> then "so why can't I see any of them?", and the only answer anybody
>> has come up with is "well, maybe they're really tiny..."
>
> That one is easy. Simply because our eyes can only see in 2d. We can
> perceive 3d images because of the stereoscopic effect of having 2 eyes.

That doesn't explain why visible objects around us only move in 3 
dimensions. If there were more dimensions and we should somehow only 
"see" 3 of them, we should see objects constantly zipping into and out 
of the 3D slice we can perceive.

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On 26/07/2013 8:47 PM, Orchid Win7 v1 wrote:
>>
>
> That doesn't explain why visible objects around us only move in 3
> dimensions. If there were more dimensions and we should somehow only
> "see" 3 of them, we should see objects constantly zipping into and out
> of the 3D slice we can perceive.


Why would they move in the other dimensions, if they are only moved in 
our three or four?
What force would move them?

-- 
Regards
     Stephen

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On 26/07/2013 08:57 PM, Stephen wrote:
> On 26/07/2013 8:47 PM, Orchid Win7 v1 wrote:
>>>
>>
>> That doesn't explain why visible objects around us only move in 3
>> dimensions. If there were more dimensions and we should somehow only
>> "see" 3 of them, we should see objects constantly zipping into and out
>> of the 3D slice we can perceive.
>
>
> Why would they move in the other dimensions, if they are only moved in
> our three or four?
> What force would move them?

Why would they *not* move in the other dimensions? Why would all forces 
just happen to be perpendicular to those dimension?

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On 26/07/2013 9:58 PM, Orchid Win7 v1 wrote:
>
> Why would they *not* move in the other dimensions? Why would all forces
> just happen to be perpendicular to those dimension?

I thought I had said, why would a force be applied to them?
If they are dimensions that not much happens in.

-- 
Regards
     Stephen

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Orchid Win7 v1 <voi### [at] devnull> wrote:
> > That one is easy. Simply because our eyes can only see in 2d. We can
> > perceive 3d images because of the stereoscopic effect of having 2 eyes.

Perceiving three-dimensional space is not related to stereoscopic vision.
It helps, but it isn't what makes it three-dimensional perception.

> That doesn't explain why visible objects around us only move in 3 
> dimensions. If there were more dimensions and we should somehow only 
> "see" 3 of them, we should see objects constantly zipping into and out 
> of the 3D slice we can perceive.

Talking about slices is, as I see it, nonsensical. A camera doesn't see
a "slice" of the three-dimensional space. It sees a *projection*, which
is a completely different thing. If there were a fourth dimension that's
like the other three, we would likewise see a three-dimensional projection
of it, not a slice.

Anyway, according to general relativity, spacetime *is* four-dimensional,
and everything actually moves in the fourth dimension all the time.
Moreover, the reason why gravity (seemingly) accelerates objects is
because of this movement in 4-dimensional spacetime. (The spacetime is
curved, which is what causes the apparent acceleration. In reality it's
not acceleration but inertia.)

So, technically speaking, when you drop an object, you are seeing movement
in the fourth dimension (or, more precisely, the effects of the curvature
of spacetime, from which we see a 3-dimensional projection, which is what
causes us to perceive it as accelerating motion, even though in reality
it's just inertial motion. It's a similar idea as how a railroad seems
to converge at the horizon in a photograph.)

-- 
                                                          - Warp

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