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Author Topic: is our 4D space a slice or projection of higher dimensional space?  (Read 2451 times)

Offline chiralSPO

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When people talk about a "higher dimensional universe" I often wonder how these extra dimesnions are supposed to map onto our perceived universe. Is our 4-dimensional space-time a slice of this higher dimensional universe? or a projection? or some combination thereof? or is there some other more complex operator that maps one to the other?

Projections would contain much more information than slices, especially if there is some effect analogous to the anomalous dispersion, which can be taken advantage of in x-ray crystallography to determine the absolute 3-D configuration of a chiral molecule using information from a 2-D projection (in reciprocal space): the chirality of a molecule is a property of its 3-D structure. A perfect projection should not contain enough information to do this, but anomalies in the diffraction pattern allow for back-calculations.

Is it possible that the difference between the three spacial dimensions and time is that time is a projected dimension with an anisotropy due to some "extra information" leaking through from a higher order anisotropic structure, while the spacial dimensions are just a 3-D slice (or projections of isotropic structure)? Does that make any sense whatsoever?
« Last Edit: 21/05/2014 13:41:35 by chiralSPO »


 

Online yor_on

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It's a headache, isn't it. What is a dimension? We have three spatial, one we call 'time'. Time has only one direction , from my birth, to my death. The other dimension then? They just exist, and it doesn't matter from where you measure a distance (assuming you to be at rest with it so to speak), and we prove them through matter. A empty space needs matter to be defined dimensionally as I see it. I'm starting to think that ones local arrow (clock) craves frames of reference to be able to exist, in the same manner as quantum logic (uncertainty, indeterminism) macroscopically falls out into certainties. The moon will be there macroscopically even if I forget to look at it, and time must be there too.
 

Online yor_on

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You might be able to assume that the idea of 'energy' is enough to start a universe and dimensions naturally, but then you also need to prove how and why this 'energy' suddenly came into existence creating it. 'Energy' if we assume it as a property, should have been there before the universe ('clocks' and 'dimensions') as I consider it.
==

It's as everything else also a question of how you like to define the 'container'. If you do it for example from some 'holographic principle', also thinking of it from a equivalence of local constants in 'all points'. Then maybe there are other way to define a birth of a universe than some 'pinprick(s)' of energy inflating into particles dimensions clocks and a universe. By holographic principle I'm just suggesting that there might be ways to define all points in our measurable universe as equivalent (locally defined) and so consisting of a unitary point from some theoretical aspect. But then you need to go from that to the universe we measure on :)
« Last Edit: 22/05/2014 20:25:59 by yor_on »
 

Offline JP

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I don't know---but from what I recall from pop-sci sources (I'm a layperson in this vein of physics), some theories use the slice idea (brane theories) and some use the projection idea (holographic principle). 
 

Offline jeffreyH

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The 3 spatial dimensions and 1 time dimension are not continuous. If you were to consider a point infinitely far from the universe it can be considered to suffer none of the effects of relativity. No time dilation and no length contraction due to gravity. Every point from that position that is nearer to our universe would experience a degree of temporal slowing or physical contraction however infinitesimal. Another dimension can be considered this gradient of change with respect to gravitational sources.As a consequence of this the normal 3D geometry is altered or curved if you prefer, giving yet another dimension. Although these are not dimensions in the sense that we think of spacial direction they are still dimensional. As are fields, which are not visible to us.

When considering dimensions consider the following.

dimension
/dɪˈmɛnʃ(ə)n,dʌɪ-/
noun
noun: dimension; plural noun: dimensions
1.
a measurable extent of a particular kind, such as length, breadth, depth, or height.
"the final dimensions of the pond were 14 ft x 8 ft"synonyms:   proportions, measurements, extent, size;

footage, acreage
"the approximate dimensions of the master bedroom"

a mode of linear extension of which there are three in space and two on a flat surface, which corresponds to one of a set of coordinates specifying the position of a point.

Physics
an expression for a derived physical quantity in terms of fundamental quantities such as mass, length, or time, raised to the appropriate power (acceleration, for example, having the dimension of length time −2).
2.
an aspect or feature of a situation.
"we must focus on the cultural dimensions of the problem"synonyms:   aspect, feature, element, facet, side
« Last Edit: 29/05/2014 22:12:44 by jeffreyH »
 

Offline JP

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The 3 spatial dimensions and 1 time dimension are not continuous. If you were to consider a point infinitely far from the universe it can be considered to suffer none of the effects of relativity.

There's no such thing as a "point infinitely far from the universe" since all points by definition are within the universe. 
 

Offline jeffreyH

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Mathematically there can be a point infinitely far from the universe.
 

Offline JP

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Mathematically there can be a point infinitely far from the universe.

No there can't, since that point would be within the universe.
 

Offline Bill S

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Quote from: JP
No there can't, since that point would be within the universe.

How does that square with various multiverse theories?
 

Offline JP

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Quote from: JP
No there can't, since that point would be within the universe.

How does that square with various multiverse theories?

I'm not sure, but typically if you define a distance you're talking about a geometry within our universe.  Even with brane cosmology or hidden dimensions in string theory, I believe you're dealing with dimensions that are part of our universe--just inaccessible to us.  Of course, this isn't my area of expertise, so someone who does this for a living might have a better answer.
 

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