Tagged Questions

6
votes
1answer
160 views

A Game Of The Number Of Space-Time Dimensions

Holger Bech Nielsen, one of the founders of string theory, has apparently just played some sort of game between different potential dimensions for space-time and reached the conclusion that D4 wins in ...
2
votes
2answers
112 views

Do we live in an integer dimension?

I have read that there exist non-integer fractal dimensions and the images generated from these dimensions look organic and they seem to provide a new way of describing the world around us, which ...
1
vote
0answers
91 views

Higher dimensions

1) How we determine whether the higher dimensions are Unstable or Unpredictable? Or on the basis of what assumption we make this prediction? (Source of Image: Max Tegmark. See also this Wikipedia ...
2
votes
1answer
163 views

Why does the universe exhibit three large-scale spatial dimensions? [duplicate]

Possible Duplicate: Is 3+1 spacetime as privileged as is claimed? Regardless of your favorite theory of how many dimensions the universe has in total, the universe seems to have a deep ...
2
votes
2answers
190 views

Did the universe always have 4 space time dimensions?

Is the dimensionality of spacetime in all usual models constant?
1
vote
1answer
138 views

Is there a relation between the number of dimensions of space time and the number of fundamental forces?

Is there a relation between the number of dimensions of space time and the number of fundamental forces? Also, did the universe always have 4 space time dimensions? And could there exist a world ...
6
votes
5answers
358 views

More than one time dimension

We know that space-time dimensions are 3+1 macroscopically, but what if 2+2? Obviously it is tough to imagine two time dimensions, but mathematically we can always imagine as either having two ...
5
votes
1answer
329 views

Intuition for multiple temporal dimensions

It’s easy, relatively speaking, to develop an intuition for higher spatial dimensions, usually by induction on familiar lower-dimensional spaces. But I’m having difficulty envisioning a universe with ...
4
votes
1answer
121 views

Limit on space-time dimension from susy

I read an argument saying that it would be impossible to write down a super-symmetric theory in more than 11 dimensions, this limit coming from the dimension of the Clifford algebra that goes as ...
3
votes
2answers
408 views

Do we live in a world with 4 or more dimension?

A NOVA show have told the audience that we are live in 3 dimensional world, the world we lived in is compose by 3 element: the energy, matter, space. By the time Einstein have invented the ...
13
votes
3answers
506 views

Can light exists in $2+1$ or $1+1$ spacetime dimensions?

Spacetime of special relativity is frequently illustrated with its spatial part reduced to one or two spatial dimension (with light sector or cone, respectively). Taken literally, is it possible for ...
3
votes
2answers
594 views

Why does string theory require 9 dimensions of space and one dimension of time?

String theorists say that there are many more dimensions out there, but they are too small to be detected. However, I do not understand why there are ten dimensions and not just any other number? ...
0
votes
0answers
25 views

How can we know the size of a dimension? [duplicate]

Possible Duplicate: Measuring extra-dimensions I was watching a layman's documentary and it said: "The 11th dimension is incredibly small, like a long tube about $10^-30m$ in diameter". ...
-4
votes
1answer
205 views

What do scientists believe about existence in dimensions? [closed]

I couldn't really think of a suitable question title, I'm not sure if it's completely related or not. But this is as far as I know (well, I thought it all up last night and it seemed extremely ...
3
votes
2answers
191 views

About space-time and its four dimensions

I explained to someone I know about General Relativity (as much as I know). He said that he didn't see how it could be correct. He argued: How is 4-dimensional space-time space different to ...
4
votes
3answers
568 views

Why are there 4 Dimensions and 4 Fundamental Forces?

Is it a coincidence that there are four fundamental forces and four spacetime dimensions ? Does a universe with three spacetime dimension contain four fundamental forces? Can magnetism be realized in ...
14
votes
2answers
472 views

Has the concept of non-integer $(n+m)$-dimensional spacetime ever been investigated by theoretical physicists?

The following image serves to aid the reader in understanding the "privileged character" of $3+1$-spacetime. The wikipedia article on spacetime, and the sub-article "The priveleged character of ...
6
votes
2answers
366 views

Some questions regarding $n+m$-dimensional spacetime [duplicate]

Possible Duplicate: Has the concept of non-integer $(n+m)$-dimensional spacetime ever been investigated by theoretical physicists? The following image: serves to aid the reader in ...
1
vote
3answers
224 views

Is there a single metric for a given system?

Let imagine a tunnel that connect two distant places at the globe (eastern-western or north-south) There are a lot of posible "distances" or metrics, defined by maps, routes, "as the crow flies", ...
22
votes
5answers
1k views

Is 3+1 spacetime as privileged as is claimed?

I've often heard the argument that having 3 spatial dimensions is very special. Such arguments are invariably based on certain assumptions that do not appear to be justifiable at all, at least to me. ...
7
votes
7answers
1k views

Why are extra dimensions necessary?

Some theories have more than 4 dimensions of spacetime. But we only observe 4 spacetime dimensions in the real world, cf. e.g. this Phys.SE post. Why are the theories (e.g. string theory) that ...
1
vote
1answer
444 views

What is the 4th dimension? [closed]

I have heard before that the 4th dimension is time, however, another theory makes a lot more sense to me. This is that the 4th dimension is the third dimension stacked on top of each other in a ...
8
votes
6answers
1k views

Experimental evidence of a fourth spatial dimension?

As human beings, we observe the world in which we live in three dimensions. However, it is certainly theoretically possible that more dimensions exist. Is there any direct or indirect evidence ...
31
votes
5answers
2k views

Does Coulomb's Law, with Gauss's Law, imply the existence of only three spatial dimensions?

Coulomb's Law states that the fall-off of the strength of the electrostatic force is inversely proportional to the distance squared of the charges. Gauss's law implies that a the total flux through a ...