Why universe appears to have only 3 spatial + 1 time dimension

[Parametric]

Because one 3 dimensional view can be observed at a time or at once.

Edited January 26, 2013 by Parametric

[DarkStar8]

Albert Einstein NEVER said Time is a dimension!!

Spacetime is 4D.

In another thread I argued that by condensing a region of Spacetime within a smaller volume, into a spatial 4D direction, the rate of Time is naturally slowed.

Next time you look at a star field screen saver on your PC then contemplate all directions of motion.. Forward & Backward, Up & Down, Left & Right,and.... In and Out.

Why don't we see In and Out as a dimension? It is because any motion within it towards IN produces free energy that opposes motion,(electrostatic forces)while all the other dimensions require the storage and then expulsion of energy to produce motion.

Sometimes when I walk down a narrow street on my way to work I imagine as I move ever closer to distance objects that I am observing them at higher and higher magnification.Does anyone else?

[SamBridge]

Time is often treated as dimension and is used pretty frequently in the dimensional analysis of most fields. It changes coordinates in and effects other variables and outputs just as other dimensions can.

[swansont]

Albert Einstein NEVER said Time is a dimension!!

 

At best this is semantics. He certainly treats time as a variable that is orthogonal to the spatial ones. From early on in On The Electrodynamics of Moving Bodies:

 

"To any system of values x, y, z, t, which completely defines the place and time of an event in the stationary system …"

 

4 independent variables.

[ajb]

No one really knows why 3+1 dimensions.

 

It might be that we live in higher dimensions, or even that dimensions are not really the correct notion. It could be that the low energy limit of some larger theory gives us an effective 3+1 dimensional theory. No one really knows.

[DarkStar8]

I'd like to say more but it is unfair to continue here when I set up another thread.

It is strange though that both Time and Size vary but Time is treated as a dimension yet scale isn't.

Edited January 27, 2013 by DarkStar8

[SamBridge]

A dimension just describes the location of something in n dimensional space, sometimes the way the location of something changes cannot be described with an equation that uses only 3 dimensions, like the hypercube for example. You could say the cube is somehow magically expanding and shrinking at random angles, or you could go for the mathematically simpler way and just use a 4th dimension.

Edited February 1, 2013 by SamBridge

[ACG52]

Sam, a dimension is direction of possible movement. Forward-back, up-down, left-right, are the three known spatial dimensions.

[derek w]

Sam, a dimension is direction of possible movement. Forward-back, up-down, left-right, are the three known spatial dimensions.

Movement of what?

[michel123456]

Sam, a dimension is direction of possible movement. Forward-back, up-down, left-right, are the three known spatial dimensions.

Following this definition time is not a dimension.

[SamBridge]

Sam, a dimension is direction of possible movement. Forward-back, up-down, left-right, are the three known spatial dimensions.

Well what I'm saying is it takes n coordinates to descrie something in n dimensional space. If you want to describe the 4 dimensional coordate of something you use [x,y,z,t]. If you want 3 dimensions its [x,y,z] and 5 it's [x,y,z,t,u] and ect. Direction comes from using vectors or slopes in those dimensions. If I have the dimension time, just saying that doesn't mean anything, but if I say the 4th dimension coordinate increases according to some equation as other dimensions increase or decrease then I have something.

Time is definitely a dimension because you can describe the 4 dimensional location of something using time. In the spacial coordinates (x,y,z) at time (t). A coordinate in time is like a location in the past or present or future.

Edited February 1, 2013 by SamBridge

[michel123456]

Well what I'm saying is it takes n coordinates to descrie something in n dimensional space. If you want to describe the 4 dimensional coordate of something you use [x,y,z,t]. If you want 3 dimensions its [x,y,z] and 5 it's [x,y,z,t,u] and ect. Direction comes from using vectors or slopes in those dimensions. If I have the dimension time, just saying that doesn't mean anything, but if I say the 4th dimension coordinate increases according to some equation as other dimensions increase or decrease then I have something.

Time is definitely a dimension because you can describe the 4 dimensional location of something using time. In the spacial coordinates (x,y,z) at time (t). A coordinate in time is like a location in the past or present or future.

Yes. a location, I agree.

The mainstream states that an object in space can be at many such locations.

The mainstrean interpretation says that an object is (was/will be) at T1, T2, T3 and represents the whole object as a line expanding in spacetime.

 

My own pet theory states that those locations are mutually exclusive, the same way that spatial locations are mutually exclusive.

When an object is at location T1, it cannot be at T2 or T3. When the object is at T1, coordinates T2 and T3 are empty.

[SamBridge]

Yes. a location, I agree.

The mainstream states that an object in space can be at many such locations.

The mainstrean interpretation says that an object is (was/will be) at T1, T2, T3 and represents the whole object as a line expanding in spacetime.

 

My own pet theory states that those locations are mutually exclusive, the same way that spatial locations are mutually exclusive.

When an object is at location T1, it cannot be at T2 or T3. When the object is at T1, coordinates T2 and T3 are empty.

I'm not really sure what you're saying exactly, but not every part of nature is some Cartesian function.

[michel123456]

Because one 3 dimensional view can be observed at a time or at once.

One could argue that we observe only a two-dimensional view at once. That is the reason why we recognize what a still picture represents. A movie is 3D (2D picture + time), and a "3D movie" is in reality 4D.

Edited February 2, 2013 by michel123456

[ACG52]

 

 

Following this definition time is not a dimension.

 

 

That is correct. Time is not a spatial dimension.

[SamBridge]

Time isn't a spacial dimension, but this does not mean it isn't a dimension at all. In contemporary theoretical physics there's at least 6.

[ACG52]

M-theory has 10 spatial dimensions and one temporal dimension.

[derek w]

Space is nothingness,nothingness does not have dimensions,it would be the interactions between sub-atomic particles that creates dimensions?

The universe didn't start with a 3D space that was then filled.

The sub-atomic particles create a distorted space.

Edited February 3, 2013 by derek w

[SamBridge]

Space is nothingness,nothingness does not have dimensions,it would be the interactions between sub-atomic particles that creates dimensions?

The universe didn't start with a 3D space that was then filled.

The sub-atomic particles create a distorted space.

Space is not nothingness and if it was we would not be here because space contains all the dimensions.

Edited February 3, 2013 by SamBridge

[Zvonko]

I'd like to say more but it is unfair to continue here when I set up another thread.

It is strange though that both Time and Size vary but Time is treated as a dimension yet scale isn't.

Your comment resonates with and idea I have been playing with for a while, and I'm wondering if we're considering the same idea. We talk about the expansion of space from the big bang, and have found mathematical correlations/causations to give some level of confidence. But instead of the universe expanding, consider if it has a limited circumference (just for the sake of expressing my final idea), and that the scale is changing i.e. we (and everything) due to gravity are continually shrinking, or falling into a gravity well at a rate that gives us the perception that the universe is expanding. Don't know if I'm being clear here but what I have so far come out with with this thought experiment is that whether everything in the universe is getting further away from us could potentially be explained mathematically if it was not the universe moving away from us but us falling (accelerating as that's what gravity does) further inward....or shrinking into the gravity well. I know, pure conjecture, but I would love to have this idea challenged to expose why they must be wrong. In these thought experiments, it seems that mathematical integrity is maintained, albeit as an inverse function. I think I have inadvertantly led myself down the 'opposites' philosophy perspective, but there seems to be a mathematical consistency here that indicates that it is a matter of perspective. But looking at it this way does expose gravity in a new light. Opinions/thoughts?

[SaganWannaBeWannaBe]

Kind of reminds me of the Big Bang Theory scene:

 

Sheldon: I recently had a dream that I was giant, but everything around me was to scale, so it all looked normal.

Leonard: How did you know you were a giant if everything was to scale?

Sheldon: I was wearing size "a million" pants.

 

I guess in your thought experiment you need to find the "size tag" that let's us know the expansion is actually a result of a changing scale versus actual expansion. On another note though, I believe the notion of expansion is different from what we usually think. It's not "here's a big room, and there's a balloon (the universe) in it that's getting bigger". It's that the room itself is in some sense expanding, but not within another bigger room.

Edited October 10, 2013 by SaganWannaBeWannaBe

[BusaDave9]

Albert Einstein NEVER said Time is a dimension!!

Spacetime is 4D.

Uhm . . Yes, he did say time is the 4th dimension. That's his General Theory of Relativity. Time is the 4th dimension. He is the one that coined the word "spacetime" to encompass all 4 dimensions.

You say spacetime is 4D

Space is 3 dimensional and time is the 4th dimension. Together they make up the 4 dimensional spacetime continuum. I don't understand your position and I'm not sure you do either.

[michel123456]

Kind of reminds me of the Big Bang Theory scene:

 

Sheldon: I recently had a dream that I was giant, but everything around me was to scale, so it all looked normal.

Leonard: How did you know you were a giant if everything was to scale?

Sheldon: I was wearing size "a million" pants.

 

I guess in your thought experiment you need to find the "size tag" that let's us know the expansion is actually a result of a changing scale versus actual expansion. On another note though, I believe the notion of expansion is different from what we usually think. It's not "here's a big room, and there's a balloon (the universe) in it that's getting bigger". It's that the room itself is in some sense expanding, but not within another bigger room.

 

The "size tag" may be given by acceleration.

By analogy, an observer in constant motion cannot know whether he moves or not. An observer in accelerated motion can understand his motion.

The same should go with scaling.

Scaling at an accelerated pace should be knowable. And I remember one other member on this same forum explaining very well that scaling, by its geometric nature, is linked to acceleration. I'll have to dig a bit.