Strings; Existing in One Dimension

[Wormwood]

I get that strings exist as an expression of one dimensional existence, but how can something exist in one dimension? From my understanding this is more of a mathematical expression than an actual object existing in one dimension, but if this is a viable theory, then that math actually does mean something. So how could something exist as a one dimensional object? Could it have only height, and no width or length for example? This seems impossible.

 

The only dimension I could see existing on it's own, would be time (even though without matter the concept would be moot). I'm sure this is an incorrect assertion, but why? What other dimension could stand alone?

[Sayonara]

Is there any particular reason why something should not exist in one dimension?

[Wormwood]

How could it? How could something have only height for example? What has height? Any sort of line representing height has at least some miniscule width. It seems like time is the only dimension that could dodge this pitfall.

[thedarkshade]

What about the fundamental understandings of geometry (line, point)?

 

And String Theory requires 11 dimensions...

 

There is a part III on NOVA titled "Welcome to the 11th dimension"? Seen it?

[Wormwood]

What about the fundamental understandings of geometry (line, point)?

I thought about that, but those things are just symbolic representations used in math. In physical reality, anything with height will have at least some miniscule width. Even a point technically has measurments when expressed in reality (i.e. a dot on a page).

 

And String Theory requires 11 dimensions...

Only 4 of which have any profound meaning for us. I can't experience dimensions that are tightly coiled on themselves. Are you saying it was one of these other dimensions being expressed in strings?

 

There is a part III on NOVA titled "Welcome to the 11th dimension"? Seen it?

No, but I will look into it thanks.

[thedarkshade]

I thought about that, but those things are just symbolic representations used in math. In physical reality, anything with height will have at least some miniscule width. Even a point technically has measurments when expressed in reality (i.e. a dot on a page).

Physically right! Any point, no matter how small, still has a microscopic height and width!

 

Only 4 of which have any profound meaning for us. I can't experience dimensions that are tightly coiled on themselves. Are you saying it was one of these other dimensions being expressed in strings?

I can't either, no one actually can. But they are thought to exist and is one of string's theory predictions. There were some models of string theory that request up to 20 dimensions, but after all 5 models came together, the definite thing (according to Edward Witter) was that there must me 11 dimensions so the theory can make sense!

 

No, but I will look into it thanks.

Any time! They're all available on youtube. The whole three parts!

[ydoaPs]

Any time! They're all available on youtube. The whole three parts!

 

If you're worried about copyright infringement(loads of videos get removed from youtube for this), you can watch it from Nova's website.

[5614]

What about the fundamental understandings of geometry (line, point)?

I'm a physics student and I was once told that physicists are good at some career (can't remember what, some sort of computational something, maybe) because of their problem solving skills and how they are comfortable with the concepts of 0, infinity, points and lines etc. I couldn't appreciate why understanding what a point is could be so useful...

 

Now I was about to say that an electron really is a point charge, i.e. that a physical entity really is zero dimesional... but then I came across this:

http://scienceworld.wolfram.com/physics/ElectronRadius.html

so now I'm not so sure. Reading more over here:

http://en.wikipedia.org/wiki/Classical_electron_radius

it says that in things like non-relativistic Thomson scattering the electron radius (a classical property) is used. But that other modern physics experiments (none actually listed) indicate that the electron really is a point charge.

 

In fact the Wiki article is even titled classical electron radius... hmm... the electron was my example of a physical 0 dimensional entity - I think it still is, although I'm not so sure now!

 

Back to your question, the path of a photon is 1D, but that's just a path, not a physical entity. Aww, I don't like your question! But things can exist in 0 and 1, 2, 3 etc. dimensions! (sorry for the unsatisfying, non-convincing & proof-lacking response!)

[Wormwood]

Back to your question, the path of a photon is 1D, but that's just a path, not a physical entity. Aww, I don't like your question! But things can exist in 0 and 1, 2, 3 etc. dimensions! (sorry for the unsatisfying, non-convincing & proof-lacking response!)

Thanks.

 

Just to clarify, there is no way that the one dimension is time right?

[Klaynos]

Thanks.

 

Just to clarify, there is no way that the one dimension is time right?

 

Normally when we talk about 1D objects we are referring to spacial dimensions, allowing them to also have a 1D time dimension.

 

Just a point to note, mentioned above it says strings require 11 spacial dimensions, this actually isn't true as there are many variants of string theory and some require more or less than this, and one I was reading about a few months ago actually required 2 (or more I seem to recall) time dimensions...

[Wormwood]

Normally when we talk about 1D objects we are referring to spacial dimensions, allowing them to also have a 1D time dimension.

But if time is an actual dimension, wouldn't that make these objects 2d instead? Also, wouldn't that strengthen the idea that time is the only dimension that can stand alone? I'm not trying to be difficult; I just want to understand this concept.

 

Just a point to note, mentioned above it says strings require 11 spacial dimensions, this actually isn't true as there are many variants of string theory and some require more or less than this, and one I was reading about a few months ago actually required 2 (or more I seem to recall) time dimensions...

That sounds interesting; do you know what that version of string theory is called?

[Klaynos]

But if time is an actual dimension, wouldn't that make these objects 2d instead? Also, wouldn't that strengthen the idea that time is the only dimension that can stand alone? I'm not trying to be difficult; I just want to understand this concept.

 

That sounds interesting; do you know what that version of string theory is called?

 

People normally talk about time and space seperately when talking about xD objects... It's just traditional...

 

and...

 

http://www.newscientist.com/channel/fundamentals/mg19626251.400-time-gains-an-extra-dimension.html

[hermanntrude]

- I think it still is, although I'm not so sure now!

 

That would be the uncertainty principle

[Wormwood]

People normally talk about time and space seperately when talking about xD objects... It's just traditional...

 

and...

 

http://www.newscientist.com/channel/...dimension.html

Thanks for the link.

 

So which dimension do strings exist in then if not time?

[fredrik]

I thought about that, but those things are just symbolic representations used in math. In physical reality, anything with height will have at least some miniscule width. Even a point technically has measurments when expressed in reality (i.e. a dot on a page).

 

Alot of things are symbolic representations and idealisations.

 

Even what most of us consider to be common sense, like the 3 dimensional intuition alot of us have, which makes us project everything supposedly having to do with physics into litteral 3 dimensional pictures - even THIS is a idealisation that I think we evolve simply because it has been very successful. Wether it's "fundamentally accurate" at all scales we simply don't know. All we can do is guess and keep questioning.

 

And I like to think of "points" and "lines" as a representation of our knowledge of the physical reality, rather than reality itself. A point, say a triple (x,y,z) somehow represents a piece of information, a "data point", to add to my collection of incomplete informaiton.

 

I think the persistent and natural desires to always, to always try to make litteral visual paintings of physics may be inhibiting, because somethings probably get far harder to understand that what otherwise be necessary.

 

I think there is no more thinking behind the idea that a string is one-dimensional, than it is behind the idea that previous elementary particles are 0-dimensional. The idea is I guess to try to add degrees of freedom, and see if that solves anything. When the qft machinery is applied to this stuff, consistency requirements in accordance to made assumptions (right or wrong), forces the introduction of more dimensions. There was no direct experimental support for these, the where suggested as a consistency requirement coming out of theoretical reasoning based on a particular set of assumptions.

 

/Fredrik

[Norman Albers]

I am playing with interpretation of Schwarzschild metric space inside an event horizon. One can see that asymptotic to the horizon, the speed-of-light for transverse propagation becomes imaginary, and this speaks of attenuation in the two angular dimensions. If this is so, there are only radial oscillations! Voila'.

[Eric 5]

String theory is based on the assumption that there are extra spatial dimensions to the three that we are familiar with. These extra dimensions are assumed to be real physical things that occupy a space or area and can be located, just like the three spatial dimensions that we are accustom to. My question is, if these extra dimensions are something that can be searched for through some scientific means, then it would follow that they have some physical quality about them, they exist in such a way that they can be perceived in some manner. And if these extra dimensions are extra to the three spatial dimensions that we are familiar with, then that would mean that the first three dimensions have some sort of physical quality about them that allows them to be perceived as something that occupies a space or area.

 

If string theory states that the first three spatial dimensions are real physical things, then what are the first three dimensions made of that allows them to be considered as real physical things that can have extras? As of right now all reference books that include a definition for spatial dimensions, none of them say that spatial dimensions are real physical things. The reference books do agree that the term spatial dimension is used in conceptual models to communicate size or location of a particular object or mathematical concept. Spatial dimensions are numbers given to an area to convey the size, i.e. length, width, height. The concept of three spatial dimensions are used by man to communicate the size and or location of real or imagined objects.

 

Dimensions are not things that are measured, but are numbers given to things that man so desires to give them to. If spatial dimensions were real physical things that could be located in space, then these first three dimensions themselves would have dimensions. That means that the first dimension would have its own set of dimensions that is separate from the second dimension, and the third. If spatial dimensions are real physical things, and not a man made concept, then that would mean that these first three spatial dimensions are naturally occurring, and existed before mankind. So if this is true that spatial dimensions have been around before man then that would mean that at some point in time someone would have discovered at least one of these physical things and gave it the label of dimension. Who was this person? If man is looking for extra dimensions then it follows that at one time in history he had to stumble across or find the first three. Yet no one is credited with the discovery of the first three spatial dimensions.

 

For all of you who BELIEVE that the first three spatial dimensions are real things that can have extras please share your insights. Remember that the first three dimensions are used by man to describe directions such as: up/down (height), Forward/backward(depth), left/right(width). So these extra dimensions, what are they really ? Extra up’s, down’s, left’s, right’s, forward’s, backward’s? Also remember that the directions that the first three dimensions describe are all based on the viewpoint of the observer, and are given the significance of what direction is by the observer. Man is not observing an actual physical thing and then describing it. If dimensions were true physical things then they would be the same to all observers, and not open to interpretations by the observer. Again, dimensions are a concept.

[Norman Albers]

Directions are completely relative, but what is essential is orthogonality. We are free to choose any locally orthogonal basis in which to express physics. We can move in x independently of y,z, say, and forces and energy are analyzed well in an appropriately chosen coordinate system.

[Eric 5]

That would be the uncertainty principle

 

Directions are completely relative, but what is essential is orthogonality. We are free to choose any locally orthogonal basis in which to express physics. We can move in x independently of y,z, say, and forces and energy are analyzed well in an appropriately chosen coordinate system.

 

So what is your opinion of string theory and extra dimensions?

[Norman Albers]

It would be cool if some of the ideas from string theory could help mature our theory of the vacuum represented in four dimensions. A. Lisi's "Incredibly Simple Theory of Everything" is couched in 4-space. My colleague 'solidspin' is constructing quantum field theory outside the light cone. I am struck by how we have to make assumptions to interpret physics inside black holes. I thus offer the idea for consideration that physics is not equivalent there, and that the expression of energy in three spatial dimensions which we enjoy is not so except near the singular center. Then again, if Puthoff is right, interiors are a figment! What I share with him is a feeling of complete unification of gravitation and electromagnetism basically from dialing everything up from the "zero-point fields". The electric permittivity of "free space" is a locally experienced thing, and we allow ourselves to step back and say, ah, gravitation is the intensifying of this field, like a lens to light. I have not dealt yet with the strong force and helicity still scares me (though this will be coming out in the efforts I mentioned above), but I have some faith that ideas comprising a few constants and a few geometries will move us further.

[Sayonara]

How could it? How could something have only height for example? What has height? Any sort of line representing height has at least some miniscule width. It seems like time is the only dimension that could dodge this pitfall.

 

Just by being.

 

It's when objects claim to be zero dimensional that you want to start thinking about writing in with a complaint.

[Norman Albers]

I described a possible vacuum physics state where light and matter waves do not travel "sideways" . In the interior, nearer to the event horizon of a black hole, the construction of transverse (sideways on a sphere) waves is strongly absorbing, not propagating. This is like curled-up dimensions, no?

[Eric 5]

Originally Posted by Wormwood

How could it? How could something have only height for example? What has height? Any sort of line representing height has at least some miniscule width. It seems like time is the only dimension that could dodge this pitfall

 

 

Just by being.

 

It's when objects claim to be zero dimensional that you want to start thinking about writing in with a complaint.

 

 

Can you give an example of any real physical thing that only has one dimension?

 

Your answer of "just by being" does not answer the question. It begs the question-- Just by being what?

[Klaynos]

Originally Posted by Wormwood

How could it? How could something have only height for example? What has height? Any sort of line representing height has at least some miniscule width. It seems like time is the only dimension that could dodge this pitfall

 

 

 

 

 

Can you give an example of any real physical thing that only has one dimension?

 

Your answer of "just by being" does not answer the question. It begs the question-- Just by being what?

 

I can give you an example of a 1D object, a semiconductor quantum wire, I can even give you an example of a 0D object, in this case what we talk about as being 0D is the electron constriction, and is actually 0D.

[Sayonara]

Can you give an example of any real physical thing that only has one dimension?

See very well timed post by Klaynos.

 

Your answer of "just by being" does not answer the question. It begs the question-- Just by being what?

Yes, it does rather beg the question, you are right. But on the other hand exactly the same answer can be given for an object of any dimensionality; what I was trying to get across is that there is no reason to view a one dimensional entity as being any more or less peculiar than a two or three dimensional entity.