# A theory for a FIFTH dimension .

#### Don Cristo

a theory for a FIFTH dimension.....

All this talk about dimensions I am sure has bored a number of you, although here is another theory! (If it has been thought of before, I apologise!)

Bearing in mind 'time' is established as the 4th dimension, it occured to me that there must in turn be a 5th dimension - one that seemed so blindingly obvious. So I thought to myself, the 5th dimension may actually be THE MATTER ITSELF! Here is my arguement:

Matter makes up all that is everything. Without it,the other dimensions could not exist. 'Height','Depth','Length' and 'Time' must all occur within something. That 'something', as far as I can understand, has got to be the 'Matter' itself.

Is this absurd? Yes, although if time is a possible dimension,then one must not overlook the possibility of matter being a true dimension in itself! Just as 'Time' may be a dimension, as objects cannot exist if they werent there for a certain amount of time. Well - just as an object must exist for a certain amount of time - the matter that makes up the object in the first place must exist within something! That something being 'Matter' hence, the 5th Dimension.

What do you think?

NOTE - I am a mere babe-in-arms of 16 years old, so this may be one of the reasons why my theory is so poor!

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#### HallsofIvy

Homework Helper
Respond to it?

The gist of your post is "I don't know what the word 'dimension' means."

A dimension is a number necessary to precisely specify an event.

Physicists say that time is the "fourth dimension" because an event itself is defined as something that occurs at a specific point at a specific time. There are plenty of events that have nothing to do with mass.

(I am reminded of the very first "Dr. Who" episode "An Unearthly Child" in which the child in question mystifies her physics teacher by insisting that the "fifth dimension" is ... (are you ready for it)
SPACE! (And exactly what did the writers think the first three dimensions were for?)

#### jeff

Re: a theory for a FIFTH dimension.....

Originally posted by Don Cristo
...'time' is...the 4th dimension...the 5th dimension may actually be MATTER!

I am 16 years old
Okay, you wouldn't know this, being only 16 and all, but people caught claiming that the 5th dimension may actually be matter are immediately grounded by the physics police, so go to your room right now.

Okay, here's our special two step program for young misguided theorists like yourself. Follow it before it's too late.

Step 1: Say, "time is money".
Step 2: Repeat step 1 till head explodes.

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#### Don Cristo

Hehe ok ok. I knew my theory most probably was not "mine" as I was sure someone would have thought of it before. And also I knew it was ridden with flaws. Although I have learned from your responses so thank you I am willing to learn even if it involves embaressing myself along the way! ! Bye bye

#### Don Cristo

Originally posted by HallsofIvy
Respond to it?

The gist of your post is "I don't know what the word 'dimension' means."

A dimension is a number necessary to precisely specify an event.

Physicists say that time is the "fourth dimension" because an event itself is defined as something that occurs at a specific point at a specific time. There are plenty of events that have nothing to do with mass.
Hmm, although - this may seem odd but - for the events to occur in the first place - 'Matter' / 'Mass' must be present? Otherwise these events would never be able to exist at all, as they exist withing the matter as we know it? (In other words, I know nothing about anything and want someone to say how I am wrong and why)

#### Eh

But "mass" is not going to define a location in spacetime.

#### Don Cristo

No... mass is ALL of space-time. It's location is everywhere.

#### neutroncount

Originally posted by Don Cristo
No... mass is ALL of space-time. It's location is everywhere.
How is that? Matter makes up mass that OCCUPIES spacetime (super simplified of course).

#### Eh

Even if it did, so what? It's not a coordinate used to locate an event. It doesn't fit the definition of dimension at all.

#### Ivan Seeking

Staff Emeritus
Gold Member
Hello Don Cristo,
Your idea of matter or mass as a dimension is not entirely unfounded. First, we have a very specific mathematical definition for a dimension. Basically, in space, a dimension is a direction that has nothing in common with another direction. For example, a line sloped at 45 degrees has two dimensions involved: We might say part up and part over, or part Y and part X. So a 45 degree line is not a dimension but is a linear combination of Y and X. On the other hand, we get no X in Y, or Y in X. Since Y has nothing to do with X [since no combination of Y with something else gives you some X] these two axes are considered to each lie in a different dimension. With this said, we also use another idea for dimensions.

Mass, length, and time are historically treated as the three fundamental dimensions or building blocks of all other physical properties - energy, momentum, temperature, force, torque…even electric charge can be expressed in these terms alone. Considering that time and space are dimensions in the normal sense, to think that mass must also be a dimension is not so difficult to understand. I don't think mass is ever treated quite this way, but the unique concept of mass has long been place next to space and time as a fundamental quantity. The point is not that you’re right; the point is that the idea is not a bad one. Perhaps this is not true in quite the way that you are thinking, but on a fundamental level, there may be some element of truth in your idea.

As far as defining location, well, how do we specify a location? Your idea is more philosophical than physical. Since mass is another form of energy, and since energy is found everywhere in space, to say that space exists without energy I think is false. In fact, I have always wondered if this is not the very nature of space. So even though I don't think your ideas are correct, I do think that more complex ideas are discussed that are cousins to yours.

How about it mentors? Does this idea relate to concepts from string theory perhaps? If we have the dimensions of length and time, and if everything else can be expresses as mass, then ultimately is mass some representation of the other 8 or 6 dimensions?

#### Eh

It's just not a coordinate. Mass defines spacetime, but we use an x,y,z,t axis to locate a specific event within that metric of mass distribution.

#### Ivan Seeking

Staff Emeritus
Gold Member
Originally posted by Eh
It's just not a coordinate. Mass defines spacetime, but we use an x,y,z,t axis to locate a specific event within that metric of mass distribution.
Is mass actually the manifestation of all other hidden dimensions?

#### Eh

I don't know. Without getting into extra dimensions though, it seems spacetime owes its existence to mass. But it's really a philsophical question, and one could equally say spacetime gives rise to the existence of mass itself, with mass being nothing more than curvature itself.

#### Ivan Seeking

Staff Emeritus
Gold Member
Originally posted by Eh
...and one could equally say spacetime gives rise to the existence of mass itself, with mass being nothing more than curvature itself.
Is this exactly true? My formal understanding of this subject [GR] ends short of instant familiarity this statement. Mass [energy] is seen as "identically equal" to the curvature of space; and not just as a cause of this curvature?

#### Eh

It just states that spacetime is curved wherever mass is present. Whether or not they are the same thing (which many physicists believe it is) is a matter for quantum gravity.

#### jeff

Spacetime dimension is a dimensionless topological invariant of the spacetime manifold while mass is a geometrical quantity having units of inverse length (in geometrized units).

The significance of mass for the original question emerges in the context of elementary particles and is group theoretic: Briefly, mass - and spin - label the representations of the poincare group under which particle operators must transform to preserve invariances related to the local geometry of spacetime. One of these representations, the adjoint representation, under which the photon for example transforms, has dimension equal to that of spacetime.

But, mass and spacetime dimension are not in any sense interchangeable concepts.

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#### Don Cristo

Originally posted by steinitz
...

But, mass and spacetime dimension are not in any sense interchangeable concepts.
I do not see exactly how you ended up with that sentence. But if they occur within, and are made up of Mass, then surely that can't be true. What IS spacetime dimension? Excuse me if I am stating the obvious, but... assuming all of space is curved, and we call dimensions, "Straight Lines" - already we see flaws. And if space is curved, and wherever matter is present, curvature is inevitable - this shows that mass/matter is the whole "net" of space. If one was to refer to the theory (I can not remember which scientist came up with this) that space is not at all remotely spherical and consistant, but bears more resemblance to an "interlinked mangled mesh", then there must either be numerous dimensions or the spatial dimensions we can comprehend plus the perhaps more complex 'dimension' (although not a dimension as such) of 'Matter'.
Help??

#### jeff

Originally posted by Don Cristo
I do not see exactly how you ended up with that sentence.
Neither will anyone else here.

#### Don Cristo

Originally posted by steinitz
Neither will anyone else here.
[?] [?] [?]
Well if that is the case, perhaps you would like to explain how you reached your conclusion in a more understandable fashion?? And also, think about what I wrote because I would like to see your views on the matter. Thank you.

#### jeff

Originally posted by Don Cristo
[?] [?] [?]
Well if that is the case, perhaps you would like to explain how you reached your conclusion in a more understandable fashion?? And also, think about what I wrote because I would like to see your views on the matter. Thank you.
A famous physicist felt that much of a scientist's job is to prove their ideas wrong as quickly as possible.

If you make an honest effort to invent reasons to doubt your idea that mass is an additional dimension, I'll make an honest effort to translate some of what I posted into more understandible terms. I look forward to see what clever arguments you come up with.

#### Don Cristo

Ok fine. I have said before that there are a number of flaws in the theory. Clearly I do not actually know what a dimension is (according to some people on this forum). I doubt it occured to them that for me to attempt to go 'beyond' what we already know, then surely I would have to know something about dimensions in the first place???? Anyway, flaws with the theory - my theory lacks mathematical explanation. Hmm - I do not know if the other reasons I am thinking of are actually flaws as such. But I do know for sure that the idea is far more philosophical than physical. Who knows what diverse dimensions there could be other than matter. If there were, it would not be accepted. For singularity events to occur there has got to be more dimensions. Which is perhaps why I argue that matter is a form of dimension - not necessarily THE 5th dimension, just a form with dimensional qualities?? ARgh I do not know. Anyway Mr Steinitz, please explain fully what you wrote earlier as my limited knowledge of physics prevents me from understanding it.

#### Nacho

Don Cristo,

Perhaps this board consists mostly of physics graduate students eager to apply and express what they are learning? You know, the funny thing about Cosmology, or other physics subjects, or even other subjects not related to physics, is that just about any person, at any level of understanding, can learn about it and enjoy discussing it and can have ideas about it.

Also, I think philosophy has to be considered in any physics discussion, except maybe for applied physics.

#### jeff

Originally posted by Don Cristo
Ok fine. I have said before that there are a number of flaws in the theory. Clearly I do not actually know what a dimension is (according to some people on this forum). I doubt it occured to them that for me to attempt to go 'beyond' what we already know, then surely I would have to know something about dimensions in the first place???? Anyway, flaws with the theory - my theory lacks mathematical explanation. Hmm - I do not know if the other reasons I am thinking of are actually flaws as such. But I do know for sure that the idea is far more philosophical than physical. Who knows what diverse dimensions there could be other than matter. If there were, it would not be accepted. For singularity events to occur there has got to be more dimensions. Which is perhaps why I argue that matter is a form of dimension - not necessarily THE 5th dimension, just a form with dimensional qualities?? ARgh I do not know. Anyway Mr Steinitz, please explain fully what you wrote earlier as my limited knowledge of physics prevents me from understanding it.
How would distances be defined in a space consisting of 4 spacetime dimensions and one mass dimension?

#### Don Cristo

Originally posted by steinitz
How would distances be defined in a space consisting of 4 spacetime dimensions and one mass dimension?
If you consider time a spacetime dimension then you must also consider 'Matter' as a spacetime dimension.

#### Eh

You're missing the point, so here's an example of using dimensions. Take any event, say 2 particles colliding, and define what the xyzt coordinates will be. You'll have a location in space, and a time. So the coordinate tells you "where and when" to find an object. If you add matter as a coordinate, how is that going to change the location? Try to define that, and you'll see why it's not a dimension.

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