# Dimention blah

1. Feb 1, 2005

### Arsonade

ohk, i was working on some code work during a pre-calc boring reveiw fest and i want to stte some things that i seem to understand as right and some thigs that i would like to figure out

they all deal with dimentions
0d- the zero dimention- nothing exists, it is nothing
1d-the flat line-thinking like a number line
2d-a flat plane-thinking like a chess bored
3d-our world-thinking like, well, in 3d
4d-time- at this point, if you were to draw a grapth, it would like a string of 3d grapths going along a line, each grapth representing a second in time or somthing
5d-energy-asuming the grapth looks someting like a whole bunch of 3d grapths is a shape like a 2d where X is time and Y is...energy?
6d-no clue but keeping with the pattern, it would probably be a bunch of 3d grapths in a 3d shape...almost like many universes each with its own individual 3d grapth type thing only all of them in a 3d grapth type thing...wow
7d-??
8d-??

ohk those were all things that i knew/ thought i knew/had no idea about

but then, today i was thinking about somthing like a negitive dimention.

-1d, -2d, ect.

i tried reasoning it out, and i didnt get far, i dont think that its simply an inverse, i dont think its somthing we can picture wither, but then, i have no idea

and then, just to torture myself really, i started thinking
what about
id (no pun intended, im not talking about the thing you have to fake to get drinks lol, i meen i as in sqare root of -1 lol)

i asked my physics teech about this, he had been somone in the navy for a while so he started talking a lot about electrical current and so on and so forth, i didnt really get it, sorry.

and what about somthing like 1.5d?

im making this way too weird, but thats cool

id apreciate it if you would stop laughing at me now lol

anyway if you guys could help me with this i would be eternally greatfull

Adam

not usually this perky, must be the suggar high

Last edited: Feb 1, 2005
2. Feb 1, 2005

### Arsonade

ohk i just wanted to say, the way i phrased all this was obviosly not too serios, but the question was lol, i would really like to know if i have the right theorys on dimentions 0-5 and what the other 3 are (actually i know that there are 11 and then there are many more that are, from waht ive heard, insignifgant) and about anything like an i(imaginary)dimention, negitive number dimentions, or dimentions inthe form of like 3.5 d. or even Square root of 3 dimention.

Adam

3. Feb 1, 2005

### Crosson

Whoo, you sure are enthusiastic.

You have a fine grasp of 0,1,2,3 dimensional spaces. Physicist agree we live in a 4 dimensional space and percieve one of the dimensions as "time". The reason for past future and all that is because our universe has (locally) hyperbolic curvature (You know, the way a 2 dimensional surface can be curved in a variety of ways).

Two spaces of the same dimension can look very different if they do not also have the same curvature. For instance, in a two dimensional universe curved like a sphere, triangles have over 180 degrees and two parallel lines always meet eventually.

So aside from considering 1,2,3,4 dimensional spaces of different curvature, what else can we do? Mathematically, it is possible to define fractional dimensions although I do not find it intuitively satisfying. It turns out that 3/2 dimensional object embedded in 3 dimensional space has an infinite boundary. That is a shape, the size of a plate in you kitchen, which has an infinitely complex boundary (think of looking at a jagged coastline from space).

I have never heard of negative dimensions, but I think that to give them meaning we would need to form a dimensional algebra. Equivalently, can we give meaning to "one dimension plus on dimension = 2 dimensions"?

4. Feb 1, 2005

### chroot

Staff Emeritus
A zero-dimensional space is a point.

There's no reason to implicitly assume that the fourth dimension is time -- you seem to have randomly associated the fourth dimension with time, and then went on to consider the fifth dimension another of space. Iif you really wanted to keep with the pattern, forget time and just consider spaces of more than four spatial dimensions. A 4D space is one where hypercubes, etc. live. You (nor anyone else) can really visualize spaces with more than three spatial dimensions, but their mathematics are well-founded.

One techniques people use to represent 4D information is to draw a 3D volume -- a cube, say -- and draw each point in the volume with a shade of gray between black and white. Color intensity, then, represents the fourth dimension. You could even use the three primary colors of light, red, green, and blue, to each represent a dimension, and you could draw a full-color cube that could represent six total dimensions.

Negative dimensions simply don't make any sense, and aren't possible. The definition of a dimension is that of a "degree of freedom," the number of independent quantities which determine where something is in space. There's no way to have fewer than zero such degrees of freedom. There's no way it could take -1 quantities to locate an object in a space.

- Warren

5. Feb 1, 2005

### Hurkyl

Staff Emeritus
Or, you could try to get away from the idea of space altogether. As an example, the collection of polynomials with degree less than 5 forms a 5 dimensional vector space. (one dimension for each coefficient)

6. Feb 1, 2005

### Crosson

Chroot: The distinction between spatial and temporal dimensions is an arbitrary one that we have made. The only real difference in the "time" dimension is its role in the curvature of our universe (loosely speaking, a 4 dimensional hyperbola has a single axis around which it is symmetric, this is what we call the time axis).

7. Feb 1, 2005

### chroot

Staff Emeritus
Crosson,

Indeed, the only distinction is that the temporal dimension has the opposite sign in the metric.

- Warren

8. Feb 2, 2005

### Arsonade

well the analogy i generally use for dimentions is a cipher, just because thats how i learned it, now a 0d cipher, well its only one letter, it might as well be nothing
a 1d cipher, thats usually a simple shift cipher
a 2d cipher is what is called a vinigerine (spelled very wrong) cipher in whitch there are 26 of the 1d shift ciphers stacked on top of eachother, each shifted from +1 to +26 from top to bottom
a 3d cipher im going to say i came up with only because i had not seen it anywhere elce (so dont get mad at me saying that i didnt come up with it, its a very simple idea so id be surprised if noonehad come up with it), its basically the 2d cipher stacked 26 times behind itself
this goes on for a while, with 4d suually being a 3d cipher whitch calibration actually changes over time to give a code that is constantly chaning, keeping in syncrinization with the key.
now that i really think about it, for every dimention added, a new variable is created, and by that logic, to go into negitive dimentions would be imposible, there would have to be...negitive variables?...antidata?...dont know.
however when this analogy is carried over to dimentions such as 3.5, it works, having 2 variables with an extra half of a variable...a variable that does not apply half of the time?

then theres the i(imaginary) dimention whitch seems to exist more on Barney shows than physics lol

an imaginary variable?

i cant IMAGINE it ::laughs hysterically and elbows person next to me::

right then

Adam

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