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4d - 23 January, 2007
 RyeGye24 says So, I'm not exactly an expert in the field, and someone will probably quickly correct me one this, but it seems to me that there must be a fourth spacial dimension, making time the 5th dimension. When you look at Einsteins theory on gravity being like a taught bedsheet, in order for space-time to band around it mass, especially its gravity, and the "sheet" need to be 7 dimensional. This is because following the pattern of point -> line -> plane -> space means that if 4d is time, and a line, then the plane which is being bent is the 6th dimension, and in order for it to be bent it must have a 7 dimensional force acting upon it. This is complex and says that everything is somewhat 7 dimensional but for some reason we are unable to percieve past the 4th and also makes the problem of figuring out how it is that time can act as a plane in two ways (as a series of time lines and as a literal plane that is bent by mass) very difficult. But all of this can be simplified by saying that there is a fourth *spacial* dimension which is being bent by mass and gravity, and that time starts on the 5th dimension. I think that in this instance Occham's Razor can be taken into effect saying that the simplist answer is most often the correct one. Ok, so, I'm not the best writer, and its probably hard to understand what I'm saying because of that, but reply if you have anything that supports or contradicts this Total Topic Karma: 31 - More by this Author
 +2 Karma
okay, i'll read this again when I come back because I just got confused. But from what I know, it is theoretically correct to assume that the universe has n-dimensions. Where n can be any number you like. I think this was first postulated to make string theory plausible (since M-theory math works in an 11-dimensional universe).
- 23 January, 2007
 +1 Karma
correct me if i'm wrong:
you seem to be saying that time should warp in 3 dimensions, so that you have seven coordinates: x,y,z,t,tx,ty,tz. is that correct?

- 23 January, 2007
 +2 Karma
I don't think time can be interpreted in the same way that spatial dimensions are.

If I understood correctly, you're saying that time has 3 "sub-dimensions" -just as space "does"- and that those would be dimensions 4,5,6.

I think that's an incorrect assumption. In the most basic sense I could think of, that's because you don't need 3 coordinates to specify a moment in time. You do need them to specify a location in space, but you just need 1 more to specify a moment in time (and that gives 1 more dimension in the equations).

Did I understand your question correctly?
- 23 January, 2007
 +1 Karma
i agree with alex on this one - to specify an event exactly, you only need four pieces of information... hence 4 dimensions.
- 24 January, 2007
 +3 Karma
The reason I assumed that about the 3 dimensions of time is because you can see it in tic tac toe (this is what my friend showed me but it really works)
so with normal tic tac toe you have _|_|_
_|_|_
| |
that is 2D. To do 3D tic tac toe you have
_|_|_ _|_|_ _|_|_
_|_|_ _|_|_ _|_|_
| | | | | |
Front middle Back

And to do 4D you do
_|_|_ _|_|_ _|_|_
Past _|_|_ _|_|_ _|_|_
| | | | | |
Front middle Back
_|_|_ _|_|_ _|_|_
Present _|_|_ _|_|_ _|_|_
| | | | | |
Front middle Back
_|_|_ _|_|_ _|_|_
Future _|_|_ _|_|_ _|_|_
| | | | | |
Front middle Back

You can see that this 4D one looks alot like the 2D one except the individual squares are made up of entire 2D ones and it goes on and on like this in a pattern of point line plane point

But if 4D is time, then the "bedsheet" being bent has to either be 7D following this pattern or time has to be a plane (like the tic tac toe)

So I geuss I'm sort of contradicting myself here but I just thought of this
- 24 January, 2007
 +2 Karma
crap the tic tac toe squares didn't show up correctly
- 24 January, 2007
 +1 Karma
ha. the forth dimension is basically time. a square (2d) is several lines. a cube is several sqaure. the 4 d object is several cubes. or rather the lines that connect them. h.o let me see if i can find this flash video that explaint he 10 dimensions.

http://www.tenthdimension.com/flash2.php
- 25 January, 2007
 +0 Karma
I saw that, but it doesn't fit with einsteins explanation with the "bedsheet" and when you put mass on it It bends causing gravity. So either time is a plane and not a line, or all mass is 7 dimensional, or there is a 4th spatial dimension before time. Also I disagree with the video. I believe that the dimension one above time with different timelines should be interpereted differently. Think of Back to the Future. from a normal person's perspective, in 1950 the car showed up, it stayed for about a week then disappeared. 20 years later a kid was born and eventually he went in a car and disappeared. Then he reappeared for 2 minutes and disappeared again. Then he reappeared and lived his life for about 20 years. Then another version of himself appeared for a week then disappeared. Obviously that time line doesn't make much sense. However, from the main characters point of view, these events happened in a very different order. That means two timelines, both perfectly straight occuring at the same time and interconnected. In order for them to have both been perfectly chronological in the time dimension, however contradicting, they must have been bent in a higher dimension. Any ways thats the way I think of the dimension one aboce time
- 25 January, 2007
 +0 Karma
above*
- 25 January, 2007
 +1 Karma
I think Einstein's explanation wasn't meant to be taken literally, but rather as an easy-to-imagine analogy of what happens in 3 dimensional space (+time) according to his theory.

And RyeGye, I don't get the relationship between your first sentence and the second one... what reasoning did you use to conclude that time must be a plane instead of a line, if your previous example ended with gravity and not time-stretching?
- 28 January, 2007
 +1 Karma
Time has to be looked at as the old faithful explaination of Time's Arrow its a stright ever going ray in one direction. It can seem to be warped and bent because of such things as Special Realitivity but then in the end it still is the same messurement of time just that it is realitive to the observer
- 28 January, 2007
 +1 Karma
I realize that it isn't supposed to be taken literally, but the analogy shows that whatever is being bent and causing gravity is a plane. The logic comes from another post that I made further up. So, if time is a line, then its not whats being bent by gravity. So either time is a plane and causing gravity, or there's another spatial, non-time related dimension.
- 28 January, 2007
 +2 Karma
My point is that the plane *IS* the analogy... It is an easy way to understand what happens in some higher dimension, because we can't usually visualize beyond 3 spatial and 1 temporal dimensions.

Now... maybe I'm the one who hasn't read enough here, but as far as I remember gravity doesn't bend time... If I recall correctly, the explanation says that mass is the one that "bends" space-time, thus creating the effect we know as gravity.

But even if there's something "bending" space-time, I wouldn't conclude that time has to have more than 1 dimension, because I consider the plane you're referring to as the actual analogy. I would rather say that the 3 spatial dimensions are the ones being distorted.

You can also think about it in this way: suppose the plane-analogy is what's actually happening. Objects (or mass in general) fall into the depressions created by more massive objects. But they need time to do so! They need an interval of time in order to go from "the edge of the depression" to "it's bottom" or any place between them. And thus time would have to be a higher dimension that the ones being considered in that model.

And btw, I had written (2 paragraphs before this one) "I wouldn't conclude that time has to be more than a line" (instead of "has to have more than 1 dimension"), but decided not to because as I said earlier, I don't think time can be interpreted the same way spatial dimensions are.
- 28 January, 2007
 +2 Karma
"would rather say that the 3 spatial dimensions are the ones being distorted." i dis agree because then we would see the bending of space because we already are in the third dimention.
therefore i say that there has to be a 4th axis (call it "a" starting over the alpabet) that objects move down along due to their mass (thus creating gravity) inorder to create a depression in space-time. but if thats true, could we some how move UPWARD along the "a" axis to create repulsive gravity? this would definateely unify gravity more to the three QM forces.

as for space-time, i would argue that its rather a 4d (with "a" as fourth axis) speare type thing. this would alow the uni verse to be finite but at the same time not hvae any edges.

take this analogy:
if the universe were a one dimentional line, we could bend that line through the 2nd dimetion and have the universe be on the edge of the circle. if the circle were big enough, no one would notice the curve. it would aapear to be an infinate line.

take it to the next dimention:
if the universe were a two dimentional plane, we could bend that plane through the 3rd dimmetion and have the universe be on the serface of the shpere. if the shpere were big enough, no one would notice the curve. it would apear to be an infinate plane.

take it to OUR dimention:
the universe is a three dimentional space, i belive its bended through the 4TH dimmetion so its on the edge of a four dimentional shape that we cant really visualize, were which ever direction in the 3rd dimetion you go, you nevver reach thedge and in fact you may come back to the same point if you go long enough. since the shape is big enough, no one notices the curve. it would apears to be infinate space.

$
S_e_t_h = {i:i>u}
$

(the brakets didnt work)
- 01 February, 2007
 +0 Karma
@Alexv86
Actually gravity does effect time. This has been shown, such as, if you have two clocks, but one is traveling and the other is stationary, the traveling one ends up behind the stationary one. And it was einstein that said that acceleration produces gravity (I don't know if thats right but it makes sense if you view his explanaition for this). Therefore, the gravity that is caused by the acceleration is bending time.
- 02 February, 2007
 +1 Karma
I know about that experiment, but what it showed is that time is bent not by gravity, but by the speed of the moving clock. The closer you get to the speed of light, the shorter the span of time you "travel" in comparison to stationary objects.

The most known hypothetical example of that mentions two twins, one of which goes on a space trip just after being born, at a great speed (I don't know if the example mentions a specific speed, let's just assume it is really fast), and when he returns as a 18 year old boy, his brother is an old man.

It is speed, and not acceleration, that causes that time bending effect. You could travel at a constant 200,000 km/s (I'm mexican, don't remember the mph number for c), and still produce that effect.

Lastly, if what you're saying is right, it is gravity that produces acceleration and not the other way around. But, I think what Einstein said about them is that "they can be though about as being the same". I'm not totally sure about this next thing, so maybe someone can correct me: he was trying to include the idea of accelerating reference frames into one of his theories (which of the relativities, I don't remember), and realized that gravity is (or causes, as you like) acceleration. So any reference frame with an acceleration, could be thought of as having some "gravity" in that direction.
- 04 February, 2007
 +0 Karma
Oh, btw, do you call them "reference frames" or "frames of reference"?
- 04 February, 2007
 +1 Karma
@Seth
You're right, I shouldn't have said "that the 3 spatial dimensions are the ones being distorted", I just wanted to make clear that I *don't* think that the temporal dimension is the one that's being affected.
- 04 February, 2007
 +1 Karma
@Alexv86
You make a good point, but space in the third dimension is completely empty so there is nothing to be distorted in the spatial dimensions (unless you're saying that gravity works like light). However, in the 4th dimension there could be something that is being distorted, and that would fall in with the interconnectivity of speed, time, and gravity. Thats why i think that gravity is a distortion in the 4th dimension with effects in the 3rd.
- 04 February, 2007
 +1 Karma
Lastly, if what you're saying is right, it is gravity that produces acceleration and not the other way around. But, I think what Einstein said about them is that "they can be though about as being the same".

If I'm not mistaken, that's known in relativity as the principle of equivalence. In the absence of other data, the effects of gravitation and acceleration are indistinguishable from each other.

Imagine that you're standing in a closed room, with no contact with the outside world. Things are falling at 9.81 m/s^2 and all is well with the world. Except for the fact that you can't tell whether this is because this room is on the surface of the Earth, or in a spaceship accelerating at one gee in the direction of the ceiling.
- 04 February, 2007
 +1 Karma
exactly what i mean about the interconnectivity of time speed and gravity.
- 04 February, 2007
 +0 Karma
RyeGye, I still don't get how are you connecting gravity with the time-bending effect. The experiment you mentioned showed that SPEED distorts time. Gravity has nothing to do with that experiment.

The only relation I can see is that gravity can produce speed through acceleration, which is not always the case. For example, we are affected by gravity every single day and still don't have speed because of that (considering just the Earth-person system), so I still can't see a connection.

Anyway, what you say about gravity working like light... It suggested another discussion topic to me. I remember reading something about how gravity is the only known thing that acts "faster than light", since it affects instantly objects at distances greater than that traveled by light in one second. Or does it? I've never read something that proves that gravity is instantaneous. But as I said, that's another discussion topic.
- 05 February, 2007
 +1 Karma
Ok Ok

@ Rye
bedsheet example, the mysterious "4th dimension" that is supposedly "causing" gravity, is gravity.
The bedsheet is not bending in a different dimension, the bend is gravity. infact, to be more acurate, the bedsheet is not bending at all, the aparent bend is a visual explaination of the effect and shape of gravity.

@ rye

there are such things as gravitational waves, they are a form of radiation and travel at varying speeds, but for gravitational waves with small amplitudes, this just so happens to be the speed of light.

You guys might want to look into Gravitomagnetism , it is has made newtons theory of instantaneous gravity obsolete
- 08 February, 2007
 +1 Karma
sorry, the second half of that was meant to be directed at alex
- 08 February, 2007
 +1 Karma
The bedsheet is not bending in a different dimension, the bend is gravity. infact, to be more acurate, the bedsheet is not bending at all, the aparent bend is a visual explaination of the effect and shape of gravity.

The bend isn't gravity - gravity is just what we call the curvature of space-time. The bedsheet is bending, and therefore affecting things on it. Everything is still traveling in a straight line, it's just that straight lines have suddenly been rendered curved.
- 09 February, 2007
 +1 Karma
No, the bend is gravity. But what is being bent is the bedsheet, which is a visualization of gravity if the universe was 2d. since its 3d then whats being bent should be 4d and that is the space time continuum. And since we're 3d we can't see the curvature, but we can see its effects on 3D objects.
- 09 February, 2007
 +1 Karma
however this shows that mass (or at least weight) must have some sort of 4d properties in order to bend the "sheet"
- 09 February, 2007
 +0 Karma
I though the curvature of space-time is not all that real?? It just seems logical to explain gravity as a geometrical phenomenon. Hevier objects will curve the bed sheet more, and objects follow along the curve of the bed sheet. My point is that the mathematics behind general relativity only predicts how objects move by using geometry. It does not really tell us what gravity really is. What i do find interesting is the fact that gravity can act as waves. Ex: if the sun disapears suddenly, it will send out gravity waves out radially. That alone makes me wonder what is gravity? Are there really particles called "gravetons".
- 13 February, 2007
 +0 Karma
As for 4 demensions. If you think about it geometrically, you can really percive 4 demensions. It is just convinent to say 3d + time = 4d.
- 13 February, 2007
 +0 Karma
mathematical arguments that just seem to work. That is einstines theory. Logically, Can you really say there are multiple demensions. Can this be tested. What really is true is that the math works out, thats all you can extrapolate.
- 13 February, 2007
 +0 Karma
Multiple dimensions . just look up this

And more interesting. Scietists at harvard slowed down a beam of laser from "c" to 2o km/hr and then to a standstill. and then it behaved like matter for a picosecond. then the best part is
THE BEAM OF LASER DISAPPEARED AND THEN IT REAPPEARED ONE INCH FROM WHERE IT SLOWED DOWN. I dont know how they did it, but the diappearance is a little sceptical. Do you think that the beam of laser went into another dimension?

????????????????????????????????????????????????????????
????????????????????????????????????????????????????
- 15 February, 2007
 +1 Karma
RyeGye24, here is my take on your question. My General Relativity prof told me that these questions can always be considered in lower dimensions. So imagine a two-dimensional worm living on a sphere and it says - "my life is too curved, I can imagine that my world is a sphere in a 3-dimensional space". In this sense, you are right. And, dropping some technicalities, there I agree with you, we can imagine that our world is some curved surface in some flat space.
Should those extra dimension exists, it would be huge - clearly traveling in a straight line is much faster then going on some warped surface. But barring the phenomenon reported by the gentleman in the previous post, we don't know nothing about these extra-dimension.
And so, describing our world as embedded into some flat space is not at all simpler (that's where I disagree with your Occam razor). First of all, the number of additional dimensions you have to pay for your description is not 1, but might be as high as 4. Also to find the shortest path from a point to a point (without traveling through the extra-dimensions) is a daunting task, because to do that we need to consider only curves lying in our warped space - these are, trust me, very hard calculations.
But keep your razor sharp - you might want to use in the future.
- 15 February, 2007
 +0 Karma
I've actually heard a very similar analogy and i thought i might bring it up because it explains alot, including the gravity part. Imagine everything we're talking about a dimension down. So you have a Volleyball saped universe and on the inside of it are 2 dimensional creatures and objects. Now imagine that, though they think they are 2D they actually have some 3d mass that they are unable to percieve the 3d mass because light travels along the volleyball and is also attatched to it. Now imagine that, due to centrifical force or something similar, the objects inside the volleyball like universe are being pushed away from the center creating indentations in the volleyball type universe. Now any 3d person could see immediately why it is that a 2D person going "straight" in the universe would end up right back where it started, but a 2D creature would be unable to understand why it was that it ended up where it started if it went in one direction.
This also explains the example with the sun disappearing and gravity still being there. Even if the object disappeared, it would take awhile for the "bedsheet" or "volleyball" to unbend and straighten out.
So anyways, any 2D creature would percieve the volleyball as a single plane, or the shape of a bedsheet.
So. For the first dimension universes are mobius strips, for the second dimension, spheres, and for the 3d dimension ???? it would be some 4D shape that we could not possibly percieve.
- 15 February, 2007
 +0 Karma
By the way, I just found this and I think this might add a new level to the topic. post what you think about it.
- 16 February, 2007
 +1 Karma
RyeGye24, we should read this this and I'll google to find out more.
- 16 February, 2007
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