A completely different look at the 4th dimension

  • Context: Graduate 
  • Thread starter Thread starter pakmingki
  • Start date Start date
  • Tags Tags
    4th dimension Dimension
Click For Summary

Discussion Overview

The discussion explores the concept of the fourth dimension, proposing a model that diverges from the conventional association of the fourth dimension with time. It uses a two-dimensional analogy involving organisms in a finite universe to illustrate how beings might perceive and interact with higher dimensions, particularly the implications of moving into a fourth spatial dimension.

Discussion Character

  • Exploratory
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant presents a model of a two-dimensional universe inhabited by organisms that can only move linearly and cannot perceive the third dimension, suggesting that this analogy can be extended to understand our own three-dimensional universe and a hypothetical fourth dimension.
  • The model posits that if beings in a three-dimensional universe could move into a fourth dimension, they would become invisible to those in three dimensions, as their movement in the fourth dimension would not be perceivable.
  • Another participant references the concept of sequestration on Randall-Sundrum branes, suggesting a connection to the proposed model of higher dimensions.
  • A different participant mentions "Flatland," a literary work that uses similar ideas about dimensions, indicating that the concept is not new and has been previously explored.
  • One participant reflects on the tendency of individuals to reinvent ideas, sharing a personal anecdote about a friend who developed a concept that had already been established, highlighting the cyclical nature of innovation in understanding dimensions.

Areas of Agreement / Disagreement

Participants express varying degrees of interest in the proposed model, with some acknowledging its novelty while others note its similarity to existing concepts. There is no consensus on the validity or implications of the analogy, and the discussion remains open-ended.

Contextual Notes

The discussion does not resolve the complexities of higher-dimensional theories or the implications of the proposed analogy. Participants reference existing literature and concepts without fully integrating them into the current discussion.

pakmingki
Messages
93
Reaction score
1
I have an idea that completely renivents the idea of the 4th dimension that has absolutely nothing to do with time. BUt however, it will be easier to first think about the lower dimensions.

imagine a perfectly 2 dimensional universe which can be represented with a xy plane where -10 meters < x < 10 meters and -10 meters < y < 10 meters, and with the origin being at the center of this universe (0,0). So, we can say that this is a pretty finite universe.

There are only 3 living organisms, which are all perfect rectangular prisms with these characteristics: they all have equal length and height, which are 2 meters, and they all have an infinitely small depth, meaning they are infinitely thin.
An organism's location at any given time can be represented with a coordinate (x,y) of the prism's center, where x and y are any real numbers within the domain and range of the universe.

They have a very restricted motion; they can only traverse linearly, and they cannot rotate at all.

Since these organisms are in a perfectly 2 dimensional world, when they see each other, they just see a line equal to the length or height.

There is a very specific point i am trying to make by saying these are prisms with an infinitely small depth: i could say they are squares, but a square is a 2 dimensional figure. A prism is 3 dimensional, but in the 2 dimensional world, the organisms only have values for the 1st and 2nd dimension, and an infinitely small 3rd dimension (which is the depth of the prism in this case).

now, consider this situation. One of the organisms is just sitting in the upper most right corner of the universe. The other 2 are in a constant velocity. One has a velocity of (1i + 2j)m/s and the other has a velocity (2i - 3j)m/s. They both see each other moving. Suddenly, one of them changes their velociry to (i+j+z)m/s and vanishes out of the 2 dimensional universe. The one moving (2i - 3j)m/s has no idea what happened, the other organism literally just vanishes. They both stop moving. One is in the xy plane, while the other just entered the xyz plane. Since they are 2d beings,they can only see in 2 dimensional cross sections, and they cannot see each other. The one in the xyz plane starts moving again with a constantly velocity and stops some time later. The one in the xy plane has coordinates of (-3,4). When the one in the xyz plane stops, it has coordinates of (-3,4,3). They are directly above each other and completely unaware. The one in (-3,4,3) starts moving again with a velocity of (0i + 0j + kz)m/s, where k is a constant < 0. At some point in time, the two coexisted in the exact same location (-3,4) at the same time.

Some time later, the particle that entered the xyz plane finally finds its way to it's home, and sees the other particles. The one that learned how to move in the z direction realizes that even if it moves an infinite small value in the positive or negative z direction, it disapears off the plane.

So, apply that analogy to our world. What if we are just in a universe that can be represented with a xyz plane? And we can be seen as 4 dimensional shapes with an infinitely small 4th dimension. For our purpose, let's call the fourth dimension q. If 2 people are sitting right next to each other, and one of them moves even a nanometer in the q direction, he would completely vanish.

And let's go back to the 2d analogy. Let's say there is a line the organisms cannot cross; let's say it starts at (-1, 3) and ends at (1, 3). If one of the organisms went straight at it, it would just get stopped. However, if one fo the organiisms went even a micrometer in the z direction, then moved toward it, the organism would be completely unhindered by the line. You could say the line starts at (-1,3,0) and ends at (1,3,0) meaning it doest even exist in the 3rd dimension


If in our 3d universe we could traverse into the 4th dimension, then physical barriers would disappear completely, and wouldn't even exist in the 4th dimesion.

also, let's consider another interesting phenomena. Let's go back to the 2d analogy again. let's say there is a cone with a base radius of 5 meters and a height of 5 meters. Let' s say that the location of the center of the base is at (5,6,-20). So basically, the 2d organism sees nothing initially. let's say the cone now starts traversing with a velocity of (0i + 0j + 4z)m/s. Eventually the organism will see a point appear out of nowhere, and the organism will see the point basically continue to extend into a line which gets longer, until it completely disappears when the cone's center of the base has a z coordinate greater than 0.


what do you guys think about this? Do you think the 2d analogy could be aplpied to our 3d world?
 
Physics news on Phys.org
Sounds like sequestration on Randall-Sundrum branes;
an attractive idea.
Nigel
 
It is probably the property of human mind to re-invent things. Ten years ago one of my friends secretly explained me his idea about what is now known as shutter glasses (for 3D computer vision). He was very excited saying that he is going to patent the device. And how much was he disappointed when the next day I found for him in internet that there were already international conferences discussing the possibility of standartizing the 3D-vision techniques he had just re-invented. But re-inventing something that was already described in 1884 is quite a case!
 

Similar threads

  • · Replies 8 ·
Replies
8
Views
3K
  • · Replies 6 ·
Replies
6
Views
4K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 0 ·
Replies
0
Views
4K
Replies
9
Views
4K
  • · Replies 9 ·
Replies
9
Views
4K
  • · Replies 16 ·
Replies
16
Views
5K
  • · Replies 29 ·
Replies
29
Views
11K
  • · Replies 1 ·
Replies
1
Views
4K