Our universe, as we know it, has three dimensions of space, length, width, and height, and one dimension of time. But according to String Theory, there may be many higher dimensions out there that are so tiny that they are very difficult for us to detect. Some versions of String Theory, such as Bosonic String Theory, predicts as many as 26 dimensions.
But the number of dimensions decreases significantly under newer versions of the theory. For example, M-theory requires 11 dimensions, while Super String Theory requires only 10. But what are these higher dimensions, and how might we experience them given our limited awareness of only the three spatial and one time dimension?
Well, today, we will be looking at what physicists think these higher dimensions might be like! When trying to understand higher dimensions beyond the 3 physical ones that we are used to, it is important to build up from the very beginning. Let’s start by imagining a point indicating a position in a system.
It has no dimensions because it has no length, width, or height. Next, imagine a second point somewhere else in this system. The line joining these two points at a right angle gives rise to the first dimension or the length.
Similarly, taking two copies of the line and joining them at right angles to each other would define a plane with both length and width, giving rise to the second dimension. Now taking two copies of these planes and joining them at right angles to each other would result in a 3-D space, having length, width, and height, that we are all so familiar with. Now, geometrically, we can keep this process going and get higher dimensional versions of various shapes, or at least their shadows onto our 3-D plane.
But what would it be like to experience and exist in these different dimensions? Let’s build up from the zeroth dimension. If there existed a zeroth dimensional being, considering that something as ridiculous as this is even possible, it would have no size at all.
It would just exist all by itself in an infinitely small, or infinitely large, point-like state and have no concepts or ideas of anything else besides its own existence. But a being who occupies a 1-dimensional space, or a line, though will have a little more freedom. For example, it would be able to move freely but only in a straight line in the forward and backward directions.
So, some concepts of movement will definitely be present in a 1-dimensional world. Now, 2-dimensional beings get even more interesting. These include flat shapes having length and width only like squares, circles, and triangles with non-zero surface area, and zero volume.
Such entities would occupy an entire plane of existence rather than a single line. This would give them an additional degree of freedom which would allow them to move in forward, backward, left, and right along with any number of combinations of these within their plane of existence. “Flatland” by Edwin Abbott is an excellent example of such a 2-D universe and its struggle to understand higher dimensions.
Going beyond this, we have 3-dimensional beings, or us, who occupy a space with both surface area and volume. 3-dimensional beings can move in an additional direction, up and down along with everything else a 2-dimensional being can do. But moving forward from here gets a little tricky since we can only perceive the fourth dimension of time as flowing in one direction, from the past to the future.
We do not have direct control of this due to our limited mobility confined to the 3 spatial dimensions. But let’s try and imagine the third dimension in a slightly different way. Suppose a tiny ant or a 2-dimensional creature is walking on a large piece of paper.
And we fold that piece of paper into a large cylinder. In that case, the ant, or 2-dimensional being wouldn’t be able to tell the difference. For it, walking in a straight line or a curved piece of paper would be the same since it wouldn’t be able to visualize the third or higher dimension that the paper is bending and twisting in.
Thinking of higher dimensions in this way can allow us to comprehend higher dimensions beyond our three spatial ones. Now, it is commonly known that time is the fourth dimension. If we think of some object 1 hour ago, and then think of it now, the line joining these two points is the fourth dimension.
Although we can freely move in a 3-dimensional space, but without bending and twisting in the fourth dimension, no event can ever occur. The universe would be static and never changing just like a photograph without this additional dimension of time which we perceive to be only moving ‘forward’. So, similar to the flatlander that can only feel moving ‘forward’ even on a cylindrical sheet of paper even though they are moving in the 3rd dimension, we can only move ‘forward’ in the fourth dimension, or time, and are unaware of any motion along this dimension.
Now if a 4-dimensional entity were to exist, it would be able to travel through time as easily as we can travel through any of the 3 spatial dimensions! Meaning, it could choose to go back and forth at any point in time of its life at will. So, time for 4-dimensional beings would be like a physical dimension!
But one thing to keep in mind here is that the concept of parallel realities still does not exist for these beings. They can only go back and forth in time and live in only one timeline at a time. But this poses no limitation for a 5-dimensional being since the concept of parallel realities comes into existence in this dimension.
So, to imagine the life of a 5-dimensional being, we can think of a vast 2-D plane of all possibilities consisting of all possible parallel universes in which this being can reside simultaneously. However, there are some limitations even in the 5th dimension as per the principle of Causality. A 5-dimensional entity would be able to travel through all the parallel universes but with the same initial coordinates as its own universe.
For example, it cannot get to other versions of its universe which are not causally connected to the one it is in initially. In other words, it cannot go back in time & branch out in the probability plane from a point before it was born. This is because, in that universe, the events leading to its birth may not happen.
For instance, if this being was born in a universe that had the dinosaurs whipped out before its birth, it cannot go back to the universe where the dinosaurs still exist, since the extinction event is what caused the birth of this being. However, a 6-dimensional being would not have to worry about the fifth-dimensional causality. One way to think about the 6th dimension is as the ‘phase space’ of the set of parallel universes resulting from the universe’s unique initial conditions, in our case, the Big Bang.
For instance, this being will be able to travel into the universe where dinosaurs still exist regardless of whether the being itself exists in that universe. So, it would be able to leap across different universes with the same initial conditions and get to other versions of the universe without having to worry about fifth-dimensional causality. In other words, a 6-dimensional being would be able to teleport from its universe to any point in time on any parallel universe that was possible after the big bang or whatever other initial condition of its universe.
This is the only limitation of living in the 6th dimension. In the seventh dimension, however, 7-dimensional beings would have access to all the possible universes that start with different initial conditions. Whereas in the fifth and sixth dimensions, the initial conditions were the same and subsequent actions were different, here, everything is different from the very beginning of time.
So, a 7-dimensional being would be able to travel to any possible universe regardless of its initial conditions! But to be able to travel in time in these new universes would still be beyond a 7-dimensional being. For that, it would need to manipulate 8-dimensional space.
In the 8th dimension, we reach the plane of all possible histories and futures for each universe, branching out into infinity. So, an 8-dimensional being could travel in time to all the possible universes, regardless of their initial conditions. But only in the ninth dimension, all universal laws of physics and the conditions in each universe are revealed.
Here, a 9-dimensional entity can compare all the possible universe histories, starting with all the different possible laws of physics and initial conditions. Seems like absolute control and power. But only in the tenth and final dimension, we arrive at the point in which everything possible and imaginable or unimaginable is covered.
Beyond this, nothing can be imagined by the human mind, which makes it the natural limitation of what we can conceive in terms of dimensions. So, a 10-dimensional being would have infinite power over everything. This being would be no less than God itself!
And that brings us to the end of this video. If you enjoyed it, do leave a like, share, and subscribe to our channel for more content ahead! Until then, we’ll see you in the next one!
