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,
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