I initially posted this as a series of Instagram stories, which people found surprisingly entertaining given the nerdiness of the subject matter. I think maybe my total lack of expertise made it more fun and easier to understand. So, a disclaimer: this exercise is for fun and brain-stretching only. Don’t take it as hard science, and please forgive any technical inaccuracies.
When we talk about a dimension, what we are really talking about is a degree of freedom, or an axis.
A point has no dimensions. It exists at one, fixed spacetime coordinate and has no variable or degree-of-freedom.
The first dimension can be represented as a line. A line has one degree of freedom.
The second dimension can be represented by a plane. It has two axes (X,Y). Any position on a plane can be defined with two measurements.
The third dimension (you know this one!) can be defined by a cube. A cube has 3 degrees of freedom (X,Y,Z), has volume, and is, basically, space as we experience it.
Typically, we talk about the fourth dimension as time (at least we experience it as time). If we think about space as being three dimensional, but existing through time, then we can identify any point in spacetime with 4 axes (X,Y,Z,T). Let’s look at a few ways to “visualize” time.
Easy 4D Visualizations Explained
Imagine a 2d being trying to experience the third dimension. The only way a 2d being could experience a cube would be to pass through it, one 2D slice at a time.
However we, as 3D beings can experience the whole cube at once. So if we use time to represent the fourth dimension, we can say that we (as 3D beings) can only experience time one 3D slice at a time. But a 4D being would experience all time simultaneously, just as we can experience all planes of a cube simultaneously.
Here’s another way to picture time. If you poke your finger through the air, it passes through infinite 2D planes. A 2D creature living on one of those planes wouldn’t experience your moving finger, but a 2d cross section of a finger. In the same way, if a 4D being poked through spacetime, you wouldn’t see it as it is, you would see it as a 3d cross section or a blob.
The 4th dimension is easy to visualize because we are conscious of time. We’re experiencing it all the…time. And though we can’t see all time at once, higher dimensions are ‘leaky’ so there may be little hints of the fourth dimension as a nonlinear dimension in our daily lives.
When people experience deja vu or hallucinations or see ghosts…these might be little overlapping slices telling us that multiple times (T1, T2, etc) can coexist at a common set of space coordinates (X,Y,Z).
The 5th and 6th Dimensions
The fifth and sixth dimensions are closely related. in these dimensions, possible realities come into play and we start experiencing the less tangible dimensions 5–10
So before we talk about the invisible dimensions, a couple good explanations
As stated earlier, we usually define a dimension as an axis, a new degree of freedom with infinite variables. We experience spacetime in four dimensions, so we can find coordinates in spacetime with input from 4 axes, X,Y,Z,T.
The higher dimensions (5–10) are hard to see. It might be easiest to represent these higher dimensions as “folds”. I.e. if you use a piece of paper to represent a plane, and you fold that piece of paper in 2, every point on the paper has a twin that coexists at the same XY coordinates. You have another axis!
And though we can’t see higher dimensions, they are theoretically apparent in the curvature of spacetime. Here’s the ant example:
If an ant is walking a straight line down the center of a piece of paper, and you roll that paper into a tube, the ant won’y know he’s in a 3 dimensional tunnel, but if he veers right or left, he’ll be in the upside-down.
Now on to the 5th dimension, 6th dimension, causality and alternate realities…
In 4D, all time is stacked and navigable, but it only accounts for one event at each coordinate in spacetime. However, we know that if time can be navigable, it can theoretically be non-linear.
Theoretically, if you went back in time and then forward again, just as in space, you may not necessarily move forward on the same line each time. You might veer right or left (like the ant)and would create alternate realities that occupy the same XYZT coordinates…you would need a 5th axis!
If you watch sci-fi, you know all about the 5th dimension already. You can imagine the 5th dimension as a plane where all possible timelines (or branches of time) stretching back to the big bang live. Sometimes it’s called a probability plane.
One way to think of visualize navigating the 5th dimension is to think of it as climbing a tree. Imagine you were climbing a tree to 20 feet, and then you climbed back down, and back up to 20 feet, but on a different branch…both routes get you to 20 feet but they never intersect, and you can’t jump from one to the other because they diverted way down at the trunk. each choice creates a network of new choices and different realities or branches, Causality!
If you think of an event as a point, every event that led to it or is affected by it exists on its branch, and everything else is…elsewhere.
Now, what if you wanted to explore all the branches without climbing back down and up and potentially ending up on the wrong branch? You would have to ‘fold’ the tree so that all of the branches at the same height could be experienced at once. You would need to eliminate causality as a determiner of an event, to make the branches non-linear. you would need a new axis. You would need the 6th dimension!
But here’s where it gets really physics-y and theoretical…the 6th dimension is still dependent on
A) our universe’s point of origin.
B) our universe’s laws.
So if we want to account for possibilities outside of these constraints, we need more dimensions!
In the same way that the 5th and 6th dimension are interrelated, the 7th and 8th are bound to each other.
7, 8, 9, Multiverse
In the seventh dimension, we add the following degree of freedom: different origins and laws. The first six dimensions apply to our universe, with its specific origin and physical laws, but other dimensions may have different origins and be governed by entirely different laws. So, if we continue with the event tracing illustration, multiple origins mean we would need another axis to trace any event back on the probability plane.
We are now in the multiverse!
Now, if we wanted to compare all of the events that coincide across all of the different universes, each with it’s own origin, we would have to be able to fold the 7th dimension over another plane so that all of the origins coexist…we would need an 8th dimension.
In the 8th dimension, we assume that all laws in all universes remain…well…universal. Theoretically, however, laws could evolve differently from the same point of origin, creating divergent universes that COULD occupy the same coordinates in 8 dimensions. To account for this, we need a 9th dimension…in the 9th dimension, we can account for all events in all universes, with all points of origin, and all possible laws.
And finally the 10th dimension. The tenth dimension, in my very humble opinion, represents the unknown. It is all of the other variables that would be necessary to assess all data in all of existence simultaneously. It is the everything fold.
I hope this all made sense! It’s a lot to digest. If it DID make sense and you would like to learn more, there are countless great books on quantum physics for regular people, but I think the best place to start might be Flatland: A Romance of Many Dimensions. It was written in 1884 as a satirical allegory using math to illustrate different social strata. It experienced a resurgence after Einstein presented his theory of relativity, and has been name-checked by Carl Sagan and Stephen Hawking as a good way to introduce higher dimensions to anyone.