Paintings are artistic representations of the world on a two-dimensional canvas.

And for a long time, that's all that paintings could be.

It wasn't until the Middle Ages when artists started toying with perspective and figured

out that they could represent the three-dimensional world on a two-dimensional canvas.

We similarly assume that our world has four dimensions, three of space and one of time,

but isn't it possible that there are more dimensions we just haven't discovered yet?

This is Unveiled and today we're answering the extraordinary question: How Many Next

Dimensions Are There?

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Human beings perceive space in three-dimensions - length, width, and height.

A line exists in one dimension because it only has length.

A square exists in two, as it has length and height.

And a cube is three-dimensional because it adds depth.

A tesseract, on the other hand, is a geometrical concept that represents a cube in four dimensions.

We can't accurately envision what this would look like, but just because we can't see

something doesn't mean that it doesn't exist.

A number of theories about the universe posit that we actually live in many more dimensions

than we think.

The holy grail of physics is a Theory of Everything that explains all the phenomena we see in

the universe, reconciling general relativity and quantum field theory.

General relativity, which focuses on gravity, does a great job of explaining the universe

at large scales; and quantum field theory, which focuses on electromagnetism, the strong

nuclear force, and the weak nuclear force, works well at small scales.

(The strong nuclear force is what holds atoms together; the weak is responsible for radioactive

decay.)

The problem is, general relativity and quantum field theory are incompatible!

String Theory is the leading candidate for a theory that combines them, providing a unified

description of all four fundamental forces.

In order to do so, it posits a whole bunch of other dimensions hidden from our view to

make the math work out.

But . . . where could they be hiding?

Our first “new” dimension came when Einstein created his theories on relativity in the

early 1900s.

Previously, the world was understood geometrically as existing in three dimensions.

But Einstein was struggling to explain electromagnetism until he considered time as a fourth dimension.

The same principle was also able to explain gravitational fields.

In his equations, all four dimensions are bound together in what we call spacetime.

This provided a powerful new tool with more explanatory power and more accurate predictions

than in Newtonian physics.

It's a similar case to our painting example - there exists another dimension right alongside

us, we just never realized it until Einstein's theories of special and general relativity.

Immediately after Einstein's proposal, others thought about adding new dimensions to better

explain our universe.

In 1919, mathematician Theodor Kaluza tried adding a fifth dimension into Einstein's

equations, and surprisingly, it fit perfectly.

When trying to explain where this dimension was located, physicist Oskar Klein gave the

example of an ant crawling on a hose.

To the ant, it seems like he's walking on a two-dimensional object, but in fact there's

a circular dimension on the inside of the hose right below the ant's feet.

In subsequent decades, this idea underwent a series of revivals, as string theorists

tried adding more dimensions to unify the forces of nature.

According to superstring theorists, there are at least 10 dimensions in total: our four

regular dimensions, and six smaller, compact dimensions that curl up in on themselves to

form a structure called a Calabi–Yau manifold.

While this structure is impossible to imagine in its entirety, there are 2D cross-sections

of what it's thought to look like.

Ten dimensions seems like a lot, but that's not even the most that physicists are willing

to consider.

The most popular variation of string theory is M-theory, which assumes 11 dimensions!

Oddly enough, M doesn't stand for anything in particular, with Edward Witten, the theory's

creator, suggesting that it could stand for “magic”, “mystery”, or “membrane”.

Then there's also Bosonic String Theory, the original version of string theory developed

in the 1960s.

Bosonic string theory posits that there have to be 26 dimensions in total, 25 of space

and one of time.

While it may initially seem unlikely that we'd only be able to see 3 dimensions in

a universe of 26, it may be analogous to the fact that humans can only perceive a minuscule

amount of the visible light spectrum.

If we didn't need to see these dimensions to survive, maybe we never evolved to.

Again, what these extra dimensions are is impossible to imagine, but for now, physicists

say they're rolled up and compacted in the Calabi-Yau manifolds.

We just can't experience these dimensions because they're too small.

Quantum mechanics adds another layer of complexity to the situation.

At a quantum level, the world doesn't act at all how we expect it to, and things occur

that are impossible to experience at the macro level.

According to the many-worlds interpretation, quantum mechanics even calls for the existence

of infinite universes.

Strange as it is, this is actually a popular theory.

Basically, quantum mechanics seems to show that at atomic and subatomic levels, physical

systems don't have definite properties until they're measured; the many-worlds interpretation

posits that in fact, all possible outcomes are realized, just in different worlds.

Thus, there could also be many other “dimensions” in another sense: other worlds existing right

alongside ours.

Think of it like a length of rope - although it appears to be one long object, on closer

inspection there are hundreds of tiny threads alongside each other.

There's no telling yet how many dimensions there truly are.

Mathematics shows us a number of possible dimensions, but that doesn't mean they're

real.

The problem with math is that it's extremely creative and abstract and can be consistent

on paper without necessarily representing the material world.

For example, we represent dimensions in math with coordinate axes.

We usually have three: x, y, and z.

But we can add dimensions as easily as adding more letters - even if it's impossible to

draw.

Proving their existence is another feat entirely.

These extra dimensions may be too small to see, but maybe we do experience their interactions

with our world.

Some researchers have postulated that consciousness exists in another dimension - so it's possible

that one or more dimensions actually exist in our own head, so to speak.

Or perhaps death opens alternative dimensions to our comprehension, and the afterlife exists

in its own dimension.

Perhaps dark matter and dark energy hold the key to understanding where these other dimensions

are, as both are completely invisible but account for most of the matter and energy

in the universe.

In fact, according to observations, observable matter and energy account for only 5% of the

universe's total.

If there are 26 dimensions, perhaps the rest is tucked away there!

Either way, the fact that so many dimensions can feasibly exist in math highlights just

how little we know about the universe.

And that's How Many Next Dimensions There Could Be.

What do you think?

Is there anything we missed?

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