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  • How Many Next Dimensions Are There?

  • 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?

  • Are you a fiend for facts?

  • Are you constantly curious?

  • Then why not subscribe to Unveiled for more clips like this one?

  • And ring the bell for more fascinating content!

  • 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 firstnewdimension 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 CalabiYau 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 formagic”, “mystery”, ormembrane”.

  • 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 otherdimensionsin 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?

  • Let us know in the comments, check out these other clips from Unveiled, and make sure you

  • subscribe and ring the bell for our latest content.

How Many Next Dimensions Are There?

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次元は何個あるの?| 公開されました (How Many Dimensions Are There? | Unveiled)

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    林峰生 に公開 2021 年 01 月 14 日
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