4th dimension....can anyone explain it cearly?

[mistermack]

It sounds very surreal. Who came up with this idea, and why do we find it believable? It sounds far fetched and very theoretical, but perhaps I'm not thinking hard enough. I can understand and explain 1D to 3D. 1D, that's a plane with a single coordinate. 2D, has two coordinates. 3D, 3 coordinates. 4D.... 4 coordinates? Where do you put the forth one? We really need the guy who came up with the coordinate system (Descartes) to chart up a new one to illustrate the logic in this. Are there organisms who can see 4D, I wonder?...why haven't we been able to create a machine to detect 4D but we triumphs over infrared spectrum, ultra violet, and what not?

Can you really understand one dimension or two dimensions? What you really are understanding is 3D, and the 2 dimensions as part of that.
But could you understand a universe that only had two dimensions? Everything has an infinitely small thickness, ie zero thickness. So nothing has any volume, or mass, just area. Imagine trying to explain to a being from that universe what a third dimension was like. They would just not be able to get their head round it, just like you with an extra dimension. Try to explain where the third dimension goes, to a person who's whole existence happens on a single plane.
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[Rum]

It sounds very surreal. Who came up with this idea, and why do we find it believable? It sounds far fetched and very theoretical, but perhaps I'm not thinking hard enough. I can understand and explain 1D to 3D. 1D, that's a plane with a single coordinate. 2D, has two coordinates. 3D, 3 coordinates. 4D.... 4 coordinates? Where do you put the forth one? We really need the guy who came up with the coordinate system (Descartes) to chart up a new one to illustrate the logic in this. Are there organisms who can see 4D, I wonder?...why haven't we been able to create a machine to detect 4D but we triumphs over infrared spectrum, ultra violet, and what not?

Can you really understand one dimension or two dimensions? What you really are understanding is 3D, and the 2 dimensions as part of that.
But could you understand a universe that only had two dimensions? Everything has an infinitely small thickness, ie zero thickness. So nothing has any volume, or mass, just area. Imagine trying to explain to a being from that universe what a third dimension was like. They would just not be able to get their head round it, just like you with an extra dimension. Try to explain where the third dimension goes, to a person who's whole existence happens on a single plane.
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This can be used as an illustration or metaphor - one I have come across in fact. A creature inhabiting this two dimensional universe (let imagine is as a sheet of paper for the sake of this illustration) would experience a drop of water falling on it, which we three dimensional creatures would see 'falling' simply as water appearing and spreading out on the 'paper' in front of them.

[thepill]

Read Flatland (or is it flatlands) by Abbott. You cant visualise a 4 dimensional spatial system because you are a 3 dimensional being. A 4 dimensional being can see ALL of your insides bits.

edit: hey you can get a free pdf copy from here : http://manybooks.net/titles/abbottedetext95flat10a.html

[Santa_Claus]

If you place a matchbox alongside a bag of sugar on a table the matchbox is the far smaller of the 2

but if you bring the matchbox closer to you it becomes bigger than the bag of sugar.

At least that's how Dr Who explained how the Tardis is far bigger on the inside than the outside.

[Santa_Claus]

If you place a matchbox alongside a bag of sugar on a table the matchbox is the far smaller of the 2

but if you bring the matchbox closer to you it becomes bigger than the bag of sugar.

At least that's how Dr Who explained how the Tardis is far bigger on the inside than the outside.

and he's a Timelord. so knows shit loads of stuff with numbers in it that give you headaches.

[electricwhiteboy]

Yes read" Moon child" by Crowley .There is an easy explanation in there, it is also nice to note he had the eleven dimensions sorted out long before String theory (sorry esoteric foot-note there )

I've read a good cross section of the old perv's work and Moon Child is pretty thankless read. Crowley talks a lot of wank about the 4th dimension in it, mathematically he's right, but as it pertains to the Universe it is simply wrong.

The 4th dimension, as far as I understand, is a mathematical concept in Euclidian geometry; it has nothing to do with the actual dimensions of the Universe as described by physics and string theory. According to general relativity matter causes space-time to curve so it deals with Non-Euclidian geometry. Time being a dimension and the 4 dimensional hypercube (in the Sagan video) are two entirely different things.

http://en.wikipedia.org/wiki/Euclidean_space

Non Euclidian maths can be described as being like trying to draw a straight line on the inside of a tea cup, the straight line bends because the inside of the cup bends.

[mistermack]

Not only woud a two dimensional being not be able to be aware of a three dimensional world, but it would probably work the same the other way.

If I came across a two dimensional world, it would be on a plane that had zero thickness. So light would pass straight through it. You couldn't feel it, see it, or smell it, or detect it with any known instrument.

So two dimensional worlds might be all around us, we would have absolutely no idea, and never be able to detect them with 3D equipment.

The same could apply to a 4D world, it might be physically impossible to detect matter and energy that is only 3D.
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[charlou]

Not only woud a two dimensional being not be able to be aware of a three dimensional world, but it would probably work the same the other way.

If I came across a two dimensional world, it would be on a plane that had zero thickness. So light would pass straight through it. You couldn't feel it, see it, or smell it, or detect it with any known instrument.

So two dimensional worlds might be all around us, we would have absolutely no idea, and never be able to detect them with 3D equipment.

The same could apply to a 4D world, it might be physically impossible to detect matter and energy that is only 3D.
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"Worlds" ... You seem to think of dimensions as separate regions? As I understand it, it's actually about perspective capability.

[Feck]

Ah it's almost like magic I mention Crowley and Electricwhiteboy turns up . EWB

[Dory]

I read the resource and the replies. I still have some perplexing questions that are left unanswered.

1) Are there creatures that can see only in 2D?

2) Are there creatures we know that can see in 4D?

3) Is it purely hypothetical or proven? How can you prove it? Where are the evidence for a 4th dimension? Every physical concept has been so far proven. Why should we accept something just because physicists say it's a possibility without providing any evidence other than theory?

[electricwhiteboy]

I read the resource and the replies. I still have some perplexing questions that are left unanswered.

1) Are there creatures that can see only in 2D?

2) Are there creatures we know that can see in 4D?

3) Is it purely hypothetical or proven? How can you prove it? Where are the evidence for a 4th dimension? Every physical concept has been so far proven. Why should we accept something just because physicists say it's a possibility without providing any evidence other than theory?

I don’t think see is the right word here, as it’s more a question of perception. It’s not so much a failing of our eyes that prevents us from perceiving the world 4 dimensionally as the way light behaves. We could never evolve to “see” the forth dimension.

Click on the link here and scroll down to the animation where a hypercube is rotating. Note the word rotating. It’s spinning, but from our point of view it seems to be turning itself inside out!

http://en.wikipedia.org/wiki/Hypercube

Google animated hypercube, because they look completely different from other angles of rotation!

If a 4 dimensional being were to try and explain itself to us, it would probably show multiple copies of itself at various sizes, or (from our perspective) turn itself inside out through a dimension that we don’t have. If you remember back in basic maths, or arts and craft, when they got you to make cubes out of paper? It would sort of perceive 3D objects like a flattened out cube before it was assembled. It would know it was 3D through a sense of perspective unknown to us. You can now sort of understand how alien 4D objects are to us, we simply exist on a plane that does not allow us to perceive them except very obliquely.

Going back to what Feck was saying about Crowley, certain occultists claim to have contacted demons which have manifested to them in the way I’ve just described. But quite frankly I call shenanigans on that! The way magic “works” and I use that word loosely, is by exploiting several scientifically proven ways of getting off your face. Fasting, isolation, deep concentration, repetitive behaviour, sleep deprivation. Etc, etc. My guess, having not summoned any demons (honest guv!) is that they are hallucinating something which resembles that description, but obviously from an objective point of view AREN’T CONTACTING 4 DIMENSIONAL DEMONS.

[Pappa]

The 4th dimension, as far as I understand, is a mathematical concept in Euclidian geometry; it has nothing to do with the actual dimensions of the Universe as described by physics and string theory. According to general relativity matter causes space-time to curve so it deals with Non-Euclidian geometry. Time being a dimension and the 4 dimensional hypercube (in the Sagan video) are two entirely different things.

I'd been meaning to post something like the above since I started reading this thread. Three different types fourth dimensions have been brought up in this thread and they're not the same thing. No wonder Dory's a bit confused.

They are:

• Additional dimensions as mathematical concepts. These are basically mathematical curiosities and can also serve the practical purpose of being useful in mathematical theories and equasions.
• Time.
• One of the several extra "curled up" dimension predicted by the many forms of string theory.

[electricwhiteboy]

They are:

• Additional dimensions as mathematical concepts. These are basically mathematical curiosities and can also serve the practical purpose of being useful in mathematical theories and equasions.
• Time.
• One of the several extra "curled up" dimension predicted by the many forms of string theory.

Yep, and New Agey/Occulty types change between which one they're talking about mid sentence. I think I spent about two whole days trying to understand the difference between the three different terms in an effort to debunk some twaddle I was reading.

The whole space-time being curved by matter or General Relativity is proved. We have to take it into account to stop Satellite navigation drifting.

The maths works for the extra dimensions of string theory, but we haven’t yet devised an experiment to test for them. It’s a bit like if you imagine that a branch of Architecture stopped building things and went into pure theory. It worked out how to build bigger and more complex buildings through mathematics, and got well ahead of what the craftsmen could actually make. One of these Theoretical Architects designs a massive complicated Cathedral for which the maths all works. Do you think that it would fall down if it was built?

That’s pretty much a good metaphor for where we are with string theory.

[Tigger]

I like this:

[mistermack]

"Worlds" ... You seem to think of dimensions as separate regions? As I understand it, it's actually about perspective capability.

I didn't mean anything like that.
A state of existence would be a better phrase, I guess, but worlds is just a more common expression.

Dimensions are just the fundamental properties of something that exists.
Everything that we know of is fundamentally energy, so dimensions that we know are the fundamental properties of energy.

Energy is movement, in three space dimensions over time, so the dimensions we know of are 3D+time.

If energy has another fundamental property that we don't know about yet, that would be another dimension.

Also, there could be other forms of existence that we are unable to detect, and the fundamental properties of that would be dimensions, even though they wouldn't apply to the energy and matter that we know of.
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