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How To See In Four Dimensions
Posted by
timothy
on Sun Aug 24, 2008 03:31 AM
from the wrinkle-in-time-time dept.
from the wrinkle-in-time-time dept.
An anonymous reader writes "Think it's impossible to see four-dimensional objects? These videos will show you otherwise. Some mathematicians work with four-dimensional objects all the time, and they've developed some clever tricks to get a feeling for what they're like. The techniques begin by imagining how two-dimensional creatures, like those in Edwin Abbot's 'Flatland,' could get a feeling for three-dimensional objects. When those techniques are transferred up a dimension, the results are gorgeous."
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Submission: How to see in four dimensions by Anonymous Coward
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Easy to see in four dimensions (Score:5, Funny)
Re:Easy to see in four dimensions (Score:5, Interesting)
I "visualize" four dimensions and more often, when programming and setting up multi-dimensional arrays of more than three dimensions.
All one has to do is acknowledge that adding a dimension simply adds a range of points that map to every single point in the (n-1) dimensional range. So, the easiest way to visualize a four dimensional cube is to simply imagine multiple identical cubes, side by side, for as many as the range has been specified. Five dimensions is a flat square arrangement, six is a cube arranged array of cubes, and so on. This way, an infinite number of dimensions can be visualized. Perhaps the term "mental addressing" is more appropriate a name for this mental method.
The limit is, of course, this only works directly for finite and discrete arrays. I find it can be extrapolated to use non-discrete spectra, but describing the way that works in my head will not be possible using this clumsy tool we call "language".
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Re:Easy to see in four dimensions (Score:5, Insightful)
After thinking about this some more, I find that the animations in the article are not at all four dimensional, as the so called "fourth" dimension they are representing exists in the same physical space as the third.
This breaks the dimensional relationship. Imagine, if you will, a single point with no dimensions. Then extrapolate that into a line to get one dimension, imagine that line them extrapolating perpendicular to the line to form a square, and then imagine that square extruding into a cube. So far, no physical overlap has occurred. The fourth dimention as represented in these videos, does nothing but add more "balls and sticks", which is not adding another dimension, it's simply adding detail to the existing dimension.
Likewise, those 2D imaginings of a 3D object are not visualizations of a 3D object in 2d, they are the visualization of a changing 2D object, with the simulated third dimension being time.
In other words, the method that they have used does not actually visualize a fourth dimension in any mathematical or logical sense, they are really just optical illusions. Personally, my method of visualization that I described in my previous post is far superior, and more accurate from a logical and mathematical point of view, as it truly does represent a 1:M maping of every dimensional unit in the (n-1) dimensional space.
P.S., I've always wanted to start a sentence with "Imagine, if you will...".
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Re:Easy to see in four dimensions (Score:5, Informative)
I find that the animations in the article are not at all four dimensional
Duh. That's because our screens are two dimensional, and you and I are three dimensional. Certainly you can't fault them for this? (Please tell me that I'm somehow misunderstanding this objection..)
In other words, the method that they have used does not actually visualize a fourth dimension in any mathematical or logical sense
That's nonsense. Their videos show the edges of the object (although distorted) as well as the interconnections of each of the vertices. What would qualify to you as a "real" mathematical or logical way of viewing these objects in a 3-D world?
As for your previous post:
So, the easiest way to visualize a four dimensional cube is to simply imagine multiple identical cubes, side by side, for as many as the range has been specified. Five dimensions is a flat square arrangement, six is a cube arranged array of cubes, and so on. This way, an infinite number of dimensions can be visualized. Perhaps the term "mental addressing" is more appropriate a name for this mental method.
Okay, when you get down to it, this is stuff that any programmer knows when working with arrays. (ie- int[][][][][], etc.) Now your task is to *draw* your example for us in 3-D space.
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Re:Easy to see in four dimensions (Score:5, Insightful)
Imagine, if you will, that you're ignorant. That shouldn't be too hard. Do you complain that your 3D graphics card just adds more 2D pixels, where it should instead show hundreds of 2D pictures next to each other in order to represent 3D space?
Imagine, if you will, that you're also ignorant (or perhaps a member of congress). That shouldn't be too hard...
Do you think that humans actually see in three dimensions? We don't. We see in two dimensions. The retina is a plane. By using two planar sensory arrays, our brains use parallax to calculate depth. This is 2D vision with depth cues. Actual 3D vision would have us able to see the back side of the TV while watching a show on the front. When we talk about "visualizing" dimensions beyond the third, we're not talking about actually seeing things with our eyes. We're talking about mental pictures. We can "visualize" the back of the TV because our sensory system is accustomed to using a series of depth-cued 2D images to construct a model of the 3D world. Pushing that up to four dimensions isn't even remotely the same as drawing a ray traced 2D picture on a fucking computer monitor.
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Re:Easy to see in four dimensions (Score:5, Interesting)
Yeah I've had arrays with double digit dimensions.
I think my record is 16 or so.
I dont know why but I work with them incredibly easily.
Without them its like programming with a hand tied behind your back.
Cant visualize them at all, I can work with them though.
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Re:Easy to see in four dimensions (Score:5, Funny)
Cool story bro
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Re:Easy to see in four dimensions (Score:4, Insightful)
I am interested in what problem space you are working with.
In some very extreme cases, I can see it being a requirement to work the way you are, but in most real-world code, what you suggest would be far simpler to maintain (for you AND others) if you would just take a few extra minutes to think about what your data structures need to be.
Just because you CAN, doesn't mean you SHOULD. If it is a one-off script to solve a complex problem, then you have my respect. If anyone else EVER has to grok your code, for any reason, then you are just incompetent :)
BTW, this is probably an incredibly stupid question, but I just want to clarify. "The fourth dimension" is such an incredibly loaded term. In the context of this article, it is referring to time, correct?
Assuming I am correct, I have always had a very simple theory I use to wrap my mind around it. Bear in mind I am a high-level programmer, not a quantum physicist. I think that we (humans) exist within the first three dimensions while we travel along the fourth. Hence we are aware of, and can, to some extent, measure the fourth, but it is very difficult to perceive it in any concrete manner.
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it see all time (Score:5, Funny)
Take LSD and sure you'll see 4th dimension.
Try Salvia (Score:4, Interesting)
One of the most common sensations (along with the sense of absolute terror at being ripped into a void in space/time) is the feeling of moving through between more than 3 dimensions of space. In my travels I usually feel like I'm spinning and being folded in about 7 different dimensions before my visions start to settle.
To anyone who decides to take me seriously, make sure you have a sober sitter :)
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Re:Try Salvia (Score:4, Informative)
YES THERE ARE ACCOUNTS OF PEOPLE NOT MAKING IT BACK. Some have died, but many others never make it back whole again. Part of their minds, their soul maybe, never reintegrate with our reality here.
Bullshit. Salivia Divinorum is so non-toxic it has no known LD50. All this woo-woo scary crap about souls "not making it back" is about as credible as a summer camp ghost story. As with any hallucinogen, care must be taken to use it in a controlled environment so as to minimize the unpleasantness and potential for accidents (i.e. don't drive, walk tightropes, or handle rattlesnakes while high) but there's no inherent danger to it.
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Re:it see all time (Score:5, Funny)
I prefer melange.
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Scientology? (Score:5, Interesting)
Why is the story tagged scientology?
Re:Scientology? (Score:5, Funny)
Obviously, Lord Xenu has a Slashdot account.
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Re:Scientology? (Score:5, Funny)
Damn straight.
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Re:Scientology? (Score:5, Interesting)
I see a flash scientology , rather very big ad at bottom of article and in "videos", there are Google Adsense ads mentioning scientology youtube channel.
It could be related to people who sees those ads (must be scientific terms used triggering them) and think the site is Scientology supported. It could be possible but it could be the adsense only too.
BTW Google Adsense advertising Scientology Youtube channel is not really a good, pretty sight. What next? Doubleclick ads too?
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Simply imagine a space defined on R^N.... (Score:5, Funny)
then set N = 4....
not (Score:5, Insightful)
Sorry it's on my screen, so it's a 2 dimensional representation of a 4 dimensional idea in 3 dimensional space.
Re:not (Score:5, Funny)
Close one eye.
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Why parent is not insightful (Score:5, Informative)
Your retinas are, even together, a 2 dimensional array. You never "saw" anything but what your brain constructed from 2 dimensional arrays. Turns out your brain is very, very good at visualizing a 3d object based on this input. Would you say you can't visualize an actor's physical body because the screen is 2 dimensional?
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did this years ago... (Score:5, Interesting)
http://shambala.net/3d/tess3d1.gif [shambala.net]
Re: (Score:3, Informative)
Re:did this years ago... (Score:4, Interesting)
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Dupe! (Score:3, Funny)
Just imagine (Score:4, Insightful)
To think about it is mind bending, awe-inspiring, and dream provoking.
Seeing in 4 Dimensions? (Score:5, Funny)
Just go to any Burning Man concert and eat the multi colored Brownies.
Carl Sagan (Score:4, Interesting)
Does anyone remember in how a good way Carl Sagan explained the problem if there are more or less than 3 dimensions exist?
I remember he was explaining the imaginary 2d creatures not being able to see 3d creatures and so on. It was on a TV documentary. Sorry if I remember it all wrong. I was like 13 ;)
It must be an episode of "Cosmos" http://www.imdb.com/name/nm0755981/filmoseries#tt0081846 [imdb.com]
Re:Carl Sagan (Score:5, Informative)
Here you go. It was Cosmo's take on "flatland":
http://www.youtube.com/watch?v=KIadtFJYWhw [youtube.com]
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Re: (Score:3, Informative)
Indeed it was...
You can watch them (except part 5) on Guba [guba.com] (change query to find the rest)
I think it was part 8 specifically. I got the DVD but its been awhile since I wandered through it... But its fairly brief, everything on the difference between 2, 3 and 4 Dimensions is basically described as it was here, and just as brief.
However, its still a good way to spend 13 hours because of everything else he covered in that series.
Just so we are clear... (Score:5, Insightful)
A 4D object is mathematically projected to a 3D representation, that is then projected into a 2D representation for display on the monitor, that is then transformed by my brain back into a 3D representation, and then further needs to be transformed into a 4D object... /looks for his linear algebra textbook //begins drinking
Re:Just so we are clear... (Score:5, Insightful)
In a way, it's also projected into a 1-dimensional stream of bits.
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Re:Just so we are clear... (Score:5, Interesting)
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Interacting is the easiest way to learn (Score:5, Interesting)
I can visualize 11 dimensions (Score:5, Funny)
Re:I can visualize 11 dimensions (Score:5, Funny)
That reminds me of a joke:
An engineer, physicist, and a mathematician are sitting at a bar, and the bartender asks, "Can any of you guys think about four dimensions?"
"Sorry, not me," the engineer replies.
The physicist chimes in, "I suppose I can, if the fourth dimension is time."
The mathematician starts laughing. "Oh, you guys, this is easy! Picture n-dimensional space. Now, let n be equal to four..."
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OT but another mathematics joke (Score:5, Funny)
A physicist, and engineer, and a mathematician are sleeping in a hotel when fires break out in all their rooms. The physicist get up, does some quick calculations, and then gets the exact amount of water required to put the fire out, not a drop wasted. The engineer also does some calculations to work out the amount needed, then proceeds to flood most of the floor, to ensure that there is a sufficient tolerance for error. The mathematician wakes up, and does some extremely complex calculations but does them much quicker than the other two. He then exclaims "I have proven I can put the fire out!" and goes back to bed.
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Re:OT but another mathematics joke (Score:5, Funny)
Also, given an empty ice-bucket on the dresser, the sink in the hotel bathroom, and a burning trashcan, how does a mathematician put out the fire? Like any ordinary person, he grabs the ice-bucket, runs to bathroom, fills the bucket with water from the sink, and pours the water into the trashcan, thus putting out the fire. Now suppose that the ice-bucket is already full -- how does the mathematician put out the fire? He grabs the ice-bucket, runs to the sink, empties it, and returns it to the dresser. The problem has now been reduced to one that has been previously solved.
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Buddhabrot (Score:4, Interesting)
Re:Buddhabrot (Score:4, Interesting)
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Pfffft, is that all ? (Score:4, Funny)
Here is a one dimensional projection of a 5 billion dimensional sphere: _
rotating tesseracts (Score:3, Interesting)
Old maths joke... (Score:4, Funny)
Seeing four dimensions. (Score:5, Funny)
To begin, consider that a 2d picture can either be a picture (things can fall), or a map (things don't fall). Since the corresponding 3d thing is a picture/map of four dimensions, we can build objects like houses, furniture, etc from plan and views.
Not all seems to be aimple. A knife cuts: literally, it makes a surface by motion, and is therefore tipped by a space of N-2 dimensions. Rivers can be either "latrous" (1d) or "hedrous" (2d). A fault lake is 2d (since faults are a break of surface).
Holes come in two types, although these are topologically the same. One can have a "bridge" or "tunnel" kind of hole: in 3d, these are the same, in 4d they are different.
The planet rotates on clifford motion. This makes every point of the 4-sphere go around the centre. One sees this by equality of energy in modes of rotation.
None the same, there can be seasons. If the sun does not follow in the year-circle any of the circles of the earth rotating, then there will be seasons. You don't just have hemispheres in summer vs winter, but season-zones to match the time-zones. That is, for example, Christmas (normally in summer), can fall in early spring, or late winter.
The poles are replaced by circles of extreme climate. One has a "equator circle", and a "polar" circle. At the tropics (a singular torus-shape thing), the sun becomes to the zenith once a year. At the artic torus, the sun hugs the horizon for the equate of the shortest day.
Because the sun is relatively still in the sky, there is no variation in the number of hours. What makes the seasons is that the the sun is lower in the horizon, even at midday.
See, eg my site http://www.geocities.com/os2fan2/gloss/index.html [geocities.com]
Re:Seeing four dimensions. (Score:5, Funny)
Careful.
You read just like the timecube guy did, before he took that last hit of bad acid.
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You need another dimension to visualize the 4th. (Score:3, Interesting)
For the same reasons you can't visualize a 3D object on a 1D space you can't visualize a 4D object on a 2D space.
You cannot go up 2 dimensions.
Just as we can visualize a 3D object on a 2D space we can visualize a 4D object on a 3D space.
Thus we need something like this:
http://dogfeathers.com/java/hyprcube.html
*Click the Stereo button 2 times to switch it to cross-eyed view for no glasses. Simply cross your eyes to bring both shapes together in the center and it should become clear.
We see in 2D not 3D (Score:4, Insightful)
Of course, we can't really see in 3 dimensions, otherwise, we'd be able to see through stuff. The image projected onto our eyes is a 2D image, and we have 2 eyes, so it's (x*y)+(x*y), not (x*y*z). The third dimension is a cheat and is represented as 'stuff getting smaller'.
If we really could see in 3D, we can use the 'getting smaller' trick to visualize 4 dimensions much more easily.
Anyone know of some images or videos on the net using reverse perspective, where things behind get bigger instead of smaller?
Haven't seen the video yet. (Score:4, Insightful)
But I can guess how it works. A sphere passing through a plane would look at first like a dot, then a gradually wider line, then a dot. I remember flatland saying something about brightness at ends of the line.
So, a hyperball passing through a 3-space would look like a dot, gradually expanding to a sphere, and gradually shrinking to a dot.
Undoing the slasdhot effect (Score:4, Informative)
To download any of the videos directly, go here:
http://www.sciencenews.org/pictures/mathtrek/082208/ [sciencenews.org]
Alicia Boole Stott Got There First (Score:4, Informative)
Re:Tagit (Score:5, Informative)
http://bittornado.com/torrents/Dimensions-English.torrent [bittornado.com]
BitTorrent download for all the (English) movie files on the source website.
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