Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: UScaV on 23/10/2003 04:28:10
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I had an option of doing a project on the 4th dimension last year, I didn't actually do it but I looked at some books and website and things, and most of them were about the 3 dimensions we know, and that the 4th dimension is time. I don't really understand this concept, but one way I saw it related was this: Let's say you've got a little square isolated to the 2nd dimension. He can move up and down on the X and Y axes (plural for axis), but he can't move vertically through the height dimenson. Since he can't see it or ever actually move in this way, there's really no way for him to possibly understand this. You can try to explain it to him, but there's no way he can really know unless he expieriences it himself.
So I suppose if there were a creature that could use the 4th dimension it could move in and out of our vision using the 4th dimension, which I suppose could be time, meaning he could time travel? Anyway, I was just wondering what other theories were out there about this topic, and if there has ever been any speculation about something less than 1 dimension or more than 4.
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It's past my bedtime, but I can't resist a thread on dimensions. There has been a HUGE amount of speculation about higher dimensions. You could fill a good size library with studies on dimensional spaces.
Thinking of the fourth dimension as time isn't too difficult. Think about an intersection of two streets. Cars can travel through the intersection using some time to do so. Each car that passes through takes up the same space (in X, Y, and Z directions). What keeps the cars from crashing is the time dimension - they occupy the same X-Y-Z space, but not at the same time coordinate.
If there was an overpass, then multiple cars can occupy the same X-Y space, at the same time, but they are separated in the Z dimension. (Assuming that Z is up-down relative to the surface of earth).
The fourth dimension doesn't have to be time. Maybe T is the first, and X, Y, and Z are 2, 3, and 4.
I have skimmed through several theories about dimensions in the universe. Some postulate seven is the magic number. Some say 11. Some say 12. Some say several hundred. Adding one more dimension to X, Y, Z, and T gets over my head, so I'll have to save additional comments for later. Lack of sleep and medium quantities of alcohol seem to help in understanding higher dimensional spaces. [:D]
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No words of wisdom here.
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Tweener - that was brilliantly explained. Nicely done ! I've never come across such a nice analogy so well put.
UScaV - what did you do your project on in the end?
Chris
"I never forget a face, but in your case I'll make an exception"
- Groucho Marx
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Interesting subject, as tweener indicated, a lot of material has been written on the suject (of which I understand little!). However, I understand the "superstring theory" requires 9 spatial dimensions and speculation is these other dimesions are very small thus we do not interact with them in daily life. The theoretical possibility of extra dimensions is exciting and their discovery might someday completely change our view of spacetime.
However, I'm certain my clothes drier moves between dimensions.......and leaves socks behind in the process!
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Time exists so everything doesn't happen all at once.
Space exists so everything doesn't all happen to you.
[:p]
We operate in three physical dimensions, not counting time, so our brains have a hard time comprehending a 4th physical dimension.
Imagine a being that existed only in a 2 dimensional XY plane. Try explaining to that being that being a hypothetical situation where there are an infinite number of XY planes, and all he has to do to get to them is go "up" or "down." He wouldn't know what you meant. Try explaining how something could be occupying the same XY coordinates at the same time, but on a higher dimension.
Now, to make the analogy fit us...imagine you're told that something can occupy the same X, Y, and Z coordinates at the same time. But on a higher dimension. Lets call it the ZZ axis. Ming boggling, eh?
Mathematicians have it all figured out on paper. We just don't know how to do it for real yet. If you really want to warp your brain, check out n-dimensional geometry theory.
http://en.wikipedia.org/wiki/Polychora
(shameless plug for wikipedia...they rock)
This message brought to you by The Council of People Who Are Sick of Seeing More People
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wikipedia is a really cool site. Thanks for the link Jay!
I'm going to show the polychora link to my son - he'll love it.
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Some analogies I made up and like:
There's a man in two dimensions who wants to see inside a circle, but no matter which way he goes around it there are no holes and he can't see the contents. Finally he decides to cut a side open and he can see the things inside. A man in the third dimension (like us) can see the circle and everything inside with the tiniest of glances. We can see all. Then a man from the thrid dimension has a sphere in his hand. no matter which way he turns his head he cannot see inside. He finally decides to cut open a side to see what's inside. A man in the fourth dimension can see the whole sphere and everything inside all at the same time with a single glance. He can see all.
A man makes a circle on the ground and keeps increasing the radius, eventually the circle is a straight line and then it curves the wrong way when he increases it more then it traps him!! Can you guess? He's on a sphere ... then he goes to a three d space and blows up a balloon, the balloon becomes flat then it curves towards him the more he blows in it then he is surrounded by the balloon it traps him and he can't get out! He's in a 4D hypersphere!
I used to have more but forgotten them now.
Am I dead? Am I alive? I'm both!
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If we consider space-time as an unique object, do you think that time is a strange piece. In normal thought, we can not accept an ideal that we could inverse the dimentional of time, everything happen from past- present-future, while all the another componient of space can be inversed with no problem. Nowaday, physics has reached many progresses. But as you know, we get some big problems, i.e the Unification Theory, dark matter, no evidence about SUSY, ... So that a question here is that the reason maybe the absence of constraints in which time must be forced to pass only one direction. But if these constraint will be discoveried, so how about the CPT invariance.
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quote:
Originally posted by vanvinhhoang
If we consider space-time as an unique object, do you think that time is a strange piece. In normal thought, we can not accept an ideal that we could inverse the dimentional of time, everything happen from past- present-future, while all the another componient of space can be inversed with no problem. Nowaday, physics has reached many progresses. But as you know, we get some big problems, i.e the Unification Theory, dark matter, no evidence about SUSY, ... So that a question here is that the reason maybe the absence of constraints in which time must be forced to pass only one direction. But if these constraint will be discoveried, so how about the CPT invariance.
Is the 'direction' of time anything more than merely human perception?
If we look at a road from London to Birmingham, we do not ask which direction it goes, we merely look at all the connected bits of tarmac that make up the road, and consider it one long connected road.
If we then look at a car that is in London at 10:00, and in Birmingham at 12:00, and look at all the separate instances of that car in the times between 10:00 and 12:00, we say that the car has moved from London and Birmingham, but is this really anything more than merely our perception of the linkage of a single car over time. If we could simultaneously perceive the total connected instances of the car between 10:00 and 12:00, it would be no different to the connected bits of the road that exist between London and Birmingham, and the notion of direction would not be an issue.
Yes, time is strange, but not so much that it is of itself strange, but that our relationship with it is strange, that we can instantaneously perceive an image in two dimensions, and gain enough indirect information from our stereoscopic vision to instantly model the world in three dimensions; and yet we cannot look through time with the same ease that we can look through space. Our memories allow us to look in one direction in time, and yet we have no way to view time with such ease in the other direction. None of this can tell us anything about the direction in which time moves, or if it moves at all, but tells us about the limitations of our perceptions of time.
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Some postulate seven is the magic number. Some say 11. Some say 12. Some say several hundred.
Which culture considers 11 as the magic number? I think I have never heard of that... And by several hundred I guess you mean either 108 or 666.
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UScaV, you're a writer?
That question actually made sense :)
But you know the fourth dimension. And sure you could make a project out of it.
A white sheet, and in front a black mechanical, ticking, clock.
The problem would be that some people might get that as a slight actually.
And to make worse worse, some wouldn't be wrong, would they ?:)
Because as they do, they also create a intention.
It's called 'social engineering'
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I should remind you though, in our best interests, that such a behavior is no problem for anyone expect, a culprit.
The line your talking about is best represented by a clock, 'ticking' one way
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Using it geometrically makes for beautiful lines, but won't tell you a thing about anyone.
You might want to see it as geometrical 'Meta Data'
Good for statistics, and sorry, yes for defining somethings 'proper time', but, :) only as relative something else....
Kind of negating itself, doesn't it?
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there is no 'proper time' looking at it this way, using a failed proposal for it
the presumption of my clock defining what is 'right' :)
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Turned around it states that all 'local definitions' of 'time' must be correct.
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You can translate that to a statement in where all local definitions are equivalent. If that is true then the clock has a same rate for us all, locally defined. And that fits conservation laws, Noether, homogeneity and isotropy
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And I'm awfully sorry, hopefully you're a known author by now so you won't come back to haunt what I wrote :)
Looked at the caption, missed when it was made.
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Anyone writing about the 4th dimension should read Edwin Abbot’s “Flatland” first. Hopefully the OP did that a long time age. :)
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Anyone writing about the 4th dimension should read Edwin Abbot’s “Flatland” first. Hopefully the OP did that a long time age. :)
Possibly not read, viz the comment about the eg someone described, depends whether it was on a std school science reading list - certainly ought to be.
Unfortunately many of the multiple dimension theories don’t view extra dimensions in the same way we might.