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dummy
I am you and what I see is me
Registered: 09/29/08
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Re: 4th (and higher) dimensions [Re: Poid]
#12306552 - 03/31/10 03:33 PM (14 years, 23 hours ago) |
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i've always assumed the 4th dimension is like.... ft^4
say you have a tile... it's ft^2 if you have a cube... it's ft^3 and if you have ft^4 you have some equivalent line based thingy in the 4thD
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g00ru
lit pants tit licker
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Re: 4th (and higher) dimensions [Re: dummy]
#12306693 - 03/31/10 04:00 PM (14 years, 22 hours ago) |
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yeah but what would that look like?
maybe it would stretch through time or something
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c0sm0nautt
Registered: 05/19/08
Posts: 10,303
Loc: The Astral Realm
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Re: 4th (and higher) dimensions [Re: Poid]
#12306754 - 03/31/10 04:14 PM (14 years, 22 hours ago) |
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Quote:
Poid said:
Quote:
c0sm0nautt said: In a sense it is. I'm not denying physical reality, nor the brain as a vehicle of consciousness. I'm saying there is an ultimate, or underlying reality, which is consciousness only - where all matter springs forth from.
You're talking about God, right?
God, ether, Atman, the Self, the One... whatever you want to call it.
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dummy
I am you and what I see is me
Registered: 09/29/08
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Re: 4th (and higher) dimensions [Re: c0sm0nautt]
#12307415 - 03/31/10 06:04 PM (14 years, 20 hours ago) |
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i don't think we're meant to be able to comprehend it. probably has to do with the fact we're in 3d
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Frinkz
Strange
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Re: 4th (and higher) dimensions [Re: dummy]
#12310474 - 04/01/10 07:45 AM (14 years, 7 hours ago) |
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This ought to give you, at least, something interesting to think about when you're high.
As a physicist, we don't consider time as a dimension, nobody knows what time is. My favourite Einstein quote, "Time is just what clocks read"
I don't know if anyone's mentioned this, but in Cosmology, it is generally believed that our 3-dimensional universe is contained in (or on, depending on how you look at it) a 4-dimensional 'thing'. You may have heard that 'space is curved', but what the hell does that mean?
Almost all modern cosmological evidence points towards this.
There's plenty of things backing this up - some of them you may know about, such as cosmic background radiation.
The easiest to explain, is that when we measure the distance to any galaxy, we find that it is not only moving, but accelerating away from us. One way to interpret this, is to assume that we just so happen to be bang on, exactly in the centre of the universe (if there were such a thing). But we'll ignore that.
The other explanation is that the universe that we live in, is expanding.
A good 2D analogy of this, is to imagine a grid drawn out on a 3D balloon. Imagine you are an ant, living in a 2D universe on that grid. You would see all the other grid points around you.
If you blow up the balloon (gently, so as not to frighten the ant) then he's going to see that he has stayed exactly where he is, and that all the other points on the grid are still there, but accelerating away from him.
This is what we see, in our 3D world. As the 4D 'thing' that our 3D universe is 'on' expands, what we see is an expansion of everything in all directions. Obviously this expansion is a very small amount - so it is only noticeable when talking galactic distances, but it's measurable.
Without going into the maths, there is an equation, known as the Robertson-Walker Metric. In it, there is a parameter k (derived from the same basic maths that you would calculate distances of the 2D grid on the 3D balloon). It turns out, whatever this parameter is, defines the 'shape' of the universe, you can consider k to be a measure of the curvature of space.
Since we obviously cannot ever think of visualising a 4D object, we have to talk in 3D analogies.
If k = 0, we have a 'flat universe'. That is, imagine you are the 2D ant on a sheet of paper, the paper is expanding. If you travel in any direction, as the universe expands, you just keep going, and going, forever. We call this an 'unbounded infinite universe'. If this is the case, then we can happily say there are only 3 spatial dimensions - a piece of paper is essentially 2D.
If k > 0, we have an 'unbounded finite universe' or 'closed universe'. That is, imagine the ant back on his balloon. If he sets off running in one direction, yes he can keep going infinitely, but eventually he will end up back where he started (since he is essentially going around a sphere). This seems unlikely, as when we look out in space, we don't see ourselves looking into space, seeing ourselves looking into space, etc. it doesn't repeat.
If k < 0, we have an 'unbounded infinite universe', like we do with the flat universe. However this time (again without the maths, you'll just have to imagine it) if we bring it from 3D-4D back to 2D->3D, we have our ant running around on a hyperboloid. Now, as he runs, and this expands, we find that he will never get back to where he started.
It turns out, through years of cosmological experiments, and recently the huge WMAP project, that can determine k is not 0. It is in fact somewhere between 0 and -1. Meaning that our 3D universe must exist in some other 4D 'thing'.
We've all seen 'wormholes' in SciFi stuff, and this is where it comes from. If we have the ant on our sheet-of-paper-universe, it's quite easy to fold it so he can hop across to the other side, saving him lifetimes of travelling. Now, the ant just has to master the ability of folding an infinitely large piece of paper
If anyone else has experience in this, and wants to share there view, please do! I know I've omitted some things, but without maths it's hard to explain. I am currently revising for a cosmology module, so this seemed like an opportune moment to share some knowledge
So, if you were to consider time to be a dimension, then you would have to call it the fifth
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g00ru
lit pants tit licker
Registered: 08/09/07
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Re: 4th (and higher) dimensions [Re: Frinkz]
#12311232 - 04/01/10 10:49 AM (14 years, 4 hours ago) |
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actually just about everybody considers time a dimension.
but you're right it doesn't have to be the fourth.
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Frinkz
Strange
Registered: 02/25/10
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Re: 4th (and higher) dimensions [Re: g00ru]
#12311271 - 04/01/10 10:57 AM (14 years, 3 hours ago) |
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Come to think of it, you're right, most of the time it is actually considered as a dimension (xyzt)
My bad, long day
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DieCommie
Registered: 12/11/03
Posts: 29,258
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Re: 4th (and higher) dimensions [Re: Frinkz]
#12311289 - 04/01/10 11:00 AM (14 years, 3 hours ago) |
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Usually its (x,y,z,ct).
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LunarEclipse
Enlil's Official Story
Registered: 10/31/04
Posts: 21,407
Loc: Building 7
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Re: 4th (and higher) dimensions [Re: DieCommie]
#12311577 - 04/01/10 12:00 PM (14 years, 2 hours ago) |
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The Fifth Dimension
One Upmanship
Edited by LunarEclipse (04/01/10 03:13 PM)
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Frinkz
Strange
Registered: 02/25/10
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Re: 4th (and higher) dimensions [Re: DieCommie]
#12316569 - 04/02/10 08:35 AM (13 years, 11 months ago) |
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Quote:
DieCommie said: Usually its (x,y,z,ct).
That'll be why I failed special relativity last year
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