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Can we comprehend the 4th dimension.

  1. Apr 5, 2005 #1

    JamesU

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    If we exclude time as the fourth dimension, is it possible that over many years of trial and study, that our thee-dimensional brains can comprehend a higher dimension? :bugeye:
     
  2. jcsd
  3. Apr 6, 2005 #2
    :P where are all those dimensions

    A very interseting question indeed. In theory of coarse, hidden dimension do exisit. Again, in theory, they might be all around us. However, from an evolutionary perspective, it is highly unlikely that at any time in the near your question will become reality. You have to remember that physicists use the concept of hidden dimensions in order to simplify mathematical equations. But mathematical concepts do not always translate into 'real' world concepts. For now, it's all theoretical, and a theory is only useful if it can be disproved. That's what it means to be a theory. I am not sure what your level of math or phsyics is, but if you want a book that is written specifically for the lay audience about cosmic strings, black holes, hidden dimensions, I'd recommend Brian Green's books.
     
  4. Apr 6, 2005 #3

    JamesU

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    Thanx

    Is it possible though that even seeing a hyperbeing(while not comprehending it.) is even probable? :confused:
     
  5. Apr 7, 2005 #4
    Just a random thought but would an aether be considered as another dimension or simply something moving through our three conventional dimensions?
     
  6. Apr 7, 2005 #5

    selfAdjoint

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    This is the source of confusion for some posters. The traditional ether was an elastic fluid IN space (this was before relativity). Much later, Einstein sometimes spoke of an "aether". But he didn't mean anything IN spacetime, he meant curved, dynamic spacetime itself. This spacetime responds to energy and momentum, including that of light, by chamging its curvature, and the changing spacetime curvature feeds back to the light by altering its path (among other things). So Einstein saw that spacetime was replacing the outdated and unnecessary concept of a physical ether.

    The spacetime of Einstein's general relativity is four dimensional, one time dimension and three space dimensions. These dimensions are unified because the physics of Einstein's equations mixes them dynamically. If you follow the threads on this forum, especially the posts by Marcus and the links, you will see how physicists are trying with some success to quantize this Einstein spacetime. The quantization will be required to keep the dynamic two-way "aetherial" interaction between spacetime and light and matter.
     
  7. Apr 7, 2005 #6

    ohwilleke

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    First off, I think it is possible to conceive of multiple dimensions fairly easily by analogy. Think like a computer. From a computer's point of view, a dimension is simply the size of the vector needed to fully describe a point.

    Now, pretend that you don't know that temperature has anything to do with kinetic energy, and that temperature is continuous right down to the quantum level. These things are, of course, false, but because you use those assumption on a day to day practical basis in a crude operational model of the universe, it shouldn't be hard to pretend.

    Furthermore, suppose that we enact a new law of nature. This law of nature states: Two objects of different temperatures can be in the same place at the same time. For instance: An ice cube and a pot of boiling water could co-exist.

    Now, to describe a point, you need to know its location (in 3D space), the time, and its temperature. You could display this in a computer screen with a nice 3D graph that runs in video, with points colored blue to red to represent "temperature".

    Moreover, suppose that the temperature dimension was small. Maybe it was only three points wide - blue for cold, white for neutral and red for hot. You could visually display purple for a point where blue and red were inhabited, light blue for a point where blue and white were inhabited, pink for a point where red and white were inhabited, and black where blue, white and red were all inhabited. Indeed, in any small finite dimension, you could partision the finite dimension such that a three point system could be used to approximate it visually (i.e. you could view the last small finite dimension at very low resolution).

    Personally, I think that the universe is probably 4 dimensional and that the M-Theory, String Theory, Brane theory and the like are wrong, while loop quantum gravity in an emergent four dimensional universe or some variant thereof, is probably right (to a great extent because there is no real empirical evidence suggesting the existence of other dimensions), but the example above illustrated how it might be possible to think of a five dimensional universe (which is really what you mean when you talk about a four dimensional universe excluding time).
     
    Last edited: Apr 7, 2005
  8. Apr 7, 2005 #7
    There always exist some kind of naive fascination with the idea of "the fourth dimension" that is not satisfied when I tell people that time is the fourth dimension. They say "Yeah, but what I am really interested in is another space dimension".

    There are not "time dimensions" and "space dimensions", they are all on equal footing. The only reason we call our fourth dimension "time" and percieve it so differently than the other three, is because of the curvature in the fourth dimension!

    Imagine spacetime as a 4 dimensional cone (picture a 3d cone); note the symmetry we get if we rotate the cone (2 of the dimensions in a 3d cone are interchangeable). But one of the dimensions has a special, nonsymmetric place: it is the center axis of the cone. This is the place occupied by our time dimension.

    So when people say to exclude time from a discussion about dimensions, they are saying "I have my own (vague) idea of what a dimension is and time is just not satisfying to this discussion."
     
  9. Apr 8, 2005 #8

    JamesU

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    It's a good point, but if we saw 11 dimensions as in m-theory, would we "percieve" the as differently as space or time, or could they be different factors of both?
     
  10. Apr 8, 2005 #9

    JamesU

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    And what I meant was:

    Could we see a 4-D being moving in our three dimensions, but when it moves in a fourth spacial dimension, it dissapears or morphs in shape.
     
  11. Apr 8, 2005 #10

    ohwilleke

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    If there are more dimensions, we are in all of them ourselves. We are 4-D beings, if that is the correct number of dimensions. The question of whether there are places we can't go is entirely distinct from how many dimensions there are. We don't have any practical way of going to most of the Milky Way, or to any place not within the 70+ year span of our lives. Everything has a place in every dimension. The idea that more dimensions exist does nothing to imply that we aren't in them right now or that something can "hide" in another dimension, in and of itself.
     
  12. Apr 8, 2005 #11

    JamesU

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    If we're in these dimensions right now, (let's assume) How come that over millions of years of existance, we still aren't able to "move" in a four-dimensional way. If we're in these dimensions, wouldn't our minds adapt to these dimensions over time?
     
  13. Apr 9, 2005 #12
    In response to that quote. Its just too hard for the human mind to comprehend. Example. when you watch a film people IN the film move in a 3D world that is only 2D to the viewer. As difficult as it is for the person in the film to step out into the higher dimensions of the viewer, we as humans cannot comprehend the higher dimensions. Similair to the universal loaf theroy, we can reach and reach but we wont be able to move into the higher dimensions, that is until someone figures out how to! :tongue:
     
  14. Apr 9, 2005 #13
    Could photons and Electrons have a part of their dimension smaller than the planck length? Thus they would have properties of both matter and energy. If that were the case then electrons and photons would be examples of objects that we can see from the fourth dimension.

    Huck
     
  15. Apr 11, 2005 #14

    JamesU

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    But the viewer isn't in higher dimensions, they'r in different parts of one- time
     
  16. Apr 11, 2005 #15

    ohwilleke

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    The comprehension question is the easier one.

    General relativity is an extremely mind stretching way to think about the universe. And, why shouldn't it be? Humans evolved in a particular niche of space where the equation g=9.8 m/s^2 in the down direction. Human had no need to have any more sophisticated understanding. Additional understanding of gravity imparted no evolutionary advantage.

    Likewise, in all but the last century of the hundreds of thousands of years of history, human have had no occassion to encounter matter engage in anything other than chemical reactions, except for a few naturally radioactive sites that could be chalked up to the much more plausible explanation of evil spirits. Why should humans understand quantum theory? And, in particular, why should they understand either nuclear strong force or nuclear weak force?

    Humans are not finely tuned perceptual creatures. For example, we can't tell the difference between vision at twenty-four frames a second and a continuous view of an object. As long as we appeared in a common part of the 4th dimension every 24th of a second, who would notice the difference? Even artists, for example, took well over a thousand years before they could draw horses in motion with their legs the way they really worked, for essentially that very reason.

    Now, don't get me wrong. A 4-D universe, three dimensions in space and time, would be a highly convenient physical relaity. BUt, imperfect human peception isn't necessarily the best argument for its existence.
     
  17. Apr 11, 2005 #16

    JamesU

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    You're saying it has no evolutionary advantage, but we can't know that until we understand the bnefits of the fourth dimension. We were, and still are, faced with so many problems a day, and with no knowledge of the fourth spacial dimension, you're saying we have no need for it.
     
  18. Apr 13, 2005 #17

    ohwilleke

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    I'm saying that knowledge of an additional dimension was not particularly important for allowing humans to live long enough to reproduce for the first 100,000 or so years of the human species when we existed as hunter-gathers and later as primative agriculturalists in an era before modern medicine, internal combustion engines, electricity, printing presses, intercontinental travel, etc.

    It may indeed be useful knowledge, but clearly, it wasn't all that important to know in order to be able to kill mammoths, to avoid being eaten by tigers, and to domesticate corn.
     
  19. Apr 13, 2005 #18

    JamesU

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    I see your point, but other species have gone extinct because of a lack of evolutionary advantage, and what if in the future, we'll have a need for a hyperdemension. :approve:
     
  20. Dec 27, 2010 #19
    The only animals to comprehend the fourth dimension are whorled mollusca, they have bypassed left and right and embrace the curvature of the universe, which is the spiral caused by the universe spinning while expanding(torsion)
     
  21. Dec 28, 2010 #20
    The shading represents the position in the fourth dimension.
    [​IMG]

    Can you comprehend that?
     
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