The end of space

Discussion in 'Astronomy, Exobiology, & Cosmology' started by Fil, Feb 11, 2001.

  1. Fil Registered Member

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    My high school maths teacher was trying to make the class understand about the concept of the infinite.
    He said space is infinite, which i proceeded to argue. He said because space is nothing, and there is nothing after it, it is infinite.
    I started thinking and came up with this idea.

    One of the characteristics of space is that it has the potential to be filled (we can put a man in space).
    Beyond space nothing can exist for it is there is no longer any space or time.
    The end of the space time contineum if you will. If anything travelled into this it would cease to exist.

    I would love to here some thoughts on this, expecially if there is some scientist guy who thought it up before me, or even better if there wasn't.
     
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  3. Cris In search of Immortality Valued Senior Member

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    Fil,

    I think of something infinite as something that has no beginning and no end.

    If space were infinite then it would be meaningless to discuss going beyond the end of space since you would never be able to find the end to go beyond, i.e. the end does not exist.

    As a philosophical issue if you consider space, i.e. the universe, to be infinite, and therefore has no beginning then you elliminate the possibility of a creator type god. Since only something that has a beginning could be deemed as having been created.

    Not sure that this answers your question, but it was fun anyway.

    Cris
     
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  5. Fil Registered Member

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    You gave me an idea then.
    Space has always existed because there was no time before there was space/time. So it has always been there. and it will go on forever coz when/if it ends, no time will pass.
     
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  7. Doc Brown Registered Member

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    I think our universe is the surface of a 4-D sphere, just as our 2-D world is actually a 3-D sphere.
     
  8. Fil Registered Member

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    hey, i like that
     
  9. Weitzel Simon Fraser University Registered Senior Member

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    I agree with Doc Brown. The universe is likely finite, but without bound--just like the Earth. It was an intuitive idea when I was thirteen, and reading physics books since then I haven't found any reason to doubt my instincts.
     
  10. PaulD Registered Member

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    The universe can only be infinite. It is impossible for there to be an end because there has to be something on the other side of that end. Even if its nothing. Nothingness is still something.

    Please don't think I'm mad. It di make sense when I was writing it.

    I agree with Cris, there can't be a creator because universe has always been there and will always be there.

    To confuse things further if you assume that the universe has always beenin existence then it makes the issue of how life was created even more perplexing. If you were to trace it back to its absolute beginning, I'm talking about pre big bang as big bang only answers the question of life from a certain point onwards, then you have to assume that there must have been some elements or matter infinetely in existenece aswell.

    Now that goes against logic or the way we perceive life however it can not work any other way because if you take the premise that there was a point of time when the universe had a beginning you have to assume thatthe moment before this beginning was a time of nothingness and nothing can not create something.

    Am I making sense?

    Perhaps the right approach is to ignore all this and do something else like veg out in front of the telly.
     
  11. Cris In search of Immortality Valued Senior Member

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    PaulD,

    That's good, I understood what you were trying to say. But the religionists would say that a creator is immaterial which overcomes the lack of matter at the beginning. But then since such a creator would equate with our definition of nothing then there is the question of how can such an entity be said to exist at all. The simple answer is that either such an entity is impossible or is completely beyond our ability to comprehend, even to the point of implying that such a thing could exist.

    Hope you followed that.

    Cris
     
  12. PaulD Registered Member

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    Thanks Cris,

    Your right about our ability to comprehend these issues.

    What I find amazing is that what starts of as a cosmological issue impacts on so many other fields including religion.

    It has to be the holiest of all holy grails.

    Paul
     
  13. phangwk8 Registered Member

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    Fellow Friends,

    From my point of view, I felt that the idea of a bounded, infinite universe as a rather convincing model. The idea of a higher-dimensional sphere, on which its surface lies our space-time continuum.

    However, while the universe being so vast, and uniform, couldn't the possibility of have a "self-repeating" universe which reflects images of itself be likewise possible. Us would be held captive within a universe just as within a box that had mirrors on its inner sides. Thus limited and bounded, yet APPARENTLY infinite.

    Wonder how's your opinions on this?
     
  14. Spindle Registered Member

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    Its time!

    How can the string contain the box? It must be knoted in some unique way such that all possable directions the box might move, yet the box is restrained. Precieve the bow on wraped gift. Note that the bow, containing the box, must assume some box like configuration. Whether net or the simpler bow, the act of constraint, forces shape upon the string.
    The box on the other hand need not assume some non box like shape to contain the string. This is the difference between time and that higher dimention. In your daily lives you are presented with time assuming charterstics of the larger form. As inquireing minds, and only a inquiring mind would read this, we seek the form.
    Humans like all animals need on occasion to think quickly. If all answers could be thought up before hand and then remembered as needed... All answers cannot, yet most of us plan the day before it occures, so we try for some answers. The question here however is form, time is the string. The mind to beat time has a host of generic answers that allow quick responce. A simple one is the parabolic trace of a thrown ball. Few people can calculate the path on paper with hours of thought and given inital conditions yet a small child can catch a ball given only fractions of a second . This ability stems from built in answers. Those answers are that form. Those answers are also the reason most people will never understand the universe. You see by accepting the bow as the form of time you are forever prevented from seeing the net. In reality time is a artifact of human preception, it has existance only to the degree we precieve it, time is not the container of the universe nor is it the limit. Time is the limit of the mind and the container of those simple animal thoughts which as children allowed us to catch base balls, or in the distant past spear lions. I caution you now if you understood this that all men are your brother all women your sister, that you are both father and child, and that this knowing is only for the kind. For time does not exist and to change anything is to change everything. Fold it, spindle it, manapulate it.
     
  15. blueshift Registered Member

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    Space

    Space is not empty. We cannot go 'out into space', nor can we
    put a man into space. We are already in space and have never
    been anywhere else.
     
  16. blueshift Registered Member

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    Could you then explain the difference between a
    space-time continuum and a time-space continuum.
     
  17. Plato Registered Senior Member

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    In general relativity the question if the universe is finite or infinite is translated to the question :
    Is there enough matter in the universe to bend spacetime back into itself ?
    So given the validity of the theory (it hasn't been disproven since its conception in 1917) we simply need to 'weigh' the universe to answer the question.
    Of course, this is far from simple however some brave attempts have been made in the past.
    For example a statistical analysis of observable matter has shown there isn't enough matter by far to make the universe finite. Some other attempts by taking into account the possibility of dark matter (which would outweigh the visible matter by a factor of 10) came to the same conclusion.
    So for the moment for all we know, we are living in an infinite universe. Infinite in space that is, not in time since the big bang implies a beginning in time, however it would also be infinite into the future because the low matter content also implies that space would expand forever...
     
  18. Malaclypse Perturber Registered Senior Member

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    "Equipped with his five senses, man explores the universe around him and calls the adventure science."

    - E. P. Hubble -
     
  19. George LoBuono Registered Member

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    reply to Fil

    I remember thinking similarly, Fil. Stephen Hawking, a famous astrophysicist in your country, has suggested that there is no "end" to space. Instead, there may be what is called a no-boundary condition. This means that deeper curvatures of gravity (like that in black holes and inside denser quanta) would cause space to curve in upon itself, thus making the universe intravert or involute (fold in upon and through itself)--hence the "no-boundary condition" of having no edge, no end, no distinct barrier. If you think about it, what you are asking is in terms of the material notion of an end (to material "things"). Space-time, as Einstein called it is not a material thing, hence there is simply no need to expect there to be a distinct end to it. This brings up the basic question: where did space come from in the first place? Some say it suddenly leaked out of a weird, weird black hole that existed before the Big Bang. (It must have been weird if there was no space outside of it). So, if space was within the black hole then (or, in a sense, "not" then--because this was before time, remember?), there should be weird kinds of back door connections throughout the universe, owing to the fact that it was all connected before this universe came into observable being. *Some think that gravity and strange fluctuations of gravity in empty space (called squeezed state fluctuations in the vacuum of space-time) may point toward a kind of negative cycle (see Elders) that connects all mass, matter, and black holes through deeper, invisible dimensions. (They all came out of the same weirdly connected singularity, didn't they? One way to think of this would be to remember that the only true whole number quantity in the universe would be that of the entire universe when "seen" from the beginning of time until the very end(s) of the universe. Even then, as the universe was observed to approach its whole number (one) quantity, it would suddenly do weird tricks; it might fold back into or upon itself, causing a kind of "non-local" character to all of its observable quanta (or discrete units of energy, etc.). In short, the actual physics of the universe would best be modelled in terms of fractions or numbers much less than one (mere decimals of the universal whole number one). Thinking in such terms, it is easy to see how "space," or the unobserved interval between distinct characteristics, would fold back in upon itself. As you will read later on, quantum physicists think that even what appears to be empty space may not even be "empty." Instead, it is full of weird little particles that appear and disappear so fast that we can't measure them. They "borrow" energy from empty space and then return it instantly, causing them to annihilate and disappear. This is how energy skips across space---these weird "virtual particles" carry it across the distance. Science is weird, isn't it? So is marriage, and government... just kidding.
     
  20. Javier Registered Senior Member

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    As far as we know only this universe to exist(and in the case of finding something "outside" it ,we would have to re-name the total as universe and find a new name for what we nowadays call such),wether it has or not enough matter to continue its expansion of spacetime against the contractive gravitational force does not make a difference in order to the fact that was/is/will be actually,in fact ,finite:
    In the beggining,spacetime had infinite density and 0 radius,hence started in this point.

    If the dark matter is enough abundant the universe will achieve a maximum spatial size when it gets to the balance point between the expansive force of the Big Bang and the attractive of gravity,but will continue to exist in spacetime until its total collapse("spherical" model).
    We have here a finite amount of values for space and time,and therefore "always" has limits .


    If the total quantity of mass can t countermeasure the expansive speed,that would mean that will continue its growth forever,but will always have boundaries or limits:no matter the amount of years we choose, will give a finite value for the spatial radius,and no matter the span of radius we may think of, will always correspond to a finite quantity of years for the universe to achieve it,(for example,now, about 15-20 thousand million light years) :

    We have here an infinite secuence of values for the LIMITS of the universe,which is not the same to say that it hadn t, hasn t or won t have them(Spacetime expands at a finite rate,and therefore will never actually achieve an infinite size),for any actual observer of it:
    Only the abstract representation of it delivers an infinitude...
     
    Last edited: Apr 29, 2001
  21. nilkin Registered Member

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    Bounded infinity

    There will not be a simple answer to this question for a very long time if ever. But I believe the universe is a finite age, so it must be of finite size. It isnt possible to come to an end of the universe, which would be a good thing. I imagine it would be a rather messy singularity of sorts.
    Quick question for anyone, what is the latest guess on the age of the universe?
     
  22. Plato Registered Senior Member

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    One could also look at it this way :
    spacetime has four observable dimensions, within these dimensions, it is infinite. Meaning : one can go on forever en keep on encountering new things. (this is assuming of course that we are not living in a hypersphere)
    Outside these four dimensions however there is no spacetime hence these represent the end or limit of the 'universe'. The anwer to the question, where is the limit or end of the universe would simply be : here and in each other point. Since if we would somehow be able to shift ourselves into a fifth dimension, we would be 'outside' of our 'universe'.
    It is obvious that words like 'universe' and 'outside' should have a different meaning here since normally the universe means everything that exists so whatever you do, a simple change in definition makes that there is no 'outside' to the universe...
    Perhaps 'multiverse' would be a good candidate, any thoughts ?
     
  23. nilkin Registered Member

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    Re: Bounded infinity

    You are right, unless you were traveling faster than the expansion you could never catch up, and it would appear to be infinite.
     

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