does the univerce have an end, a limit?

Discussion in 'Astronomy, Exobiology, & Cosmology' started by Shadow1, Jan 1, 2010.

  1. Hacker-Cracker Registered Member

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    yeah Universe will end when Allah will do the Judgment day
    He Create the Universe he will destroy the Universe
     
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  3. Shadow1 Valued Senior Member

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    yeah,
    the univerce is now expanding, and one day, it will start to become smaller, to shrink, intill it collapse.
     
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  5. Emil Valued Senior Member

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    What do you mean by the "universe"?
    My universe is my family, my friends, places where I was, my knowledge, my childhood, my memories.
    If I die or lose my memory I lost my universe.

     
    Last edited: May 21, 2010
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  7. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    Not according to current physics POV. Dark Energy is growing stronger - Will in distant future "explode the galaxies" much later the stars and then their planets. Eventually in the inconceivable distant future even the very atoms.
     
  8. joepistole Deacon Blues Valued Senior Member

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    You have any thoughts on dark energy, Billy T? Is there anything being done to further explore, define, understand dark energy that you are aware of? It is really a facinating concept.
     
  9. Fraggle Rocker Staff Member

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    The word has two common meanings in scientific discussions.
    • 1. Our Hubble Volume. All the matter and energy resulting from the Big Bang, a local phenomenon that may occur/have occurred/will occur many times and in many places. It is a sphere that includes all the matter and energy we can see, which has been expanding since the Big Bang and is now something like two hundred light years in diameter. There is no good reason to assume that there are not other similar spheres out there, but are so far away that their light has not yet reached us, and/or is so far away that by the time it reaches us it has attenuated to the point that we can't detect it.
    • 2. The space-time continuum. All locations at any arbitrary distance and time from us, all the way to infinity in all directions. Most of them are probably empty. But if we can describe them with spatial coordinates (e.g., 600*10^10^10^10 light years in the direction of Alpha Centauri but far beyond our Hubble Volume) and with time coordinates (e.g., 600*10^10^10^10 years in the past or future), then they "exist." Note: the space-time continuum may not be infinite because it could conceivably be a non-Euclidean space (such as a hypersphere), but there is no reason to assume so.
    These are two quite different definitions. The first describes a clearly measurable and finite space and time, but I find no convincing reason to assume that this is "all there is," and therefore it does not deserve the name "the universe." The second describes something that is infinite, but perhaps more conceptual than physical. (This is the problem with cosmology: it's an awkward mixture of physics, pure mathematics and philosophy.) Still I find no convincing reason to assume that space and time don't extend infinitely in all directions beyond us, even if there's nothing there. Since there is a small possibility that there really is nothing beyond our Hubble Volume, it may not be appropriate to call the space-time continuum "the universe," either. This is why I avoid using that word.

    Depending on the quantity of dark matter and dark energy in our Hubble Volume, it may continue to expand forever. Therefore, as time approaches infinity, the dimensions of our Hubble Volume will approach infinity as well, and it will fill a larger and larger portion of the space-time continuum. At infinity, our Hubble Volume will occupy all of space-time, so at that point I guess it would be fair to refer to both of them as "the universe."

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  10. Emil Valued Senior Member

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    Right.
    Must define what we are talking about
    Word = universe?
    In my opinion
    time is not a dimension of space.
    It is a dimension off the universe in motion.
    The fourth dimension of space is purely theoretical.

    I do not know if I remember correctly.
    Einstein said:
    Two things are infinite, the universe and human stupidity.
    The first I'm not sure.
     
    Last edited: May 22, 2010
  11. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    Yes. See: http://www.sciforums.com/showpost.php?p=2538468&postcount=17

    Perhaps "speculations" is a more accurate discription than "thoughts." There is a recent Phy Revs. Letter that suggest, as best as I can tell (It is well above me.) that the vaccuum polarization energy can be converter into dark energy in very intense gravity fields (gradients?) Near neutron star surface for example. After years of fighting with MacM on his model of gravity I stole part of it and modified it to connect it to this Phy. Rev. Letters paper.

    I am suggesting that gravity and Dark Energy are two sides of the same coin. The link above paper gives more details about my idea.
     
  12. Shadow1 Valued Senior Member

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    very interresting
     
    Last edited: May 22, 2010
  13. Shadow1 Valued Senior Member

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    lol, but human stupidity is infiny for sure!
     
  14. joepistole Deacon Blues Valued Senior Member

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    Thanks Billy T. that is an intriguing idea and it does make some intuitive sense.
     
  15. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    Thanks. My idea might even explain dark matter too! I.e. the idea only works if there is a huge flux of these extremely weakly enter acting with matter "DE gravitons." As they presumably travel very fast (speed of light?) and definitely carry momentum they must have energy too.*

    If they travel at the speed of light, there is an excellent chance** they have kinetic gravitational / inertial mass (but not rest mass if their speed is C as I think it probably is.) Dark Matter, being >90% of the universe mass is very consistent with there being a huge number of "DE gravitons."

    -------------
    * Energy, E, and Momentum, p, obey the relativistic energy-momentum equation

    E^2 = (mc^2)^2 + (pc)^2 and very likely for DE gravitons, E = pc

    ** I have a simple rule that often works for deciding if energy makes gravity (of the Newtonian type). It is:

    If the value of E is the same in all frames, then the E has gravity same as the mass m= E /(c)^2. For example, a hot brick makes very slightly more gravity when hot than later when it has cooled off as its temperature, T, is the same in all frames.

    One can be certain that T is a frame invariant - if not then the melting T of lead would be frame dependent. Impossible as it is not a solid in one frame and a liquid in another. Simply changing your POV (different frame) will not make a solid pour like a liquid.
     
    Last edited by a moderator: May 23, 2010
  16. Acitnoids Registered Senior Member

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    535
    Shadow1,
    I have given this topic a LOT of thought throughout the years and I've come to the conclusion that yes, the universe does have a limit but it's not located beyond the edge of our visible horizon (Hubble Volume). The only thing that exists beyond the vast expanse of space is, ... more space. Now, my communication skills are sub-par at best and I've spent the last three weeks trying to compose a post for this thread without incisive ramblings. Well, this is the best I came up with. I'll be happy to elaborate more upon request.
    .
    I believe there is exactly one limit that simultaneously represents both the beginning and end of the universe (two sides of the same coin). This limit rests at the absolute smallest scale possible. As of right now the smallest known scale is called the Planck length. You must keep in mind that the Planck length (like the edge of our Hubble Volume) represents a numerical limit, not a physical barrier so it should not be thought of as an end to the universe but instead a limit to our understanding of Natural Law. Space and time exist beyond the Planck scale even though we have yet to figure out how. I am led to believe that the "end" of the universe exists beyond this know limit. It is here where all of space and time draw back down to a single point which comes to rest at the same location as the big bang (the BB happened everwhere at the same time). Following this point of view, the edge of our Hubble Volume would represent an inflated inverse-depiction of this single point as seen from our particular orientation off of said point. Sense the big bang, everything has been "falling away" from this point at exactly 299,792,458 m/s and this is what allows us to observe an expanding universe. When plotted out correctly, this shows that the further we look from our point in space the faster we will observe the universe expanding. But then again, what do I know? I may be completely off base.
     
  17. Fraggle Rocker Staff Member

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    24,690
    I suppose you're getting into semantics here. But from a scientific rather than linguistic standpoint, I don't see any persuasive reason to treat time any differently from any other dimension. Thumb through a physics book and look at all the formulas. Time is just one dimension. It undergoes the same mathematical operations as all other dimensions.

    The fact that we don't perceive time the same way as length, width and height is just the way life on earth happened to evolve. Perhaps somewhere else in the universe there are creatures who perceive it differently.
     
  18. sifreak21 Valued Senior Member

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    as far as we know there is no end to the universe
     
  19. Fraggle Rocker Staff Member

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    24,690
    But we can just as easily say that as far as we know it may also not be endless. We have no persuasive evidence that the universe is a Euclidean space and therefore infinite. It could just as easily have a different kind of geometry and be finite.

    After all, the ancients assumed the world was flat based on their limited perception of it. The universe could, similarly, be a hypersphere so enormous that its curvature is too slight for us to measure with our current technology.

    Look how long it took us to discover the lightspeed limitation.
     
  20. Acitnoids Registered Senior Member

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    As far as we know the Earth is the only place in the universe where life exists. Out of all the people I know in the world only a handful of them truly believe this to be true. I could go on an on with this "as fas as we know" thing which means that you'll have to elaborate on what you meant. I mean no disrespect or anything. Being that I disagree, all I'm asking is for you to articulate what your statement means to you. I agree that we only know so much but, should this be the last word on the subject?
     
    Last edited: May 26, 2010
  21. Emil Valued Senior Member

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    2,789

    I just try to sync: My world of engineering and your world
    We have three dimensions.
    If we add time to the three dimensions, then we move.
    We can not separate the movement and the time.
    In your world:if only the times change, the three dimensions not then you do not move.
    In my world this is wrong because it can rotate.
    If you have time then we have six dimensions, three linear and three rotational.
    So we have 3 + 3 + 1 dimensions.

     
  22. thinking Banned Banned

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    1,504


    no

    if we add time then we measure the movement by objects , only

    true

    but the movement is not based on time
     
  23. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

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    18,639
    Um, in engineering rotation is a degree of freedom, not a dimension. Anything that rotates does so in (one or more of) 3 dimensions but doesn't introduce a dimension.
     

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