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What do you think ?

  1. Sep 16, 2008 #1
    Question 1- what's beyond the Universe?

    If the universe if finite, there must be something outside it, right? I've heard many people say "it's just time- and no space", but how can this be?

    Our Universe is composed of space, so if it's finite, there must be more space outside it.

    Question 2- Motion without time?

    Secondly, can there be motion without time? This ties in with my next question, so please read question 3 before answering this.

    Question 3- Is time man-made?

    I believe that time is man-made, and not a natural phenomenon. I think that time was invented by us to help explain things.

    However, I'm unsure, so please give me a reason why I'm wrong.

    Question 4- Time travel?

    If time is man-made, is time travel technically possible?

    But if time is NOT man-made, if it actually "exists", is time travel TECHNICALLY possible?


    What do you think about these statements? Do you agree or not?

  2. jcsd
  3. Sep 16, 2008 #2
    For question one, what is outside, i guess its all theoretical. If you were to be on the outside of the universe im guessing you would see the big bang happen and the universal expansion and all that. As for reality, there is no time and no space created yet, so in simplest terms, nothing I guess. It makes you think though! For question two, there has to be time. Motion is a movement through space and time. Question four, a really good book that would help explain this is Physics of the Impossible by Michio Kaku. You cannot really go back in time, however you can manipulate it with motion and gravity. You can relatively slow time down by being close to a large body with high gravitational force, like the edge of the event horizon of a black hole, or by moving at speed close to the speed of light.
  4. Sep 16, 2008 #3


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    That is a logical fallacy. something can be finite without supposing any edge or boundary or outside to it.

    Think of a ring. A perfect circle. Not a ring that is contained in some larger space, but a ring that is all there is.
    Last edited by a moderator: Oct 3, 2008
  5. Sep 16, 2008 #4


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    Aquw, please give us links to the sources of your quotes.

    Assuming you found them on line, it would be helpful for us to know what you are quoting and to be able to see the quotes in context. So links to your sources would be great. Thanks.
  6. Sep 16, 2008 #5
    I disagree with you here.

    Yes, a sphere has no edge, but it has boundaries. If you're inside the ball, as we're inside our Universe, of course there's a boundary. And if there's an inside to the ball, there must be something outside of it.

    Everything has to be contained in something. If something's not there, it doesn't exist. The space outside of the object can be infinite and totally an uterly empty, but space itself is still "something outside".

    And no sorry, I don't have the sources- these quotes were some I found many months ago and saved to my PC.
  7. Sep 16, 2008 #6
    and to think, we used to believe the earth was flat and if you traveled far enough you would fall off the edge...

    I have always found that people have a difficult time wraping the grey matter around the concept of 'nothingness'. Perhaps 'infinity' can be just as difficult. But when you stop trying to picture things in your mind and just accept the concept then it becomes easier with things that are so counter intuitive.

    Since the subject of time was brought up...

    I have a question or lots of questions about time. So help me understand it a bit. I know that it is considered a dimension which is somewhat interchangeable with the other 3 dimensions of space from GR. so that by changeing the speed at which you move through space, you change your position in time relative to a stationary observer. but.... I can imagine a universe which contains no matter or energy, would there be a such thing as time in that uninverse? are we required to have motion in order to have time? If so then is there an equivilance of time and motion or of time and energy, and if so then could time be considered to have a wave particle duality? could we envision some experiment where time waves could be detected?

    ...if there is gray matter, is there gray energy? jk ;)
    Last edited: Sep 16, 2008
  8. Sep 16, 2008 #7


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    This is an assertion from ignorance, not a fact. There's no reason why this statement must actually be true.

    Anyway, nothing in this thread relates to cosmology -- it's pure philosophy. So, I'm moving it there.

    - Warren
  9. Sep 16, 2008 #8
    Originally Posted by Aquw


    Sorry, but I disagree here as well. An object must be contained within something, whether it's a liquid, a solid, a gas or an empty space. Space has the capacity to contain things, i.e. our uNIVErse is contained within an empty space.
  10. Sep 16, 2008 #9
    the thing is, what is outside our universe hasnt been created yet. The only assumption we can make based on science is there this is nothing there, because it has not been created. We can make philisophical theories, but nothing based on any science.
  11. Sep 16, 2008 #10
    TalonD, there is no reason why we are unable to imagine something.

    Granted, when we don't know the answer to something, imagining it is very hard, but once we know how something works, we can imagine it.

    I do not let my imagination get in the way of what I believe. Just because I don't know how something works, or can not imagine something, it does not mean that my opinons and logic change.
  12. Sep 16, 2008 #11
    Okay then, let's assume that there is nothing except space outside our Universe. At the moment, I guess this seems quite likely.

    But my point is, so long that there is SOMETHING, our Universe for example, there is going to be something ELSE, and that something else is SPACE. Empty space tthat contains our Universe.

    If there is no space in which our uNIVERse is contained, the Universe couldn't exist.

    what has yet to be created outside of our Universe remains a mystery, but is also irrelevent. The fact remains that there must be some sort of space outside of the uNIVERSe.
  13. Sep 16, 2008 #12


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    You're welcome to disagree as much as you like, but saying something over and over doesn't make it true.

    The simple fact is that we have no idea what's outside the universe, or if the concept even makes any sense. If the universe were the surface of a sphere, it'd have no boundary, no edge, and nothing "outside it" in the two dimensions in which it exists. Mathematically, it's well understood that such a two-dimensional surface does not require a higher-dimensional space to contain it -- it's perfectly valid without any embedding at all. Embedding is optional.

    There's no reason to believe our universe should be any different from the surface of a sphere. It may be very different, but there are no empirical reasons to think it is. You believe what you believe because it appeals to you, not because it must be true. You might want to consider that carefully.

    - Warren
  14. Sep 16, 2008 #13
    There is not space outside our universe either. Space has yet to be created. Space and Time are created with the universe.
  15. Sep 16, 2008 #14
    if there was space outside our universe then that would be part of our universe also and then it wouldnt be 'outside', so where's your boundary then? is it some membrane? The real point is, none of us know if there is an 'outside' or not. No, an outside is not requred, Yes, it would be conceptually pleasing. But no one realy knows for certain.
  16. Sep 16, 2008 #15
    How is our Universe like the surface of a sphere. The surface of a sphere is two-dimensional; our Universe is three-dimensional.

    I still don't think anyone understands what I'm really getting at- this may be my fault, not explaining very well.

    Space is "something", okay? When I say "space", i don't mean like an empty room. "Space" for me is infinite and contains nothing, not even itself. Thus, I suppose you could say that space doesn't really exist. Space is a void.

    If something has an inside, that is, if it has some sort of boundary, regardless of its shape, that boundary must have "something" (space) on the other side. That's what a boundary is- a "wall" (for want of a better word) that can be reached from either side. If our Universe has no boundary, it can not be finite.
  17. Sep 16, 2008 #16


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    The quotes were in a thread at BAUT from 2003.
  18. Sep 16, 2008 #17


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    And there are three-dimensional spaces (manifolds, to use the proper mathematical terminology) which are finite and without bound, just like the surface of a sphere. The only difference is that they're harder to visualize -- but we may well live in such a space.

    These statements are vacuous. They're not rigorous, they're not well-defined, and they're not even related to the common meaning of the word 'space.' If you wish to redefine the words as you see fit, and give them imprecise, useless meanings, then you're never going to get beyond arguing about words.

    This is, again, an argument from ignorance. I could argue the inverse argument just as vehemently, and neither of us would be right.

    This is not so -- the surface of a sphere has no boundary, and is most certainly finite. All you need to do is bump up the dimensionality by one, a simple mathematical task, and you have a model of a universe that is finite, without a boundary, and completely self-consistent.

    - Warren
  19. Sep 16, 2008 #18
    TalonD, the Universe does not mean every space available. The Universe can be an object (thus with boundaries) within a space.

    I do not know, nor claim to know excatly what form these boundaries dicatate.

    All of what I have said is not meant to be, nor designed to be "conceptually pleasing". Simple logic dicatates that there is always two sides to a wall, even if that wall is sat in empty space.
  20. Sep 16, 2008 #19


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    Aquw, if you do not intend to listen to the people that have replied that know what they are talking about, this thread will be closed. You do not seem to want to do anything except repeat yourself.
  21. Sep 16, 2008 #20
    i dont think what you guys are getting is that at the boundaries of the universe, the big bang is happening. Space is being created. Our universe is being created. Your talking about objects that lie in our universe, but at the boundaries, our universe is being created.

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