Poll: Is the Universe infinite or finite?

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  1. #121
    Void Lord Elegiac's Avatar
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    Quote Originally Posted by tianvay View Post
    IIRC string theory has yet to make it's first prediction? If the existance of the Higgs boson is verified and more than a "maybe we found it but it could still be something else" then we will talk again about string theory. If however the Higgs boson can't be verified then I am curious about how the scientists are going to explain that while using string theory.

    I think the universe is finite but unmeasurable because it expands further and, a thing that I did not see in this thread yet, it also speeds up it's expansion rate. However, we are just talking about the observable universe, we cannot know what lies beyond the boundaries of our vision.
    Last I recall the Higgs Boson wasn't necessarily contingent upon string theory, more like a component necessary to explain the mechanic of mass under the Standard Model.
    Quote Originally Posted by Marjane Satrapi
    The world is not divided between East and West. You are American, I am Iranian, we don't know each other, but we talk and understand each other perfectly. The difference between you and your government is much bigger than the difference between you and me. And the difference between me and my government is much bigger than the difference between me and you. And our governments are very much the same.

  2. #122
    Legendary! Wikiy's Avatar
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    Quote Originally Posted by Didactic View Post
    It depends on what you define as evidence. We haven't observed 'strings', no, but the evidence for the theory comes from observation of certain phenomena and the mathematical calculations required in order to bring said phenomena in line with our current proven understanding of physics.
    I'm not saying the string theory doesn't fit the image and isn't possible, it's just that there are certain predictions that string theory makes that haven't been discovered yet. The string theory is just the mathematically beautiful and most simple model, but nature doesn't always work according to Occam's Razor.

  3. #123
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    Quote Originally Posted by Wikiy View Post
    I'm not saying the string theory doesn't fit the image and isn't possible, it's just that there are certain predictions that string theory makes that haven't been discovered yet. The string theory is just the mathematically beautiful and most simple model, but nature doesn't always work according to Occam's Razor.
    The funny thing is, it almost always does.
    Quote Originally Posted by Marjane Satrapi
    The world is not divided between East and West. You are American, I am Iranian, we don't know each other, but we talk and understand each other perfectly. The difference between you and your government is much bigger than the difference between you and me. And the difference between me and my government is much bigger than the difference between me and you. And our governments are very much the same.

  4. #124
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    Quote Originally Posted by Conor View Post
    IMO it's infinite because there will never be a away to measure it at any stage because its expanding.
    That doesn't equal infinite.

  5. #125
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    Quote Originally Posted by Didactic View Post
    The funny thing is, it almost always does.
    I wont hold my breath though, at least not until they discovered monopoles or some other testable, physical evidence.

    Edit: At the moment, I'm more of a loop quantum gravity proponent FYI.
    Last edited by Wikiy; 2012-12-24 at 01:38 PM.

  6. #126
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    Quote Originally Posted by DanielBrems View Post
    That doesn't equal infinite.
    Something finite that is will expand indefinitely equals infinite.
    Quote Originally Posted by Marjane Satrapi
    The world is not divided between East and West. You are American, I am Iranian, we don't know each other, but we talk and understand each other perfectly. The difference between you and your government is much bigger than the difference between you and me. And the difference between me and my government is much bigger than the difference between me and you. And our governments are very much the same.

  7. #127
    nobody knows (atleast noone on earth)

  8. #128
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    Quote Originally Posted by Didactic View Post
    Something finite that is will expand indefinitely equals infinite.
    How so? It only means it's potentially infinite. Doesn't mean it's infinite right now, or that it will be infinite a gazillion years from now, it only means it will be infinite an infinite amount of years from now.

  9. #129
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    Quote Originally Posted by Wikiy View Post
    How so? It only means it's potentially infinite. Doesn't mean it's infinite right now, or that it will be infinite a gazillion years from now, it only means it will be infinite an infinite amount of years from now.
    Because if it expands into infinity, then even a finite object then becomes infinite. Infinity + 1 is still infinity.
    Quote Originally Posted by Marjane Satrapi
    The world is not divided between East and West. You are American, I am Iranian, we don't know each other, but we talk and understand each other perfectly. The difference between you and your government is much bigger than the difference between you and me. And the difference between me and my government is much bigger than the difference between me and you. And our governments are very much the same.

  10. #130
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    Something is something at that moment. Whether it does something (expands) is irrelevant. It is what it is right then and there. A finite Universe in the progress of expanding - whether it be infinitely or not - is still a finite Universe.

    When you look at something, you look at what it is, right at that moment. You can theorize about it's potential, but your data is from a snapshot in time.

    In other words, our observable Universe is finite, and whether the rest of the universe is infinite or not, is based on snapshots of data, which means it either is or isn't, and I don't know that we have any definite proof either way.

  11. #131
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    Its not finite nor infinite, its al magic! m-theory and such (yes I know 'm' doesn't stand for magic).

  12. #132
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    I go with finite, see multiverse
    Take a break from politics once in awhile, it's good for you.

  13. #133
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    Quote Originally Posted by Kangodo View Post
    xD

    Well if you would try to give magic a definition it would be: shit that happens for a reason we don't understand
    So yeh, the entirety of the universe is magic.

  14. #134
    Quote Originally Posted by Activi-T View Post
    I believe it to be both. An infinitely expanding finite closed system. What I mean by that is you can't go past the the 'bubble wall', or the outer edge if you were to suddenly be transported there, into the medium the universe is expanding into but the expansion of the closed system is infinite (no 'big crunch' point). That is my layman's opinion at least.
    That's finite. There is no medium it's expanding into, space is growing internally.

    Quote Originally Posted by Didactic View Post
    Probably this. Space is infinite, the matter and energy filling it is not.
    Nah, space itself is finite. It's space that's expanding.

    Unless you mean that space is infinitesimal. In which case space would be infinite even if the universe was the size of a peanut.
    Quote Originally Posted by Tojara View Post
    Look Batman really isn't an accurate source by any means
    Quote Originally Posted by Hooked View Post
    It is a fact, not just something I made up.

  15. #135
    I believe Carl Sagan says "Finite but boundless" and that is truly the quickest way to sum it up.

  16. #136
    Quote Originally Posted by Conor View Post
    IMO it's infinite because there will never be a away to measure it at any stage because its expanding.
    How can something that is infinite be expanding? The fact that the universe is expanding basically means that it's finite.

  17. #137
    When we get a big enough telescope, the universe will figure out if it is finite or infinite.
    While you live, shine / Have no grief at all / Life exists only for a short while / And time demands its toll.

  18. #138
    Mathematician here, hopefully I can clear up some confusion in this thread:

    It's finite, but its potential size is infinitely large.
    What I think this means to say is that it is finite but unbounded. We can find an easy example in terms of the natural (counting) numbers 1, 2, 3... and so on. Each number is finite, but they become arbitrarily large. However, under our current understanding, it is likely that a finite (i.e., closed - see the sphere analogy below) Universe would eventually stop expanding and collapse.

    An infinite thing can't expand.
    Sure it can, and we can construct simple examples depending on your precise definition of expansion. To use, say, two-dimensional area in the same way you would in a geometry class, consider a bar in the plane which extends infinitely far to the left and right, but is only one unit tall. It is easy to imagine such a bar expanding so that it remains infinite in extent to the left and right but is now two units tall. In both cases, the area is infinite, but in some sense the second object is "bigger" in the intuitive sense you're referring to.

    If it's finite, it has an edge
    Not necessarily. Our current understanding of the Universe models it as an object called a manifold. Roughly speaking, a manifold is an object that looks like normal Euclidean space as you did it in high school geometry, but only if you "zoom in" far enough. A simple example would be the surface of a sphere - if you stand at a point on the Earth's surface, the area around you looks like a plane. The surface of a sphere is finite in some sense (mathematically, we might say it has finite measure or is compact, both of which have suitably rigorous definitions), but it has no boundary. It simply loops back around on itself. Similarly, our universe looks on a small scale like the usual three dimensions of space and one of time world that we're used to, but under extreme conditions or on large scales behaves differently. If our Universe is closed, it would be structured similarly to the sphere, except that the surface of a sphere is two-dimensional and our Universe to the best of our understanding is four-dimensional (although some speculative theories use many more).

    Infinity is infinity! There's no bigger or smaller infinities!
    False in almost any suitably rigorous sense. I direct you to Wikipedia's article on cardinality.

    There's just no evidence of an infinite amount of energy in the universe. Sure, there is a lot of it, but no matter how far it expands or how long it goes on it's still a finite number.
    The total energy can be infinite even if the density of that energy is not. Consider the plane filled with a uniform density of energy, so that the amount of energy contained in a region is proportional to the area of that region. Since we, and any other point in the universe, can only observe a finite volume at any finite time due to speed-of-light constraints, the total energy of the universe may well be infinite even if the energy we observe is always finite.

    Now how is that supposed to work? If we follow the Big Bang, this universe started condensed in one spot. So you're telling me that, in 13.7 billion years, it managed to expand ~6.78 x the speed of light?

    Something seems off about this math.
    Matter cannot move faster than light under current physical understanding. But this expansion is not motion in the normal sense - roughly speaking, the way the Universe measures distances is, over time, measuring larger and larger ones even between objects that are not (with respect to their own space) moving. The effect is tiny enough to be unobservable at small scales (within, say, a galaxy), but in the voids between galaxies it dominates, and it is not limited by speed-of-light concerns because proper motion is not involved. In addition, objects that we see today emitted the light we see when they were considerably closer to us than they are now.

    For instance, suppose we all lived on a straight line where distances double every year (and for the sake of keeping calculus out of things, let's assume that doubling happens instantaneously at 12:01 January 1), and where the speed of light is two units/year. An object that emitted light one year ago on December 31, 2000, when the distance between us and the object was 1 unit, would be seen by us on December 31, 2001 as it was on December 30, 2000 - but as we see it, that object is now two units away from us even if it didn't "move" with respect to its own space. Such an object would cease to be visible eventually. This analogy is very simplified and ignores the fact that there is no absolute notion of "distance in space" in the Universe, but it serves to illustrate the point.

  19. #139
    Quote Originally Posted by Pugbot View Post
    I believe Carl Sagan says "Finite but boundless" and that is truly the quickest way to sum it up.
    A nice tl;dr that I'd also tend to agree with.
    "In order to maintain a tolerant society, the society must be intolerant of intolerance." Paradox of tolerance

  20. #140
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    Quote Originally Posted by Didactic View Post
    Because if it expands into infinity, then even a finite object then becomes infinite. Infinity + 1 is still infinity.
    The infinity that it's expanding "into" isn't part of the universe, it's something else or nothing at all. If space itself isn't infinite then neither is the universe because space contains energy and it's space and energy which are governed over by the laws of physics, and that's the definition of the universe; spacetime, energy and the laws of physics.

    Seriously, I'm puzzled as to how you think that just because space can expand indefinitely, it must mean space is infinite. And as I've said, it only expands into infinity at t=infinite. Which is where we aren't, and where we'll never be, so it's silly to say that the universe is now infinite just because it's expanding into infinity (although there technically doesn't have to be anything with volume "outside" space).

    It might be infinite for other reasons but not because of that. The only clue so far that physicists have that points towards an infinite universe is the topology of space. If physicists thought that the fact that space is expanding is enough to declare that space is therefor infinite, then they would've done so, and there would be no open question as to the finiteness of space/universe.

    ---------- Post added 2012-12-24 at 05:44 PM ----------

    Quote Originally Posted by Dezerte View Post
    A nice tl;dr that I'd also tend to agree with.
    Well, with all due respect, Carl Sagan died 20 years ago. Physics is an ever-changing science, and those that don't adapt to the changes and accept them as they are aren't proper physicists. Back then, there was no reason to think that space was infinite. Today, we pretty much know that it is. And that pretty much means the universe is unbounded since space is its defining part.
    Last edited by Wikiy; 2012-12-24 at 04:48 PM.

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