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Chronic7

Registered: 05/08/04
Posts: 13,679
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Finite Universe?
#7971924 - 02/03/08 07:17 AM (15 years, 11 months ago) |
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Could someone clarify for me how the universe is finite?
Does that tie in with it being a cycle/balance of the expanded ONE?
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Seuss
Error: divide byzero



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Re: Finite Universe? [Re: Chronic7]
#7971930 - 02/03/08 07:20 AM (15 years, 11 months ago) |
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> Could someone clarify for me how the universe is finite?
What domain are we speaking of? Volume, mass, age, etc...
-------------------- Just another spore in the wind.
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Anno
Experimenter




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Re: Finite Universe? [Re: Seuss]
#7971957 - 02/03/08 07:34 AM (15 years, 11 months ago) |
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All of them.
If the universe would be infinite, there would be no night.
Something to think about...
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danlennon3
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Re: Finite Universe? [Re: Anno]
#7971989 - 02/03/08 07:59 AM (15 years, 11 months ago) |
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just becasue the universe if finite,it doesnt make it any smaller
-------------------- "Psychedelics should be used not to escape reality, but to embrace it"
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deimya
tofu and monocle



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Re: Finite Universe? [Re: danlennon3]
#7973503 - 02/03/08 02:47 PM (15 years, 11 months ago) |
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It all depends on the actual topology of the universe. Just before explaining this further, lets make a short intro to general relativty, which is the theory we actually use to ponder on these questions.
So in GR, the mass and energy content of the universe (that is planets, stars, galaxies, photons, dust, black holes, whatever you want) determines how it's shaped. Most of general relativity revolves around Einstein's equation. The easiest way of expressing it (which is not altogether false, just simplified) is simply
G(g) = T
where G(g) stands for the a certain mathematical object (called Einstein tensor) describing the geometry of the universe and T is a mathematical object (called stress-energy tensor) describing the mass and energy content of the universe. I wrote a small g between brakets to mean that this "G"eometrical object ultimately dependents only on the metric g, i.e. the way we must measure (space-time) distances in this universe satisfying G=T. So what one normally does with this equation is given a known matter content T, try to find the unknown metric g. This is the hard part since G=T is a very complicated differential equation. But suppose you end up finding the right g such that G(g)=T for your given T, then you're happy and you pretty much know all about what's going on in your universe at any given space-time point, e.g. you can calculate trajectories, derive corrections to planets' orbits, derive the potential existence of black holes, etc.
But if you analyse g a little bit further, which normally is not a simple formula, you could end up determining the general shape of a universe with such a g. This is call the topology of g, of your universe. A bit like the topography on a map.
This said g is not known very accurately for our universe, but there's several contenders (none of which really make sense upon closer inspection but let's not go into that). Somes are "open", meaning that they extends toward infinity, such that the universe having this topology, or form, would then be of infinite "space-time volume". A few others are closed, similar to the surface of a donut or the surface of a sphere. If that would be so, then there would indeed be a finite volume to the universe, even though it wouldn't be apparent for someone in it. Indeed an ant walking on the surface of a balloon could walk around it several times without really noticing.
The actual best contender (dervied from actual observations on the cosmic microwave background) is of the open kind, meaning the universe might be infinite. But this is still a hotly debated topic in which enters these concepts known as dark energy, dark matter and the cosmological constant.
Much more better and precise informations on wikipedia, say there, about the shape of the universe.
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Chronic7

Registered: 05/08/04
Posts: 13,679
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Re: Finite Universe? [Re: deimya]
#7986096 - 02/06/08 10:08 AM (15 years, 11 months ago) |
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Thanks, i just dont understand as if its definately finite, it should be measurable, but then maybe we are just not advanced enough to measure it, or contemplate it.
I know its all connnected so maybe thats how its not infinite, as if it was infinite how could it all be connected, how could one action create a reaction if there was infinity.
I dont see time correlating to space on a universal scale as time is only a measure we put on things, so saying no point in space can be at the same point in time is meaningless, matter and dark matter and light still exist regardless of "time" as to me there is no time in space at all. Unless you measure revolutions of suns and moons planets etc...and place marking points onit.
I dont know

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deimya
tofu and monocle



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Re: Finite Universe? [Re: Chronic7]
#7987552 - 02/06/08 04:36 PM (15 years, 11 months ago) |
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One can measure what one has information on. The measured, fastest speed at which information can travel is the "speed of light". Therefore there's always a finite "visible" universe, an horizon beyond which you cannot see, you cannot know and you cannot influence, or said otherwise, beyond which you can not causally connect with. Suppose the universe is 13 billions years old, then this horizon is roughly 13 billions years time the distance light traveled per year, i.e. 13 billion light-years. It doesn't mean it doesn't extend further, that there's nothing beyond the horizon, only that we cannot know.
While you might want or desire, for ideological reason, everything to be connected in a instantaneous and information bearing way, it is rather understood to be impossible according to what we know of nature. Only acausal correlations carried over by entanglement. Even things not infinitely separated share this same fate, all this because, as said above, there's a maximal distance reachable in a certain amount of time.
Time is a measure we put on things yes, but it is a measure which behaves in very precise and quantitative ways. You find the same unit of time everywhere, in the core of nucleus, in the electronic shells of atoms, in bindings of molecules, in crystalline vibrations of every solids, in the blinking of a star, in the diffusive process of fluids, and yes, in the revolution of planets around stars. Some of these phenomenons includes incalculable amounts of smaller bodies interacting together in complex ways, some are simpler, smaller processes, but they all seem to "treat information" (sure, it is in the eye of the beholder) at the same rate, the "proper time" in Einstein's special relativity, a very well tested theory which tells you how proper times relate for different observers why it has to be so if you accept that 1. there's no priviledged observer, i.e. frame of reference, and 2. there is a speed (the speed of light) which is the same for all observers. While 2 sounds counterintuitive, it is almost a corollary of 1. It is a bit like the next best thing : if there's no absolute frame of reference, there might be an absolute speed of reference, which is a rate of change between frame of references, and this is why things get messed up or a bit more complicated between time and space when you approach this speed. Maybe this resonate more with your question about how time might be connected to space.
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VisualLearner
Stranger

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Re: Finite Universe? [Re: deimya]
#7992084 - 02/07/08 03:01 PM (15 years, 11 months ago) |
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Mind bottling! So what is outside?
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deimya
tofu and monocle



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I don't see why you would feel "bottled" by these ideas. It is your own interpretation of them which bottles your mind.
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VisualLearner
Stranger

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Re: Finite Universe? [Re: deimya]
#7999458 - 02/09/08 09:20 AM (15 years, 11 months ago) |
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Can you readQuote:
So what is outside?
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deimya
tofu and monocle



Registered: 08/26/04
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You sound very confrontational, would you care explaining a bit more what's troubling you ?
The present, accepted theory doesn't speculate too much about it and nobody claims it to be final. No theory is ever final. The fact is, we just don't know, and if you feel the unknown as something bottling your mind then you're welcome to fill it with something which suits your mood, your dogmas, your biases or with whatever else you want it badly to be. Infinite chocolate fudge or turtles all the way down, if this is your style.
Edited by deimya (02/09/08 10:11 AM)
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MAIA
World-BridgerKartikeya (DftS)


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Re: Finite Universe? [Re: deimya]
#7999659 - 02/09/08 10:50 AM (15 years, 11 months ago) |
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The universe is infinite to us but finite to itself.
What could possibly lay outside itself is the rest of everything which could be nothing.
MAIA
-------------------- Spiritual being, living a human experience ... The Shroomery Mandala
 Use, do not abuse; neither abstinence nor excess ever renders man happy. Voltaire
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Seuss
Error: divide byzero



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Re: Finite Universe? [Re: MAIA]
#8000579 - 02/09/08 03:14 PM (15 years, 11 months ago) |
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> The universe is infinite to us but finite to itself.
Very cool paradox! You can also look at it the exact opposite. The universe (meaning everything that can be, not everything that exists) is finite to us (we can measure it), but infinite to itself (expanding forever).
-------------------- Just another spore in the wind.
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Newbie
User of semicolons.



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Re: Finite Universe? [Re: deimya]
#8000813 - 02/09/08 04:09 PM (15 years, 11 months ago) |
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Quote:
deimya said: I don't see why you would feel "bottled" by these ideas. It is your own interpretation of them which bottles your mind.
I think he meant "Boggled"
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VisualLearner
Stranger

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Re: Finite Universe? [Re: Newbie]
#8001588 - 02/09/08 06:18 PM (15 years, 11 months ago) |
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Never seen taledaga nights? No but what is outside of what is inside. Inside of us is the smallest form or is that infinite too?  
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MAIA
World-BridgerKartikeya (DftS)


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Re: Finite Universe? [Re: Seuss]
#8004035 - 02/10/08 09:57 AM (15 years, 11 months ago) |
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Quote:
Seuss said: > The universe is infinite to us but finite to itself.
Very cool paradox! You can also look at it the exact opposite. The universe (meaning everything that can be, not everything that exists) is finite to us (we can measure it), but infinite to itself (expanding forever).
Hmmm ... True indeed !
MAIA
-------------------- Spiritual being, living a human experience ... The Shroomery Mandala
 Use, do not abuse; neither abstinence nor excess ever renders man happy. Voltaire
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