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Infinite Universe Or Not?


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#1 litespeed

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Posted 10 December 2008 - 11:31 PM

As a matter of general principle I am skeptical of any actual infinities in the natural world. For instance, it seems to me if the Universe is infinitely large one of two things would seem to also be true.

1) The universe has ALWAYS been infinite from the very first plank time unit one; or

2) It would need to have BECOME infinite at some later time.

Neither of these options seem very satisfying to me.

#2 Essay

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Posted 11 December 2008 - 12:39 AM

It is your expectations and pre-conceptions which determine your level of satisfaction.

Logically, for you, it must be one of the two choice you present above; and yet neither is satisfactory.

Even more unsatisfactory is the idea that some other possibility may be the correct answer; that neither of your seemingly exhaustive choices is correct.

Maybe it just depends on your perspective....
...infinite from within, but not from without....

~ :)

#3 sanctus

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Posted 11 December 2008 - 02:20 AM

and I actually wonder if 2) is possible in a finite time

#4 coldcreation

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Posted 11 December 2008 - 02:38 AM

As a matter of general principle I am skeptical of any actual infinities in the natural world. ...


What about a third simple possibility:

3) The universe has ALWAYS been infinite.

This would be a universe, obviously, with no beginning and no end, both spatially and temporaly.

It follows that there is no paradoxical boundary condition (no t = 0 :phones:).


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#5 sanctus

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Posted 11 December 2008 - 03:11 AM

why is t=0 paradoxical?

#6 litespeed

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Posted 11 December 2008 - 07:42 AM

Cold - You wrote:

What about a third simple possibility: 3) The universe has ALWAYS been infinite.

I believe this is coverred under my number 1), which assumes the Universe came into existence at about time plank unit 1. Accordingly, in that scenario, the Universe has always been infinite in size, if not age. Specifically, anything that had a begining also has an age.

One problem I have with 'infinite' universe, is the relentless descriptions of how large the universe was during its early stages. I have read everything from softball size, to galactic in size after inflation.

NONE of these descriptions, in my recolection, EVER describe space inside these volumes as being infinite.

#7 litespeed

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Posted 11 December 2008 - 07:51 AM

Essay - you wrote: "...Logically, for you, it must be one of the two choice you present above; and yet neither is satisfactory."

You have entirely missunderstood my post. I BEGAN by saying I am skeptical of ANY infinities in the natural world. Then provide a coupe of unsatisfying explanations that seem REQUIRED if space IS infinite.

The obvious conclusion is I am STILL skeptical the universe is infinite. But if it is, I will need some sort of explanation for either or 1) or 2). In my admitedly limited range on these issues, I have never seen a strong discussion in the litterature or elsewhere on these matters, and welcome reference to same.

Once again, if the universe is infinite now (so far un- proven whether 'flat or not) then I need someone to include my numbesrs 1) and 2) in the eventual proof, if one is found.

#8 litespeed

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Posted 11 December 2008 - 08:01 AM

sanctus - you wrote: " ... I actually wonder if 2) is possible in a finite time..."

I don't see how. If the universe was not infinite when it was the size of a softbal, why would it become such later. None-the-less few of us even SUSPECTED the universal expansion is actually increasing velocity. In the entire history of cosmological history, that is, indeed, one great big oops. I put it right up there all the great screw ups.

For instance, it was reasonalbe to assume our galazy was the Universe untile Hubble nottece other ones . Huge cosmological adjustments have been made on a continuous bassis. I expect these will continue, and many of them will be as wrong as the slowing universal expansion.

#9 litespeed

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Posted 11 December 2008 - 08:21 AM

Speaking of Infinities

It has become recently fassionalbe to speak of infinite replications of our own and other universes, generally inluding small differences. Then, of course, because all these things are infinite, each and every variation is replicated infinitely, with additional variations ad infiniteum.

I am no Einstien, but I am wondering if too many scientists just have too much time on their hands. It is easy for my to accept theories of extra dimensions. After all, when a particle jumps the plank length or exists in two place at once, such explanations seem almosts required. Infinities of all kinds, however, seem a bit like kids sniffing gjue.

One cute hypothetical is the famous granfather paradox. Now HERE I can entertain extra universes. You know, go back in time, kill your grandfather so how do you invent the time machine.

This never bothered me because such a seminal event as back travel could easily result in a new universe. You would simply have dissapeared from the original one. And nothing you could do in the back one would ever be noticed in the first, because you have created an entire universe of new quantum happenings. Maybe you COULD make a killing in the stock market. But like they say at funerals, you just can't take it with you.

A bit of clarification. This guy could go forward in time by simply traveling near the speed of light for the requred duration. He simply goes into a sort of suspended animation, but once he reimerges, he is still in the SECOND universe. The one in which he accelerated to the speed of light.

#10 coldcreation

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Posted 11 December 2008 - 11:31 AM

Cold - You wrote:

What about a third simple possibility: 3) The universe has ALWAYS been infinite.



I believe this is coverred under my number 1), which assumes the Universe came into existence at about time plank unit 1. Accordingly, in that scenario, the Universe has always been infinite in size, if not age. Specifically, anything that had a begining also has an age.




Almost.

In adding that he universe has always been infinite "from the very first plank time unit one" where it "came into existence" makes this scenario very different from the conjectured number 3 above. An infinite spatiotemporal universe has no beginning and hence, no age.




One problem I have with 'infinite' universe, is the relentless descriptions of how large the universe was during its early stages. I have read everything from softball size, to galactic in size after inflation.

NONE of these descriptions, in my recolection, EVER describe space inside these volumes as being infinite.


That depends of the curvature. If curvature is infinite, then the universe could be said to be infinite. That, though, is what leads to a paradox at t = 0, not to go into the problems associated with t = 0, such as the break-down of the physical laws, GR, QM, etc.



why is t=0 paradoxical?


You see, Sanctus, infinite spacetime curvature (in the Gaussian or Reimannian geometrical sense) produces at the very least a time paradox (and that would be so even as curvature approaches infinity without actually attaining it).

A universe such as this would have the bizarre feature of allowing the coiling of time around itself, leading to the hypothetical prospect of an observer experiencing his own past (or his own future)—a notion inconsistent with a fundamental description of nature; the arrow of time (e.g., irreversibility).

It is precisely this contempt for explanations that lay behind Einstein’s infamous remarks about not just the big bang but other singularities as well (singularity of not, there is a distasteful boundary condition), and the question of understanding simply did not concern him, except as something to dismiss. He certainly did understand the enigmatic inscriptions encoded in the equations and the complicated liaisons they had with nature, but he also realized their predisposition in the direction of abstraction.

For this reason Einstein’s obduracy towards the synthetic concept of spacetime singularities was clear enough. That this should be so, followed naturally from general relativity itself—the theory is not speculative in origin; it owes its invention entirely to the desire to make physical theory fit observed fact as well as possible—just as it followed from the “statements about reality” or the laws of nature, i.e., propositions which have to show their validity when applied to sense experiences covered by primary concepts (see Einstein 1954, 1982 p.293 for the full scoop).

It would also be paradoxical if a theory (GR) based on the laws of nature would ultimately describe a universe where the laws of nature break-down (as they do at t = 0).

As a result of this break-down, the purely mathematical character of the boundary condition as described by current cosmological theory is devoid of any natural physical significance; the analogue between the mathematical description and physical reality break down at both infinity and zero.


Seems to me an irreconcilable paradox.




One problem I have with 'infinite' universe, is the relentless descriptions of how large the universe was during its early stages. I have read everything from softball size, to galactic in size after inflation


Regarding inflation: To fathom the possible existence of this decisive state, it is not enough to consult a physics textbook. It is a new breed of physics, one that has not been tested and one that is unlikely ever to be tested. Cosmology, so it seems, has been lulled into the false security of a phony vacuum imposed on it by a plague of setbacks resulting from peculiar spatiotemporal paradoxes. The false vacuum is an unappetizing intrusion, a false promise. It preserves the illusion that the standard hot big bang model need not be sacked.

Inflation is more than a storm in a coffee cup; the fundamental forces of nature are nowhere to be seen.



CC

#11 Kharakov

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Posted 11 December 2008 - 12:25 PM

An infinite spatiotemporal universe has no beginning and hence, no age.

[math]age=\infty[/math], in other words, it's older than dirt. :D

#12 max4236

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Posted 11 December 2008 - 05:16 PM

The universe stops about 53 gigaparsecs out. Nothing can traverse beyond the barrier without randomly tunneling into another epoch. My cat told me.

#13 LogicTech

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Posted 11 December 2008 - 05:49 PM

Almost.

In adding that he universe has always been infinite "from the very first plank time unit one" where it "came into existence" makes this scenario very different from the conjectured number 3 above. An infinite spatiotemporal universe has no beginning and hence, no age.


That's not true. The Big Bang Theory in no way prohibits the possibility of a spatially infinite universe, or a universe that has no beginning. In fact, a spatially infinite universe doesn't mean that the universe is not finite.

#14 LogicTech

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Posted 11 December 2008 - 05:57 PM

Cold - You wrote:

What about a third simple possibility: 3) The universe has ALWAYS been infinite.

I believe this is coverred under my number 1), which assumes the Universe came into existence at about time plank unit 1. Accordingly, in that scenario, the Universe has always been infinite in size, if not age. Specifically, anything that had a begining also has an age.


Why must it have a beginning in order to have an age? Why not just make your reference point to the time when the universe was as small as the primordial atom...

One problem I have with 'infinite' universe, is the relentless descriptions of how large the universe was during its early stages. I have read everything from softball size, to galactic in size after inflation.


I think this stems from the misunderstanding that there must be something outside the universe.... The universe, by definition, contains everything that exists. It does not make sense to talk about what is outside of it or before it.

#15 Pluto

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Posted 11 December 2008 - 07:25 PM

G'day from the land of ozzz

The universe as a total unit is infinite.

The parts within the universe being matter that forms stars and galaxies and what ever have a cyclic process that takes place. This being so, it's quite difficult to age anything.

Stars go through their phases and rejuvination and some turn to Neutron stars and black holes in the spiral arms of the galaxies. These star bodies eventually go to the centre of the galaxy where in due time form part of the so called centre Nucleon called the black hole and are ejected via jets that reform the galaxy.

And so it goes on in a cyclic process. You can google for the process.

[0709.4026] Recycling Matter in the Universe. X-ray observations of SBS 1150+599A (PN G135.9+55.9)
Recycling Matter in the Universe. X-ray observations of SBS 1150+599A (PN G135.9+55.9)

Authors: Gagik Tovmassian, John Tomsick, Ralf Napiwotzki, Lev Yungelson, Miriam Peña, Grazyna Stasińska, Michael Richer
(Submitted on 25 Sep 2007)

Abstract: We present X-ray observations of the close binary nucleus of the planetary nebula SBS 1150+599A obtained with the XMM-Newton satellite. Only one component of the binary can be observed in optical-UV. New X-ray observations show that the previously invisible component is a very hot compact star. This finding allows us to deduce rough values for the basic parameters of the binary. With a high probability the total mass of the system exceeds Chandrasekhar limit and makes the SBS 1150+599A one of the best candidate for a supernova type Ia progenitor

.

Research into the recycling process is an important issue and the extent of research has been held back by Big Bang theories and cash flow to projects that worked along the lines of the BBT.

[astro-ph/0401557] The Evolution of Tidal Debris
The Evolution of Tidal Debris

Authors: Chris Mihos (Case Western Reserve University)
(Submitted on 26 Jan 2004)

Abstract: Galaxy interactions expel a significant amount of stars and gas into the surrounding environment. I review the formation and evolution of the tidal debris spawned during these collisions, and describe how this evolution depends on the large scale environment in which the galaxies live. In addition to acting as a long-lived tracer of the interaction history of galaxies, the evolution of this material -- on both large scales and small -- has important ramifications for galactic recycling processes, the feeding of the intracluster light and intracluster medium within galaxy clusters, and the delayed formation of galactic disks and dwarf galaxies.



#16 coldcreation

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Posted 11 December 2008 - 08:31 PM

[math]age=\infty[/math]


That's like saying age = 0. It makes little sense.




In adding that he universe has always been infinite "from the very first plank time unit one" where it "came into existence" makes this scenario very different from the conjectured number 3 above. An infinite spatiotemporal universe has no beginning and hence, no age.


That's not true. The Big Bang Theory in no way prohibits the possibility of a spatially infinite universe, or a universe that has no beginning. In fact, a spatially infinite universe doesn't mean that the universe is not finite.


There are very few things prohibited by the bb theory. You are correct in that sense.

I was thinking more in terms of a steady state-like model where this problem of 'infinite yet bounded' (or finite without bounds) does not arise.


An infinite universe has no birthday.



CC
The partypooper is back!



#17 Pluto

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Posted 11 December 2008 - 09:40 PM

G'day CC

There goes Xmas