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Author Topic: Big Bang & depiction of universe - two part question  (Read 10587 times)

Offline yor_on

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Re: Big Bang & depiction of universe - two part question
« Reply #25 on: 12/02/2015 09:55:39 »
"And if we could take a snapshot of the universe as it exists now? What shape is it? Since it's space expanding, how can it be expanding into anything? What would you see if you were 76 billion light years away from here? A black half to the sky? One half of the sky looking like a mirror image of the other? None of the above?

It's interesting stuff, far more interesting than the "infinite universe" non-answer that just doesn't square with big-bang cosmology. "

I've been wondering about how to define it too John. For me the best way I've found is through assuming that it is 'information & communication' that defines it. That one fit observer dependencies as well as the idea of a commonly agreeable upon universe existing. If you 'back track' that type of logic, asking yourself what such a universe would need to start a communication, then it's those 'points', junctions, whatever, that need to be existent. Furthermore you need something 'doing' the communication. And of course, a arrow if we want a logic similar to the one we meet. The arrow is weird in that it is locally unchanging for you, being a 'constant' for you, but when looking at a 'common universe' creating those time dilations. If you 'back track' that one you will find that the arrow is a local definition, and that what we call 'repeatable experiment' also are strictly local definitions, although presumed applicable over a whole universe. The same should then go for all constants.

In essence, the way I see it this universe is created and defined locally. If it is, then a inflation which starts 'in all points' becomes a natural.
 

Offline yor_on

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Re: Big Bang & depiction of universe - two part question
« Reply #26 on: 12/02/2015 10:07:11 »
As for how it can 'expand', that's more a question of our presumptions to me. We can't avoid them as this is how we find it to be from a inside, a solution diluting in another for example. But if we assume that you need 'points' and this communication, then information is all. Tweak the information and the universe 'expands' for me. And the thing one might wonder there is if this needs some 'background', on where it can do it, myself I don't think so. The junctions define a universe geometrically and topologically, no 'back ground' needed. We're inside it, and we measure from a inside too. That doesn't state that there must be a 'outside' or 'back ground' on where a universe 'takes place'.
=

It's a symmetry break to me. And the arrow is what defines 'c', locally, always locally. The universe defined this way is constricted by constants and rules, emergences and 'properties'. There is no 'box' in where it is 'fitted', and the best way to define a size is to call in indefinable. And the 'light sphere' you see around you tells you when this symmetry break happened, as measured through constants (local clock or 'time'), and that one you will find everywhere you go. You have something else though, that's really interesting to me, much more interesting than defining a 'size to a universe'.

You have scales, as in QM :)
=

And the closest you get to a 'container model', in my thoughts, are conservation laws. But those are rules too. And if you look at time in itself there are two ways. One is time as a essence more or less, as a 'property'. Then it should be a 'smooth phenomena'. Or you define it by Planck scale, making it into 'bits', impossible for us to separate other than by theory. The last makes the arrow I have into a macroscopic 'emergence' using scaling (see why I'm so interested in it?). But, nota bene, also a local constant, shared equivalently in all 'points'. I guess one can call that a 'property' too, depending on taste. Actually the last definitions won't matter for us, as we can't separate them measuring. You consist of 'time', as do I. No way we can measure in between those 'bits', if they exist.

« Last Edit: 12/02/2015 12:01:21 by yor_on »
 

Offline yor_on

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Re: Big Bang & depiction of universe - two part question
« Reply #27 on: 12/02/2015 11:45:30 »
There's another thing with defining time my way. If you think of this universe as a 'field', then translate that into 'points' in a mathematical space, using 'c' as a constant local speed, information carrier, and clock, equivalently, you find two directions. One is the macroscopic arrow, the other represented of this field. In the field I don't want light to propagate, I want it as a 'beat' following rules, a 'flickering universe' following Mach principle so that when a event unfolds it is a representation of the whole 'field', well in essence although one can argue that one. So the fields 'beat' has one direction, the macroscopic arrow though, as described by us, have another.
=

But both obeys 'c', which is why I find Planck scale so appropriate for defining a smallest 'bit/quanta' of 'time'. Whatever exist past that one, if that is correct, has nothing to do with the arrow we define though. Even though it may be what results in it. And the way this field should exist, avoiding ideas of ftl  :) although you do have entanglements, is in a equilibrium. A event is a change of that equilibrium into a new unique configuration, or pattern. Well, as a suggestion:)
« Last Edit: 12/02/2015 11:59:52 by yor_on »
 

Offline yor_on

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Re: Big Bang & depiction of universe - two part question
« Reply #28 on: 12/02/2015 16:29:12 »
And then, just add 'free will' and non linearities, as well as those patterns and constants expressed in chaos mathematics. Then you are where we live.
 

Offline PhysBang

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Re: Big Bang & depiction of universe - two part question
« Reply #29 on: 20/02/2015 14:12:21 »
However the next bit of the WMAP article isn't reasonable:

"This suggests that the Universe is infinite in extent; however, since the Universe has a finite age, we can only observe a finite volume of the Universe. All we can truly conclude is that the Universe is much larger than the volume we can directly observe."

This is a non-sequitur. A flat universe does not suggest that the universe is infinite in extent.
Actually, yes it does, as long as one accepts general relativity and that the universe is as (roughly) homogeneous and isotropic as it appears to be to us. It might be hard for one to accept, but a good cosmology textbook can probably walk one through the steps in this essentially mathematical proof.

Quote
We cannot truly conclude is that the universe is much larger than the volume we can directly observe. If anybody says we can, ask them to explain this conclusion. They will not be able to.
It might be the case that nobody can explain this to a particular person, but this thing is explained every semester in hundreds of classes across the planet.
 

Offline Bill S

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Re: Big Bang & depiction of universe - two part question
« Reply #30 on: 23/02/2015 15:54:25 »
Quote from: John
This is a non-sequitur. A flat universe does not suggest that the universe is infinite in extent.

John, are you making a distinction between infinite and boundless? 

My feeling is that much confusion could be avoided if those terms were kept apart.
 

Offline PmbPhy

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Re: Big Bang & depiction of universe - two part question
« Reply #31 on: 23/02/2015 16:47:05 »
Quote from: JohnDuffield
This is a non-sequitur. A flat universe does not suggest that the universe is infinite in extent.
Of, for cripes sake. Of course it does. EVERY relativist and cosmologist knows this as a FACT.

See? Yet another error that I told you that you keep making all the time.

Quote from: JohnDuffield
We cannot truly conclude ....
So what? This is physics, dude. In physics nobody can "truly" conclude anything!!! Sheesh! Read something on the philosophy of physics for once.

Read http://home.comcast.net/~peter.m.brown/ref/philosophy_physics.pdf
 

Offline JohnDuffield

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Re: Big Bang & depiction of universe - two part question
« Reply #32 on: 23/02/2015 17:15:04 »
John, are you making a distinction between infinite and boundless?
Yes. An infinite universe is one that goes on forever. A boundless universe might be finite, wherein you never reach any kind of edge, and instead you end up coming round full circle. 

Quote from: PmbPhy
Of, for cripes sake. Of course it does. EVERY relativist and cosmologist knows this as a FACT.
No they don't. Because it isn't a fact. It's a non-sequitur. A myth. 

Quote from: PhysBang
Actually, yes it does, as long as one accepts general relativity and that the universe is as (roughly) homogeneous and isotropic as it appears to be to us. It might be hard for one to accept, but a good cosmology textbook can probably walk one through the steps in this essentially mathematical proof.
I accept general relativity, but I do not accept that the universe is homogeneous and isotropic. That's an assumption, that's all. For all we know, some guy fifty billion light years away might be looking up at the night sky, and one half is totally black. 
 

Offline PmbPhy

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Re: Big Bang & depiction of universe - two part question
« Reply #33 on: 23/02/2015 17:18:33 »
Quote from: JohnDuffield
No they don't. Because it isn't a fact. It's a non-sequitur. A myth. 
Nonsense. You have a server problem here. You seem to be of the opinion that all you have to do is make a claim and everyone will accept it just because you claimed it was true. That's nonsense and you know it. Therefore instead of claiming that the entire physics community is wrong why not at least attempt to justify this ridiculous claim of yours? Or remain the fool.

In the mean time I'll prove that it is.

Postulate: The universe is spatially flat (everywhere).

Theorem: A spatially flat universe is spatially infinite.

Proof: Since spatial geodesics are straight lines it follows that any straight line going off in one direction and never terminates. This holds for all spatial geodesics. This implies that since all these geodesics go off into infinity the space must be infinite. Otherwise the line would simply stop in space which is physically absurd. Therefore a spatially flat universe is infinite.
« Last Edit: 23/02/2015 17:24:39 by PmbPhy »
 

Offline JohnDuffield

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Re: Big Bang & depiction of universe - two part question
« Reply #34 on: 23/02/2015 18:16:35 »
LOL! That's no proof! Look again at this:

Otherwise the line would simply stop in space which is physically absurd.

Now imagine that a wave in space can be likened to wave inside a water droplet. It travels in a straight line. When it encounters the edge of the droplet it undergoes total internal reflection. That isn't absurd. Nor is the "hall of mirrors" mentioned in this article featuring cosmologist Neil Cornish. What's absurd is proposing a spatially flat infinite universe that was a singularity 13.8 billion years ago.
 

Offline PhysBang

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Re: Big Bang & depiction of universe - two part question
« Reply #35 on: 23/02/2015 18:25:53 »
LOL! That's no proof! Look again at this:

Otherwise the line would simply stop in space which is physically absurd.

Now imagine that a wave in space can be likened to wave inside a water droplet. It travels in a straight line. When it encounters the edge of the droplet it undergoes total internal reflection. That isn't absurd. Nor is the "hall of mirrors" mentioned in this article featuring cosmologist Neil Cornish. What's absurd is proposing a spatially flat infinite universe that was a singularity 13.8 billion years ago.
That article describes a curved space, not a flat one, and not one with reflection.
 

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Re: Big Bang & depiction of universe - two part question
« Reply #35 on: 23/02/2015 18:25:53 »

 

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