Universal 'Now' at Time-Zero

[tar]

Strange,

 

We could be, because of inflation and expansion, out of possible view of parts of the universe further away than the parts that have just cleared and are viewable as the CMB. But how would Hubble expansion make anything closer than the CMB disappear? If we ever saw it, we can still see it because it is closer than the CMB.

 

Regards, TAR

String Junky,

 

Just how hot and just how dense? I mean if it is not one point, and has depth and width and height, then it would take time for an impulse to get from here to there, within it.

 

Regards, TAR

[StringJunky]

 

String Junky,

 

Just how hot and just how dense? I mean if it is not one point, and has depth and width and height, then it would take time for an impulse to get from here to there, within it.

 

Regards, TAR

If the hot, dense state was homogenous then any reaction/change was simultaneous everywhere; doesn't matter how big or small it was.

Edited August 16, 2016 by StringJunky

[tar]

String Junky,

 

Well simultaneous everywhere might go for when the place turned transparent, for instance, but this does not mean the one end could see the other end immediately. Perhaps I can't understand your usage of the word simultaneous. If you subscribe to the two senses of now idea, then what happens everywhere in the universe, like every part's 13,780,954,567th birthday, happens everywhere at once, but this does not mean you can see even what is happening on a close star, immediately.

 

So how big it is makes every difference. Like a sugar cube dropped into a hot cup of coffee at once...there is a corner of it, that gets wet before the other. And if you have an observer at one end of the hot dense, and an obsever at the other, they will experience an event that happened to the whole place at once, at the same time, but they will not experience the other end experiencing that thing, for billions of years, or potentially as Strange allows, maybe never. So size matters.

 

Regards, TAR

[StringJunky]

String Junky,

 

Well simultaneous everywhere might go for when the place turned transparent, for instance, but this does not mean the one end could see the other end immediately. Perhaps I can't understand your usage of the word simultaneous. If you subscribe to the two senses of now idea, then what happens everywhere in the universe, like every part's 13,780,954,567th birthday, happens everywhere at once, but this does not mean you can see even what is happening on a close star, immediately.

 

So how big it is makes every difference. Like a sugar cube dropped into a hot cup of coffee at once...there is a corner of it, that gets wet before the other. And if you have an observer at one end of the hot dense, and an obsever at the other, they will experience an event that happened to the whole place at once, at the same time, but they will not experience the other end experiencing that thing, for billions of years, or potentially as Strange allows, maybe never. So size matters.

 

Regards, TAR

In the hot, dense state there are no signals travelling anywhere because the universe is one bit of 'stuff'. The idea of 'seeing' from one side to the other is irrelevant.

Edited August 16, 2016 by StringJunky

[tar]

String Junky,

 

"Seeing" is irrelevant, of course, because the place did not become transparent to photons for many many years, but very relevent is if the one part of the place could feel the other through impulses and vibrations, and gravity and heat exchange and such. These actions, putting one piece of the place within the causal reach of any other peice of the place is exactly the thing the universe had before you could share info with photons, and is central to the thread question.

 

Regards, TAR

If galaxy formation happened around 1 billion years old and the CMB is around 400,000 thousand years old, then the opaque time of the universe, after hydrogen was ionized and before neutral hydrogen reformed, there was lots of time when the place was hot and dense, but not the same everywhere. The CMB shows anisotropy, or hot and cold spots at the 400,000 mark, so stuff was happening differently over here than it was over there, at that point. Suggests that if you would go back from there toward the BB, lets say to 200,000 years, it would be different over here then over there. At what point to you suggest that we had an over here and an over there that was not unique in position, arrangement, heat, and motion?

[StringJunky]

I don't know. I asked the question to learn, not offer ideas.

 

String Junky,

 

"Seeing" is irrelevant, of course, because the place did not become transparent to photons for many many years, but very relevent is if the one part of the place could feel the other through impulses and vibrations, and gravity and heat exchange and such. These actions, putting one piece of the place within the causal reach of any other peice of the place is exactly the thing the universe had before you could share info with photons, and is central to the thread question.

 

Regards, TAR

If galaxy formation happened around 1 billion years old and the CMB is around 400,000 thousand years old, then the opaque time of the universe, after hydrogen was ionized and before neutral hydrogen reformed, there was lots of time when the place was hot and dense, but not the same everywhere. The CMB shows anisotropy, or hot and cold spots at the 400,000 mark, so stuff was happening differently over here than it was over there, at that point. Suggests that if you would go back from there toward the BB, lets say to 200,000 years, it would be different over here then over there. At what point to you suggest that we had an over here and an over there that was not unique in position, arrangement, heat, and motion?

Edited August 16, 2016 by StringJunky

[tar]

String Junky,

 

Sorry I don't have the answers, just speculations, but I don't agree that there was a "timeless" time. It makes no sense to suggest such. How could you have a time period in which there was no time. How long could such a period last? If it lasts longer than no time, then it is not timeless.

 

Regards, TAR

[StringJunky]

String Junky,

 

Sorry I don't have the answers, just speculations, but I don't agree that there was a "timeless" time. It makes no sense to suggest such. How could you have a time period in which there was no time. How long could such a period last? If it lasts longer than no time, then it is not timeless.

 

Regards, TAR

You need to get rid of your 'god-like' perspective holding your heavenly stopwatch in your hand timing everything. The universe at time zero may not have been space-like or time-like so the notion of a signal travelling from one point to another becomes moot doesn't it? This is in the hard science forum and I put it here because I want to know what the current science is.

[tar]

String Junky,

 

Sorry, I will bow out. I don't know any hard science.

 

Regards, TAR

[sethoflagos]

Perhaps if we think backwards.

 

There are a few universal clocks.

 

The exact here and now will vary, but every observer in the universe will be able to pinpoint a moment when the average CMB temperature in their observable universe matched the triple point temperature of helium for example.

 

Going back in time there will be a series of similar thermodynamic milestones which one would presume ultimately to converge on a common state at a time of universal causal linkage when all clocks could be synchronised. Even if that synchronisation was at an asymptotic approach to zero.

 

Or maybe I'm just talking cojones. Wouldn't be the first time.

[MigL]

Even a hot, dense initial state will have a size, and so, geometry and space-time.

All parts of this initial universe will need to be in causal contact to ensure isotropy and homogeneity.

That is one of the reasons for postulating inflation.

You will of course still have quantum fluctuations to provide the 'seeds' for future structure.

 

If the initial universe is small enough however, such that quantum effects don't allow for geometry, or if its actually a singularity with no geometry, then of course there cannot be space-time.

And if there is no time, how do you define a universal 'now' ?

[StringJunky]

 

And if there is no time, how do you define a universal 'now' ?

With difficulty; no past or future. There's no signal going anywhere because it's happening everywhere. Sticking to relativity, time is always relative to something else. If something is happening uniformly and simultaneously everywhere, what is its time relative to in the universe... there isn't one is, there? It can't be relative to itself. My viewpoint is from within the the universe, not from outside looking in at the universe as a discrete object, extant to myself as an observer, like Tar was doing.

Edited August 17, 2016 by StringJunky

[geordief]

Is there a notion of what time may or could have emerged from before(causally before?) it was /is the measurable quantity we now use?

 

We say rightly or wrongly) in certain conditions we cannot speak of time but is there some other condition that allows the emergence of time?

 

Is it an absolutely absurd notion that one day physicists will hold a news conference to announce that they have isolated a state where time does not exist and they are contemplating what tests it may be possible to probe this state with.

 

At least could someone write a novel about it ?

Edited August 17, 2016 by geordief

[michel123456]

With difficulty; no past or future. There's no signal going anywhere because it's happening everywhere. Sticking to relativity, time is always relative to something else. If something is happening uniformly and simultaneously everywhere, what is its time relative to in the universe... there isn't one is, there? It can't be relative to itself. My viewpoint is from within the the universe, not from outside looking in at the universe as a discrete object, extant to myself as an observer, like Tar was doing.

What you say reminds me the block universe, where nothing happens. Time exists as the 4th dimension and everything in the universe is there like frozen in time. The observer is then given the illusion of time elapsing because of the constraints of observation. IOW the observer cannot contemplate the whole block universe but only bit by bit.

In this scenario, nothing really happens in the block universe, it is a solid block of marble that contains all the events, past present and future.

To speak frankly, it looks wrong to me.

Edited August 17, 2016 by michel123456

[StringJunky]

Is there a notion of what time may or could have emerged from before(causally before?) it was /is the measurable quantity we now use?

 

We say rightly or wrongly) in certain conditions we cannot speak of time but is there some other condition that allows the emergence of time?

 

Is it an absolutely absurd notion that one day physicists will hold a news conference to announce that they have isolated a state where time does not exist and they are contemplating what tests it may be possible to probe this state with.

 

At least could someone write a novel about it ?

These are the sort of questions I ask myself at that stage in the universe's evolution. Is the notion of time in the pre-inflationary universe non-sensible?

Edited August 17, 2016 by StringJunky

[geordief]

it is a solid block of marble that contains all the events, past present and future.

To speak frankly, it looks wrong to me.

If this is an accepted scenario is there any notion of how there could have been a transition to a state where it was possible to conceive of temporal distances?

 

This must go into quantum territory surely.

 

Does it have anything to say?

 

Does the concept of phase transition come into play? Is that idea bound up with "emergent properties" ?

These are the sort of questions I ask myself at that stage in the universe's evolution. Is the notion of time in the pre-inflationary universe non-sensible?

Sorry do you mean "sensible" in the sense of "reasonable" or "detectable"?

 

I sometimes get confused as in French it has the latter meaning and I am no longer certain of its use in English in all circumstances....

[StringJunky]

If this is an accepted scenario is there any notion of how there could have been a transition to a state where it was possible to conceive of temporal distances?

 

This must go into quantum territory surely.

 

Does it have anything to say?

 

Does the concept of phase transition come into play? Is that idea bound up with "emergent properties" ?

Sorry do you mean "sensible" in the sense of "reasonable" or "detectable"?

 

I sometimes get confused as in French it has the latter meaning and I am no longer certain of its use in English in all circumstances....

Detectable.

[Strange]

Is there a notion of what time may or could have emerged from before(causally before?) it was /is the measurable quantity we now use?

 

Markus Hanke has a good analogy for why it doesn't make sense to ask what happens "before"; it is like asking what is north of the North Pole.

[StringJunky]

 

Markus Hanke has a good analogy for why it doesn't make sense to ask what happens "before"; it is like asking what is north of the North Pole.

Yeah

[geordief]

 

Markus Hanke has a good analogy for why it doesn't make sense to ask what happens "before"; it is like asking what is north of the North Pole.

Yes but GR only applies so far back . There is a "space " for a new model between the "singularity" and the point where GR becomes applicable, isn't there?

 

I am not saying the singularity is a thing but there is a "space" where GR does not apply and that area of non applicability could be referred to as "before" -just not in a temporal sense.-more in the sense that it is an area (which looks to us from our vantage point like "before" ) which is perhaps something like a step change in "reverse".

 

And you said the N Pole description was just an analogy.

 

Prepared to admit I may not be making sense......

Edited August 17, 2016 by geordief

[StringJunky]

Yes but GR only applies so far back . There is a "space " for a new model between the "singularity" and the point where GR becomes applicable, isn't there?

 

I am not saying the singularity is a thing but there is a "space" where GR does not apply and that area of non applicability could be referred to as "before" -just not in a temporal sense.-more in the sense that it is an area (which looks to us from our vantage point like "before" ) which is perhaps something like a step change in "reverse".

 

And you said the N Pole description was just an analogy.

 

Prepared to admit I may not be making sense......

Let's not forget, that this part of the universe's evolution is very unknown scientifically so we are talking out of our derriere's really.

[geordief]

Let's not forget, that this part of the universe's evolution is very unknown scientifically so we are talking out of our derriere's really.

Well I hope that is just an analogy..

[StringJunky]

Well I hope that is just an analogy..

There ain't no light to be found there.

[Strange]

Yes but GR only applies so far back . There is a "space " for a new model between the "singularity" and the point where GR becomes applicable, isn't there?

 

The singularity is part of GR. So the space for a new model is in replacing the singularity with something else by extending/replacing GR (which may or may not allow for "before" questions, and may or may not answer them!).

[Bird11dog]

A related question, how fast would time be moving at T = 30 sec as compared to today's Universal time?