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Author Topic: Will the universe experience another phase of inflation?  (Read 6335 times)

Offline Alan Fuller

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Alan Fuller asked the Naked Scientists:
   
Inflation, as I understand it, is a period when the universe expanded faster than the speed of light.

As the universe expands faster and faster (dark energy) will it re-enter inflation?

What do you think?
« Last Edit: 20/04/2011 06:30:02 by _system »


 

Offline yor_on

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Will the universe experience another phase of inflation?
« Reply #1 on: 20/04/2011 09:21:28 »
It already does, depending on your views and definitions. Although the universe at no place expands faster that light you will find that when looking over vaster expanses, those galaxies (possibly) there will be moving 'away' from us, faster than light speed in a vacuum. And that's that :)

But it's not really the same. The inflation is an idea of a universe 'growing' from a pinpoint to something larger that we can measure. That's also why we, even though being able to say that some galaxies we do see is very 'near' time-wise to the Big Bang, they do not specify where the end of that 'inflation' is. It may well be that the inflation stretch 4ever and that you from any point in it can see the same as us time-wise, even without our galaxy being included, as we will be too far away. The inflation is a little like an island breaking the water (like a volcano raising), but instantly, if you can accept the idea of a infinite instant 'island'. It's not the same as something growing concentrically from some point, in all directions.
==

The idea of 'SpaceTime' having a 'speed' for its expansion makes sense. Speed and distance are definitions we see macroscopically. The 'inflation' though, took 'place' somewhere where we can't really be sure what 'time' it took, or even if 'times arrow' had any meaning for it, and if taking no time, can we really speak about a distance then? We define a lot of things from our own macroscopic arrow, giving them different properties. Tunneling takes no 'time' at all, as I understands it, the same goes for a entanglements 'wave collapse', as when you measure one of the 'twins' will force the other one to fall out into a defined state too, no matter how far away it is macroscopically. So you might say that the 'concept' of 'no-time' exist inside our 'arrow' too, even today. Maybe the 'expansion' we see now is a form of controlled 'inflation'? Limited by the restrictions set by our macroscopic SpaceTime?

It was a really nice question Allan :)
==

Had to correct my English.
Painfully so.
« Last Edit: 20/04/2011 17:39:29 by yor_on »
 

Offline Alan Fuller

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Will the universe experience another phase of inflation?
« Reply #2 on: 22/04/2011 20:47:24 »
Thank you for your answer yor_on.

I just watched Alan Guth in a two part series on Cosmic Inflation and the Accelerating Universe at YouTube. At the end of the second episode I understood him to say the universe would eventually enter a period similar to inflation.



 

Offline yor_on

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Will the universe experience another phase of inflation?
« Reply #3 on: 23/04/2011 02:51:46 »
Tried to find something about that but no, couldn't. But it make sense if we assume that all new 'stretches' of space also can give birth to new stretches, giving birth too, ad infinitum. then we will have something in the end that gallops away into 'infinity'. If that was what he meant? That's also what irritated me before thinking of inflation :)

That, if I assume this, we seem to end up in an universe of one galaxy per 'light-sphere'. As well as the distances will break any 'speed records' made 4-ever :) But this is just a guess.
==

Found this though. Time Since the Beginning; Alan H. Guth (MIT)  13 Jan 2003.
« Last Edit: 23/04/2011 03:37:29 by yor_on »
 

Offline Alan Fuller

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Will the universe experience another phase of inflation?
« Reply #4 on: 23/04/2011 12:16:15 »
Here is the link to the video I mentioned. It is the second of two.

newbielink:http://youtu.be/lFkGTzMm7lQ [nonactive]
 

Offline yor_on

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Will the universe experience another phase of inflation?
« Reply #5 on: 23/04/2011 14:02:13 »
Thanks, he has a good mind Alan :)
Will be fun.
 

Offline yor_on

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Will the universe experience another phase of inflation?
« Reply #6 on: 23/04/2011 14:27:22 »
Okay, it's coupled to the idea of 'dark energy'.

"I think dark matter is more relevant to the next age of particle physics experiments ó hopefully supersymmetry and perhaps other interesting things that we may discover. On the other hand, thereís at least a good chance that dark energy is energy of the vacuum, so it seems to be telling us something about the fundamental structure of physical law, which is a big surprise. The vacuum energy has been a haunting question for particle theorists since the advent of quantum field theory in the 1930ís. As soon as we had quantum field theory we knew that the vacuum was not a simple state: It was a very complicated state with all kinds of quantum fluctuations going on. And there was no reason at all why the energy of the vacuum should turn out to be zero or small.

In fact, nobody knows how to calculate the energy of the vacuum, but if particle physicists were to try to estimate it, the natural answer would be something like 120 orders of magnitude larger than the experimental bound. So it was always a big mystery, but until the advent of dark energy, the belief was that the real number was zero, because of some kind of symmetry that we didnít understand yet ó an exact cancellation between the positive and negative contributions. If dark energy is the energy of the vacuum, now you need that symmetry to make it almost zero, and then some small breaking of that symmetry to make it a small number thatís not zero. And it all gets very complicated and baroque. Nobody has the faintest idea of how it might actually work. There is also the possibility that the vacuum energy is not determined at all by the fundamental laws of physics, but instead itís determined anthropically, using the idea of a multiverse.

Itís quite possible in the context of string theory that there are many vacuum-like states, and all of them are stable enough that they could provide the underpinnings of a universe. And the one that we happen to find ourselves in is determined by random choice. One would imagine that the universe would inflate eternally through all the different possible vacua of string theory, with infinite amounts of space of every type of vacuum produced ó eventually... If this is right, it would mean that in most regions of space the cosmological constant is enormous, and there are some rare regions of space where the cosmological constant happens to be very small. But life can only form if the cosmological constant is very small. So itís not a surprise that we find ourselves living in one of those regions. An idea like this five years ago would have been completely anathema to particle physicists. It is still anathema to many, but people pay much more attention to this kind of idea now."

Does this connect to the idea of eternal inflation, with different universes bubbling off?

AG: Yes, there are two ideas coming together here. One is the idea from string theory, that thereís a huge number of possible vacuum states. And the other is the idea of eternal inflation, that once inflation starts, it never ends, and it explores all possible vacua." From Here..


I don't know there myself :)

Maybe, this is speculation based on theory. String theory to be precise, and in string theory everything becomes possible. There we all are branes, strings or loops, vibrating and 'dimensions' becomes something you can handpick to fit your definitions. It might be so, but there are other variants of string theory too. And in the end we still need to find evidence for string theory actually existing as a 'fact'. It's pure mathematical theory, just as the proof of all parallel lines converging into a point. Mathematically impeccable as I understands it, but nowhere to be seen in our universe, yet. Made sometime in eighteen-hundred if I remember right(?) By a (French) mathematician.

And 'energy' is a conceptual property, defined through interactions. That we found a logic telling us how those 'interactions' will deliver this amount of 'energy' doesn't mean that 'energy' as such exist. We use the concept and I do too, but you could as easily define it as outcomes from a game with rules, no energy at all. You roll the dice and get a six, move three steps to the left. Most of the definition of 'reality' we have is constructed around the Newtonian concepts, which are the ones most suitable, until now, for describing our kind of reality. We now find more and more 'breaks' in that reality and so adapt it. But doing so we still assume that this reality is what counts. Which in a way is perfectly understandable. Then we have others that decides that this reality does not count, and so look at anything that can let us build a 'universe' where one of the outcomes become 'SpaceTime'.

Myself I don't know :) Wish I did though.
==

I can say this though, I think the problem isn't with us needing a more complicated reality. The real problem lies in our definitions of what 'reality' should be. That's what blinds us to the reality we exist in, and that one we inherit, each one of us, when growing up. The way you relate to the world you live in will color your perception, and there no 'mind' however sharp, can escape. Einstein is a rare exception there.
« Last Edit: 23/04/2011 14:43:25 by yor_on »
 

Offline Alan Fuller

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Will the universe experience another phase of inflation?
« Reply #7 on: 23/04/2011 14:50:45 »
You make some astute observations yor_on.

Thanks :)

 

Offline MikeS

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Will the universe experience another phase of inflation?
« Reply #8 on: 25/04/2011 13:37:31 »
"Inflation, as I understand it, is a period when the universe expanded faster than the speed of light.

As the universe expands faster and faster (dark energy) will it re-enter inflation?"


I guess it depends upon the definition of inflation
I think it is wrong to describe inflation as happening faster then the speed of light.  The speed of light is a constant and nothing can travel faster than the speed of light.  However speed has two components, distance and time.  The rate of flow of time is a variable.  Consider then, if the rate of flow of time is infinite, so is the speed of light.  This in no way affects the speed of light which in a vacuum is always constant.  However, I believe inflation, in a sense took place outside of time, before time was born.

Personally I do not believe in the tooth fairy, nor do I believe in dark energy or invisible mass for that matter.  No, the universe will not undergo inflation again (well not until the birth of the next cycle).  The processes that led to the birth of time are still present in the universe so inflation as such can not happen again.  However, as the rate of flow of time is a variable, it does not matter how fast the universe expands, the rate of flow of time will always ensure that the universe will never expand at anything approaching the speed of light.  The speed of light is a constant because the rate of flow of time is a variable.

Anyone care to disprove this?

Mike
 

Offline imatfaal

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Will the universe experience another phase of inflation?
« Reply #9 on: 26/04/2011 13:15:09 »
The rate of flow of time is a variable.  Consider then, if the rate of flow of time is infinite, so is the speed of light. 
As the flow of time approaches infinity then any finite speed must approach zero. 

Quote
Anyone care to disprove this?

See response in other thread. http://www.thenakedscientists.com/forum/index.php?topic=38895.0
 

Offline MikeS

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Will the universe experience another phase of inflation?
« Reply #10 on: 26/04/2011 19:39:26 »
ummm interesting.

I need to think about this some more.
I assume your logic is speed = distance divided by time, as time approaches infinite then speed must approach zero.

However we are not talking about time but the rate of flow of time.  At the moment I can't get my head around what difference that makes.  Will think about it tomorrow.  Quick thought, I don't believe you can substitute the rate of flow of time for time

Mike
 

Offline MikeS

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Will the universe experience another phase of inflation?
« Reply #11 on: 27/04/2011 11:23:21 »
ummm interesting.

I need to think about this some more.
I assume your logic is speed = distance divided by time, as time approaches infinite then speed must approach zero.

However we are not talking about time but the rate of flow of time.  At the moment I can't get my head around what difference that makes.  Will think about it tomorrow.  Quick thought, I don't believe you can substitute the rate of flow of time for time

Mike


Yes, I was right in my last post.  If the rate of flow of time is less than infinite then any "block for lack of a better word" [within that flow]has a finite size and can therefore be divided into the arbitrary units we are familiar with as time.  Speed remains unchanged the same formula, speed equals distance divided by time still applies.  The speed of light is still a constant.

Mike
 

Offline imatfaal

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Will the universe experience another phase of inflation?
« Reply #12 on: 27/04/2011 12:53:38 »


Yes, I was right in my last post.  If the rate of flow of time is less than infinite then any "block for lack of a better word" [within that flow]has a finite size and can therefore be divided into the arbitrary units we are familiar with as time.  Speed remains unchanged the same formula, speed equals distance divided by time still applies.  The speed of light is still a constant.

Mike

Quote
Consider then, if the rate of flow of time is infinite, so is the speed of light.

So does it remain constant or does it become infinite, or is there a discontinuity? You use the word "rate" without defining it - if you mean the ratio of seconds to pass over some unknown variable - then as this rate goes to infinity then speed will drop to zero.  rate is normally reserved as a ratio to time d/dt- so I really don't understand what you can mean by the "rate of time"
 

Offline MikeS

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Will the universe experience another phase of inflation?
« Reply #13 on: 27/04/2011 13:50:48 »


Yes, I was right in my last post.  If the rate of flow of time is less than infinite then any "block for lack of a better word" [within that flow]has a finite size and can therefore be divided into the arbitrary units we are familiar with as time.  Speed remains unchanged the same formula, speed equals distance divided by time still applies.  The speed of light is still a constant.

Mike

Quote
Consider then, if the rate of flow of time is infinite, so is the speed of light.

So does it remain constant or does it become infinite, or is there a discontinuity? You use the word "rate" without defining it - if you mean the ratio of seconds to pass over some unknown variable - then as this rate goes to infinity then speed will drop to zero.  rate is normally reserved as a ratio to time d/dt- so I really don't understand what you can mean by the "rate of time"

The rate of flow of time, I use this term as it best describes what I am trying to say.  Language when talking about time can seem a little lacking.  Consider a river, it has a rate of flow, maybe fast maybe slow.  If you stand on a bridge and drop sticks in at say one a second then they will have a certain spacing depending upon the rate of flow.  Someone downstream can count off the seconds as the sticks pass them.  The rate of flow of time is something that normally we don't have cause to think about and some people find it a difficult concept.

Does what become infinite, the speed of light?
The speed of light is constant.  However, if the rate of flow of time is infinite so is the speed of light but it is still a constant.  Probably best not to talk about infinity anyway.  "or is there a discontinuity?" Can you explain what you mean?
 

Offline MikeS

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Will the universe experience another phase of inflation?
« Reply #14 on: 27/04/2011 14:46:55 »
"The speed of light is constant.  However, if the rate of flow of time is infinite so is the speed of light but it is still a constant."

I know you are going to pick me up on this, the sentence is contradictory.  What I am trying, not very effectively, to say is that although the speed of light is a constant within the universe.  To an outside observer the speed of light would be infinite.
 

Offline imatfaal

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Will the universe experience another phase of inflation?
« Reply #15 on: 27/04/2011 16:10:59 »
Mike - to get any recognition (or to get serious people to prove you wrong as you were asking) you need to give explanations that work outside your own consciousness.  Everyone who has tried realises how difficult it is to move something intuitive and wordless within one's mind  to the stark reality of a handful of ascii characters on a forum; but it has to be done. 

I will re-iterate - a rate, a ratio, a differential etc is the amount of change of A per unit (perhaps a very small unit) of B.  Whether you call it the speed of time, the rate of time, the rate of flow of time etc you need to define it.  If it is merely the time dilation of an observer's proper time within a gravitational potential compared to the coordinate time of an observer at an arbitrarily large distance then you should say this.  But I will warn you that this is nothing new and despite your assertions elsewhere it is taken into account.
 

Offline MikeS

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Will the universe experience another phase of inflation?
« Reply #16 on: 27/04/2011 17:47:53 »
Ok, any chance of some help in how to express 'the rate of flow of time' mathematically.  I expressed it like that as I thought it obvious what it meant but perhaps not.  Did you understand my flowing river analogy?  Another way of describing the rate of flow of time is consider a clock face.  The arbitrary markings represent time, yes?  The distance between the markings represents the rate of flow of time.  No matter how large or small the clock face the markings are constant but the distance between them varies.  I can't think how to express this in mathematical terms and an internet search has not helped.

"But I will warn you that this is nothing new and despite your assertions elsewhere it is taken into account."
What are we talking about here?  The Pioneer anomaly and General Relativity?  If so, as I said in a post on this subject, The Guy in charge of the investigation at JPL has written a paper, updated last year which states General Relativity was not used when analysing the spacecraft data.
 

Offline imatfaal

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Will the universe experience another phase of inflation?
« Reply #17 on: 28/04/2011 13:30:37 »
Mike - without some dynamic aspect the markings on the clock face are described by distances/angles nothing more.  With movement added they can provide an accepted quantification of time - I have seen clock faces with different markings (12 divisions, 24 divisions, 60, and 3600 divisions) they indicate different ways of measuring and displaying time but not different rates of flow of time (a. because I don't know what this means and b. because they have no means of displaying this (not enough degrees of freedom)
 

Offline JP

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Will the universe experience another phase of inflation?
« Reply #18 on: 28/04/2011 16:01:24 »
Perhaps what Mike is getting at with "rate of flow of time" has to do with time dilation?  If I have a moving clock and a stationary clock, I can say, for example, that the moving clock ticks out X seconds per 1 second of the stationary clock.
 

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Will the universe experience another phase of inflation?
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