The Big Bang and Inflation:

Discussion in 'Astronomy, Exobiology, & Cosmology' started by paddoboy, Jul 20, 2015.

1. SchmelzerValued Senior Member

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No. In the standard model, where DE is simply Einstein's cosmological constant, it plays no role at all for inflation. There are some other models, but I have not heard of any model which explains inflation and actual accelerated expansion using the same thing.

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We are in speculative territory here Schmezer as I'm sure you know. Something also had to be the impetus for the BB itself,and I gave my version, as to what that may be. ie; Whatever was the impetus for that, could also explain why [as I explained] the expansion is accelerating.
No agenda on my part at all.

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http://supernova.lbl.gov/~evlinder/defaq.html#infl
Q: How are Dark Energy and Inflation related?
A: Probably not at all.

Both the current epoch and the inflation epoch in the early universe are times of accelerating expansion of the universe. Both may be due to physical components described by scalar fields (possessing a value, but not direction at each point in space. Think of a field of tall grass: if you trample it down, then at each point you can measure the length of the stalk of grass and the direction it is lying on the ground -- that is a vector field. If instead you cut the grass raggedly without trampling it then at each point all you measure is the length of the grass -- that is a scalar field.)

But:

• The energy scale of inflation is possibly 1024eV, while the energy scale of dark energy is around 10-3eV. This is as different as the weight of a flea and that of the whole Earth! Since physicists actually talk about cosmological components in terms of the energy density, which is proportional to the fourth power of the energy scale, it's even worse -- then the ratio is 10108!

• Inflation occurred when the age of the universe was perhaps 10-35 seconds, while dark energy acceleration began when the age was about 7 billion years.
So it's a long way to go to connect one to the other.

As before though, it is an attractive idea to try to tie these two phenomena together. Speculations involving some connection exist, but in the simplest pictures dark energy and inflation are independent.

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http://iopscience.iop.org/1742-6596/259/1/012082
Relation between inflation and dark energy
ABSTRACT:
In this talk, we have shown that current cosmic acceleration can be explained by an almost massless scalar field experiencing quantum fluctuations during primordial inflation. Provided its mass does not exceed the Hubble parameter today, this field has been frozen during the cosmological ages to start dominating the universe only recently. By using supernovae data, completed with baryonic acoustic oscillations from galaxy surveys and cosmic microwave background anisotropies, we infer the energy scale of primordial inflation to be around a few TeV, which implies a negligible tensor-to-scalar ratio of the primordial fluctuations. Moreover, our model suggests that inflation lasted for an extremely long period. Dark energy could therefore be a natural consequence of cosmic inflation close to the electroweak energy scale.

http://iopscience.iop.org/1742-6596/259/1/012082/pdf/1742-6596_259_1_012082.pdf

8. danshawenValued Senior Member

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For most folks, invoking (a hypothesis) and creating (a hypothesis) means pretty much the same thing, but I take your point.

The CC is still as good an answer to my questions as is possible, just as it was over 50 years ago.

I still reserve judgement on the BB until someone can explain the energy dynamics before and after in detail and in a manner that can be verified today. A collider experiment of sufficiently high energy may actually do that, and it is true that there is a better chance of finding a clue than ever before. "Coal face" is an appropriate term to describe dumping the defocused beams into tons of graphite after 10 hours of continuous operation. Astrophysics isn't as confined or as dirty a job unless you are retrofitting Hubble, but there is a great deal of work associated with both observations and computations.

It is the nature of cosmological evidence that it may be interpreted in more than one self-consistent way.

Vera Rubin invoked the idea of DM because of the anomalous velocity profiles of spiral galaxies which should have shed the outer 1/3 of their mass because it had already reached escape velocity. I agree in principle that this phenomenon is at variance with any idea other than DM.

By way of analogy with DM alone, the type 1a supernova data confirms that something like DE is necessary to explain the increasing rate of expansion of galaxies at cosmological distances. But until the cause of gravity (not just its behavior) is understood in the near field, I would be reticent to ascribe a different behavior to it at cosmological distances, or at the time of the BB or inflation, or all of the above.

Guth's superforce actually makes less sense to me as a cause for DE since you showed us Tyson's video explaining it in graphic form. If every basic force in the universe is changing at the same time, I see no good reason why the nominal energy levels the forces might settle into would not continuously change along with them. What theory is it that injects that sort of rock-solid deterministic insight into a uncertain quantum universe?

Perhaps the CC is simply not "constant" over cosmological distances. What collection of free parameters would make it so if it were? The Hubble constant certainly wasn't.

9. danshawenValued Senior Member

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Electroweak is the same as EM as applied to the function of W, Z bosons in atomic structure. This seems to be saying that electric charge is responsible for DE.

How could that possibly be? Isn't the net electric charge of both atoms and the universe at large equal to zero? It would be easy to test that, right here, in this room, with an electroscope connected to Earth ground. Try it.

If there is that much electric charge (or electroweak charge without atoms) hanging about the cosmos, this is news to me, and will also require a major revision of the Vacuum Expectation Value. Besides which, you'd never see an interstellar neutrino if you waited for 13.7 billion years. Isn't anyone competent peer reviewing this stuff anymore? I formerly had a lot of respect for iopscience.

Last edited: Aug 6, 2015

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Then you went to the dark side.

Not sure I understand what you are saying, but the way I see it, invoking Occam's Razor, is that just as temperatures/pressures dictate what form matter takes, so to do they dictate the energetic form.
As temperatures/pressures dropped, the Superforce simply "uncoupled"...further uncoupling saw matter in the form of plasma "evolve" and come into existence.

11. TruthSeekerFancy Virtual Reality MonkeyValued Senior Member

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I have heard so many people talking about "inflation" as something that is unavoidably true and sure that it makes me suspicious... I feel the same way when economists talk about "inflation" as unavoidable. Haha.
Let's back track a little... what is the argument for "inflation"? What is the data we are interpreting as "inflation"? Is there any other possible explanation?
Wouldn't the universe require some kind of energy to expand it? Where would this energy be coming from?

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12. SchmelzerValued Senior Member

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The strongest argument for inflation is the so-called horizon problem. Without inflation, there would be a''(t)<0. Then, there would be only a finite, quite short time for causal influences between different places. And even if the distance between far away places goes to zero in the limit, the region which can be causally influenced by some single event remains finite and is, in fact, quite small.

The image of the BB singularity as a single point is quite misleading. Take some event after the BB singularity. Compute the light cone which can be causally influenced. This is a finite region. Now move the event into the past, closer to the big bang singularity. The light cone, of course, increases. But this increase is limited, it cannot become greater than some limiting light cone, if a''(t)<0. This limit is the horizon. It appears quite small, much less than the part of our universe we can observed as the CMBR.

But what we observe as the CMBR is, first of all, very homogeneous. But if one wants to explain this homogenity as some thermal equilibrium, one has to presuppose some causal contact - without causally influencing each other, one cannot create an equilibrium. This problem could be solved by postulating, without further explanation, a homogeneous distribution as the initial value. But, unfortunately, what we observe is not an exact equilibrium. It has some small (in amplitude) but large (in size) inhomogeneities. For an explanation based on thermal equilibrium this would be unproblematic, this would simply be fluctuations. But fluctuations require causal contact even more. And the excuse with an exactly homogeneous initial value does not work for the fluctuations. The size of these fluctuations is much larger than the horizon, thus, cannot be created after the BB. One would have to assume a quite complex configuration as the initial value, almost homogeneous but with large (in their size) inhomogeneities - very implausible as an initial value, not as horrible but comparable with assuming the world we observe, with all the dinosaurier remains, as an initial value 5000 years ago.

So, what we need to use the much more natural explanation of the CMBR picture we see as some thermal equilibrium with fluctuations? We need much more time before the start of the CMBR, enough time to obtain a thermal equilibrium in all the visible universe. The a(t) at CMBR time is much too large for this. Thus, a(t) should have been much smaller before. This is what can be obtained only with a''(t)>0. This is named "inflation".

To name it inflation is very misleading, because what is named "inflation" in common sense is high inflation rate, thus, big a'(t), while this "inflation" means increasing inflation rates. So, we have the strange situation that in the initial part of "inflation" the inflation rate has been much lower than the inflation rate after the end of "inflation".

But to summarize: All the empirical evidence one needs is the picture of the CMBR, with its almost ideal homogenity, but also with its small inhomogenities, which have nonetheless a large size. This picture is incompatible with a theory which assumes a''(t)<0 all the time, simply because in this case no causal mechanism exists which could explain the homogenity as well as the fluctuations on such a large scale.

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13. danshawenValued Senior Member

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I was under the impression that inflation proceeded faster than light in a vacuum, which is an issue all by itself.

Even if you were an observer positioned outside of the area of inflation from a vantage point of 10 billion light years, you could not even verify whether or not it had expanded that fast, because by the time the flash of creation catches up to you, it's not only over: there wasn't even enough time for there to ever be a photonic record of the event left behind after it unfolded. One moment there is nothing to see; the next, it has already formed and is living large.

If you watched it all happen again today, what you would not see is considerably more of the process than what you would, taking science beyond the range of our instrumentation and senses and into the realm of superstition and magic. That's a problem alright. Of the rabbit out of a hat variety.

This is a way of saying what was referenced in the last post without Minkowski light cones.

Last edited: Aug 7, 2015
14. originHeading towards oblivionValued Senior Member

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Why?
Huh? The universe inflated, how could an observer be outside of the universe?

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15. SchmelzerValued Senior Member

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If the universe is large enough, and one computes the "velocities" of far away galaxies assuming that the rulers do not shrink, that means, in the standard expanding universe picture, then the velocity is proportional to the distance, so, becomes as large as one likes, with large enough distance, and certainly greater than c. And no inflation is necessary for this, a small expansion is sufficient - as small as one likes.

But, of course, this way to compute a velocity of expansion means nothing physical. In the shrinking ruler interpretation of the expansion this "expansion velocity" is simply zero. And the velocities related with the shrinking of some local rulers are quite small.

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16. danshawenValued Senior Member

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Perhaps the observer was a remnant of another universe. Besides which, it would be equally ridiculous to think of an observer viewing it happening from the inside.

The point is, the whole process is over in less time than it would take for any part of it to actually be viewed affter the fact. Such a process would destroy information about whatever happened more effectively than a black hole.

17. danshawenValued Senior Member

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So inflation at superluminal speeds entails a complete destruction of information (the horizon problem) beyond which no science or knowledge of whatever came before is possible, including I would presume, any energy levels associated with any subsequent phase changes. Not all that elegant, but convenient, if you wish to suggest this would result in the creation of a super force.

Except for what we know about gravity getting out of black holes, and that energy black holes may exist with none of the other fundamental forces other than EM working inside of it. The EM would not break the gravity even if the entire universe mass / energy were concentrated there, particularly if dark matter and dark energy were there as well.

Perhaps a collision of the black hole with dark energy could explain whatever happened. Since evidently we can't see the source of that either, why not? Now we're back to the premise of an unstoppable force colliding with an immovable object. I can think of only one element missing. Can G-d make a stone so large that not even he can move it? And Voila! We arrive right back where Ptolemy started. With enough magic and superstition properly applied, literally anything becomes possible. These are what you get with any science which can never be tested. Supposition in its purest form.

And a perfect fit to a finite mind that must use symbols to communicate bits of an infinite whole truth, only empowered to falsify tiny pieces of its unity. Made in his or her image, there can be no doubt.

Last edited: Aug 8, 2015
18. brucepValued Senior Member

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Go to the WMAP site and research your query. They have discussions on cosmology for lay folks to the experimental literature associated with this great cosmological experiment. A couple of things from Alan Guth on Eternal Inflation theory.

Inflation would predict that there is an outside of this universe. What inflated was a soliton in a quantum scalar field. This quantum scalar field would be the inflation field.

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19. danshawenValued Senior Member

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If repulsive gravity exists, then instead of time dilation, as you would have for gravity which attracts, there would need to be time interval COMPRESSION associated with that, wouldn't there? By means of analogy, obviously. Once things get moving, the kinematic term dominates time dilation, but according to Guth's analysis, this effect is not even a consideration. Whatever else Guth had in mind, a second observer at rest with respect to inflation is not in there. It can't be, since inflation proceeds at superluminal speed.

Worse, inflation requires no second observer at rest in order to make its predictions about the way inflation proceeded with respect to time. You can't even do a relativistic analysis unless there is a second observer, that is unless you subscribe to the flawed ideas of autodynamics, a physics cult started by an obscure WWII era Italian physicist who immigrated to Argentina, and whose ideas about single observer relativity were carried forward for the next 40 years by lunatics and fellow Einstein haters like David de Hilster.

Yet Guth speaks of inflation as an expansion that is GEOMETRIC in LINEAR time (as in time which proceeds as if there were no time dilation at all). At least he realizes, it would need to start out at low density. So much for any semblance of energy conservation.

I see no justification for the idea of repulsive gravity in anything Guth says. We already know from experiments that antimatter exhibits the same normal attractive gravity which matter does. We already know that black holes with masses in the range of 100 trillion galaxies the size of our own seem to have had attractive gravity and have been sucking in surrounding mass for in excess of 10 billion years, in which case, the repulsive gravity of inflation would have prohibited its formation in the first place. Or does not attractive gravity interact with repulsive gravity at all? By means of this test, inflation theory already does not stand up to experimental and observational muster.

It doesn't work. No surprise, quantum gravity doesn't work either, or at least not as well as GR. Any theory which ignores time dilation or just time in general is not a likely candidate for a theory that explains much of anything. If you don't have a clue what time is, what really are the chances of understanding gravity?

Try again.

Last edited: Aug 9, 2015
20. wellwisherBannedBanned

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If you look at GR, changes in local space-time (or space-time well) are only dependent on changes in mass and/or distance. They are not dependent on time. We can change the mass and/or distance slowly or quickly in time. We can do it discontinuously or continuously in time, or even in a quantum way in time where we skip time; quantum pauses. The resultant space-time reference will be the same in all cases. GR is not time dependent, even though the time in space-time will change. Space-time is a dependent variable that is dependent on mass and distance but not time.

If we zero out distance in GR, but change mass; increase or decrease mass, space-time will still change. This is analogous to the massive primordial atom, or a black hole. If we zero out mass but vary distance, space-time does not change. This would be like changing the observation volume within empty space. This mental exercise does not impact space-time in any real way. This analysis implies the hierarchy within GR is mass, then distance, then time; MDT.

Most models of the BB use the wrong hierarchy to explain inflation and BB. Time is not as important in GR as mass or distance. The same inflation can occur in any time period or sequence in GR, to get the exact same post inflation space-time reference. Most models assume a distinct tiny increment of time is needed, which is done for drama, not for GR, since GR is not about time, until after the fact (space-time).

21. danshawenValued Senior Member

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wellwisher:

The density (mass per unit volume) has a huge effect on the surface acceleration that is due to gravity, and therefore, by means of the principle of equivalence, the amount of time dilation at a given distance from a gravitating body.

Guth has referenced time needed for inflation to double size without even referencing.a frame in which it is measured. The whole dang universe is in there. It's not an insignificant detail, even for a general audience. Leaving it out gives the impression that he did not consider it even in small measure. Sorry, I'm not gullible enough to believe any part of this theory is worth tossing out other theories that have withstood more criticism for twice as long as the time between discovery of the CMBR and Guth's theory of inflation.

A quantum field which expands with no reason, giving rise to a universe full of recognizable matter and energy limited in their propagation by c some time later, is really a steady state theory anyway. If its creation was superluminal, there should be superluminal things still in it. Are there? How could you tell? As an adjunct to the Big Bang theory, this is not credible. At least the BB only violates one law of physics. Inflation violates a lot more than that.

Last edited: Aug 9, 2015
22. wellwisherBannedBanned

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I was not discounting the BB or inflation. I was only pointing out that in GR, changes in space-time are not dependent on time. Rather they are only dependent on mass geometry; mass and distance. Acceleration, due to gravity, which does contain the units of time, is also dependent on final mass and distance. One can vary the time at which mass and distance change toward steady state, with the final space-time reference and acceleration due to gravity always the same.

If we zero out distance and change only mass; mass point, space-time reference will change independent of changes in time and distance. If we zero mass, but alter distance nothing happens. The hierarchy behind space-time is mass first, then distance, but not time, per se. There is an explanation for this that requires a quantum universe.

23. danshawenValued Senior Member

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It does not violate relativity for something as large or with as much mass / energy as our entire universe to seem to pop into existence out of thin vacuum provided that that proceess was some sort of collision (elastic, inelastic) of one universe with another of equivalent or nearly equivalent mass/energy. Under those conditions, conservation of energy is satisfied because the energy exchanges would mean, from the frame of reference of one of those colliding universes, that the energy needed for Guth's superluminal inflationary period comes from the acceleration (deceleration) of one of those universes with respect to the other. And like the Big Bang, you would not even see such a collision coming until it arrived and you were in the middle of it.

The inflationary period would indeed appear to be superluminal in terms of the relative rates of Lorentz expansion for an object the physical size of a universe slowing to near rest with respect to another such universe quite abruptly. There is no limit imposed by relativity on the rates of length expansion caused by any such decelerations. This is a relativity thought experiment I do not believe anyone has yet proposed, but superluminal rates of expansion might actually be physically possible by means of such an interaction. I'm thinking BIG instead of HOT. No superforce or quantum field expansion is necessary to this model. It recreates Guth's inflation without breaking any laws of physics, nor creating any new or exotic forms of matter or energy.

Models of what happens when galaxies like the bullet cluster collide would be a model of what happened, but on a much smaller scale. Dark energy would simply be a remnant of accelerations which were present before the collision, and the search fir the nominal value of the cosmological constant continues because it has nothing to do with the minuscule collision which created our universe. No doubt, our universe was a bit more compactified when the collision occurred.

The WMAP and Planck data would reveal nothing out of the ordinary for any universe, which, from its point of view, was steady state to begin (and also end) with. 13,7 billion years at rest with respect to our point of view can obscure a lot of forensic ballistic evidence.

There is even a perch from which G-d can sit and observe, or even orchestrate the entire interaction. What more could anyone ask of any creation theory?

Last edited: Aug 10, 2015