Standard Cosmology and Thermodynamics

[Buffy]

...or a multi-verse model, which is the direction I lean!

There is absolutely zero empirical evidence to support the multiverse model; nor is there any qualitative or quantitative necessity for it.

Huh?Unless you subscribe to a steady-state model--for which there are at least as many counter examples as are claimed against BB--then if you say that there's "something missing to explain why a bang occurred"--which was the proposal being discussed above--then there's *obviously* a "necessity" for it (or some other probably currently "empirically unprovable" theory).

 

To say otherwise is merely being self-servingly obtuse! :)

 

Vegetarianism is harmless enough, although it is apt to fill a man with wind and self-righteousness, :)

Buffy

[coldcreation]

 

...or a multi-verse model, which is the direction I lean!

 

There is absolutely zero empirical evidence to support the multiverse model; nor is there any qualitative or quantitative necessity for it.

 

Huh?Unless you subscribe to a steady-state model--for which there are at least as many counter examples as are claimed against BB--then if you say that there's "something missing to explain why a bang occurred"--which was the proposal being discussed above--then there's *obviously* a "necessity" for it (or some other probably currently "empirically unprovable" theory).

 

True, within the context of my own personal beliefs there is no qualitative or quantitative necessity to add anything to the BBT (such as inflation, multiverse, etc.), since the entire theory should be abandoned, axe-canned, and replaced by: Not by something even more untenable, but by a model that is altogether more in accord with what is observed in nature (both macroscopically and microscopically).

 

I do realize that the big bang-hardliners (like Hawking) won’t give up an agenda that is essential to the BBT survival. For them, (initially at least) the false vacuum was set sail under false pretenses, and now it’s time to pull the plug. Surely something else has to be cooked up. For every drain you find yourself sucked through, there is another gurgling underneath.

 

Like so many others with an ageless talent for bending the rules, Guth (and, yes, Linde) more or less abandoned the standard model along with the restraints imposed by the British administrative system, i.e., Hawking. It was deteriorating hard and fast and was now a sorry sight. It seems he had placed his hand deliberately on a hot pan; he had stretched his dough to far. Inflation had become a raucous hen party. Inflation had become a battlefield for competing groups, the setting for a primordial brawl, a fight for Ground Zero, a primeval struggle for food.

 

Whether or not the new inflationary model solves the problems for which it was conceived is arguable, and far less significant than one might presume. Both standard inflation as well as the multiverse concept (e.g., chaotic inflation, open inflation or eternal inflation) create such insurmountable problems that the others, intrinsic to standard BBT, appear trivial in comparison.

 

Linde’s high-flying quasi-stateless nomadic spirit has created the so-called multiverse. Something as unique as a big bang universe didn’t seem natural to him. So he repeated it (over and over again). He made a series of patterns, different universes, with different laws, different rules, and different models all wrapped up into one multi-extravaganza.

 

The original ballsy inflation had sexily metamorphosed into an irresistibly trendy Belle du Jour, in a sequin of bubble universes, each with different colors immersed in a vast, frothy sea of eternally expanding false vacuums. It seemed the only way to rid the standard BBT of its problems, notably, the break-down of energy conservation and entropy non-decrease (the first and second laws of thermodynamics), but all the other laws as well.

 

 

Prevention is better than cure

 

 

Or so it was thought. That's when Hawking and Neil G. Turok (during the 1990s) stepped up to the plate. They had something better, something newer and far-out. They suggested to their parishioners yet a fourth type of inflation: the spontaneous creation of an open inflationary bubble from nothingness that detours the need for false vacuum decay—in this way killing the former version. (Vilenkin and Linde of Stanford University have disputed their assumptions in the calculations). The universe still goes through its rapid acceleration at the outset, only now, the authors seem to be caught up in an oil-for-food probe.

 

 

 

 

To say otherwise is merely being self-servingly obtuse! :)

 

 

You may have a point here. Again, I do understand that something is missing from the standard model, even with inflation. But I never did like inflation. Hawking hated inflation too. It seemed every new inflation model that entered the arena was wackier the predecessor, each seemed to offer more razzmatazz than the last. Years before he had locked it up and thrown away the key, but not for good. It was back, and this version was now his.

 

Turok shared Hawking’s sense that the false vacuum was an appalling gag from which neither could break free. So Hawking, too, a zealot dreaming of a Greater Cosmology, took action. And here is where Hawking made a catastrophic mistake (not to use the term blunder): he acquiesced. Open inflation is a mournful (laughable) reminder of what happens when a physicist acquiesces in the face of his own militants.

 

Hawking manages to incarnate a more dramatic inflation: his is open. Yet his quest to reconcile the irreconcilable has ended up, too, with a universe (or many of them) that pops into existence from nothing, and thus has ended up standing for nothing very clear. Or rather, Hawking stands as an equivocator in his eternal dance between acceptance and rejection, between Church and State, between physics and new physics, and just about everything else, for the circumvention at all cost of the breaking apart of the canonical hot big bang cold-dark-matter camp (with some form of inflation to wipe out the problems) Hawking reckons is crucial.

 

 

After all, when the enemy is in your own camp nothing is worth fighting for.

 

 

In sum, the multiverse concept is not a reasonable response to the problems of the big bang, just as the use of metaphysics is not a reasonable response to unphysical aspects of metaphysics. So, is it better to discard a model that basks in an aura of disappointment and futility or add an appendage onto it that too basks is the same aura?

 

 

 

Vegetarianism is harmless enough, although it is apt to fill a man with wind and self-righteousness, :)

Buffy

 

 

Here, we are in total agreement. The stakes are high. But this is all holistic vegetarianism and Feng-Shui cosmetics; let’s get down to the meat of the subject. There is no meat, only indigestion related gastric disturbances, noise.

 

With a certain obvious logic, lost to some modern vegans, inflation and multiverse concepts are poor substitute for the skilled shopping of the past.

 

 

 

It’s time to freeze the funds.

 

 

 

 

CC

[Buffy]

True, within the context of my own personal beliefs there is no qualitative or quantitative necessity to add anything to the BBT (such as inflation, multiverse, etc.), since the entire theory should be abandoned, axe-canned, and replaced by: Not by something even more untenable, but by a model that is altogether more in accord with what is observed in nature (both macroscopically and microscopically)....

 

I do realize that the big bang-hardliners (like Hawking) won’t give up an agenda that is essential to the BBT survival....

 

Like so many others with an ageless talent for bending the rules, Guth (and, yes, Linde) more or less abandoned the standard model...

A very eloquent but essentially content-free exposition using the most pejorative language possible! Bravo! Quite a mastery of the persuasive arts you have there!

 

Carry on...

 

I don't like country music, but I don't mean to denigrate those who do. And for the people who like country music, denigrate means 'put down', :)

Buffy

[coldcreation]

A very eloquent but essentially content-free exposition using the most pejorative language possible! Bravo! Quite a mastery of the persuasive arts you have there!

 

Carry on...

 

I don't like country music, but I don't mean to denigrate those who do. And for the people who like country music, denigrate means 'put down', :)

Buffy

 

I certainly did not intend to denigrate those who support the multiverse hypothesis. There is nothing personal about it.

 

I simply expound that modern cosmology does not have a single convincing narrative as to how the multiverse might work. It is one thing to denigrate a metaphysical idea — recall that this is how Einstein's lambda was treated until the late 1990s — another to say how it can be remade to meet new realities and threats on the observational front. To state there must have been more than one big bang is not enough.

 

 

As far as Guth or Linde are concerned; their creative merit lies in the ability to recognize and acknowledge that what they have invented will elude forever the physical world (recall the “implausible” fine-tuning).

 

In 1980 (during the inauguration of the Iran-Irak war) Hoyle and Narlikar presented their ideas concerning the quasi-religious doctrine of the hot-short-tempered beginning: “Many people are happy to accept this position. They accept [the big bang picture] without looking for any physical explanation of the abrupt beginning of the particles. The abrupt beginning is deliberately regarded as metaphysical—that is, outside physics. The physical laws are therefore considered to break down at t = 0 and to do so inherently...To many people, this thought process seems highly satisfactory because ‘something’ outside physics can be introduced at t = 0.

 

My personal view-point: The laws of physics (thermodynamics included) should never break down, but they do inherently at t = 0. So your sentence,

"I have always preferred to view this "special case" as not at all special: the beginning was the one time--at least so far--when the universe was not a closed system, and thus would by definition not be breaking the conservation law"

is optimistic soul-searching, wishful thinking even.

 

Let's face it, the 'primeval atom' (t = 0) is something that can neither be fully understood nor overcome by rational prudence. Call it what you will: a cryptic malevolent, a hidden God, blind fate, solicitations from hell, or the brute fury of Chi.

 

The legend holds us not through its adoring savor, not through the beauty of some bygone era, not through observable consequences, but because it exorcises something absolute that exists deep within ourselves. Sure, Father Lemaître tested the idea of destruction to the limits of Creation. And what came through in the beginning is a primal force, the mother of all explosions. There’s just one snag. The house of delusions has not yet been illuminated.

 

 

 

Creation and destruction are twins, as once were love and justice…Like the Sphinx with its missing nose it must attend the mutilations of time before it can capture the eye of the poet (Henry Miller).

 

 

 

CC

[Erasmus00]

My personal view-point: The laws of physics (thermodynamics included) should never break down, but they di inherently at t = 0. So your sentence, is optimistic soul-searching, wishful thinking even.

 

This is asked and answered. If there was a beginning (a true t=0) of time, we EXPECT that the conservation of energy must break down, as the conservation of energy states, essentially, that we aren't at a special place in time. You never directly respond to this, but its true. This criticism is essentially meaningless. I really suggest reading up on modern mechanics (try Landau and Lifshitz volumes 1/2 for a terse but insightful overview of modern classical mechanics/classical field theory).

 

Now, the other criticism you lob that is without merit is that the big bang is metaphysical, i.e. no physics can describe it. This is not true- we expect that the "singularity" at the beginning is a sign that GR is breaking down and we need a full theory of quantum gravity. This is why there exist (speculative) theories that DO allow descriptions of the beginning. Both string theory and loop quantum gravity, though speculative in that neither has been shown to be THE theory of quantum gravity, do have things to say about such singularities.

 

Let's face it, the 'primeval atom' (t = 0) is something that can neither be fully understood nor overcome by rational prudence. Call it what you will: a cryptic malevolent, a hidden God, blind fate, solicitations from hell, or the brute fury of Chi.

 

This is exactly what I'm talking about above.

-Will

[modest]

It seemed the only way to rid the standard BBT of its problems, notably, the break-down of energy conservation and entropy non-decrease (the first and second laws of thermodynamics), but all the other laws as well.

 

Three threads and hundreds of posts later, I still haven't seen the math or physics or observations to back this up. BBT does not violate the laws of thermodynamics. The thought has been squashed by different people many times. The foundation for these rants is hollow. Perhaps you could simply and clearly explain how the BBT describes decreasing entropy? Or, how the arguments against the claim are wrong? Could you use some physics or perhaps the thermodynamic equations to prove your claim?

 

Make me a believer.

 

-modest

[coldcreation]

... If there was a beginning (a true t=0) of time, we EXPECT that the conservation of energy must break down,...

 

 

This is well known, and echos what I have been saying from the outset.

 

Note; the fact that we EXPECT the break-down of energy conservation does not make it OK.

 

 

Note too that in my opening post it was linked The TalkOrigins Archive, within which it is written:

 

Assuming we have some way to handle notions of time outside of our spacetime' date=' the universe appearing out of nothing would only violate the first law of thermodynamics if the energy beforehand were different from the energy afterwards. Probably all people will agree that "nothingness" should have an energy of zero; so the law is only violated if the energy of the universe is non-zero. But there are indeed good arguments that the energy of the universe should be exactly zero![/quote']

 

In this sense, we are both correct (mistaken). No one knows...

 

Are not both concepts equivalent to a free lunch?

 

 

 

“Maybe a person's time would be as well spent raising food as raising money to buy food.” Frank A. Clark.

 

 

 

... as the conservation of energy states, essentially, that we aren't at a special place in time. You never directly respond to this, but its true. ...

 

 

I didn't think I needed to respond to this.

 

I have always been one to believe, like Buffy in a sense, that there is no special place or time in the universe, where the laws of physics are said to be different, non-applicable, irrelevant, useless, replaceable.

 

Notwithstanding, ‘emptiness’ by some means converted itself into a high-energy state of extreme density and enormous heat, about fourteen billion years ago. This is the first truly artful portrayal of an explosion (not into space, but of spacetime iteslf), something that germinates from nothing. In this model there is no chicken or egg, but, all of a sudden, the Herculean turkey appears out of nowhere. All attempts to determine what might have been the ignition source of the initial firestorm have been disappointing. The notion had planted itself in the scientific eye, where it festered until a few cosmologists started to complain.

 

 

And complain they did.

 

 

 

Now, the other criticism you lob that is without merit is that the big bang is metaphysical, i.e. no physics can describe it. This is not true- we expect that the "singularity" at the beginning is a sign that GR is breaking down and we need a full theory of quantum gravity.

 

That was no lob. It was a bullet that went straight to the heart of the big bang event itself (which would be removed from the BBT for the very reason of its metaphysicality). Without merit it certainly was not.

 

That t = 0 was removed from the BBT is proof enough, not that Einstein's general postulate is incapable of describing the event due to its break-down, but that the theory itself (which was in some ways derived from GR) is inconsistent with the fundamental laws of physics.

 

The idea that a full theory of quantum gravity is need is certainly an understatement.

 

 

 

This is why there exist (speculative) theories that DO allow descriptions of the beginning. Both string theory and loop quantum gravity, though speculative in that neither has been shown to be THE theory of quantum gravity, do have things to say about such singularities.

 

 

With such theories as inflation (you choose the version), quantum loop gravity, string theory, etc., late twentieth-century cosmology (with its new physique) was about to manifest its own destiny. It was to become nothing more and nothing less than fiction pure and simple, words on a page, literature undamaged by observation, there was nothing to be seen, to be felt, to be touched, tasted or smelled. It was invisible, pure imagination, nihilism, empty, godlike, vacuous, flat, naked beyond words, beyond reason, beyond nature.

 

Nothing was impossible anymore. And yet, the final frontier had not been attained. There was still no unified theory of quantum gravity, no theory of everything. String and inflation could not be absorbed into the standard model, and the big bang still had all its defects. This is finally, then, a fable far more forbidding than sought-after and, in a sense, a constructive introduction as to why things appear so gloomy at this point in time, and what to do about it.

 

The error of thinking that new physics represented, both in practice and in principle, was to transcend with artificial convention the very essence of what it was supposed to accomplish: the development of a better understanding of nature and how evolution could have lead to what is observed in the environment.

 

Religion, metaphysics, numerology, gastrophysics, wanton melodrama, Dadaistic forces and surreal dimensions conspire to produce a succession of completely gratuitous (and how!) problematically interconnected scenes dependent on one imperceptible common denominator, elevated not by its lack of rigor to the status of pure, unadulterated art.

 

 

A sublime masterpiece was born

 

 

 

CC

[coldcreation]

Three threads and hundreds of posts later, I still haven't seen the math or physics or observations to back this up.

 

I only count two threads.

 

BBT does not violate the laws of thermodynamics. The thought has been squashed by different people many times. The foundation for these rants is hollow. Perhaps you could simply and clearly explain how the BBT describes decreasing entropy? Or, how the arguments against the claim are wrong? Could you use some physics or perhaps the thermodynamic equations to prove your claim?

 

Make me a believer.

 

-modest

 

Regarding the first law of thermodynamics see the above post (#58).

 

 

Back in my opening post, regarding the second law, it was written in Evidence for the Big Bang:

 

Indeed' date=' as shown by Kolb & Turner, the entropy of the early universe was extremely low. This makes sense if one remembers that, in the very early stages of the universe, the distribution of matter and energy was very, very ordered, as demonstrated by the uniformity of the CMBR. [/quote']

 

I have not yet read Kolb & Turner on this subject, but I have read Pagels, who writes:

 

Entropy is a thermodynamic quality of matter' date=' defined by the degree of disorder (randomness) of a system. It is known to increase with time. When applied to the universe as a whole, the entropy should have been very low to begin with, and increased with time. By deduction, the universe must have been a very ordered system in its very early stages. Why? Entropy is essentially a conserved quantity in an expanding universe. The conclusion must be that the entropy of the universe has always been huge. The standard models do not explain why (Pagels 1985). [/quote']

 

First, the use of the CMBR as proof or evidence that the entropy of the very early universe was low is too massive an extrapolation to take seriously into consideration. The CMBR is no such demonstration.

 

Indeed if entropy increases with time it should have been very low during the very early stage(s) of a big bang universe, as Kolb, Turner and Pagels state.

 

However, I have yet to see the physics as to how a universe that is blowing apart at the seams—with extent temperatures in excess of 10 billion degrees Kelvin, where antimatter and matter annihilate (asymmetrically) to form gamma rays (if that is what happened), where protons and neutrons are formed from free quarks and gluons, when after one minute of cooling, baryons combine to form the nuclei of deuterium (3), helium (4), and lithium (7)—has extremely low entropy, how this state (where "the distribution of matter and energy was very, very ordered") could have been uniform. It sound like a chaotic, random, disorder mess to me. Certainly within the context of classical thermodynamics, where the change in entropy represents the amount of energy input to the system, that state would not qualify as one of low entropy.

 

Within the context of statistical mechanics—where microscopic constituents of the system play an important role, where the kinetic energy of each molecule in the system defines a microstate, and where temperature T of a system defines a macrostate, where the entropy becomes a function of statistical probability, where entropy is a measure of the macrostate probability; where high entropy means a high probability state, and a low entropy indicates a low probability state—the low entropy necessity at the outset of a big bang universe seems exceedingly unlikely.

 

As such' date=' one could characterize the entire distribution of matter and energy in the universe with a single number (the temperature) to a very good approximation. [/quote']

 

This phrase goes against everything I've ever read regarding entropy.

 

 

Compare that to the universe we see now' date=' filled with complicated, disorderly distributions of galaxies, stars and gas. The amount of entropy in these objects is enormous (recall our earlier discussion about the lack of coherent orbits for stars in elliptical galaxies and galaxies in galaxy clusters). [/quote']

 

There are those who consider the distribution of galaxies ordered, and others disordered. The above argument seems to go against the mathematical definition for entropy. There are those who consider entropy a measure of the disorder of a system, and other a measure of the order a system.

 

 

Hence' date=' the idea that the entropy of the universe has somehow decreased in violation of the second law of thermodynamics is largely nonsensical.

 

Given that the entropy of the universe has only increased, how did it get such a low entropy when it came into being? [/quote']

 

Good question.

 

 

At the current time' date=' this is still an open question in cosmology. Obviously, many of the problems we outlined in the previous section regarding time before the Big Bang and the applicability of physical laws at the origin of the universe come into play here, but there is, as of yet, no simple answer. [/quote']

 

It seems that is where we stand today.

 

 

 

CC

[modest]

I think it might be helpful to recap the essence of (at least one) aspect of this discussion so far without all the tangents or animal, religious, tao, zen, and devil analogies attached to the Big Bang. Here are some quotes in order of appearance - I absolutely tried not to take them out of context which should be obvious.

 

Clearly, the universe according to the canonical-hot-big-bang-DE-CDM expansion hypothesis the universe is heading straight toward a state of absolute zero temperature (the big freeze) as time t tends to infinity, where entropy is equal to zero.

 

Entropy is a decreasing property in an expanding universe. It starts out rediculously high and tends to zero with time t.

coldcreation,

you do make a good point about T approaching infinity… Would that make S infinitely small? We would have to account for volume and pressure being infinites as well

You could ask the same question for any gas/fluid expanding. I.e. as a gas undergoes adiabatic expansion, as t gets large T gets small. Does this mean entropy is decreasing?

-Will

Certainly.

 

It means that entropy is decreasing. I can only conclude that the second law is violated within the context of the Lambda-CDM model (note: two of the Friedmann models had the same problem, the open and critical models).

 

Will entropy in an expanding universe ever reach zero? Probably not. Entropy will tend to zero with time t. But either way, the second law still seems to be violated.

 

 

Is there something I'm missing? How could this be?

Not at all. By definition, the adiabatic nature of the expansion means entropy is a constant, even as the temperature falls. How is this possible? Entropy ALSO depends on volume.

 

Hence, even though an object is cooling quickly, if the volume is very large (and growing) entropy can increase. Even very close to absolute zero, a very, very large volume could lead to a huge entropy.

-Will

 

Here CC changes his position deciding that the issue is now too complex to solve with an expanding gas model and, as far as I can tell, has not made the BBT-tends-toward-zero-entropy argument again.

However, we were discussing entropy in the real world where it is observed the formation of stars and galaxies, not the dispersion (to the same extent) of gas and dust into a smooth background, as depicted in the box experiment.

 

In other words, the rudimantary picture drawn by the box experiment is insufficient for the broad understanding of what is entropy and how entropy manifests itself in this observable universe.

 

The argument then moves on to "what came before the big bang" and "something from nothing violates the first law"

 

But, it is of interest to me how hundreds of posts over multiple threads comes down to such a simple mistake "hey, you're forgetting about pressure-volume work"

 

I hope people can see the forest for the trees -

 

-modest

[modest]

I only count two threads.

Well, I guess I was counting Big Bang Blasted where this whole thermodynamic question got started. But 2 is probably a more accurate number.

 

 

At the current time, this is still an open question in cosmology. Obviously, many of the problems we outlined in the previous section regarding time before the Big Bang and the applicability of physical laws at the origin of the universe come into play here, but there is, as of yet, no simple answer.

 

It seems that is where we stand today.

CC

 

Well, if we have gone from:

• the BBT absolutely violates all three laws of thermodynamics

to:

• thermodynamics is still an open question in cosmology

then we are on the right track.

 

But I think it would be a mistake to forget that entropy on a global level is a relative term. The only value the entropy of the early universe can be compared to is entropy of the later universe. And, the only way to compare entropy today and a short time after the BB is to also factor in the enormous expansion involved. The enormous negative-pressure-work done on a universal scale compared to the work done by gravity giving the universe order on a global scale would be hard to calculate in thermodynamic equations for many reasons - some of which are unknown variables.

 

However, the point is that such a description of unfolding events does not violate the thermodynamic laws at face value. The variables are inversely proportional and could lead to somewhere around no change in entropy - or an increase.

 

-modest

[Erasmus00]

Note; the fact that we EXPECT the break-down of energy conservation does not make it OK.

 

You are missing the point (again). Perhaps willfully.

 

I have always been one to believe, like Buffy in a sense, that there is no special place or time in the universe, where the laws of physics are said to be different, non-applicable, irrelevant, useless, replaceable.

 

No one is saying that the laws of physics are irrelevant, etc. What I am saying is that one specific symmetry breaks down, and without this symmetry there is no conservation law, and no reason to expect a conservation law.

 

Buffy was referring to models where we postulate some larger geometric space outside the universe, and we can rescue the symmetry by embedding our idea of "time" with some larger dimension in the higher geometry. This means that even without "our" time there is a reason for an energy-like conservation law. However, there is no reason to assume this has to be the case (though it is interesting). Quantum gravity will allow for us to penetrate a little further back, and maybe some questions will be answered. Unfortunately, quantum gravity appears to still be a long way off.

 

That t = 0 was removed from the BBT is proof enough, not that Einstein's general postulate is incapable of describing the event due to its break-down, but that the theory itself (which was in some ways derived from GR) is inconsistent with the fundamental laws of physics.

 

Asserting this doesn't make it so. Einstein's GR is not a quantized theory, so it breaks down for things that are "small" (on the order of the plank length, most probably). GR simply cannot describe something like the very, very early universe. This is the only reason we cannot describe the "singularity." This is also the reason that both string and loop quantum gravity guys DO try and discuss this.

 

The idea that a full theory of quantum gravity is need is certainly an understatement.

 

In what way is this an understatement? It seems to me to be a statement of fact.

-Will

[coldcreation]

 

I have always been one to believe...that there is no special place or time in the universe, where the laws of physics are said to be different, non-applicable, irrelevant, useless, replaceable.

 

 

No one is saying that the laws of physics are irrelevant, etc. What I am saying is that one specific symmetry breaks down, and without this symmetry there is no conservation law, and no reason to expect a conservation law.

 

The fact is, the laws of physics do become useless, irrelevant. There is no reason to expect that physics breaks down or changes depending on and according to the whims of a theory.

 

 

... Quantum gravity will allow for us to penetrate a little further back, and maybe some questions will be answered. Unfortunately, quantum gravity appears to still be a long way off.

 

 

In light of the serious deficit or incompatibility with the BBT and the empirical laws of physics (based on or characterized by observation and experiment rather than on theory, derived as knowledge from experience, sensory observation and with the application of logic) it strikes me as curious why it would be preferable to change the laws rather discard the theory (void of empirical backing).

 

 

... GR simply cannot describe something like the very, very early universe. This is the only reason we cannot describe the "singularity." This is also the reason that both string and loop quantum gravity guys DO try and discuss this.

 

 

The aim of this debate, and in fact the crux of my participation in this forum, is to open an objective discussion of the evidence, or lack of evidence, that supports or undermines the standard model, our interpretations, and our uncertainties (particularly regarding thermodynamics); not based on a dogmatic proclamation of unconditional truth based on some future theory that may never materialize, but to open locked doors that will lead to fresh insight, or at least indicate the most hopeful direction and method of exploration; and which hold the most promising potential for reaching a solid conclusion in the future.

 

 

 

 

Now, the other criticism you lob that is without merit is that the big bang is metaphysical, i.e. no physics can describe it. This is not true- we expect that the "singularity" at the beginning is a sign that GR is breaking down and we need a full theory of quantum gravity.

 

 

The idea that a full theory of quantum gravity is needed is certainly an understatement.

 

In what way is this an understatement? It seems to me to be a statement of fact. -Will

 

The idea that a full theory of quantum gravity is needed is an understatement for several reasons: your statement expresses less strongly or strikingly the gravity of the situation than the facts would bear out. You set forth defending the big bang by rhetorically denying it's metaphysicality, even though a quantum theory of gravity capable of rendering IT physical does not exist.

 

The idea that a "singularity" at t = 0 is simply "a sign" that GR is breaking down is a statement that is restrained in ironic contrast to the fact that the break-down of GR close to t = 0 is absolute and unequivocal. It is no sign, it is a billboard.

 

Your restrained, moderately termed phrase: "a singularity at the beginning is a sign that GR is breaking down," is less than complete, it understates the extent of the disaster. It is not only GR, but QM, thermodynamics, all the conservation laws, along with every other fundamental law of physics that breaks down. So even if a quantum theory of gravity was found capable of rendering the big bang physical—I wouldn't hold my breath in anticipation—the problem related to the rest of physics (thermodynamics included) would still persist.

 

My point is that the laws of physics, GR, QM, thermodynamics and the conservation laws DO NOT break down since there is NO "special" place or time in the universe. It is the BBT that breaks down, nothing more, nothing less.

 

 

 

 

CC

[Erasmus00]

The fact is, the laws of physics do become useless, irrelevant. There is no reason to expect that physics breaks down or changes depending on and according to the whims of a theory.

 

No one is claiming that the law of physics break down, merely ONE symmetry. Even in standard Newtonian mechanics if we have something that breaks the symmetry in our system (friction, for instance)mechanical energy isn't conserved anymore.

 

In light of the serious deficit or incompatibility with the BBT and the empirical laws of physics (based on or characterized by observation and experiment rather than on theory, derived as knowledge from experience, sensory observation and with the application of logic) it strikes me as curious why it would be preferable to change the laws rather discard the theory (void of empirical backing).

 

Because we understand conservation of energy, we know when, and how to apply it. A true "beginning of time" would be a situation where we don't apply it. We aren't at all changing the laws, we are applying them correctly. I'd once more recommend picking up a classical mechanics textbook (Landau's for instance, is very good).

 

The aim of this debate, and in fact the crux of my participation in this forum, is to open an objective discussion of the evidence, or lack of evidence, that supports or undermines the standard model, our interpretations, and our uncertainties (particularly regarding thermodynamics);

 

If the big bang model violated known physics it would be thrown out. It does not. I'd recommend, strongly, learning thermodynamics on a mathematical level (again, I strongly recommend Landau). This is preferable to relying on quotes out of context from experts.

 

You set forth defending the big bang by rhetorically denying it's metaphysicality, even though a quantum theory of gravity capable of rendering IT physical does not exist.

 

The fact that the theory breaks down doesn't make it unphysical, especially because the "breakdown region" is small, and we are aware it is breaking down. We also know from other things that GR and quantum field theories aren't really compatible. Its not as if this breakdown were pulled, ad-hoc, to save the big bang.

 

It is not only GR, but QM, thermodynamics, all the conservation laws, along with every other fundamental law of physics that breaks down

 

This is simply not true. If you had a theory of quantum gravity, you would avoid the singular curvature and it would be business as usual. The problem is that GR determines the "backdrop" on which physics takes place.

 

My point is that the laws of physics, GR, QM, thermodynamics and the conservation laws DO NOT break down since there is NO "special" place or time in the universe.

 

Then present a steady state model that allows for this. You have made this claim many times, without ever really talking about the model. Until you present the theory you support, I see no reason to continue this discussion.

-Will

[coldcreation]

... The problem is that GR determines the "backdrop" on which physics takes place.

 

Yes, good point, that is why it's break-down in more-than-catastrophic.

 

My opinion (off-topic) is that more can be learned by studying the backdrop in the low-energy, ultra-low-temperature regime than by seeking a solution to something (on-topic) without a solution that violates its foundation in the ultra-high-energy, ultra-high-density, ultra-high-temperature regime.

 

 

My point is that the laws of physics, GR, QM, thermodynamics and the conservation laws DO NOT break down since there is NO "special" place or time in the universe.

 

Then present a steady state model that allows for this. You have made this claim many times, without ever really talking about the model. Until you present the theory you support, I see no reason to continue this discussion.

-Will

 

 

If I do that here, then this thread, too, will be relegated to the Alternative Theory section. So, the topic here is the standard model and its relation to the laws of thermodynamics — the third of which is still on the back burner, for now.

 

 

 

Cheers

 

CC