Strangeness Nuggets to Strangeness Condensation

[Chronos]

Earlier this week, I was reading this paper by Brown [of Brown and Bethe fame].
http://arxiv.org/abs/nucl-th/0504029
Title: Relation of Strangeness Nuggets to Strangeness Condensation and the Maximum Mass of Neutron Stars
Authors: Gerald E. Brown, Chang-Hwan Lee, Mannque Rho

It expands upon the equation of state that Smolin cites as a pillar of his CNS principle, and looks pretty solid. But reading between the lines, I see a more insidious result [for CNS], our universe favors the formation of neutron stars. I was daydreaming about this and the thought occurred to me - when/why do stellar cores collapse? And this thought popped to mind: when the mass density of the iron core exceeds the Chandrasekhar limit.

Somehow that made sense. It explains things like why neutron star masses cluster right around the Chandrasekhar limit.

 

[marcus]

Earlier this week, I was reading this paper by Brown [of Brown and Bethe fame].
http://arxiv.org/abs/nucl-th/0504029
Title: Relation of Strangeness Nuggets to Strangeness Condensation and the Maximum Mass of Neutron Stars
Authors: Gerald E. Brown, Chang-Hwan Lee, Mannque Rho

It expands upon the equation of state that Smolin cites as a pillar of his CNS principle, and looks pretty solid. But reading between the lines, I see a more insidious result [for CNS], our universe favors the formation of neutron stars. I was daydreaming about this and the thought occurred to me - when/why do stellar cores collapse? And this thought popped to mind: when the mass density of the iron core exceeds the Chandrasekhar limit.

Somehow that made sense. It explains things like why neutron star masses cluster right around the Chandrasekhar limit.

thanks for posting the link.
I will check it out.
I don't think the Chandrasekhar limit (about 1.4 solar) provides any kind of upper bound on the masses of a neutron stars that can form from a very massive star at its life's end. Nor does it an upper bound on the masses of neutron stars that grow by accretion.

But it is an interesting idea, we would need information on accretion mechanisms: If you could "turn off" the collapse to Black Hole possibility and imagine neutron stars growing without limit by accretion, sort of the way we see black holes grow in reality----accretion disks etc.---then might you not get supermassive neutron stars the way we now have supermassive black holes. Odd thought.

[strictly speaking have to qualify this by saying that the idea of a neutron star isn't so simple, people reckon they have "quark star" cores----dividing line between one type and the other is not clear. so just take "neutron star" to mean all that kind of thing up to but not including black hole]

the paper by Brown et al has a relevant bit about accretion:
"In this Section we briefly touch on astrophysical implications relegating details to a future publication [6]. The important astrophysical consequence of the low maximum NS mass is that the standard scenario for binary neutron star evolution [35] does not result in a double neutron star, but in a black-hole, neutron-star binary. In this scenario, after the first born neutron star is formed, it goes into common envelope evolution with the companion giant as the latter expands in red giant stage. During this common envelope evolution it accretes a substantial amount of matter from the hydrogen envelope of the giant companion, as it removes this envelope. Bethe and Brown [36] estimated this amount to be about 1Msol for a 1.4Msol neutron star, whereas with more accurate calculation [37] found 3/4Msol for this mass neutron star. The accretion is 0.5Msol for a 1.1 - 1.2Msol neutron star. Obviously these will be sent into black holes and the result will be a black-hole, neutron star binary. "

what Brown et all are talking about is that if collapse to BH wouldn't happen there is an extra accretion possibility of about 1 solar mass to be picked up right away just from the binary companion. Other kinds of accretion would depend on circumstances, like the normal material and other neutron stars encountered, and would thus vary. But this is all based on the unrealistic assumption that collapse is "turned off" whereas we know it occurs.

 

[Chronos]

Agreed, marcus. What I see is the possibility black holes evolve from neutron stars via accretion - and very rarely the direct result of a stellar core collapse. When you look at the mass distribution chart for neutron stars, it is remarkable how it clusters right around the Chandrasekhar limit.

 

[SpaceTiger]

Agreed, marcus. What I see is the possibility black holes evolve from neutron stars via accretion - and very rarely the direct result of a stellar core collapse. When you look at the mass distribution chart for neutron stars, it is remarkable how it clusters right around the Chandrasekhar limit.

With Type II supernovae, one might form neutron stars near 1.4 solar masses if the rest of the envelope is given sufficient kinetic energy to escape the collapsed core. If there is much fallback, however, one either gets a black hole or a more massive neutron star. However, as you said, neutron stars tend to cluster around the Chandrasekhar mass, so this implies one or both of the following:

1) Neutron stars have a very "soft" equation of state, meaning neutron degeneracy can't support much more than 1.4 solar masses.

2) There's little or no fallback.

Most of the people I hear talk about it seem to lean towards #1, but I've never heard people say that #2 isn't possible as well, so you could be right.

 

[marcus]

... If there is much fallback, however, one either gets a black hole or a more massive neutron star. However, as you said, neutron stars tend to cluster around the Chandrasekhar mass, so this implies one or both of the following:

1) Neutron stars have a very "soft" equation of state, meaning neutron degeneracy can't support much more than 1.4 solar masses.

2) There's little or no fallback.

Most of the people I hear talk about it seem to lean towards #1, but I've never heard people say that #2 isn't possible as well, so you could be right.

Basically the CNS premise is in line with what is #1 here.

a roundabout way of rephrasing is that if you could turn off black hole formation, then we would observe neutron (neutron/quark etc) stars of considerably higher masses which would have formed from
A. fallback in type II Sne
B. accretion during the binary partner's red giant phase
C. opportunistic accretion and merger
...and so on (I don't know enough to list all the possibilities)

The CNS idea is that parameters of the standard model have been iterated so that they are optimized for the formation of black holes. In effect, this predicts a "soft equation of state" for neutron stars. Finding even one neutron star whose mass reliably measured more than something like 2.5 or 3 solar would falsify CNS.

Postdictions as a range of basic constants (as well as a few actual predictions making CNS falsifiable) are discussed in
http://axiv.org/hep-th/0407213

 

[SpaceTiger]

The CNS idea is that parameters of the standard model have been iterated so that they are optimized for the formation of black holes. In effect, this predicts a "soft equation of state" for neutron stars. Finding even one neutron star whose mass reliably measured more than something like 2.5 or 3 solar would falsify CNS.

Yeah, I heard about this. It sounds like a cool idea and makes a lot of sense, if you ask me. I question its capability of making predictions in the long term, however.

 

[marcus]

Yeah, I heard about this. It sounds like a cool idea and makes a lot of sense, if you ask me. I question its capability of making predictions in the long term, however.

I don't understand what you mean by "making predictions in the long term".
Please repeat it in different words.
It actually has not so far achieved what I would call a startling success in making any predictions AT ALL (long term or short).
So far there is mostly this kind of lackluster prediction about a "soft" equation of state of neutron stars leading to some kind of upper bound of what masses will be observed.

My sense is that other predictions can be derived but not enough work has been done. Smolin discusses other kinds of predictions but he does not derive definite numbers, as I recall.

Do you mean that you have doubts that CNS will EVER be able to generate a good bunch of testable predictions? I could understand doubting that because the idea has been floating around since maybe 1995 and there still are not a lot of predictions on record.

well, I'm just curious, so please explain with a few more words what you mean by inadequate predictions in the long term

 

[SpaceTiger]

Do you mean that you have doubts that CNS will EVER be able to generate a good bunch of testable predictions? I could understand doubting that because the idea has been floating around since maybe 1995 and there still are not a lot of predictions on record.

That's pretty much what I mean. I qualified it with "in the long term" because I figured it could probably make some superficial predictions (like the soft equation of state) that would keep people interested in the short term, but nothing that would give rock solid confirmation of the theory. Whenever I think about the anthropic principle, this is the kind of theory I generally use as a mental prototype.

 

[marcus]

... Whenever I think about the anthropic principle, this is the kind of theory I generally use as a mental prototype.

That is interesting. I think of CNS as the opposite of AP

CNS offers a mechanism for the constants to converge on certain values,
and it doesn't have anything to do with Conscious Life, or Me or Us the Anthropoi. Furthermore it is predictive----it UNpredicts massive neutron stars, whose observation would refute CNS.

AP seems to offer no mechanism and discourage looking for any. The constants just are what the are, and permit our existence.
AP UNpredicts nothing. Our existence is compatible with any observation we could conceivably make! therefore our existence is not predictive.

So I see a strong logical contrast.

When you think about AP and use CNS as a mental prototype, do you think of CNS as a prototype of AP or (as I do) a kind of opposite of AP----a scientifically more meaningful alternative to AP?

 

[SpaceTiger]

I agree with you that they don't necessarily go together (the principle and this theory), but this theory provides a basic framework upon which many universes could be created as possible hosts to life. In the absence of a theory like this, that's just an assumption of most anthropic arguments.

Now I should say that I haven't read the paper explicitly and everything I know is from word-of-mouth (and it may not even be the same theory I'm thinking of), so I might say something about the model that is incorrect. If so, my apologies.

CNS offers a mechanism for the constants to converge on certain values,
and it doesn't have anything to do with Conscious Life, or Me or Us the Anthropoi. Furthermore it is predictive----it UNpredicts massive neutron stars, whose observation would refute CNS.

I wouldn't say that's any more or less predictive than the anthropic principle, really. The anthropic principle predicts things like the necessity for certain fusion chains to create certain elements, but it doesn't predict anything with which you can really feel confident about its ideas.

AP seems to offer no mechanism and discourage looking for any. The constants just are what the are, and permit our existence.
AP UNpredicts nothing. Our existence is compatible with any observation we could conceivably make! therefore our existence is not predictive.

Hmm, I don't think I agree here. The UNprediction you're talking about here is one in which it's predicting that something won't be observed (like a massive neutron star). The anthropic principle does just as well, UNpredicting anything that's incompatible with the existence of life.

This might be inconsistent with the AP if the only universes that can create a lot of black holes are those that cannot create life. There's no reason to assume this should be the case, however.

 

[marcus]

The anthropic principle does just as well, UNpredicting anything that's incompatible with the existence of life.
...

but how could we, living, observe something incompatible with the existence of life

whatever experiment you can imagine doing, and whatever be the outcome of that experiment, that outcome is compatible with the existence of life. so the AP "predicts" every outcome we can observe of any conceivable experiment. In that sense it predicts nothing.

another way of saying this is that the AP cannot be falsified by empirical observation (it is mushy enough to accommodate any observation)

It would probably be better for you to glance at the first 3 or 4 pages of Smolin's paper, easy enough to do (they arent technical or timeconsuming) and superior to my attempted paraphrase. The paper is quite straightforward---explicitly states what version of AP he is critiquing, and so on.

I hope you do because I would value your response to it! I am glad that you know of CNS by hearsay. Grad students in Astronomy probably would do well to be thinking about CNS now, at least in my opinion. I think both it and LQG have potential for generating questions to be settled by observation.

 

[Garth]

I think of CNS as the opposite of AP

One question is what do we actually mean by the "Anthropic principle".

Taking Stephen Hawking's definition, "The world is as it is because we are" it simply acknowledges that the existence of any type of complex life anywhere in the universe requires some pretty tight constraints on various physical constants and laws. This can then lead onto various sub-divisions of the principle:

1. The Weak AP - It is a selection effect. There is a multiverse of different universes and we are in this one because we can be in no other.

2. The Strong AP - There is some as yet unknown physical principle that determines these constants to be within the narrow bands that are propitious for life. If there were a multiverse then every universe would have to be propitious for life as a logical necessity.

3. The Participatory AP - The existence of 'conscious' observers today affects'/'affected' the outcome of the original quantum wave function so that it had to collapse to produce an 'observable' universe that allowed the existence of 'conscious' observers today. The original 'boot-strap' theory!

4.The 'Fluke' (coincidence) hypothesis - There is only one observable universe, the AP depends on a statistical argument, you cannot do statistics with a sample of one, therefore all we can say is that the anthropic coincidences are just a fluke, a coincidence, a brute fact; we wouldn't be here if otherwise.

5. The Design hypothesis - the world is as it is because it has been designed to be so teleologically. If design then perhaps a 'Designer' - God in traditional belief or perhaps scientists in a former universe playing at God by creating a new universe in their lab! (Would this be wise?) But then, who created them - indeed who created 'God'?

If the AP simply reflects of the existence of these coincidences necessary for our existence then CNS is not the opposite of it, rather it is simply one possibility for one of its options - the Strong AP. The CNS would be the mechanism by which, after enough iterations, every universe would maximise the number of BHs and hence the existence of life. (But isn't it a coincidence that the two should be so linked?!)

Garth

 

[marcus]

... The CNS would be the mechanism by which, after enough iterations, every universe would maximise the number of BHs ...

I don't see any evidence for the existence of more than one universe, unless you say that what came before the big bang is a separate universe (even tho causally connected and temporally antecedent) because it may have had slightly different values of some constants.

the words are a bit slippery because we are unused to thinking of the CNS, but I would say we live in a section of spacetime. somewhat like a branching plumbing fitting, or a car's intake manifold, it has one black hole intake joint (the big bang) in our past and multiple outgo black hole joints into different futures. so it is a section of the universe, which comprises many such

maybe one could call it a branch of spacetime

but I think you know what I mean even tho the words are problematical.

Anyway, I'd say pretty much the same as the quote from you, Garth, except maybe I'd say

... The CNS would be the mechanism by which, after enough iterations, THE universe would maximise the number of BHs ...

'cause all I know about is this one universe. (altho I admit it may have branches, time may fork at black holes and go separate ways etc, but its all one whole----same basic laws throughout but with some parameters allowed to vary)


the reference to life confuses me, in your post, since i don't see life as part of the logic or having explanatory power

about life, i see IT as something to be understood and explained,
it is some opportunistic chemistry that can take advantage of the tuning of the parameters that evolves with BH reproduction, which is great.
we should study it. but it doesn't explain the paratmeters! that's cart before horse.

 

[Garth]

some opportunistic chemistry that can take advantage of the tuning of the parameters that evolves with BH reproduction, which is great. we should study it

Such study or conscious thought is predicated on the existence of a complex system, that is, a conscious mind. The existence of such a mind is to be explained every bit as much as the existence of stars, galaxies, black holes or anything else in the universe, especially as it could much more easily been otherwise.

Garth

 

[SpaceTiger]

another way of saying this is that the AP cannot be falsified by empirical observation (it is mushy enough to accommodate any observation)

Yes, of course, I see what you're getting at, I was confused by your language. I'll try to take a look at the paper sometime soon.

 

[marcus]

... The existence of such a mind is to be explained every bit as much as the existence of stars, ...

I am glad you think so too, Garth!

The evolution of intelligence, and self-awareness, essentially from mud and pond-slime, is a truly wonderful thing and indeed much deserving of study, even as are stars and galaxies (just as you say!)

Clearly some survival and reproductive advantages go along with the ability and pre-disposition to think as humans do----at least in some situations and cultural contexts.

Perhaps you can tell me of some good book on the evolution of intelligence in animals (it should not be limited to one species, there is a type of spider in which the ability to plan and outwit another spider serves to obtain it food: namely the less conscious and foresightfull of the two, and of course there is a major unsolved problem in the phenomenal verbal ability of certain parrots )

the fact that something like the brain can evolve from scum, where the CONSTANTS in that scum are determined by something totally unrelated to the scum or the mind----the constants may well have converged on their present values because they promote BH formation----is wonderful and demands explanation from first principles, i.e. from the laws of nature.

What I find a bit silly is when people turn this around backwards and try to explain the laws of nature (which got here without us!) on the basis of the existence of the mind. To that all I can say is and I take it you might very well agree.

 

[turbo]

The fact that something like the brain can evolve from scum, where the CONSTANTS in that scum are determined by something totally unrelated to the scum or the mind----the constants may well have converged on their present values because they promote BH formation----is wonderful and demands explanation from first principles, i.e. from the laws of nature.

What I find a bit silly is when people turn this around backwards and try to explain the laws of nature (which got here without us!) on the basis of the existence of the mind. To that all I can say is and I take it you might very well agree.

Thank you. The fact that we have evolved out of lifeforms that arose earlier in our universe is flipped in the AP to provide "proof" that our universe is fine-tuned to produce us. Kind of silly. Our entire existence is less than a eyeblink compared to the existence of our Earth, and is impossible to comprehend relative to the ages of our Solar System, Milky Way, or Universe.

The AP tells us that all the properties of the Universe must be "just so", so that the Universe can host our exhaulted presence for a tiny speck of time. I propose extending the AP to the even more finely-tuned FP. This is the Ferrethropic Principle. My ferret is the absolute epitome of character and chutzpa (plus he's really cute). He would not be here if the Anthropic Principle were not true, AND if I were not here to have raised him. I hate to think about the logical extensions of this theory, though, in light of the fact that he had to exist in order to have gotten ear-mites as a baby. I have little respect for ear-mites, and will firmly resist any extension to the Ear-mitethropic Principle.

 

[marcus]

I was awestruck, turbo, at the thought that ear-mites might at this moment be observing and speculating about the universe, and thinking that their very presence here explains the value of the cosmological constant

have to go pick up my wife at her class, the ferret and the ear-mites will give me something pleasant to think about in the rush-hour traffic. thx.

 

[Chronos]

With Type II supernovae, one might form neutron stars near 1.4 solar masses if the rest of the envelope is given sufficient kinetic energy to escape the collapsed core. If there is much fallback, however, one either gets a black hole or a more massive neutron star. However, as you said, neutron stars tend to cluster around the Chandrasekhar mass, so this implies one or both of the following:

1) Neutron stars have a very "soft" equation of state, meaning neutron degeneracy can't support much more than 1.4 solar masses.

2) There's little or no fallback.

Most of the people I hear talk about it seem to lean towards #1, but I've never heard people say that #2 isn't possible as well, so you could be right.

I perceive that a soft EoS for neutron stars is exactly what Brown is driving at. And the mass clustering just below the Chandra limit is pretty compelling. This nice paper by Chevalier seems to affirm that notion:
http://arxiv.org/abs/astro-ph/0409013
Young core collapse supernova remnants and their supernovae

 

[marcus]

I perceive that a soft EoS for neutron stars is exactly what Brown is driving at. And the mass clustering just below the Chandra limit is pretty compelling. This nice paper by Chevalier seems to affirm that notion:
http://arxiv.org/abs/astro-ph/0409013
Young core collapse supernova remnants and their supernovae

Chronos thanks for both the Chevalier paper and the one by Brown with which you started the thread!

Both papers lend interest to CNS because CNS predicts a soft equation of state for neutron stars (as you may have mentioned already)

I would elaborate on that by saying that physicists do not seem able to predict from first principles how large a neutron star can be before collapsing to BH under its own weight.

However CNS predicts that this mass limit should be low----i.e. that n-stars shd be "soft" and subject to collapse when they reach only a few solar masses.

this is a real prediction, not derived from the Standard Model first principles, as I mentioned, and it could be falsified by finding a n-star of say 2.5 or 3 solar, which would show CNS wrong (I am not sure about the actual limit but something like that)

I just took a quick look at the Chevalier and saw a lot about fallback being so much in a SN that the remnant is not even a neutron star but instead collapses directly to a black hole!
What this suggests to me is that if one could "turn off" the collapse to BH and give neutron stars a very hard equation of state
(just to see what masses one would get, statistically)
then Supernovae would supply us with a lot of massive neutron stars

if we could turn off BH formation and make n-stars hard, in other words, we would be seeing plenty of n-stars with masses like 3 and 4 solar!

So this is very good news for CNS, because it says that since we do NOT see lots of massive n-stars (with masses exceeding 3 solar) that really does signify that the EoS is soft

which is a prediction made by CNS and apparently not arrived at by some alternative route from SM principles

this is cause for some cheerfulness, so thanks again for the paper. also the paper was real high quality, I thought. kudos to Chevalier whoever he is.

 

[marcus]

the Templeton foundation has emerged as a powerful slush fund aimed at blurring the distinction between empirical science and some type of neo-creationist spirtuality masquerading as such.

this may make it harder for the CNS hypothesis to get a hearing, if it is liable to get drowned out by the Templeton boom box. here are some links about conferences, prizes, publications and websites supported by questionable sources, including Templeton money.

Sean Carroll's 18 April 05 blog
http://preposterousuniverse.blogspo...erousuniverse_archive.html#111387591806156772

a 29 March 05 op-ed NYT piece by Lawrence Krauss
http://genesis1.phys.cwru.edu/~krauss/29comm.html

Peter Woit's 18 April 05 blog
http://www.math.columbia.edu/~woit/blog/archives/000183.html

Leonard Susskind is apparently distancing himself from the "Intelligent Design" movement
http://blog.olympus.het.brown.edu/science/archives/000248.php
look about halfway down the page, a couple of lines before the trackback listings where it says
"Another point to be made is that he [Susskind] repudiated any connections with Inteligent Design: He is a strong believer of Evolution and science, he said so himself several times."

 

[ohwilleke]

For what it's worth, I have a very dim view of the "Cosmic Natural Selection" theory of setting constants, and think that Smolin has done his credibility a disservice by advancing it. There is virtually no evidence that new universes are created by black holes or that black holes cause fundamental constants of the universe to differ in any way.

The central point is not that it can be falsified by the existence of neutron stars over 3 solar masses, but that there are plenty of other far more plausible arguments for why neutron stars are the size that they are.

It makes far more sense to say that the universe looks the way it does, and not some other way, because the fundamental constants of physics led to a universe that looks like this and not some other way.

In the same vein, mammals have twenty-four hour biological clocks, not because the Earth evolved to fit mammals, but because mammals evolved to fit the Earth.

Until someone can show the existence of another universe, CNS is dead in the water. The fact that there are other ways of killing it is irrelevant.

 

[marcus]

For what it's worth, I have a very dim view of the "Cosmic Natural Selection" theory of setting constants,...

It makes far more sense to say that the universe looks the way it does, and not some other way, because the fundamental constants of physics led to a universe that looks like this and not some other way.

In the same vein, mammals have twenty-four hour biological clocks, not because the Earth evolved to fit mammals, but because mammals evolved to fit the Earth.

Until someone can show the existence of another universe, CNS is dead in the water. The fact that there are other ways of killing it is irrelevant.

thanks for commenting Ohwilleke, I'll respond point by point

For what it's worth, I have a very dim view of the "Cosmic Natural Selection" theory of setting constants,...

your opinion is worthy----carries weight with me. but I disagree with you

It makes far more sense to say that the universe looks the way it does, and not some other way, because the fundamental constants of physics led to a universe that looks like this and not some other way.

I fully agree that it makes excellent sense to say the universe looks this way because the fundamental constants are the numbers they are. this agrees with CNS just fine. CNS is a way to go deeper and ask "why are the fundamental constants those particular numbers?". It offers a mechanism for automatic self-tuning of the constants.

Life, and in particular conscious life (whatever that is) is irrelevant to the proposed self-tuning mechanism. The CNS hypothesis is based on two explicitly stated assumptions---which I think you'v read if you looked at the "Scientific Alternatives" article.

In the same vein, mammals have twenty-four hour biological clocks, not because the Earth evolved to fit mammals, but because mammals evolved to fit the Earth.

I certainly agree! In its general tenor, I think what you say agrees strongly with CNS. If this is somehow an objection to CNS please clarify.

The point Smolin makes with CNS is that the apparent fine-tuning of the constants can be explained in alternative ways to those invoking the existence of (conscious) life. CNS is an example of this ---- analogous to an existence proof in mathematics, as he points out.

Life is seen (as in your reference to mammals) as evolving to fit the constants of nature----essentially as a BYPRODUCT or side effect of whatever mechanism caused the constants to take on those particular values.

Until someone can show the existence of another universe, CNS is dead in the water. The fact that there are other ways of killing it is irrelevant

This sounds a bit like wishful thinking, Ohwilleke, as if you would like to eradicate all discussion of CNS, and wish that it actually were dead in the water . But indeed it is not dead in the water until it has been empirically falsified. The PREMISE that our universe expanded from a gravitational collapse in some other universe is simply that: a premise of the theory. It has recently gained some credence from the theoretical studies of BH collapse (as in gr-qc/0503041). But the fact that the premise has become more credible recently is not essential. The premise does not have to be shown. With a scientific theory what one is supposed to do is look at the predictions and test them.

As for my personal point of view. I hope that lots of other theories emerge that offer mechanisms explaining the fundamental constants---and which are falsifiable, that is which unpredict possible outcomes of future experiments so that they risk empirical refutation. So far CNS is all we have! So I think it deserves our focused attention at least until some other empirically predictive (falsifiable) explanation of the constants comes along.

If you know of another such testable theory, or can make one up, please let me know.
IMHO these things are almost all that is standing as a bulwark between us and pseudo-science like the "Anthropic Principle"

 

[ohwilleke]

My comments about Earth and life are analogies, not about life itself. The argument of CNS is in essence, an argument that the values of the constants are they way they are which is deduced deduced from characteristics universe has particular characteristics, rather than the more plausible argument that the universe has the particular characteristics that it does as a result of the values of the fundamental constants.

The "why are the fundamental constants the way they are" question only makes sense if indeed the constants are in fact not fundamental. If they are truly fundamental constants, then it is equivalent to asking: "Why isn't the color green the color blue?" or "Why isn't 17 equal to 12?" It isn't a question of a "testable theory", it is a question of whether the question is anything other than nonsense. How do you empirically falsify 17 is not equal to 12 when it is evident on the face of the question?

Now, there are several kinds of non-fundamental constants. One kind of non-fundamental constant is a derived constant. For example, you could have a constant called the "sphere volume constant", but rather than making 4.1887790205 another number that everyone must memorize, we find it convenient to call the transendental number pi equal to roughly 3.14159265 . . . fundamental, and to call the volume of a sphere 4/3pir^3. There is good reason to believe that many constants that are now viewed as fundamental for lack of a good alternative and determined empirically, like higher order quark and lepton masses, are probably really derived constants whose formula we are still working on determining (although some very clever suggestions have been made: https://www.physicsforums.com/showthread.php?t=67134).

There are also constants which are emergent from a physical system. For example, the 9.8 N/m^2 figure for gravity on Earth flows from the mass and shape of the Earth and the universal law of gravity (or GR if you prefer).

The Machian view is that more constants than one might suspect are emergent rather than truly fundamental.

But, the notion that the activities that take place in a black hole change "fundamental constants" just doesn't have any support. And, you can't do experiments that involve counterfactual situations. We can't, for example, do an experiment in which the speed of light is 3c.

The PREMISE that our universe expanded from a gravitational collapse in some other universe is simply that: a premise of the theory. It has recently gained some credence from the theoretical studies of BH collapse (as in gr-qc/0503041). But the fact that the premise has become more credible recently is not essential. The premise does not have to be shown. With a scientific theory what one is supposed to do is look at the predictions and test them.

If I choose as my premise that the Moon is made out of green cheese, one can develop quite a weird cosmology involving extraterrestial cows and cheese makers. But, it doesn't mean much. Also, CNS has two premises, neither of which are proven or plausible. One is that black holes in one universes create different universes that are elsewhere. (Note that it is one thing so say that the big bang flows from the collapse of a black hole, and another to say that the big bang flows from the collapse of a balck hole in a different universe, there is theoretical support and empirical data to back up related ideas -- there is no evidence for the existence of any other universe, however). The other, far more radical theory, is that blacks holes have a mechanism which change fundamental constants. There is no evidence whatsoever for any instance in which fundamental constants have every been changed. Extraordinary claims require extraordinary proof.

 

[marcus]

My comments about Earth and life are analogies, not about life itself. The argument of CNS is in essence, an argument that the values of the constants are they way they are which is deduced deduced from characteristics universe has particular characteristics, rather than the more plausible argument that the universe has the particular characteristics that it does as a result of the values of the fundamental constants.

The "why are the fundamental constants the way they are" question only makes sense if indeed the constants are in fact not fundamental. If they are truly fundamental constants, then it is equivalent to asking: "Why isn't the color green the color blue?" or "Why isn't 17 equal to 12?" It isn't a question of a "testable theory", it is a question of whether the question is anything other than nonsense. How do you empirically falsify 17 is not equal to 12 when it is evident on the face of the question?

...

I didnt mean to get into a debate about the meaning of words, like "fundamental", Ohwilleke, though I respect your interest in philosophy as a matter of individual taste.

What Smolin calls these several dozen numbers is "the parameters of the standard models of physics and cosmology". these are the dimensionless numbers you need to plug into Standard Model particle physics (said to be about 26) and standard LambdaCDM cosmology (roughly a dozen?) to make them fit the data.

ratios of particle masses to the Planck mass, for example.

the list would not include the speed of light because that is dimensionful

the parameters of the Standard Model are the sort of thing traditionally called "fundamental physical constants" but whether you want to call them that in this or that context and what you believe you mean by "fundamental" is ultimately up to you.

if you want to converse in Smolin's own terms, as a courtesy to the CNS idea, it is dimensionless parameters. and they would naturally vary depending on details of the version of the Standard Model currently in use.

 

[marcus]

...
Also, CNS has two premises, neither of which are proven or plausible. One is that black holes in one universes create different universes that are elsewhere. (Note that it is one thing so say that the big bang flows from the collapse of a black hole, and another to say that the big bang flows from the collapse of a balck hole in a different universe,

according to the accepted model of BH, timelike directions are down the hole. therefore if spacetime continues past the classical singularity (see
http://arxiv.org/gr-qc/0503041 ) it must be a separate branch of the universe.

there is no possibility of a bounce at the classical BH singularity "rebounding" and exploding in a big bang back in our branch of the universe. this would violate causality or the directionality of time

hmmmm, you seem incredulous

maybe you don't believe that the BH classical singularity can be removed by quantizing GR and spacetime continued on through the regime of the former singularity. But papers which purport to do this in various restricted cases have been accumulating lately.

Why don't you have a look at this one? I've cited it several times:
http://arxiv.org/gr-qc/0503041 .
It is only 4 pages, so what's to lose?

there is theoretical support and empirical data to back up related ideas -- there is no evidence for the existence of any other universe, however). The other, far more radical theory, is that blacks holes have a mechanism which change fundamental constants. There is no evidence whatsoever for any instance in which fundamental constants have every been changed. Extraordinary claims require extraordinary proof.

I think that was a Freudian slip, you wanted to say "there is NO theoretical support" but you left out the "no". And in fact there IS theoretical support in the form of what is AFAIK the best, most up-to-date, models of black hole collapse which we have.

Personally I tend to go more by empirical evidence than theoretical support. But if you want theoretical support it is there in recent papers by Viqar Husain, Otto Winkler, Leonardo Modesto, Bojowald, Goswami, Maartens, Singh. And a much larger body of papers by these and others about the removal of the big bang singularity and extension of our spacetime back thru the former singularity to a collapse in a prior branch.

this is not a conspiracy These people are not working for Smolin! they are just today's quantum cosmologists doing their job and calling as they see it.

Smolin conjectured this business circa 1995, ten years ago. But he has not been doing the theoretical research on the BB and BH singularities. Nor do I see any indication that the people doing it are motivated by having a CNS ax to grind.

It must be pleasant for Smolin to watch, but it is not his doing.

 

[hossi]

total energy?

Hi there,

found this old thread while googling for cns... Have a very simple question. Let's assume that creation of universes through black holes somehow works, and that while doing so the parameters of the (cosm)SM change a little bit each time. What happens to the total energy of the universes?

I.e. if the mother universe made 10^18 black holes, then each of them has only a small fraction of the mother's total energy M_m. Let's say the baby universe has energy M_b << M_m. Keeping all parameters close to the mother's ones will mean a severe drop in the number of black holes in the baby universe, since 10^18 is an absolute number for our universe and should be accordingly rescaled to 10^18 * M_b / M_m.

The only way out of this would be to regard M_m as a parameter itself but it's not dimensionless. So you would have to regard all mass-scales as parameters (also the Planck mass etc). Then you could avoid the above problem by rescaling all mass-scales with this ratio, but this is neither a small change of parameters, nor a random one.

Did I get something wrong?

Hoping for enlightenment,

B.

 

[marcus]

. Let's say the baby universe has energy M_b << M_m. ...
B.

inflation creates energy (no conservation law applies) so we couild have
M_b = M_m.

or also M_b > M_m.


according to the usual LambdaCDM model that most people use, our universe (if it is finite) is even now increasing in total energy
because Lambda represents a constant (dark) energy density and so if the volume expands the total energy must grow

the whole thing happens a lot faster in the brief inflation episode assumed to occur near the bounce

it does not seem that finding enough energy to make a universe similar to our own-----starting from the pit of a stellarmass black hole----is a problem

but I'm not an expert in these matters so would be glad to hear different views on this

 

[hossi]

and so if the volume expands the total energy must grow

huh? Einstein's field equations imply energy conservation. If the total energy is not conserved, the field equations are not valid. I think you are forgetting the pressure of the components. the energy of the inflaton later goes into that of the 'usual' matter (reheating), so the energy of the 'usual' component only is not conserved, if that's what you mean. But I am talking about the energy content of 'everything', including inflatons, scalarons, dilatons, radions or other-ons. B.

 

[hossi]

and so if the volume expands the total energy must grow

huh? Einstein's field equations imply energy conservation. If the total energy is not conserved, the field equations are not valid. I think you are forgetting the pressure of the components. the energy of the inflaton later goes into that of the 'usual' matter (reheating), so the energy of the 'usual' component only is not conserved, if that's what you mean. But I am talking about the energy content of 'everything', including inflatons, scalarons, dilatons, radions or other-ons. B.

 

[Garth]

Einstein's field equations imply energy conservation.

Einstein's field equations imply energy-momentum conservation, not, in general, energy conservation.

Energy is a frame dependent quantity, you have to specify a specific frame to make any measurement of energy meaningful it, and then, if there is not a time-wise Killing vector, it is not conserved.

Energy-momentum is a frame independent quantity and in GR is conserved:

$$T^{\mu}^{\nu};_{\mu} = 0$$

Garth

 

[marcus]

Einstein's field equations imply...

Energy ... is not conserved.

IIRC there is a Usenet FAQ about this, that I used to get via John Baez site. the fact that Gen Rel doesn't conserve energy has bothered people and they have used various kludges, like "pseudotensor", to get some form of energy-conservation.

but two naive observations are:

if our universe is infinite then it does not have a total energy! So then the question is hard to ask. On the other hand, if it is finite then according to the standard cosmology it's total energy is even now growing rapidly as it expands------since Lambda is a constant energy density (around 0.6 joules per cubic kilometer)

a constant energy density like our current Lambda is usually assumed as the mechanism of inflation----the same as today but souped-up

===============
also here is another thought: when we are talking about "big bounce" where QG replaces classical Gen Rel, and gets rid of the singularity, then classical Gen Rel is no longer in control------it breaks around the former singularity

so if classical Gen Rel is no longer in control at that point, then maybe we should be asking not does Gen Rel have an energy conservation law but DOES QUANTUM GRAVITY have an energy conservation law? what sort of quantities does one expect to be conserved in the socalled Planck regime right around the moment of the bounce?

 

[marcus]

would anybody like to discuss how, even in classical GR, the energy-momentum tensor could be conserved GLOBALLY, that is as an integral over some spatial slice?

I mean to distinguish this from having a quantity defined at a point that is conserved locally.

if we are talking about a global quantity belonging to the whole universe (as I think hossi was talking) then how do you define it? what time evolution conserves it? what sort of machinery do you need to make the idea of conservation meaningful? how do you integrate?

it would be great if someone wants to explain, simply what the mathematical setting would be to have either energy or energy-momentum globally conserved on a universe-wide basis----even in just CLASSICAL gen rel.

 

[Garth]

Even in an infinite universe you can always work with a representative volume of average cosmological density.

Garth

 

[marcus]

Even in an infinite universe you can always work with a representative volume of average cosmological density.

Garht

I know, Garth
but it is just one more complication (the volume has to expand with the universe) so suppose we keep it simple and consider a finite universe!

I still have my question. You can extend it to cover infinite case if you want:

would anybody like to discuss how, even in classical GR, the energy-momentum tensor could be conserved GLOBALLY, that is as an integral over some spatial slice?

I mean to distinguish this from having a quantity defined at a point that is conserved locally.

if we are talking about a global quantity belonging to the whole universe (as I think hossi was talking) then how do you define it? what time evolution conserves it? what sort of machinery do you need to make the idea of conservation meaningful? how do you integrate?

it would be great if someone wants to explain, simply what the mathematical setting would be to have either energy or energy-momentum globally conserved on a universe-wide basis----even in just CLASSICAL gen rel.