Will LQG explain the constants?

[marcus]

I want to find out about the Vaidya thing, since it occurs in both papers it may be a significant detail

...
the way it looks to me right now there are two representative papers about removing the BH singularity continuing into a BB expansion
and these two are recent (March and April 2005) and by Bojowald-Goswami-Maartens-Singh on the one hand and a less-well-known young researcher named Modesto on the other (but Modesto is at marseille with Rovelli)

and both of these recent papers mention ideas of Vaidya, some possible links are
http://arxiv.org/gr-qc/9804075
http://arxiv.org/gr-qc/9803038
these are not papers by Vaidya but they may clarify things a bit so I am going to have a look.
...

like for example in Bojowald et al on page 3 around equation (19) one sees
"a generalized Vaidya region" and "the usual Vaidya mass"

...

well here are the two leads I found in Bojowald et al references:

http://arxiv.org/gr-qc/9804075
Initial data and the end state of spherically symmetric gravitational collapse
P. S. Joshi, I. H. Dwivedi
31 pages no figures
Class.Quant.Grav. 16 (1999) 41-59

"Generalizing earlier results on the initial data and the final fate of dust collapse, we study here the relevance of the initial state of a spherically symmetric matter cloud towards determining its end state in the course of a continuing gravitational collapse. It is shown that given an arbitrary regular distribution of matter at the initial epoch, there always exists an evolution from this initial data which would result either in a black hole or a naked singularity depending on the allowed choice of free functions available in the solution. It follows that given any initial density and pressure profiles for the cloud, there is a non-zero measure set of configurations leading either to black holes or naked singularities, subject to the usual energy conditions ensuring the positivity of energy density. We also characterize here wide new families of black hole solutions resulting from spherically symmetric collapse without requiring the cosmic censorship assumption."

http://arxiv.org/gr-qc/9803038
Generalized Vaidya Solutions
Anzhong Wang, Yumei Wu
Gen. Relativ. Grav. 31 (1), 107-114 (1999)

"A large family of solutions, representing, in general, spherically symmetric Type II fluid, is presented, which includes most of the known solutions to the Einstein field equations, such as, the monopole-de Sitter-charged Vaidya ones."

MY COMMENT: so far it doesn't look like anything special. just some people assembling a large variety of solutions to the Einstein equation which are cases of black hole gravitational collapse. It turns out that some of the solutions give rise to naked singularities, like black holes but not shrouded in an event horizon---very hard for me to imagine---but the main value seems to be that this work gives lots of different readymade cases of matter collapsing down to a classical singularity. Something that LQG can then work on and investigate removing the singularity in these various cases.
Here is from Wang and Wu (great co-author names, Wang and Wu)
"In 1951, Vaidya[1] found a solution that represents an imploding (exploding) null dust fluid with spherical symmetry.

Sincethen, the solution has been intensively studied in gravitational collapse[2]. In particular, Papapetrou[3] first showed that this solution can give rise to the formation of naked singularities, and thus provides one of the earlier counterexamples to the cosmic censorship conjecture[4]."

 

[wolram]

By MARCUS
tho reason warns me that it must be, as with all outer-limits speculation, treated with caution. there is no paths where we are now and there are lots of cliffs to fall off of, which we would see if it wasnt so dark. Fun, isn't it?
To be sure, absolute of the wall speculation, and it is fun.

 

[spicerack]

tut tut fellas, shame on you

This not the place to be having fun in the dark

but I can honestly say I am starting to get a handle on this cosmology sciencey thing

note I said handle not torus

 

[marcus]

... but I can honestly say I am starting to get a handle on this cosmology sciencey thing

nice to hear from you, spicerack. as your nick name suggests you often add zest to the discussion

 

[marcus]

I posted a short reading list for this thread here:

https://www.physicsforums.com/showthread.php?p=527991#post527991

that thread is serving as a kind of reference library for LQG links

the reading list is 5 articles
1. two about removing the cosmological (BB) singularity
2. two about removing the gravitational collapse (BH) singularity and continuing the model so as to begin a big bang expansion
3. one article about what getting a welded joint like this might mean
in terms of explaining the basic physics and astronomy constants
(why the parameters of the Standard Models of particle physics and
cosmology are the numbers they are).

 

[nightcleaner]

Spicerack appears to be a cute lady. She just mentioned Intelligent Design (tho archly denying its appeal to her in the same breath). This causes me think what a debased sacrilege the notion of Intelligent Design is. It offends ones feeling of the sacredness of nature to be told that some Divinity has chosen the value of the fine structure constant.
I assume that alpha's value (near 1/137) was arrived at naturally, by some (probably sweet and elegant) mechanism to be eventually discovered.

If someone wants to say that a divine power created the whole Works, well fine and dandy! But I shall suppose that some analysable mechanism such as natural selection created details like the electron and the gazelle.

I wish to show my reverence for nature by supposing that natural selection chose the streamlined shape of birds, and the beautifully adjusted cosmological constant Lambda.

Part of the way I revere nature is my sporadic but repeated efforts to understand how it works.

I assume that some evolutionary mechanism arrived at the periodic table of elements---by a process of gradually adjusting the parameters like alpha which determine it.

The idea that a Designer interfered in the construction of the periodic table with its 90 or 100-odd chemical elements, is basically offensive to the spirit, it desecrates something which I feel is sacred.

So basically I would say that what is wrong with Intelligent Design is gives a debased idea of God. It is ignoble and a bit perverted for a Divinity to get down and tweak physical parameters of the Standard Model in order, say, to make Marilyn Monroe, or eels, possible. Or to save the bacon of some contemporary theoretical monster like "String Theory" with its "Landscape", if it is possible to forestall its self-destruction.

People who promote talk of Intelligent Design are involving the Creator in petty mechanistic details, which runs counter to what I see as the main direction of of Western monotheism and also, I suspect, the forms of spirituality in other high religious traditions.

And they are also eroding the standards of scientific inquiry. So they are, in my view, harming two of our highest and most precious traditions. they are managing to degrade both at once!

But this is not the topic of this thread. the main thing I want to focus on, as I said to spicerack, is how do you explain why the parameters of the Standard Models as we measure them seem so marvelously adjusted to favor the production of black holes? If indeed, as Smolin's paper suggests, they are.

Bravo Marcus. I can only take exception to this: "they are also eroding the standards of scientific inquiry". Not while people like you are watching. Well met.

Richard

 

[nightcleaner]

Hi Marcus

CHOP has two Friedmann equations listed, one to solve for the second derivative of the cosmological scale factor, the other to solve for the square of the first derivative of the cosmological scale factor. The first involves -4piG/3 and the second involves 8piG/3. I notice that the equation given by Bojowald in 0309478v1 involves a factor of 16piG/3. The Bojowald equation has a lot less stuff on the right, and solves for the square of [(the first derivative of a) divided by a].

I am doing a yard chores run up to the deep woods, will return this pm. I look forward to getting a chance to read up on the list of articles. Thanks.

Richard

 

[wolram]

This internet does not work as advertised, I am going into seclusion
until i can make some sense of all this.

 

[Kea]

By MARCUS: tho reason warns me that it must be, as with all outer-limits speculation, treated with caution. there is no paths where we are now and there are lots of cliffs to fall off of...

And since it's poetry month and we're all digressing:

..."Happiness - how indeed could one find happiness among such
buried-alive and solitary ones! Must I yet seek the last happiness
on the Happy Isles, and far away among forgotten seas?
But all is alike, nothing is worth while, no seeking is of
service, there are no longer any Happy Isles!"
Thus sighed the soothsayer; with his last sigh, however, Zarathustra again became serene and assured, like one who hath come out of a deep chasm into the light. "Nay! Nay! Three times Nay!" exclaimed he with a strong voice, and stroked his beard - "that do I know better!
There are still Happy Isles! Silence thereon, thou sighing
sorrow-sack!

Nietzsche, Thus Spake Zarathustra

 

[nightcleaner]

IIRC naked singularities are BH matter where the solid part may lie outside the event horizon. Do black holes get amnesia? What does a black hole that does not have amnesia look like? Marcus, what if the memories do not fade away, but only sink so far from us in time that we can no longer see them, like a coin into sunlit depths.

Far away is up close in singularities, is that not so? All that has fallen in is still there at the horizon waiting for eternity to pass, but it does not know it waits, only we see it so. It is accelerated until to our puny halflives it stands still! For we are created beings, agreed? And that which is created must one day fail. We are because of our limits, it is our endpoints that define us in entirety.

We see time as infalling, the past as if it were very far away. In a sense it is we who fall, and we fall faster and faster as we go. In a sense timespace is a landscape that we rush past, just at the surface, where we read the changes in what the moving finger has writ before us. We change as we rush through. Of course the idea of reading the wall as you fall past it is an analogy, and the fall is very much like a rush of time, moments piling on moments. The weight of them is very dense behind us, we stand upon the surface of the Earth because it rushes outwards.

The stars and galaxies rush away from us, and we pursue almost exactly as fast, and accellerating together toward an unknown great attractor destination creates our mutual gravity, our common field, our universe. It is the universe, it is the only universe, all of it, but what we can imagine is only the tiniest fraction of the very smallest part. It branches and unbranches before us, tree-like as we pursue our fibere bundles through it. The wall analogy fails in so far as it does not acknowlege that we are three dimensions falling through whatever it is, more that than falling past it. The rubber sheet analogy lacks the aspect of three dimensions in which it is not curvature we need to discuss, but density. Time falls away within us as we increase in scale. Think then of what the future is when you look outward to the ends of the universe.

Maybe BH and BB are not such good names for the phenomena in which we are witness and particpant. I suggest that very small and very large are a dimensional pair, a superdimension if you like, not a measly little compacted Calabi-Yau kaliflower or brussels sprout, but a full blown Being extended to the max in it's own idea of limits, which are not ours. We are not even cells in it, but only the tiniest of fibers, strings if you like.

Is it an analogy to say that a being is a string extended in time? In time, we do not begin or end, but we have a length, and it is punctuated by the extent of our memories. You pass your hand along a rope, the fibers begin and end, but the rope goes on. Every cell is a being, a fiber in the universal rope, every grain of sand is a being, with its own future and history.

Time is not what we think it is. Is it a record, is it a wall, is it a set of memories?

So I propose in and out as a first set of dimensions. In is the past which we have absorbed within us and from which we are excluded, just as you cannot dig down in the Earth beneath your house and find 1950. The past is receeding from us and is exceedingly small. If you stood on the solid surface of a Dyson sphere, expanding as fast as the nanobots could build it, and looked up, what would you see?

The future is very large, until we get there. It flows through us and dissappears from view, as if down a drain, but everywhere, and the drain goes nowhere. The future is very large. What are the stars? What are the galaxies? Each star is a fiber in spacetime, we weave the rope.

In we have, and out. And there is that which is before us and that which is behind, up and down and left and right. I count four dimensions, one of which is time. Arachne's Spinets! Connecting us to the very very large, the very very small, the very very long ago, the very very far away.

 

[marcus]

...but I can honestly say I am starting to get a handle on this cosmology sciencey thing
...

there is getting to be some pretty good writing on this thread! NC liked your recent piece a lot. However I am interested to know if spicerack is following the basic argument---about the topic question.

we should try to keep it together even as we occasionally digress.

spicerack, do you follow the central argument that IF it turns out that hole can connect to bang at the technical level (where these things are modeled by LQG) then this MIGHT afford an explanation for why the fundamental physics parameters seem to favor the production of a lot of black holes?

have you by any chance taken a look at Smolin's article
"Scientific Alternatives to the Anthropic Principle" ?
or maybe you can follow the general line of reasoning without ever actually eyeballing the essay that the thread's about?

 

[wolram]

nightcleaner
get real, the most part of your post is metaphysical, i know i am one to
think that anything is possible but improbable, i want facts," the missing
part of all cosmology", oh for a ruler, the BH debate may give an etheral
proposition for why we exist, but i doubt its authentisity, the real nuts
and bolts, depend on "space time", as a realistic model of our universe.

 

[marcus]

nightcleaner
get real, the most part of your post is metaphysical, i know i am one to
think that anything is possible but improbable, i want facts," the missing
part of all cosmology", oh for a ruler, the BH debate may give an etheral
proposition for why we exist, but i doubt its authentisity, the real nuts
and bolts, depend on "space time", as a realistic model of our universe.

I can respect that preference. BTW Smolin's idea, if it checks out and is not disproved by observations, only offers to explain at most a few dozen NUMBERS. It does not offer to explain why the laws of physics are what they are, only why certain basic numerical parameters (in the standard models) are what they are.

I see things proceeding step by step---parameters first then spacetime and the embodiment of the Laws----or whatever is next (how can we really tell what is next?)

and along the way people will inevitably get excited and speak in tongues and recite poetry and sing ancestral battle songs etc. (or get to thinking about the universe before they'v noticed have drunk too much wine). It is human nature. But I promise you, wolram, that for my part I will not neglect the clunky nuts and bolts part.

 

[Kea]

Arachne's Spinets! Connecting us to the very very large, the very very small, the very very long ago, the very very far away.

I like nightcleaner's way of putting things a lot. And I think he's way closer to the right picture than most - according to some weird subjective metric of mine.

Renormalisation ... smaller and smaller and larger and larger ...

 

[Kea]

Smolin's idea, if it checks out and is not disproved by observations, only offers to explain at most a few dozen NUMBERS.

Like the cosmological constant?

Kea

 

[spicerack]

IF it turns out that hole can connect to bang at the technical level (where these things are modeled by LQG) then this MIGHT afford an explanation for why the fundamental physics parameters seem to favor the production of a lot of black holes?

have you by any chance taken a look at Smolin's article
"Scientific Alternatives to the Anthropic Principle" ?

Yes. I have had a look at that article and for the most part it went whooosh, right over the top of my head

So are you asking if the black hole mechanism for universe production acts as a regulator to stabilise our universe and thus maximise the potential for life to exist in it and that the finetuning of the constants is the result of this, the interplay between universal inflation and contraction through matter loss in black hole universe production and that this process is dynamic and ongoing ?

If so then the answer is a firm, I don't know

To be honest, I don't even know what the constants are or what they do. I'm crap with numbers, have a hard time wrapping my head around the anthropic principle and falsification just leaves me for dead so I'm really not the one to ask

I think the only constant I know is the speed of light and I think that only applies to this sector of the universe or this universe in the possible multitude

It might be that it depends on whether the holes lead to different parts of our universe that are still in 4d but beyond our vision like the soccer ball "patch" analogy or whether they actually lead to totally distinct universes which would be like an individual bubble connected to all the other foamy bubbles like what's on the surface when I'm washing dishes. Maybe then extra dimensions are necessary but only some of the time and not in all of the universes reproduced but it's handy to have them as a get out of jail card

Sorry, if I'm coming off ignorant again and missed the thrust of your question but it really does help if you try not to get me to think, I do my best work just reacting to stuff because then I don't have to make sense and you can interpret whatever as freethinking rants with no substance

I do really like NC's last post

The way he puts it that there is more in heaven and Earth than can be accounted for in smolins or anyone's current philosophy and that it is up to the individual to weave their own strand into the fabric and become their own link in the great chain, to see through rose tinted glasses the best of what's out there and not worry about the darkness to much or maybe I read more into it than what's there.

I have this nasty habit of reading between the lines, figuring what's not there and filling in the gaps by assumption with no real basis other than it instinctively feels right. Maybe it's that intuition thing that Kea called a weird subjective metric...I like that too

I hope that helps if it doesn't then no harm done. It means little in the general scheme of things so don't get too hung up on it.

 

[nightcleaner]

Hi all.

Sorry Wolram. Thanks everybody.

I am reading Smolin 0407213 on the anthropic principle, and immediately come into difficulties. On page four, Smolin says:

"In recent discussions, the version of the anthropic principle that is usually put forward by its proponents as a scientific idea is based on two premises.

.A There exists (in the same sense that our chairs, tables, and our universes exists) a very large ensemble of "universes", M which are completely or almost completely causally disjoint regions of spacetime, within which the parameters of the standard models of physics and cosmology differ.

.B The distribution of parameters in M is random(in some measure) and the parameters that govern our universe are rare.

This is the form of the Anthropic Principle most invoked in discussions related to inflationary cosmology and string theory, and it is the one I will critique here."

I apologise to Dr. Smolin for I have trimmed the re-keying a bit, as I couldn't make any more sense of what followed. However you can read it yourself in ArXiv, I guess.

My point here is .1 that this is not the anthropic principle I recall from my rather ancient degree preparation at University, even though admittedly that was nothing more than an undergraduate in biology, and .2 that multiverse theory as I have come to know it does not assert those things anyway. I was reading along fine under .A until I came to the letter M, after which the territory became alien to me. I don't know what others have said, but for my part, the multiverse idea does not insist that neighboring member universes in the multiverse be "completely or almost completely causally disjoint regions of spacetime..." Did I miss something important? What happened to the branching part?

Causality is violated by any spacelike view of time. Running three dimensions even in a limited set forwards and backwards shows that teacups in our experience do not commonly un-upset themselves, and steam does not roil back into the pot on the stove. You and I know instantly if the film has been reversed on common events. More so to imagine taking time in a spacelike curve back to murder that nasty old man who started all this fuss. We know how these things work. Causality is not violated in our experience, which after all is composed of memory, the cache of bits and images we have made to hold onto and take with us as experience collapses into us. Uncertainty, for us, lies in the future. The past is solid as the Earth beneath our feet.

Multiverse theory is not just that other universes branch off beyond black holes. That is only an extreme example. The process is intimate all around us in every action. Nearly all the multiverses we come into contact with in our local region of spacetime are so identical that you would not, and do not, know when you transition from one instant to the next. Only when you go far among the multiverses do you notice any sense of change. The distances we measure are huge, and the times we know are almost unimaginably long. If you do not believe me now, sit on some hot coals, or gaze into the eyes awhile of that pretty friend. The passage of time is maleable. Dynasties rise and fall in a sigh. The Planck length and the Planck time are not the spacetime you know and rush through. They are eternal. They stand still, and it is we, the watching ones, who flee, and who fall.

I have thought of a good word for what the universe does. It is Burgeoning.

Ok. I am going to skip over Smolin's arguments against the multiverse theory, because none of them are directed against the multiverse theory I have come to know and love. I'll read on after he gets done bristling at .A and .B.

nc

 

[marcus]

.A There exists (in the same sense that our chairs, tables, and our universes exists) a very large ensemble of "universes", M which are completely or almost completely causally disjoint regions of spacetime, within which the parameters of the standard models of physics and cosmology differ.

.B The distribution of parameters in M is random(in some measure) and the parameters that govern our universe are rare.

This is the form of the Anthropic Principle most invoked in discussions related to inflationary cosmology and string theory, and it is the one I will critique here."

I apologise to Dr. Smolin for I have trimmed the re-keying a bit, as I couldn't make any more sense of what followed. However you can read it yourself in ArXiv, I guess.

My point here is .1 that this is not the anthropic principle I recall from my rather ancient degree preparation at University, even though admittedly that was nothing more than an undergraduate in biology, and .2 that multiverse theory as I have come to know it does not assert those things anyway. I was reading along fine under .A until I came to the letter M, after which the territory became alien to me. I don't know what others have said, but for my part, the multiverse idea does not insist that neighboring member universes in the multiverse be "completely or almost completely causally disjoint regions of spacetime..." Did I miss something important? What happened to the branching part?

I don't think Smolin said anything against the "branching part" here. (as in the multiple or parallel universes interpretation of quantum mechanics). It is not an issue here because he only wants to address what is typically invoked in string theorizing and inflation models

in the parallel universes picture there are many versions of 'Me' but I have different experiences according to the different possibilities envisaged by quantum theory. uncertainty is replaced by multiplicity----living on many levels----so that many similar but different worlds are layered like filo dough or the way corned beef, or pastrami, sometimes comes----a plethora of thinslice existence with me living in all of them and vaguely aware of this----BUT THIS IS NOT THE MULTI PICTURE THAT PEOPLE LIKE ANDREI LINDE AND LENNY SUSSKIND INVOKE

when the AP is invoked to address problems in, say, stringy business the picture is of many disjoint shards most of which are horribly inhospitable to life---universes that collapse almost immediately, universes with only 2 or 3 stable elements, universes where no stars can form, where fusion doesn't work, where everything is radioactive. the AP is then invoked as a roundabout way of giving up the effort to explain why the numbers are what they are.
The message is that WE CANNOT EXPLAIN why our region has numbers which permit us conscious entities to exist. (but if it didnt have parameters permitting galaxies, solar systems, complex chemistry, life etc, then, to say the not-very-helpful obvious, course we wouldn't be here)

 

[marcus]

I guess I would put it this way

the existence of life doesn't explain anything. Instead, what we should be trying to do is explain the existence of life (and as many of the other wonders of the natural world as we can)

I suspect that the basic numbers in the standard models of physics and astronomy can be explained. People who invoke the "Anthropic Lack of Principles" (as it has wittily been called) are sending out the message
"You can't explain it. Don't even bother trying."

Currently, Smolin CNS is the only physical theory that offers a physical explanation for why the numbers in the Standard Models are what they are.
It sketches a framework in which these parameters can vary and proposes a mechanism that makes them tend towards their present values, or stabilize in a narrow range around the observed values.

It won't be the only such theory, I think eventually there will be others.

I don't think Smolin is bristling at the the "parallel universes" picture, but at the message "dont even bother trying to explain the physical constants"

have to go, have to finish later
I'm back.

Yeah, it certainly isn't news that some physical constants are within a percent or so of what they would have to be for carbonbase life like us to work. I remember being impressed by that thirty years ago---especially as regards alpha---and it made me really curious as to why alpha is that number.

Saying that I wouldn't be there if alpha was 5 percent different doesn't cut it. it doesn't explain why alpha is what it is (near 1/137)

but Smolin CNS DOES offer a physical explanation for how it got near 1/137
(that has nothing to do with life or consciousness or Me). So that could be the main thing about it. There could be better theories that do the same thing but they haven't appeared yet (string theorists once aspired to explain all Std.Mdl. numbers with one number, but they seem to have given up and the theory to have imploded, so at present CNS doesn't have much competition)

 

[nightcleaner]

I guess I would put it this way

the existence of life doesn't explain anything. Instead, what we should be trying to do is explain the existence of life (and as many of the other wonders of the natural world as we can)

I suspect that the basic numbers in the standard models of physics and astronomy can be explained. People who invoke the "Anthropic Lack of Principles" (as it has wittily been called) are sending out the message
"You can't explain it. Don't even bother trying."

Currently, Smolin CNS is the only physical theory that offers a physical explanation for why the numbers in the Standard Models are what they are.
It sketches a framework in which these parameters can vary and proposes a mechanism that makes them tend towards their present values, or stabilize in a narrow range around the observed values.

It won't be the only such theory, I think eventually there will be others.

I don't think Smolin is bristling at the the "parallel universes" picture, but at the message "dont even bother trying to explain the physical constants"

have to go, have to finish later

Hi Marcus

Thanks.

I went on and read more of the paper later, in fact was up very late last nite reading. I see now that it is not the multiverse idea that Smolin is attacking, but one version of it, which I don't accept either, so that is fine. I prefer to imagine the multiverse as contiguous, adiabatic, and very, very large, so that locally the radical universes with nothing but radiation and so on are not observed.

A model for consideration: two astronauts get in spacecraft and accelerate at one g for one year in opposite directions. At some point in their journey they will lose radio contact with each other due to relitivistic effects. Under no conditions will radio waves transmitted by one reach the other, since they are moving away from each other faster than light can cross the distance between them. This is a local analogy of the horizon problem encountered in cosmology. How can universes, even if they exist, that are over the horizon, have any effect on our universe? If they cannot, then there is no use in postulating that they exist.

I am saying that the two astronauts exist in two universes, or at least in universes that are over the horizon from each other. In no way can anything one astronaut does ever influence anything the other astronaut does.

BUT! What if the astronauts turn around and go back to Earth, where they can meet up again and shake each other's hand?

Then it is not true that one cannot ever effect the other, since if one of them made a horrible mistake and flew into a black hole or something, then the other would return to find no hand to shake. That is why I think universes branch out, and also why I think they can join back together again. They may be isolated from each other in some spacetime regions, but not isolated from each other in other, contiguous regions.

What do you think?

nc

 

[marcus]

Dynasties rise and fall in a sigh. ...

I have thought of a good word for what the universe does. It is Burgeoning.

burgeoning is a good word

BTW your multiverse vision (though it may not resemble the string theory Landscape) could be close to a striking, maybe even beautiful, inflation scenario (eternal, chaotic, I am not sure of the terminology: some version of inflation). I assume you know this and are more aware of the details than I. I don't deny the appeal to the imagination of some of these scenarios. Rather am focusing on the "burgeoning" or budding, forking, branching evolutionary model of Smolin because it offers hope of explaining values of some physical constants.

about the two astronauts, have to think. To turn around and rejoin each other they would, I suppose, have to turn the rockets around and decelerate, also let's say at gee. So they would spend a while turning around. At some point news would reach them of the other's doings and they would get the emails or telegrams they had sent each other. so by the time they met they would have caught up on the news. I don't see them separated by a real horizon. something I'm missing?

 

[nightcleaner]

Hi Marcus
I made it into my cabin today, and heard the first spring peepers. There are not so many of them as there used to be in my memory years, but they sing sweetly and I keep a mark of their first song each spring. Two ravens flew to my right, one carrying something white in his bill.

I found my espresso maker, and am now sipping the first full bitter brew since last fall. I thought I had it in my gear but got back down to town just ahead of last years first real snowfall, and without it. All winter I have been drinking American Perk.

I don't get back into my cabin much in winter any more, since I broke my leg in a fall off a roof two and a half years ago. I haven't snowshoed or skied for the past three winters, and I don't even get to hike much. So the half mile walk down the driveway and back was a good exercise. The snow is almost all gone, just lingering in banks on north facing slopes.

The sloughs are a little dry this year, and the seasonal creek that often runs in my tire tracks for a hundred yards down into a black ash swamp hasn't made an appearance. The wardens have just yesterday posted fire notices. We do not want a dry season this year.

Well, the astronauts. The point I am trying to make is that if they had not turned, their universes would have been separated forever, just as in the causality breeching models. My point is that they can seperate, and can rejoin, and in fact commonly and regularly do both. There is no need to assume that once separated they can never affect each other again. Nor is there any need to assume that the universes are separated by sharp boundaries with widely varying constants on either side. The constants may be different, I don't know, but for the most part the increment of variation between adjacent universes seems to be very small. That is, after all, a necessary condition if we are to recover our three dimensional continuity from the multiverse idea.

I must admit I am disenchanted with the string landscape, so far as I have been able to understand it. Perhaps this will make you smile. All those little Calabi-Yau manifolds clinging to a wire cage-like background...at best I can accept this as a first approximation. But do they interact? Are they stacked in three dimensions? No one I have talked to wants to address these questions for me. I suppose I may just be naive, and the questions aren't any good, but it bothers me.

And I too am very interested in the quest to generate the constants from first principles. There was a time when I thought I could generate them myself, but I have learned a lot about this topic in the past couple years and the more I learn, the less I seem to know. I still want to extend my 4d vision and attempt to learn enough math to attempt the calculations, but the goal is still a long way off.

Lots to think about.

Be well,

nc

 

[marcus]

Hi Marcus
I made it into my cabin today, and heard the first spring peepers. ... espresso maker, and am now sipping the first full bitter brew since last fall. ...

sounds great, being at your own cabin in the big woods, listening to the frogs and drinking the only good coffee for miles around

I was just up our local hill and watched a red-tail hawk circling near the top. I hadnt known their tails were so red, til this one caught the sun just right and I saw the glow.

having a cabin where you can enjoy spending time by yourself sounds enviable. from your saying slough I think it is near some lake, what lake?
my idea of a slough is a finger off of a lake that collects snow-melt water and feeds it to the lake. (not sure of the meaning)

how can you use your computer at a remote cabin, do you have power lines?

 

[wolram]

I think of the universe as a continuum filled with electro magnetic radiation,
our galaxies are just "hot spots" in this continuum, as i do not believe in a
"hand of god" universe, these "hot spots" could only form if the range of
possibilities of interactions is very limited, maybe these interactions are
limited by the possible harmonics of two primordial waves, the most important
harmonics giving us the constants and the lesser fading away in significance.
These "waves" could have been self canceling until some event threw them out of sync.
so if gravity is the major player in the formation of our universe, it must
be one of the first or second harmonics of these waves, the ones that give
us spin foams, the other harmonics would give us EMR and particles.
I guess the question is, is it possible to construct "every thing", from these
waves?

 

[marcus]

I think of the universe as a continuum filled with electro magnetic radiation,
our galaxies are just "hot spots" in this continuum,...

I also believe in this, with certain modifications. So also do many others, probably. So, I think, did Einstein, who sought the unified field for many years after his productive life as a physicist ended.

For me, tho, beliefs don't cut the mustard. what excites me are the tiny steps of progress along the way.

I think that Einstein would not have called his unified field the "electromagnetic" field. He was looking for something that was analogous to both the EM field and the gravitational field. So where you, for definiteness, say "electromagnetic" he would say a kind of master field that would have these other things as facets.

(sort of like, the EM field is one field, with several facets already: it includes both electrostatic attraction/repulsion and magnetism as different facets, plus its undulations can represent lightwaves as you well know.)

I actually don't know very much about Einstein's thought, after, say, 1920 to his death 50 years ago in 1955. but I probably know enough to say what I am saying, which is that his idea of a unified field that describes space, time, material (all being, in effect) has been not just his idea but is a widely shared notion.

For insttance, look at ohwilleke's post about Alexander's paper
https://www.physicsforums.com/showthread.php?p=530777#post530777

Willeke says he has detected a kind of movement or trend in research where people are trying to unify LQG with the standard model----or unify LQG with QCD (quantum chromodynamics) which would achieve that goal, I expect, if it were successful.

wolram, I think your vision is basically on target.
And it is coherent with the long-range vision of many scientists.

where we differ most, I suspect, is in the category of patience. By my standards you seem to be chomping at the bit. You see the goal and you already want to be there.

I am craving for even a tiny step of visible progress. I see humanity like a toddler just beginning to walk, or crawl even, so if I can see it making even an inch of headway I shall be greatly cheered by this.

right now I am excited simply because the Bojowald, Goswami, Maartens, Singh paper has found that the LQG model of black hole collapse continues on into something like the LQG model of big bang expansion. I think that will eventually contribute to a better understanding of the unified field encompassing spatial geometry (or gravity) and matter----why the numbers in that field (which you call its harmonics and others call the constants of nature) are what they are

I'm not saying it is wrong to chomp at the bit, or that it is always good to be patient. It is just a difference in temperament which I notice. Someone could do good research either way, I imagine. Perhaps highly impatient scientists even have some advantage or odds in their favor. But I tend to see it as neutral.

 

[marcus]

there is now a CNS thread in Astronomy forum.
https://www.physicsforums.com/showthread.php?t=71608

Chronos started it.

 

[wolram]

Hey Marcus i like big steps, The one i am eagerly awaiting is the
discovery of the Axion, I have just posted a link in the "Alexander paper - CP and lambda" thread, it seems this major player is about to be ranked
or not, I am sure you will agree that will be a BIG step.

 

[spicerack]

I like to think of the connected bubbles in a foam type of multiverse scenario where ours is separated by another membrane with black holes being the connections to channel energy form one to another which I think is not too dissimilar to smolin's model and allows for wormholes and white holes. And in this multiverse there is ME in this universe and an echo of me that is slightly different given the time difference in creation but like all echoes they fade as my consciousness gets diluted through seepage into other universe such that the more disconnected I am from this universe as in one that is separated by many degrees of separation it can allow for universe that do not even have a ME in it and that is assuming that the constants are such in those echoverses that it can evolve carbon based life forms.

I also think having extra dimensions does help for consciousnes to transcend the multiverse and for some universe to have collapsed spatial dimensions and only be 2 d or 11d or whatever and that these dimensions are interchangeable at Planck level and superluminal speed such that we as conscious entities might just be threads weaving our way through the mulitverse foam all the time but always in a 4d universe as we are only 4d entities. Maybe even the presence of life/consciousness changes the constants to suit us specifically.

And maybe then it is possible for some people to loop back around to this one as a deja vu/dream but not physically

hmmmm...ok so maybe this post would have been better in the crackpot section or the metaphysical one. Don't you think it's funny how we all jump from thread to thread in different forums of this one site but still retain our conscious thoughts that define us but they get changed by interaction with other sites and even to the point where we post links to other sites. Just think the internet as a model for the universe and evolution bits and bites of on off switches in virtual reality.

oh well it's out there make of it what you will cos that is a lot of may be's to deal with... I had fun writing it I hoope you have fun reading it but don't get too hung up on it either. They are after all just random thoughts.

 

[marcus]

Chronos (in the other CNS thread) has come up with two recent papers tending to support the CNS hypothesis!

Cheering news.

I will get the links.

my discussion of the Chevalier paper is here
https://www.physicsforums.com/showthread.php?p=533290#post533290

Chronos post, giving the link to the Chevalier paper was

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

the other paper, the one by Brown et al, was also flagged by Chronos

http://arxiv.org/abs/nucl-th/0504029

Brown is interesting for several reasons. He wrote some papers with the late Hans Bethe (one of the greats of 20th Century physics) and these Brown-Bethe paper were cited by Smolin in
"Scientific Alternatives to the Anthropic Principle" which was the paper that sparked current interest in CNS

 

[nightcleaner]

about the two astronauts, have to think. To turn around and rejoin each other they would, I suppose, have to turn the rockets around and decelerate, also let's say at gee. So they would spend a while turning around. At some point news would reach them of the other's doings and they would get the emails or telegrams they had sent each other. so by the time they met they would have caught up on the news. I don't see them separated by a real horizon. something I'm missing?

You miss very little, Honorable Librarian. What if only one were to turn? I am, by the way, not convinced that the hands which return to shake the Earth are the same hands that left it in another universe. They meet and touch after being beyond the border lands of places they could never meet or touch again. In what sense are they the same?

And in the multiverse, every outcome is the real one, you must count them all if you want to speak of everything. Space and time are not just like each other, they are the same thing. We should speak, the frogs tell me, not of space-like time or time-like space, but of what it is, seen like space or seen like time. Why do we see it thus? How do we choose, this shall be space, and now this shall be time? A simple two step, one space one time, results in a velocity of c.

We all run far in timelike for every step we take in spacelike. In fact almost all our worldlines are timelike. Once in a very great while, we skip a beat and transition one spacelike. Many steps in time for each step in space. We could look at these spacetime transitions as a ratio of time steps to space steps. Perhaps the ratio is something like 1/137, what then? What if there are one hundred and thirty seven time steps for each space? That determines an instant of velocity.

Instants of velocity cannot take on just any value, we know that they must be more than one spacelike for each timelike. This is to say that c is the limit of velocity in a universe, where a universe is defined as everything within a set of horizons. Each object has its own set of horizons, so in that sense, its own universe. But Spacetime is shared between objects, so that each universe overlaps, greatly with those objects in proximity, less for those objects at some distance. But distance, in the multiverse, does not stop at the horizon.

Consider two astronauts who do not turn back. They go on accelerating forever away from each other. Since they are soon moving at relitivistic speeds in opposite directions away from Earth, they soon lose contact and never choose to regain it. Note that both have to choose to regain contact for it ever to be again, and that in the multiverse every choice that can be made has to be made, some wherewhen.

Each of the two who do not turn back carry their horizons with them. For a goodly timespace, their universes overlap, but eventually they come to a placetime where they do not overlap at all any more. They are now still each in the multiverse, but each has a totally separated universe. Can they still rejoin? If they do rejoin, how do they know they have remet the twin in the universe they left, and not some other twin from some other branch of the multiverse? What if, for example, they met their anti-matter twin instead?

Watch out for the left handshake. (Who have I stolen the left handshake from? I know I read that about the anti-matter handshakes somewhere.)

And, what if they do not turn back, what if they keep on going in a straight line. Will they ever come to a place where the multiverse curves back on itself and repeats? Maybe they come to another Earth, another twin. After all, in infinity, every sequence must repeat.

We do S/T as Velocity, and T cannot be zero. Can S be less than one?

And is S^2 some nS? And what is T^2?

I am late for work and want to lay on my back by the lakeshore and look at the stars.

Have you ever looked at the stars through a night vision scope? Stalking the sky. Did you know that the N.E. shores of Lake Superior were known to the Anishinabe Nations as Stalking the Spirit lands? There was a sacred truce and war parties were not supposed to come here. But that dream remains broken.

Be well, or at least, be better. Better than me behind the grease trap tonight anyway, I hope. I have a deep fryer boil-out to do, and two kitchens to clean. I'll be back here again near dawn, and I have Tucker with me tomorrow. Sleep, blessed sleep, and the silence between the stars.

Richard

nc

 

[marcus]

Who have I stolen the left handshake from?

I think from Feynman. Unless my memory tricks me, he had this story where you have communicated over longdistance with some people and defined (by some physics experiments) what lefthanded and righthanded means and then you agree that when after a lengthy voyage one of them will come to visit you should shake hands earth-fashion. And if he then extends the wrong hand to shake you should get out of there fast because he thinks positrons are electrons and such people are not healthy to be around. Isnt that a Feynman physics story? Can somebody with a more reliable memory say?

Have you ever looked at the stars through a night vision scope?

No, never had that pleasure. It would help compensate for my fading natural nightvision and the urban haze around here. Might be nice.

I have a deep fryer boil-out to do, and two kitchens to clean. I'll be back here again near dawn, and I have Tucker with me tomorrow. Sleep, blessed sleep, and the silence between the stars.

I hope you had several peaceful days and nights out at the cabin. It sounded wonderful. now you seem to be back in the daily grind. I don't know what a grease-trap is, exactly, but cleaning out plumbing can be dreadful and our kitchen drain goes into a poorly designed section of pipe in the basement, where a hefty electric-drill-powered snake must occasionally be used. Opening up that section of pipe to get the snake into it can be an unforgetable experience.

 

[Chronos]

Opening up that section of pipe is beyond unforgetable, marcus. It is foul, disgusting, nasty - you basic essence of all evil - Hela's jello. Is there enough drop in the plumbing? You should have no less than 1/8" per foot over the entire length - especially coming out of the drain. A friend had a pvc line that clogged due to a bow in a long, improperly supported straight section. A few strategically placed pipe hangars can do wonders.

 

[nightcleaner]

Good morning. Fog. I drove home from Duluth along the North Shore Scenic Route, numbered 101 hereabouts. Old Highway 61, the one Bob Dylan sings about. 25 miles at seventeen miles per hour...from London Road in Duluth to The Stewart River north of Two Harbors. Night birds are singing spring songs.

I suppose my life may sound idyllic except for the grease trap part. Dawn on the north shore of Lake Superior can be unforgettable. So can the smell of a grease trap. Especially if no one has bothered to clean it out for a year and a day. I clean the one at Betty's more often. It is good to wait until there is a few inches of grease, but not good to wait until the grease goes to cake. A rich gravy is what you are looking for, easy to dip out, not too smelly. Don't get any on you. The odor does not go away.

My cabin is totally rustic and very haughty about electricity. We are off the grid. I use a few batteries for radio and bright lights but mostly like it quiet and dark. I can't see an electric light from my window, but if I stand in just the right place on the porch I can glimpse a red flasher atop a commo tower about four miles to the north.

I've had this land thirty years now. Bought it from a paper company. Big trees, it hasn't been logged in a hundred years. Seven miles of gravel to tar, then eight more miles to town. My driveway is a pair of ruts through the woods, half a mile long, most of it through a neighbor's property. The cabin is logs laid up on concrete piers, a railroad tie steps up to the tiny porch. 10' by 16' overall, and sixteen feet high off the ground to the peak of the gambrel roof. I always have meant to add an addition to the north side. A large picture window looks to the south, nothing but trees and a stone firepit. I have a wood stove.

Slough? Maybe you are right, Marcus, maybe it is a swampy arm off a body of water, but to me "the slew" has always just meant a soupy area, too thick to paddle and too thin to plow. We have a drumlin morraine landscape here, rough gravel and every size of stone, with a good measure of clay to hold it all to a concretion. Northern Boreal, mostly balsaam fir, black spruce, sugar maples and paper birch. In the low places, alder thickets, kitty willow and marsh mallow. Moose live here. Black bears. Gray wolves, timber wolves, brush wolves, coyotes, feral dogs, weasles, martins, fox and skunk, deer and cougar, lynx, bobcat, fisher, beaver, bald eagles, ravens, crows, red tail hawks, peregrine falcons, great gray owls, and I have not named all my neighbors yet. Yeti tracks were seen two months ago in the next county.

But as for me, I take my pleasures straight. Black coffee, sippin' whiskey, cold clean water. The air before dawn in the early spring after a fog. And sleep, sweet and long.

Be well, Marcus and all.

Richard

 

[marcus]

... a soupy area, too thick to paddle and too thin to plow. We have a drumlin morraine landscape here, rough gravel and every size of stone, with a good measure of clay to hold it all to a concretion. Northern Boreal, mostly balsaam fir, black spruce, sugar maples and paper birch. In the low places, alder thickets, kitty willow and marsh mallow. Moose live here. Black bears. Gray wolves, timber wolves, brush wolves, coyotes, feral dogs, weasles, martins, fox and skunk, deer and cougar, lynx, bobcat, fisher, beaver, bald eagles, ravens, crows, red tail hawks, peregrine falcons, great gray owls, and I have not named all my neighbors yet. Yeti tracks were seen two months ago in the next county.

But as for me, I take my pleasures straight. Black coffee, sippin' whiskey, cold clean water. The air before dawn in the early spring after a fog. And sleep, sweet and long.

...

this raised a surge of enthusiasm----a proper sort of life.

Someone reminded me of something i posted back in July last year about earlier Smolin papers (mid 1990s) discussing the CNS idea.

------quote from earlier post-----

Smolin's 1995 Landscape of Physical Law idea


It's interesting that Lee Smolin used the idea of an evolutionary Landscape of physical law back in 1995

http://arxiv.org/gr-qc/9505022

We just had that young quantum gravity researcher Leonardo Modesto at Marseille remove the Black Hole singularity so that spacetime extends thru the black hole to somewhere else ("Disappearance of the Black Hole Singularity in Quantum Gravity" http://arxiv.org/gr-qc/0407097 )

Smolin explicitly anticipated that kind of result in Quantum Gravity---eliminating classical GR's Black Hole glitch----in his 1994 paper
"The fate of black hole singularities and the parameters of the standard models of particle physics and cosmology"
http://arxiv.org/gr-qc/9404011
This 1994 already is describes the Landscape concept but doesn't apply the word "landscape" to it.

----from 1994 abstract---
The implications of a cosmological scenario which explains the values of the parameters of the standard models of elementary particle physics and cosmology are discussed. In this scenario these parameters are set by a process analogous to natural selection which follows naturally from the assumption that the singularities in black holes are removed by quantum effects leading to the creation of new expanding regions of the universe.
---quote---

In the 1995 paper the analogy is drawn between the genes of an organism and the parameters of physical law which generate the universe---the genes are to the organism as the fundamental constants and the laws of physics are to the universe----different values of the constants means a different universe.
In evolutionary Biology the ensemble of all possible sets of genes for an organism constitute a "Fitness Landscape" and this will have hills and valleys determined by a fitness function, with selection driving the gene pool to higher nearby levels of fitness (reproductive success).

Smolin draws the analogy explicitly (see e.g. page 33) and proposes a way the ensemble of possible sets of physical constants can be seen as a reproductive fitness Landscape.
the act of reproduction in this case being the formation of a black hole.

He is able to make a falsifiable prediction from this--which as of today still stands and has not been refuted

"... leads to a definite and testable prediction, which is that, Almost every small change in the parameters of the standard models of particle physics and cosmology will either result in a universe that has less black holes than our present universe, or leaves that number unchanged..."

----end quote---

 

[marcus]

I've not yet tried having a "signature" line to my PF posts. Maybe this 1995 testable prediction of Smolin would be a good thing to try as a "sig".

It is an experimentally testable proposition----you don't have to believe or disbelieve it: that is not what it is for.

what it is for is to make some experiment or astronomy observation that proves it wrong. Like the neutron star mass thing. If you could sometime detect a neutron star with mass 3 solars, then (Smolin says) that would disprove it because by making a small change in the physics parameters one could make the N-star equation of state a little softer and that particular neutron star would go *glup* and form a black hole. this would INCREASE the number of black holes: contradicting the prediction.

 

[marcus]

Page 31 of Smolin's "SA to the AP" paper seems to be the heart of it, for me at least:
---quote---
The crucial conditions necessary for forming many black holes as the result of massive star formation are,

1. There should be at least a few light stable nuclei, up to helium at least, so that gravitational collapse leads to long lived, stable stars.

2. Carbon and oxygen nuclei should be stable, so that giant molecular clouds formand cool efficiently, giving rise to the efficient formation of stars massive enough to give rise to black holes.

3. The number of massive stars is increased by feedback processes by which massive star formation catalyzes more massive star formation. This is called "selfpropagated star formation", and there is good evidence that it makes a significant contribution to the number of massive stars produced. This requires a separation of time scales between the time scale required for star formation and the lifetime of the massive stars. This requires, among other things, that nucleosynthesis should not proceed too far, so that the universe is dominated by long lived hydrogen burning stars.

4. Feedback processes involved in star formation also require that supernovas should eject enough energy and material to catalyze formation of massive stars, but not so much that there are not many supernova remnants over the upper mass limit for stable neutron stars.

5. The parameters governing nuclear physics should be tuned, as much as possible consistent with the forgoing, so that the upper mass limit of neutron stars is as low as possible. The study of conditions 1) to 4) leads to the conclusion that the number of black holes produced in galaxies will be decreased by any of the following changes in the low energy parameters:

• A reversal of the sign of Dm = m_neutron - m_proton.

• A small increase in Dm (compared to m_neutron) will destabilize helium and carbon.

• An increase in m_electron of order m_electron itself, will destabilize helium and carbon.

• An increase in m _neutrino of order m_neutrino itself, will destabilize helium and carbon.

• A small increase in alpha will destabilize all nuclei.

• A small decrease in alpha_strong, the strong coupling constant, will destabilize all nuclei.

• An increase or decrease in G_Fermi of order unity will decrease the energy output of supernovas. One sign will lead to a universe dominated by helium.

Thus, the hypothesis of cosmological natural selection explains the values of all the parameters that determine low energy physics and chemistry: the masses of the proton, neutron, electron and neutrino and the strengths of the strong, weak and electromagnetic interactions.

---end quote---

 

[marcus]

Smolin CNS offers an explanation for why the fundmental constants are their observed values (incidentally very important to the life that has arisen with these constants in place, essentially as a by-product or side-effect of optimality for black hole reproduction).

this explanation is contingent on CNS being sufficiently elaborated and tested to gain substantial credibility. It might, as a part of CNS, be proven wrong by empirical tests----but so far (in the 10 years since Smolin proposed it) has not been.

This explanation is, in a sense, antithetical to the "Anthropic Lack of Principles" which essentially gives up on finding an empirically testable theory explaining the constants. the "AP" does not unpredict the possible outcome of any future experiment--nothing we could possibly observe is incompatible with the existence of conscious life--the "AP" is not falsifiable and so is not part of empirical science.

I came across a post by Peter Woit on sci.physics.reasearch which gave some valuable background on the struggle against the "AP", which goes back to 2003.
-----quote from Woit on SPR----

Lubos Motl wrote:
>On 26 Oct 2003, Peter Woit wrote:

>>http://online.kitp.ucsb.edu/online/strings_c03

>Superstring cosmology is still a new subfield and this conference shows
>how preliminary many results in this subfield are. I enjoyed e.g. David
>Gross's talk that said - among formal things - that there was one thing
>that everyone agreed upon: the anthropic principle is nonsense. :-)
>Well, Lenny is wrong, but his lecture was well-presented, as always.

"Preliminary" is a very polite way of characterizing the results
presented at that conference.

David Gross is clearly quite upset about the way string theory is
going, for more detailed comments by him about the anthropic
principle, see his comments at the recent Kavli-CERCA cosmology
conference

http://www.phys.cwru.edu/events/cerca_video_archive.php

In these comments he describes the anthropic principle as a "virus"
or disease and tells the following story: evidently last year his
colleague Joe Polchinski at UCSB was saying he would resign
his professorship if anthropic arguments took over in string theory.
Recently Polchinski has gone over to the other side and become
a convert to anthropic reasoning. Gross is getting very worried
and even accuses his colleagues of essentially giving up on
science and instead invoking something close to the
"intelligent design" arguments of religious fundamentalists.

You can also hear Gross's closing talk at Strings 2003 on the web at

http://www2.yukawa.kyoto-u.ac.jp/~str2003/speakerspro.html

He ends by quoting a supposed speech of Winston Churchill's. In
Gross's version, near the end of his life Churchill rose to give a
campaign speech: "Never, never, never, never, never give up". This
story is similar to one repeated by many people, but the details
seem to be as much a fantasy as the rest of Gross's talk. A friend
points out to me that some of Churchill's speeches are online at

www.winstonchurchill.org

and the real source of Gross's quote is probably a speech
Churchill gave at Harrow school during the war, which contains
the lines:

"this is the lesson: never give in, never give in, never, never,
never, never-in nothing, great or small, large or petty - never give
in except to convictions of honour and good sense."

I'd always wondered what would happen when string theorists
finally started to realize that their theory would never predict
anything. It now looks like, at least for now, the answer is
that they stick to claiming string theory is true, but become
devotees of the anthropic principle. I can't believe they won't
soon realize how silly this is and can't wait for the next
episode. The fact that you can watch all this on video in
nearly real time is pretty amazing.

Pass the popcorn...
------end quote----

http://olympus.het.brown.edu/pipermail/spr/Week-of-Mon-20031027/015106.html

 

[marcus]

Chronos has pointed out that Smolin CNS conjecture has been drawn into the struggle against the "Anthropic Principle".

to clarify the issues we can take a look at the history

the Anthropic non-Principle is pretty obviously pseudo-science since it doesn't have predictive value (testability, falsifiability)---it's mushy in other words.

the AP was always around, but didnt emerge as a threat until String/M was faced with a disaster (the January 2003 KKLT vacuums paper) and a faction led by Leonard Susskind began appealing to AP.
then the lines were drawn and a struggle against the AP took shape.

up to the appearance of the KKLT vacuums paper the shared hope of String theorists was that the theory would eventually make falsifiable predictions
so that it could be tested. But many of them lost hope of that as a result of KKLT which seemed to say that String could never be predictive.

Susskind's move was an attempt to save String by changing the requirements of what a theory of nature was expected to do. If a theory was not supposed to bet its life on predicting "this but not that"---selecting between possible outcomes of future experiment---if it didn't have to be testable, then String was all right.

this caused a split, which in 2003 was called "The Great String Theory Crackup", with David Gross a prominent opponent, and the thing was discussed on sci.physics.research vociferously and at length during 2003-2004.

also somewhere along there the Templeton Foundation, with a program to blur distinctions between science and religion, started paying prestigeous big name scientists to attend conferences where they mix with theologians and flirt with the idea that the universe was designed for our benefit, to make us possible etc. John Templeton made a mint in the stock market and he was pouring money into undermining the tradition of empirical science, so there was a reaction to that.

Smolin's 2004 paper is intended for a book derived from one of these Templeton-funded conferences featuring anthropic multiversalists. AFAIK his may be the only effective dissent in the whole book, which is called "Multiverse or Universe" and due for publication this year.

=====but there is another more peaceable side to CNS=======

CNS came out around 1994, and the basic ideas go back to John Archibald Wheeler (Feynman's mentor, Princeton Inst. Adv. Study).
In its origin it had nothing to do with countering Anthropic tendencies in String, or the encroachments of religion, or any of that----all that stuff was not so important back in 1994.

here is Smolin's 1994 paper:
http://arxiv.org/abs/gr-qc/9404011
The fate of black hole singularities and the parameters of the standard models of particle physics and cosmology
27 pages

"A cosmological scenario which explains the values of the parameters of the standard models of elementary particle physics and cosmology is discussed. In this scenario these parameters are set by a process analogous to natural selection which follows naturally from the assumption that the singularities in black holes are removed by quantum effects leading to the creation of new expanding regions of the universe. The suggestion of J. A. Wheeler that the parameters change randomly at such events leads naturally to the conjecture that the parameters have been selected for values that extremize the production of black holes. This leads directly to a prediction, which is that small changes in any of the parameters should lead to a decrease in the number of black holes produced by the universe. On plausible astrophysical assumptions it is found that changes in many of the parameters do lead to a decrease in the number of black holes produced by spiral galaxies. These include the masses of the proton,neutron, electron and neutrino and the weak, strong and electromagnetic coupling constants. Finally,this scenario predicts a natural time scale for cosmology equal to the time over which spiral galaxies maintain appreciable rates of star formation, which is compatible with current observations that Omega = .1-.2."

 

[ohwilleke]

So, why should J.A. Wheeler's suggestion have any credibility? What backs it up?

 

[marcus]

So, why should J.A. Wheeler's suggestion have any credibility? What backs it up?

Hi Ohwilleke, you are talking about something that comes up in chapter 44 of the standard textbook often called "MTW"

Misner, Thorne, and Wheeler Gravitation (Freedman, 1971)

I don't know of any other reference for it. this is the reference which several authors give for this idea of Wheeler's.

Wheeler, as everybody knows, was one of the grand old men of 20th Century theoretical physics. Quotes and ideas of his often come up. If you want to know what reasons he offers for his idea, the best would be to look it up in Chapter 44 where he presents it.

I PERSONALLY CANT GIVE YOU ANY JUSTIFICATION for Wheeler's idea, at least that would be better than whatever he gives himself, which you can get "from the horse's mouth" instead of as secondhand hearsay.

=========footnote to this============

the idea Ohwilleke is asking be justified is the idea that the parameters of the Standard Model might not survive absolutely intact during a process where they suffer gravitational collapse to a quantum regime where ordinary spacetime breaks down in extreme density, curvature, and temperature, followed by a big bang including inflation.

To my mind it would seem a wonder if the parameters of matter were not altered one iota in that process. But Ohwilleke sees it differently and asks that the notion they might change slightly be justified.

this is all pretty interesting. I think of the parameters of matter (numbers describing masses and forces in terms of the natural or Planck units) as being immanent in spacetime----as being inherent in a region like some extra labeling on the spin network state of the gravitational field (if that description is correct).

If you put that piece of spacetime thru the wringer, and essentially "melt" it, virtually annihilate its geometry, or make it have all kinds of geometry at once, then it seems reasonable to me (as non-expert bystander) that the physics parameters "riding along" with that piece of spacetime might suffer some slight alteration. maybe John A. Wheeler thought so too, back in 1971.

But no substitute for reading it in his own General Relativity textbook

 

[ohwilleke]

I asked because I don't have $100 to spend on a textbook right now, even if its a classic that I've skimmed in a college bookstore a few times and longed to buy. Being a professor doesn't pay nearly as well as being a full time practicing lawyer.

 

[marcus]

I asked because I don't have $100 to spend on a textbook right now, even if its a classic that I've skimmed in a college bookstore a few times and longed to buy. Being a professor doesn't pay nearly as well as being a full time practicing lawyer.

we are both in the same boat Ohwilleke, sorry to say. But we must both be close to university libraries! Let's both get over to the physics departmental library and look this up----I just have secondhand references too and it is not really satisfactory.