Will LQG explain the constants?

[wolram]

The penny has droped MARCUS, sometimes it takes a huge push,but i can
give no input yet, god i am so thick, i must ponder the enigma, it may take
hours or years but i will be thinking.

 

[selfAdjoint]

Smolin talks in his paper about the top quark mass. Why is that important?
why would having that mass be in a certain range help with black hole production? Maybe that is too hard a question for us.

Mmm, I remember that top quark mass constrains Higgs and superpartner masses (raising top mass a smidgen narrowed a window of posssiblility for the MSSM last December). If it can do all that then it probably influences early hadron production, which is critical for BH. But I haven't yet read Smolin's reasons. Gotta get on that.

 

[wolram]

It seems to me that particle energy and life time must have something
to do with constants, if i remember correctly, the top quark is not the
most energetic, but averaged over some time period it is the most
prolific, so take energy over time and you have a constant.

no miss spellings found wow.

 

[marcus]

this just came out today
http://arxiv.org/abs/gr-qc/0504043
Quantum Gravitational Collapse
Leonardo Modesto
13 pages

"We apply the recent results in Loop Quantum Cosmology and in the resolution of Black Hole singularity to the gravitational collapse of a star. We study the dynamic of the space time in the interior of the Schwarzschild radius. In particular in our simple model we obtain the evolution of the matter inside the star and of the gravity outside the region where the matter is present. The boundary condition identify an unique time inside and outside the region where the matter is present. We consider a star during the collapse in the particular case in which inside the collapsing star we take null pressure, homogeneity and isotropy. The space-time outside the matter is homogeneous and anisotropic. We show that the space time is singularity free and that we can extend dynamically the space-time beyond the classical singularity."

2 or 3 years ago Modesto was still doing string theory research at Torino U. He has come up in the world

the main thing about this paper as compared with his earlier two on the same subject (removing BH singularity and extending the spacetime on beyond where the singularity was)]
is that in this paper he includes matter

 

[Kea]

Conceptual Problems with Resolution of Singularities

...In my view IT IS JUST THE SAME UNIVERSE so I do not perceive anything different from the normal business of extrapolating back in time except that it does not stop at the former, or classical, singularity.

So I don't see any new philosophical problem arising.

Hi Marcus

Ashtekar and Bojowald, in their "Black Hole Evaporation: A paradigm", make it clear that classical spacetime is not even a valid approximation "near" singularities. I have no problem with your classical picture of an extension back in the same universe except that it is invalid!

Now there seems to be some confusion about multiverses. I also agree that, by definition, there is only one universe. Does that mean there is only one classical reality? Let's assume that we restrict ourselves to one classical reality. Perhaps the Wiltshire universe. The consideration of quantum geometries outside the realm of applicability of the classical geometry leads to a picture of "quantum multiverses", ie. multiple geometric states. OK - bad terminology - agreed. The MWI people talk like this all the time though, and they don't mean classical babies.

Let's assume now that we are permitted to consider the existence of a fixed (classical) black hole, which is after all a nice solution of Einstein's equations. The work of Bojowald et al views the transition from this geometry to the quantum regime as a sort of continuous muddying of our vision. I am afraid I have serious conceptual problems with this picture, as I do with any picture that attempts to describe quantum gravity from such an objective perspective. Do you see what I'm getting at?

The way I understand it the actual mathematical resolution of singularities comes down to the nature of the volume spectra. In other words, the appearance of a MASS GAP. Now, let me be quite clear here: I do not mean a mass gap because, yeah, volume - something to do with mass maybe. I mean MASS GAP as in THE PROBLEM in QFT. A blowing up of curvature near BH singularities is dual to an understanding of the mass gap question. Now I happen to have my own opinions on how we should understand this, as I have previously discussed, and it requires us to relinquish objectivity and set up QFT in a categorical framework.

Sorry for all the italics. Maybe I'm not making sense. Anyway,
All the best
Kea


P.S. Have you looked at the 2 latest versions of the Wiltshire papers, yet?

 

[marcus]

... I have no problem with your classical picture of an extension back in the same universe except that it is invalid!
...

you may have misunderstood something I said, Kea. I don't have a classical picture of an extension. Not sure what you could be talking about.

I urge you to read the fine print in the recent Ashtekar and Bojowald paper, they qualify so much, and are so tentative, that there is not much to be drawn by way of conclusions.

Personally, i will take a wait and see attitude towards what is valid and invalid

cheers

 

[Kea]

I don't have a classical picture of an extension...

OK. Then I'm confused. So we're considering a singularity? Is it always there when we're not looking at it?

Kea

 

[selfAdjoint]

A blowing up of curvature near BH singularities is dual to an understanding of the mass gap question.

You mean this literally, I suppose. Could you expand the thought / "break open the scripture" as the religious people say?

 

[marcus]

would people interested in this thread please have a look at Modesto's new paper?

this just came out today
http://arxiv.org/abs/gr-qc/0504043
Quantum Gravitational Collapse
Leonardo Modesto
13 pages

"We apply the recent results in Loop Quantum Cosmology and in the resolution of Black Hole singularity to the gravitational collapse of a star. We study the dynamic of the space time in the interior of the Schwarzschild radius. In particular in our simple model we obtain the evolution of the matter inside the star and of the gravity outside the region where the matter is present. The boundary condition identify an unique time inside and outside the region where the matter is present. We consider a star during the collapse in the particular case in which inside the collapsing star we take null pressure, homogeneity and isotropy. The space-time outside the matter is homogeneous and anisotropic. We show that the space time is singularity free and that we can extend dynamically the space-time beyond the classical singularity."

I guess some people may miss this, so I had better make the point explicit.

Modesto let's time fork

so in his quantum model, space and time extend past the singularity

Ashtekar and Bojowald, in their recent paper explicitly make the assumption (which they do not need to make) that time does not fork and there is only one (not two) futures at infinity. this constrains their analysis and forces their conclusions. they say outright that this one-future premise is an assumption on which their analysis is based.

To my mind that is biasing the results with a straight-jacket constraint on the outcome. I can see why they would want to do that, given the widespread preconceptions surrounding the "BH information paradox".

Modesto, on the other hand, does NOT make that assumption. Since he is a Marseille postdoc working with Rovelli and has co-authored with Rovelli, that makes me very hopeful.
Rovelli may have decided that we can stop trying to constrain time not to fork at a black hole and, so to speak, "let the mathematics tell us what it is trying to say."

 

[marcus]

Duh, I had forgotten about this paper by Bojowald et al
http://arxiv.org/abs/gr-qc/0503041
so much is happening now with LQG and black holes that my memory is not keeping it all together, I should write things down in a list of links that just apply to this one thread.

A black hole mass threshold from non-singular quantum gravitational collapse
Martin Bojowald, Rituparno Goswami, Roy Maartens, Parampreet Singh
4 pages, 3 figures
AEI-2005-020,IGPG-05/3-3

"Quantum gravity is expected to remove the classical singularity that arises as the end-state of gravitational collapse. To investigate this, we work with a simple toy model of a collapsing homogeneous scalar field. We show that non-perturbative semi-classical effects of Loop Quantum Gravity cause a bounce and remove the classical black hole singularity. Furthermore, we find a critical threshold scale, below which no horizon forms -- quantum gravity may exclude very small astrophysical black holes."

this one also does allow time to fork at the black hole, that is, there is a bounce and spacetime continues through the singularity.

there is a transition from studying BH collapse to studying (with the same model a few moments later) a BB cosmology situation with inflation automatically supplied by the LQG dynamics.

"Then dj remains finite as a -> 0, unlike in conventional quantum cosmology, thus evading the problem of the bigbang singularity in a closed model [6]. Intuitively, one can think of the modified behavior as meaning that gravity, which is classically always attractive, becomes repulsive at small scales when quantized. This effect can produce a bounce where classically there would be a singularity, and can also provide a new mechanism for high-energy inflationary acceleration [7]."


OK so Bojowald, Maartens, Singh, Goswami HAVE provided a quantum model that depicts black hole collapse, with matter, and then moves right on ahead into a new big bang.

I had not registered that clearly in my sluggish brain.

they preceded Modesto in reaching this stage and he cites them. Also they use more standard representative LQG methods.

Here are a few more exerpts to give the flavor:
"In the semi-classical regime (where the spectrum can be treated as continuous), dj has a smooth transition from classical to quantum behavior, ... In loop quantum gravity the Hamiltonian of a scalar field in a closed universe is...
...This leads to a modified Friedmann equation [7, 8], ... Then the Friedmann equation becomes ...The energy density and pressure are modified as..."

Friedmann equation is the basic equation in cosmology. they have a quantized version. They start by modeling black hole collapse and move smoothly into the grand opening of a new branch of the cosmos. One leads to the other as the night the day. cool.

 

[marcus]

Bojowald Goswami Maartens Singh use a diagram called a Eddington Finkelstein diagram. here is a link where Andy Hamilton explains and illustrates several BH spacetime diagrams including this kind:

http://casa.colorado.edu/~ajsh/schwp.html

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.

the Bojowald et al, and the Modesto papers are the closest so far to making the connection hole-to-bang, so since they both happen to mention work of Vaidya I want to check it out

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

 

[wolram]

In the beging there was only gravity and radiation in the universe,If we call
gravity, "space time" or "metric", then, a short time after the BB it would be
feature less, deviod of any infomation, the only thing that could imprint information
onto, the "metric", is radiation, this imprinted information could be remebered
by the mico states of the metric by, spin or tensions in the connections, or some
other unkown, "to me".
For some particles to exist, as in our universe, some limit would have to be imposed
on the max, min freqeuncy allowable in the metric, this max, min frequency would
give the fundamental constants.

Fundamentalphysical constants.

# the mass of the up quark
# the mass of the down quark
# the mass of the charmed quark
# the mass of the strange quark
# the mass of the top quark
# the mass of the bottom quark
# 4 numbers for the Kobayashi-Maskawa matrix

# the mass of the electron
# the mass of the electron neutrino
# the mass of the muon
# the mass of the mu neutrino
# the mass of the tau
# the mass of the tau neutrino
# 4 numbers for the Maki-Nakagawa-Sakata matrix

# the mass of the Higgs boson
# the expectation value of the Higgs field

This max, min frequency, would have to be connected to the Hubble constant, for obvious
reasons.
From the above list, the Top quark couples to the "higgs Field", more strongly than
any other Fermions, I am not sure about the Higgs Field, but it is supposed to give
particles Mass.
------------------------------------------------------------------------------------------
This part needs to be filled in.



So if the expanding uninverse can not "out run", the interactions of the imprinted
information in the metric, the metric will densify to such an extent that the information
contained in it will no longer be coherent, and will separate into pure gravity and information

 

[wolram]

I guess that space time that is excited below a certain energy level
could be termed," dormant", or not imprinted with information, this would be where only zero point energy is "active".

 

[wolram]

I guess under, this part needs filling in, i should put.
It is only the Hubble expansion rate, and combined mass, energy of the
contents of the universe, that will govern expansion forever, or BHs
forming in local pockets, and gradualy forming into a state of zero
information

 

[marcus]

In the beginning there was only gravity and radiation in the universe,

If we call gravity, "space time" or "metric", then, a short time after the BB it would be featureless, devoid of any infomation,

the only thing that could imprint information onto, the "metric", is radiation, this imprinted information could be remembered by the micro states of the metric by, spin or tensions in the connections, or some other unknown, "to me". [unknown to me too]

For some particles to exist, as in our universe, some limit would have to be imposed on the max, min frequency allowable in the metric, this max, min frequency would give the fundamental constants.
[that is a kind of interesting idea, wolram. the metric puts a limit on frequency of vibration...intriguing thought]

Fundamentalphysical constants... #, #, #, #...
...

thanks wolram, I am always finding that your intuition is hardworking and gutsy, and am often aided by what you say---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?

 

[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 :tongue:

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