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Make out the position of Andromeda

  1. Apr 20, 2005 #1
    Very quiet around the board today. And yesterday. Where is everybody?

    I spent a night in the deep woods, lying on my back on the ground, looking at the stars. There was very little silence in the woods. The peepers have been joined by chorus frogs and tree frogs, and they are raving in every direction. I suppose we are justified in thinking that our own rantings, here and elsewhere, are more important than that orgy down in the swamp.

    There was a light haze in the sky, but I could still make out the position of Andromeda. The great bear was almost at zenith. I didn't see any meteorites, but there were curious little flashes of light, so swift that I doubt my sight. Maybe it was just too much coffee, or maybe sprites were leaping off the thunderstorms building to the west.

    One of the troubles with being a theorist is that you have nothing to hold on to. I could wish for a telescope or a microscope, or even a big number crunching computer terminal, when the world begins to spin. Where is the calm clear center point? I have to remember, on days like today, that it is within.

    Heirarchs have always tended toward absolutism, as it is difficult to maintain an elevated position in a society where no two people can agree which way is up. We seem to need a king or a pope or a shaman of some kind to give us a sense of stability, to be the single fixed point at the center of the whirlpool. I am not surprised that those who need to worship some thing have chosen as they have, to wall themselves in against ethical relitivaty.

    So black holes are not so black after all, and may be more like tunnels than like holes. So it has become much harder to find G-d in a universe which just seems to go on and on and on. So the Big Bang may have been more of a back-fire, a pop, a baby blowing bubbles in drool. So the constants might just vary just a little bit. So the scout leader turns out to be gay and the war hero has murdered his own wife and children.

    There are no weapons of mass destruction, we have invaded a country because we didn't like their leaders style in facial hair. Rape and pillage happen in war because they always happen in war, atrocities happen because they always happen, but the leader who led us into war is innocent. His smile is still confident. He is still the leader of the free world, center of the whirlpool.

    I have heard that Andromeda sings and I would like to listen to that. I would like to understand covarient and contravarient differentiation. Well anyway I think I would. I would like to live in a world where leaders try to help their people find their own destinies, rather than in a world where leaders insist on defining and enforcing their own narrow vision of the future.

    But hey, I'll go along with the crowd. It is not much fun singing to yourself in a swamp all alone. The croaking and chirruping and chorusing is lots more fun when everyone joins in. Let the orgy begin. We can worry about G-d later, when we wake up with dry mouth and a headache.

    nc
     
  2. jcsd
  3. Apr 20, 2005 #2

    selfAdjoint

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    Covariant differentiation is not hard. I don't believe there is any contravariant differentiation :).

    First of all consider ordinary differentiation of vectors. You define quotients by taking the difference between THIS vector and some other one close by, and dividing by the gap between them. Then you take the limit of the quotients as the gap shrinks to zero. This is great if the vectors everywhere in your space line up nicely, but what if your geometry varies from point to point? How are you going to make sense of the difference between two vectors at different points?

    Levi-Civita found the answer; you move your original vector parallel to itself, over to the other vector. When they are defined at the same point, you can take the difference. But when you do this, you find your original vector "turns in your hands" although you have done your best to keep it parallel to itself, because of the varying geometry. When you get it over to the other vector yes, you can take the difference, but now it is the difference between the other and the turned vector instead of the original. Mathematically the quotients will have a term involving the metric tensor of the geomety, to allow for the turning. And when you take the limits this term won't go away, and that's what makes the covariant derivative.
     
    Last edited: Apr 20, 2005
  4. Apr 20, 2005 #3

    marcus

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    Let's agree that god is a very cool idea. Personally I like haydn's creation where there is a lot of chirruping and chorusing in praise of (personified) creation. I dont see the need to wait for later, if you want to discuss the Creator of the Universe. Let that discussion be our orgy, if we must have one.

    god:

    ?o¿


    orgy:

    :!!)
    ¿¿
     
  5. Apr 20, 2005 #4

    marcus

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    how about that smiley? AFAIK I just now made it up! never saw that combination, with the inverted question-marks, before (but admittedly I dont get around on the internet much)

    I like the idea of a Creator who boots up and starts the Works and then goes off and lets it run. but that happened way before the big bang and before the 26 parameters of the Standard Model.


    he (of course he is a guy) let's things DESIGN THEMSELVES

    and that goes for the laws of physics and the constants of nature, as well as the gazelle.

    It is a demeaning insult to His Creatorness to assume that he applied his intelligence to designing, say, the anus of a housefly or an antelope. so as, you know, to get it just right.
    And likewise demeaning to imagine (as the "Intelligent Design" philosophers apparently do) that he got down on his hands and knees and adjusted each one of the 26 constants of the Standard Model so that houseflies and antelopes would be able to exist.

    the universe, as I picture it, is a Self-Designing Tree
    worthy of whoever invented it, if someone did
    and worthy in its own right, if no one did and it sprang of its own into existence.

    what I cannot stand is these guys who think that an Intelligence had something to do with the Big Bang, and with selecting the constants that shape our version of nature. these are things which we may reasonably expect to explain, as we better understand the evolving world..

    guys who tell us the constants either were chosen by some mind (or, just as bad, must be the way they are for us to exist) are saying in effect that they have no mechanistic explanation and it is hopeless to try to find a cause why they are this way. they just are this way and we should not try to understand how they came to be this way.

    Back in the Seventies I used to think it was pretty neat that the constants seem fine-tuned to foster life, by allowing complex chemistry, longlived stars, etc. Now that idea has metastasized like a mind-cancer and threatens to obstruct empirical science' quest for understanding.
     
    Last edited: Apr 20, 2005
  6. Apr 20, 2005 #5

    wolram

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    Dead end philososophy.
     
  7. Apr 20, 2005 #6

    marcus

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    I think so too, wolram. Anthropic dead end philosophy, and dead end religion as well.
    No respectable Creator would be caught messing with those 26 knobs on the Std.Mdl. If he's going to do it, then he's going to do it right---and create the whole Shebang to self-design, back to the umpteenth level.

    I expect that some places the constants are not so nice as they are here----not so conducive to prolific reproduction, branching, whatever. Probably some tracts of spacetime are more fertile than others because infused with better constants

    have to think about how the constants can be immanent in a patch of spacetime, how a region can have a signature that tells what particles can live in it and how they interact----so if it collapses it can pass on its physics to the next branch of universe stemming from it.

    La gloria di colui che tutto move
    per l'universo penetra, e risplende
    in una parte più e meno altrove.

    Nel ciel che più de la sua luce prende
    fu' io, e vidi cose che ridire
    né sa né può chi di là sù discende;

    perché appressando sé al suo disire,
    nostro intelletto si profonda tanto,
    che dietro la memoria non può ire.

    it is natural for a person to have their own cherished image of the universe. The german word, IIRC, is das Weltall (Welt-all: the "world-all"). We dont have to be bashful about this. Dante visualized the universe. We are just as good as Dante, so we can too.

    "the glory of him (or It) that moves all
    penetrates thoughout the universe, and shines
    more in some parts than in others.

    I was in the branch that gets the most of his light
    and I saw things which nobody can retell
    who has come down from there

    because our eagerness to know
    gets us into such depths
    that memory can't follow along behind"

    Hey, I translated that without looking :smile: it is the first lines of the first canto of Paradiso.
     
    Last edited: Apr 20, 2005
  8. Apr 20, 2005 #7
    What, no contravarient differentiation? The frogs have been lying to me again. But if it doesn't exist, that should make it easy to understand.

    Wolram, forgive me for guessing but you seem young. That is a safe bet for me because it is right more than half the time at my age, but in this case it is inspired by your contempt for philosophy. I should like to find out if your armor piercing realizm gets you any further than it has the rest of us in the attempt to escape philosophy. Personally, having looked a long time for a floor that will not give way and a roof that does not leak, I have come to the conclusion that philosophy is all we are ever going to get, so we might as well be satisfied with the draught.

    I am going to go have a talk with the frogs about that contravariant thing. Doesn't exist? Preposterous.

    Thanks

    nc
     
  9. Apr 20, 2005 #8

    marcus

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    that is a strange guess, nc. Of the three of us (myself, wolram, you) I would guess you to have the good fortune, if it may be called that, of being the youngest.

    I'm inclined to consider us all natural philosophers
    (in Newton's day science was called Natural Philosophy) and although perhaps somewhat cantankerous and idiosyncratic at times, all of an intensely philosophical bent.

    It just takes different forms.
     
  10. Apr 20, 2005 #9
    Hi Marcus

    Could be I am younger than I think. Wouldn't be the first time. But it is probably just that I am the most ignorant and easily confused that makes me seem young. Wolram seems young to me because of the seeming belief in something that doesn't shift when you aren't looking. But then, again, I may be projecting my own errors on others.

    Marcus, could there be a consciousness principle to match the anthropic principle? Well it seems rude of us humans to deny that say, bonobo's, do not have a form of consciousness. Or computers. I am not sure about lug nuts. (Yes, Marcus, there are bonobos that do have computers, but you know I am not talking about that.)

    Consciousness exists so the universe has to exist, because consciousness, after all, needs some place to be in. Con-sci-ousness, is that the ability to discriminate? In the sense of telling things apart. Registering one response for one condition and another response for another condition. Heck, even electrons do that. How else do they know not to jump in to someone else's quantum swimming pool?

    Smolin's CNS prediction, per your sig line, has a curious structure. There does not exist, that is a negation. No problem with that. But can we gain anything by examining tenses? Has there ever existed or might there ever exist, under this definition, a slightly differing set of parameters which would increase the prevalence of black holes?

    I ask because the idea of an evolution seems to imply some "experimentation" to find the right balance. A few more branes here, a little thicker in the girth there, just barely touch this knob. Something changes. The parameters were different but then they adjusted somehow to regain the balance point of maximizing the quantity of black holes.

    Well it is a minor point perhaps. I don't like the image of the hairy old guy twiddling his knobs either. Is it the hairy old guy part or the twiddling knobs part that is more obnoxious? Either way, if there is a creator who deserves to be worshipped, I agree it isn't that one.

    Maybe it is LGM who are the knob twiddlers. They twink the knobs with tentacles instead of thumbs. Multidimensional, they play with us as they like. I don't like that image either. Wouldn't it be terrible if it turned out the universe was really proven to be one of them?

    The self-evolving universe is most appealing, for avoiding those images if nothing else. But again the question is, what if lug nuts have a sort of consciousness? Fermi sea on a boson shore, reflecting the universe on a quantum foam surface more complex, potentially, than the neural folding of our crude chemical brain. Maybe the universe was originally set up to reproduce lug nuts!

    We monkeys think we are so dang smart with our vending machines and computers. But who wrote the rules for the quantum universe?

    Who is not the right answer. Who implies a differentiated being, and the universe by definition cannot be differentiated. As you say, there is only one universe. We are only little threads in the whole story, but our arrogance makes us believe we are the very pattern of the cloth. We are not. The whole thing has an intelligent design, but that is not the same thing as saying it has an intelligent designer, by the hundred monkey's theorum. Sooner or later an infinite universe, or a multiverse of universes, as which you like, will produce Shakespeare, and the dreams of the nightcleaner.

    We are, collectively, G-d, while individually of course we are just a bunch of knob twiddlers.

    Happy knobs, glad twiddling,

    Richard
     
  11. Apr 20, 2005 #10

    marcus

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    I agree! If for no other reason is right.

    I am still fumbling with the wording of that CNS prediction. As Smolin stated it in a 1995 paper, it is put in a positive way:

    (remember he wants to say that we have a parameters which are as good as they can get for prolific black hole production, so any change should make black holes less prevalent if it changes things at all, so he says)

    "Any small change you could make in the parameters of the standard physics and cosmology models would cause black holes to be fewer, or leave their number unchanged."
     
  12. Apr 20, 2005 #11
    There are some twentysix parameters, IIRC? Can they be stated in terms of mass, charge, spin, time, space, what? Or are they all independent?
     
  13. Apr 20, 2005 #12

    marcus

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    I checked that article and got the exact wording, and also discovered that it was dated 1994
    ---quote from http://arxiv.org/gr-qc/9404011 ----

    ...contemplated by particle physicists and relativists for many years. As I will describe, it 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. After I motivate it, the bulk of this paper will be devoted to presenting evidence in favor of this prediction.

    2 Cosmological natural selection

    A natural solution to the problem of the fate of black hole singularities, that has been discussed for many years*, is that quantum effects cause a bounce when densities become extreme (presumably of order of the Planck density) so that the worldlines of the stars atom that have been converging begin to diverge. As there is nothing that can remove the horizon, before, at least, the evaporation time of the black hole, which is at least 10^54 Hubble times for an astrophysical black hole and therefor, plausibly, beyond the scope of this paper, whatever new region of spacetime is traced by these diverging geodesics remains hidden behind the original horizon. Moreover, any observers in this new region see themselves to be in a region of spacetime which is locally indistinguishable from an expanding cosmological solution with an apparent singularity in the past of every geodesic. Thus, it would make sense to call this process the creation of a new universe that is (at least on scales shorter than 10^54 Hubble times) causally disconnected from our universe.

    *I learned of it from Bryce DeWitt in 1980, but I do not know who was the first to discuss it.

    ----end quote----
     
    Last edited: Apr 20, 2005
  14. Apr 20, 2005 #13
    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.

    Yeah, I think you made some reasonable adjustments to the language. Can we change the parameters physically in some location? Not really the issue. He is talking generally about any change, possible now or ever or not? Why small change I wonder? Large changes too hard to predict?

    Anyway can you vary one parameter up and the other down so that they cancel? Or is there some order or dependence of one parameter on one or more of the others? How are the parameters connected? Are they all just tied up in a sack together or are they stacked in some heirarchy? Tied up in orderly bundles?

    nc
     
  15. Apr 20, 2005 #14
    Anyway I am comfortable with how many black holes we have in this universe. It doesn't seem to me to be too many or too few. I don't see any locally unless they are very small, and I am not even sure that is possible.

    With bounce or no bounce, it seems acceptable to assay that the black holes are not exactly the nothing we once thought they might be and which was so abhorant to the flock. They are something, altho what might ever be beyond the scope of this paper. I suppose they might be the cables that we ants are permitted to dream that we might walk upon in some kind of practical joker's cosmic string theory. Going around and around. Give it enough time and it isn't the same space anymore. How deep is a hole? Can we measure the horizon? How much is light bent anyway?

    Garth says that light gets twice as bent as matter in freefall. Have you discussed this already with him? I see that there are lots of posts on SCC between you but I havn't read them all.

    What has this got to do with frame dragging?

    nc
     
  16. Apr 21, 2005 #15

    marcus

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    I am still trying different rewordings. I want it to be concise if it's to be used as a sig.

    small is actually important to the idea

    think about the natural selection of animals
    it proceeds by gradual small changes and only finds "local" optimums
    the system will go up whatever hill it finds itself but it cannot 'see' a distant mountain.

    there might be some extreme change that would make a better bonobo-----say with eyes in the back of his head, or wings, or a talent for trading in junk bonds, something really radical---
    well nature is not very likely to find it.

    an extreme change is one where on the way towards it the species has to LOSE fitness, like crossing a valley, to get to a distant mountain. evolution normally wont do that. if it is on the mountain already, it will climb it. but if is not it will just climb whatever hill it is on, for local advantage.

    mostly a species will find it self on some slope and natural selection will drive it up that slope towards higher reproductive success or fitness, but only what is achievable by small changes

    the words "small change" is intentionally left vague, it will depend on context and people studying evolution of some species will know what kinds of changes to expect, and what kinds of discontinuous jumps not to expect.

    I know it's vague. but Smolin said "small changes" on purpose
     
  17. Apr 21, 2005 #16

    Chronos

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    I still can't shake the feeling Smolin proposed CNS as a challenge directed at Susskind to produce a falsifiable version of the anthropic landscapes. I saw it as a suggested course correction.
     
  18. Apr 21, 2005 #17

    Garth

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    Actually 1.5 times as much. If the light path is 2km long the extra deflection under terrestrial gravitation is only about 1 Angstrom.

    N.B. The SCC light deflection by the Sun is the same as GR - as this deflection is a combination of two effects, the free fall attraction towards the Sun plus the effect of space curvature. In SCC the first is 1.5, and the second 0.5 the GR effect.

    "The first day of creation, who can act rationally on such a day?" Aleksandr Solzhenitsyn

    Garth
     
    Last edited: Apr 21, 2005
  19. Apr 21, 2005 #18

    Garth

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    The problem with the Anthropic Principle is not that it is not verifiable but that it is not falsifiable - its predictive power is too good - the universe has to be propitious for life because we are here!

    "The first day of creation, who can act rationally on such a day?" Aleksandr Solzhenitsyn

    Garth
     
    Last edited: Apr 21, 2005
  20. Apr 21, 2005 #19

    wolram

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    Thoughts of a youngster.

    It has been said that we live in a "preposterous universe", well as our understanding of the universe is only embryonic it may seem that way,
    in trying to understand the universe we the humans contrive ways
    to define it, but how can the least part of the least part define the whole.
    I think if the human race is to endure, then at some time in our evolution
    we must travel to and inhabit other worlds, if we attempt to do this
    without a deep understanding of our surroundings we will fail and perish.
    So us human micro states have a monumental task unraveling the
    every thing fur ball that is our universe, today we seem to be entangled
    unable to make real progress, unable to undo some of the knots, lost
    in the fur ball weave, we are awaiting mother to come along with her
    scissors to snip us some new beginning.
     
  21. Apr 21, 2005 #20

    marcus

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    there are two aspects to this, one is that AFAIK the most thorough exposition of CNS is this 1994 paper

    http://arxiv.org/gr-qc/9404011

    It is a great paper, we should discuss it. BTW turns out that the essential elements in CNS go back to John Wheeler! Smolin gives some history.
    He first heard the "bounce" idea in 1980 from Bryce DeWitt (of the Wheeler-DeWitt equation). It was Wheeler's idea that the parameters of the Standard Model might change slightly when the bounce at the pit of a black hole formed a new universe.

    It looks like in 1994 Smolin just connected the dots. the paper is interesting partly because he gives his reason for considering the main constants optimal for black hole production.

    The 1994 paper is called "The Fate of Black Hole Singularities and the Parameters of Particle Physics and Cosmology"

    the other aspect, in line with what you said, is WHY THE 2004 PAPER?

    the 2004 paper is motivated, IMO, by a desire to defend empirical science (which deals in falsifiable theories) from pseudo-science (which deals in untestable belief). It explicitly targets the string landscape use of the Anthropic Principle. The 2004 paper ("Scientific Alternatives to the Anthropic Principle") argues that appeals to Anthropic Principle are not science and that we don't HAVE to appeal to the AP because there are alternatives.

    Smolin uses CNS, in the 2004 paper, as an "existence proof" as in mathematics where you show that a set is non-empty by constructing one example of something that belongs to it. There are falsifiable alternatives to AP because look, here is CNS.

    In the 2004 paper Smolin makes a detailed argument for the immorality of appealing to the Anthropic Principle. Appealing to untestable, non-predictive principles damages the community's ability to resolve issues empirically. Because scientific enterprise and communication relies on empirically resolving differences, a scientist has a moral obligation not to appeal to non-predictive beliefs (such as AP) because doing so degrades scientific discourse and blurs the distinction between science and non-science.

    So this is obviously a serious concern of Smolin (and quite a few other people these days!) and it is different from what he was doing in 1994 when he was mainly just giving a clear exposition of CNS and putting it up for testing.
     
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