Schneibster

on these forums. Books that have been recently denounced: ISBN 0-316-15579-9 The Cosmic Landscape ©2006 Leonard Susskind First Edition: December 2005 Little, Brown, and Co. New York USA May I please have an explanation why this book is not acceptable as a reference on this forum, since it is a legitimate publication by a famous physicist? Thanks in advance. Please be aware I will be informing Dr. Susskind of your response. You should be aware that he has responded vigorously in the past to accusations against him similar to yours. Good luck. While we wait, I will append a list of books you appear uncertain about: Albert Einstein, Relativity Brian Greene, The Elegant Universe, and The Fabric of the Cosmos Leonard Susskind, The Cosmic Landscape, and The Black Hole War Kip Thorne, John Wheeler, and Charles W. Misner, Gravitation Michio Kaku, Quantum Field Theory, An Introduction We'll start with those. Apparently I have to have individual ones approved by staff. Are those all OK?

Oh, yes, on that scale yes very much. That's precisely what I'm talking about. Different Calabi-Yau geometry in the vacuum fluctuation, different value of cosmological constant, different inflation, and etc. on down to different universe. Sure. This is called the "Anthropic Principle." It says, "There's lots of different kinds of universes, we're here because this universe supports ones like us." Is that what you have in mind? I think I might agree with that.

You're smart. That's a great question. We only see photons from this side of it. The other side is too far away for us to have ever seen it. Nor will we ever. The universe's expansion has started to accelerate again and it's gone forever. I think it's like champagne that got shook too hard, or a foamy keg of beer. Lots of big empty bubbles and a bit of froth in between them. That bit of froth is the Virgo Supercluster et. alii. Like our galaxy and stuff. That's the shape of the universe. Spit in the ocean. Most of everything is empty. Wow, different alpha or speed of light? Now that sounds speculative. At least anyplace we'll ever be able to see. Folks should keep in mind we can see the most we'll ever see right now. The older the universe gets the more stuff will fall off the edge as the expansion accelerates from the dark energy/cosmological constant.

I knew we were discussing alpha. It's in the title of every post. I guess I can only point out that Susskind was making an analogy he hoped lots of people could get. Sounds like you pushed it beyond its limits. Incidentally, http://en.wikipedia.org/wiki/Leonard_Susskind I also have to say that Susskind's description works well with the conceptual picture of the electric charge of the electron constantly spitting out and reabsorbing virtual photons. And that was the sort of association I made with it. I'm pretty sure that's what he intended to convey. Here's a paper on the quantum efficiency of CRTs. http://k-ids.or.kr/journal/B/11_3/1126/articlefile/article.pdf It's umaround25%withanamplifiersorry. AndwehaventevendiscussedthequantumefficiencyofcommercialCCDssorryagain.

Sensei, your argument is as good against string physics. Did you intend it to be? Not to mention, have you heard of the Hercules-Corona Borealis Great Wall? It looks like the Great Edge of the Great Bubble to me. And have you heard about the latest one, that they found with GRBs? It's ten times bigger still, and ten times farther away. The universe is huge bubbles of emptiness surrounded by a minor froth of mass that makes galaxy clusters.

He's got a really good overview of physics and physical cosmology before he gets to the multiverse stuff. You really want to pay attention. If you want to be a professional physicist, it won't help you, but if you just want to be an amateur and have a clue WTF they're talking about, you'll find it helpful, I hope.

Yes, And the rest is correct too. To give folks who are perhaps a bit more physics-oriented the idea, the majority of cosmologists are calling ΛCDM "The Standard Model of Cosmology." A small minority of astrophysicists think that's overambitious but the majority of cosmologists and astrophysicists are good with it. I'll be firing up an argument in Modern Physics about the tension between XENON and XENON II, and DAMA/LIBRA and CDMS and CDMS II before too long. I don't believe in coincidences, for example DAMA/LIBRA, CDMS, and CDMS II all having the same systematic error and it not being a systematic error due to an undiscovered property of xenon. But this is, again, not a conversation for Astronomy and Cosmology.

Lambda Λ is the cosmological constant in the Einstein field equation: Gμν + Λgμν = (8πGnewton/c4)Tμν It's the dark energy. And I will always attempt to explain things at a lower level if requested. I don't believe in "scoring points" off people because they didn't take advanced math in gradeschool. Just ask. I like helping non-experts. I'm still closer to them than to the physicists.

Ummm, OK. So this is uncomfortable. How about you write him and tell him and let's see what he says. He being famous prize-winning physicist inventor of string theory and stuff. And you being anonymous internet dude. That's the whole entire paragraph word for word unless I made a typo. There's nothing else in it, and no further explanation of the example before or after it. Susskind isn't a journalist. He's a physicist. This isn't a paper on arXiv. It's a published book. I am having a lot of trouble with a relatively anonymous moderator on a physics forum appearing to call Leonard Susskind a liar. Sorry if that wasn't what you intended but it sure looks that way to me. For that matter, if an anonymous moderator on a physics forum insists Leonard Susskind is "wrong," I'm not going to have a lot of patience with that either. Next you'll be telling me Gravitation is all wrong because Kip Thorne is an idiot. And BTW I'm an EE and know all about how televisions work. Last but not least I know the difference between an interpretation of quantum mechanics and an interpretation of alpha. And I'm trying to be nice because I consider it pretty insulting to be accused of not knowing that.

I guess I'm pretty good with quantum theory undergoing transition to classical theory as described by the Fluctuation Theorem. Are you familiar with that? This is maybe not the place. "Modern Physics" seems more likely for a conversation about the transition from classical to quantum theories.

Yes, of course. OTOH occasionally we get to see time far away; like when SN1987a sequentially illumated gas and dust clouds it had emitted millions of years before. So we pretty much know that the rate of time was the same in the Magellanic Clouds 190 thousand years ago as it is here now. And this is by no means the only such measurement; there are others farther, that there were arguments about, until they could compare them with SN1987a and verify they were the same. That makes it a fair assumption it hasn't changed in the history of the universe within the distance we can ever see. And here's a thought for the Thread Original Poster: this is the nature of time in the universe: the galaxies we can see at the furthest and dimmest at 13 billion years ago or so, only six or seven hundred million years past the Big Bang, will disappear over the next million years. And they will quite literally have "fallen off the edge of the observable universe," from our viewpoint; we can never see them again, we'd have to travel FTL to do so. That's the nature of the edge of the observable universe; and they fall out of time as well as out of space. So there's a part of the "Nature of Time," specifically how time appears to behave at the edge of the observable universe. HTH.

Do you know the Kaluza-Klein theory of electromagnetism? It postulates one additional, small dimension, added to GR. You can derive Maxwell's Equations from it, in exactly the same manner you derive Einstein's Field Equations in four dimensions. There's the first of the seven dimensions of the Calabi-Yau space that defines our universe's particular string theory. That's the "1" in "U(1)," which is the unitary symmetry group of dimension one, which is the symmetry group of the electromagnetic force. This is pretty basic; it's in The Elegant Universe, IIRC. Have you read it? On Edit: Hmmm, maybe it's in The Cosmic Landscape. And of course I don't mean to indicate that this most obvious idea is actually a mathematically correct description; a lot of really smart people looked at it and if it were that easy physics would be, heh, finished. (Snicker, this strikes me the same as the ISP commercial where the computer announces to the dude he has "finished the Internet.") OTOH, add in supersymmetry and it starts to look kinda like supergravity, which is the sixth theory in M-theory. K-theory is having quite a strong look at Kaluza-Klein theory, actually, just at the moment. Hot topic. The naïve theories have all been tried long ago; my goal is rather to help the folks who perhaps can't handle all the math understand. Your contributions in clarifying places I was unclear are appreciated and will be. The reason the naïve theories fail is simply the energy scales, as Kaku 1993 says on page 6. The relatively modest value of αem at ~1/137 governs the EM interaction and makes it tractable to a relatively naïve quantum theory. Unfortunately, none of the other forces is so convenient; αcolor at ~14 is totally immune to renormalization; and Gnewton has dimensionful components and is immune to renormalization as well, though for a different reason. Gweak is the only one in a range and of a character to support investigation, and has turned out to be a weird sort of mix with EM. Here's a brief note on supergravity which is the sixth theory of M-theory: http://en.wikipedia.org/wiki/Supergravity#N_.3D_8_Supergravity_in_4_Dimensions at the end you will find the comment: Does this sound anything like my seven dimensions of a Calabi-Yau space to you? Do you think that's a coincidence? I don't. Also, please can you explain what you think a Calabi-Yau space is if it doesn't have dimensions? Witten did actually know what he was doing including supergravity.

I'm totally confused. Feynman doesn't appear until much later in the article: http://en.wikipedia.org/wiki/Fine-structure_constant#Numerological_explanations And that's not an "interpretation."

Leonard Susskind thinks they are, and unless they've changed their minds Alex Vilentkin and Andre Linde agree with him. That's the inventor of the original string theory, and two cosmologists. OTOH the argument is not simple. So it's a bit too much for this thread. I just want to be sure we're all agreed this isn't "speculative." Your argument about energy scales is the first time I've heard a plausible argument against it, however, so that's interesting and you can expect I'll follow up. Should I conclude you've never heard of Eternal Inflation?

The cause is the exact hyperbolic relation between the time dimension and each of the three space dimensions. The proof of the constancy of the speed of light is that the theory of relativity correctly predicts the lifetimes of variously moving cosmic rays and their decay products. There are other proofs but that one is the most important in this realm. I recommend this Baez page: http://math.ucr.edu/home/baez/symmetries.html

"Schneib," actually, is the most common abbreviation. Note that it violates the English rule about is and es. Correct pronunciation is "shnaibster," or "shnibe." Thank you for the welcome.

You are stimulating long unused neurons. I'll see what I can do this evening; I'm helping my wife deal with upper jaw fillings so maybe not 'til tomorrow, but don't worry about me losing interest! We're getting out of astronomy/cosmology and into, IMHO, "Modern Physics." And I am totally stoked to have that conversation; if you haven't fired it up over on that forum by tomorrow I will. You've opened Noether's Theorem. This is just another look into the underlying symmetries; now you've got forces, symmetries, mathematical theorems, and conservation laws and fundamental invariances not only of the spacetime dimensions but of the dimensions in the Calabi-Yau geometry that defines our universe, which we will eventually establish the precise parameters of by physical measurement. And all of these things are tangled together in one single definition of the geometry of our universe. There are many other universes around us. They're no more than hundreds of billions of light years away. I read an article that claimed that the most probable distance to a universe containing another Schneibster almost just like me, writing almost exactly this message to you at almost exactly this time, is around 200 billion light years. Let me suggest something: how about the Anthropic Principle? String Theory says there are 10300 possible dimensional arrangements/Calabi-Yau spaces. Eternal inflation suggests that all of them get tried over time, over and over again. We look at the universe around us and it looks like a huge bunch of empty voids surrounded with a scum, or "web," or whatnot, of matter, of which our Local Group of Galaxies appears to be a microscopic crumb within a cluster of galaxies within a supercluster of galaxies within a thread of this scum web surrounding the huge voids of universes that collapsed nearby and left signatures in our CMBR. Most universes just collapse back into themselves and leave voids. These voids coexist with the scum web of matter that's left over from the original inflation on both sides of us. One side is the Sloan SDSS Her-CrB Great Wall, and the other is the recently discovered 10Gly square wall defined by GRBs. These events are what squeezed the matter that surrounds us tightly enough to form galaxies. Well I did better than I thought.

Actually I think that "what is time" has a pretty concrete answer: it's the hyperbolic dimension, of the four large dimensions we experience in our universe. The other large ones are all circular. And the rest of the dimensions are all small.

Hello. I like this place.

Errr, no. Those are interpretations of all of quantum mechanics. Alpha is just one variable. This bothered me all afternoon so I went and hunted it down. I got it from Susskind 2005, The Cosmic Landscape, page 49, in the section titled "The Fine Structure Constant," which is very promising for this subject.

I'm gonna like this site. Nice post, Implicate Order. My immediate reaction is to say "Bell's Theorem implies that either locality, or local realism, is wrong, and the other is right." "Locality" means that state cannot be sent faster than light; "local realism" means that Heisenberg uncertain quantities have real values even though we can't measure them. So either we violate the "locality" postulate of Special Relativity, by sending state data instantaneously with the collapse of the wave function (and BTW also trash the relativity of simultaneity), or else we claim that Heisenberg uncertain quantities have no value, in a manner that is not consistent with local reality as we experience it, very similar to the old George Carlin joke, "And now for tomorrow's weather: tomorrow there will be no weather. (Pauses for laughs.)" This delineates the limits of what we can know.

The easiest other one, I suppose, is the ratio of the strengths of the gravity and electric forces of two charged massive point particles at any distance. And a lot of authors describe it that way. (I will not pollute the language with stuff like "massful.")

Morals are simplistic attempts to codify ethics. Morals generally are short, one or two sentences; therefore they are incapable of nuance. They are suited to the meanest understanding and therefore inflexible. Ethics are complicated, and involve judging relative values, of course after assigning them. Analysis is required. There's no magic voice from the sky or some magic book to tell you what to do. You might mess up. People might not agree with you, and they might get mad. It's scary.

It's really quite simple. "Velocity" in 3d+1 can be represented as "rapidity" in 4d, that is, the angle by which the subject of observation has rotated in the x-t, y-t, and z-t planes. The foreshortening, then, is identical to the foreshortening we see when a motionless object is rotated from broadside-on to head-on. Ordinary objects around us just don't move that fast, so we never notice it; we only notice the kind that happens with the motionless object because that's all we've ever seen.

(Answering the Thread Topic Query) Yes. In simple terms: The first four are spacetime. Up-down, left-right, closer-farther, past-future. These are the degrees of freedom of gravity, and the definition of it as a force. The next one adds electromagnetism, as a single degree of freedom at every point in spacetime. The next two add the weak nuclear force, which has not only a +W and a -W current, like electricity, but also adds, with its second dimension, a "neutral current," which has a charge that is neither + nor -. Physicists call the particle that carries this charge a Z or Z0. The next three add the color force, which is the underlying force of which the strong nuclear force is a remainder force among nucleons, just as van der Waals forces are remainder forces of the electromagnetic forces among atoms and molecules generated by the charged nuclei and the charged electron clouds. There are ten: 1+2+3+4. And you will find that the math works, too. In modern physics, "symmetries" underlie our knowledge of the forces, and these symmtries have mathematical names that denote a) their type and b) their dimensionality. They are referred to as "symmetry groups" because frequently there are many different examples both from math and from science. These symmetry groups, then, are U(1), which is the symmetry of electromagnetism, and which is combined for reasons we can discuss later with SU(2), which is the symmetry of the weak force. And, of course, SU(3), which is the color force. You will note I have left out gravity. Physicists have not yet found a symmetry group that works for gravity. And last, there is the eleventh dimension. When the Second String revolution happened, it was because Witten used the eleventh dimension to unite all the string theories; they all turned out to be different branches of a single underlying theory called "M-theory." And this in turn brought in gravity; because we only had five "string theories;" but the math Witten found when he added the eleventh dimension made it clear that the most advanced non-string theory of the time, called "supergravity," was in fact the "sixth string theory." So that's where the eleventh dimension comes in. Now, this means that we have seven dimensions that all exist at every point in spacetime, but that are all so small we never notice them and can't directly measure them. And the key is, the exact shape of each of these dimensions controls a different aspect of a different force. You know, not only that one's a little bigger or this one's a little flattened, but their relations to each other, this angle and that, and are they right circular or elliptical or parabolic or hyperbolic, as well as their relations in all these ways to the four "big" dimensions of spacetime. String physicists call these little twisted-up balls of dimensions "Calabi-Yau spaces." And one of the questions is, how many of them are there? When you figure this out you come out with about 10300 possible Calabi-Yau spaces of seven dimensions, each representing different laws of physics. And that's what the eleven dimensions are.