tag:blogger.com,1999:blog-22973357.post4932257261978698578..comments2017-10-19T12:08:33.187-04:00Comments on Backreaction: The Early Extra DimensionsSabine Hossenfelderhttps://plus.google.com/111136225362929878171noreply@blogger.comBlogger67125tag:blogger.com,1999:blog-22973357.post-7758850100460712132008-04-11T04:17:00.000-04:002008-04-11T04:17:00.000-04:00By being a cause that necessarily acts where it su...By being a cause that necessarily acts where it surrounds objects in 3+1D spacetime, gravity is dimensionally self-confining. <BR/><BR/>Just positing additdonal dimensions of space from where a further cause acts nonlocally - so that, by definition, this cause does not reduce or cease in its effects with distance around objects - does not imply that gravity (or em or the nuclear forces) should merlinwoodhttp://foranageofcertainty.bloggspot.comnoreply@blogger.comtag:blogger.com,1999:blog-22973357.post-89241983547990886922007-06-19T03:05:00.000-04:002007-06-19T03:05:00.000-04:00Merlin: In case you try to point me to your blog, ...Merlin: In case you try to point me to your blog, a link would be helpful, I am not in the mood to read through all of your writings. Your idea sounds nice but it seems to me you neglect several crucial problems. I.e. how do you confine gravity to 3+1 dimensions, since this is what we observe? Best, B.Beehttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-81693123257655680592007-06-18T14:22:00.000-04:002007-06-18T14:22:00.000-04:00But then it's not really that large scale extra di...But then it's not really that large scale extra dimensions just as such that need be contentious. <BR/><BR/>But I think my blog presents a fair, if only non-mathematical, argument for maintaining that an extradimensional non-locally acting cause could both produce quantum wave behaviour and astronomically observable effects. And to the extent that a cosmological theory might be developed withoutmerlinwoodhttp://quantumreallity.blogspot.comnoreply@blogger.comtag:blogger.com,1999:blog-22973357.post-47043803147510879802007-06-18T09:58:00.000-04:002007-06-18T09:58:00.000-04:00Hi Merlin:So what physicist would take this theory...Hi Merlin:<BR/><BR/><I>So what physicist would take this theory seriously or, even if they did, touch it with a barge pole? </I><BR/><BR/>So far I am not aware of a theory with large uncompactified (flat) extra dimensions that could be taken seriously. I didn't say I have one, but I also don't think it's impossible. <BR/><BR/>B.Beehttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-87470888913491225512007-06-18T08:21:00.000-04:002007-06-18T08:21:00.000-04:00Bee: "I personally favor infinitely large extra di...Bee:<BR/> <BR/>"I personally favor infinitely large extra dimensions. I love the KK idea but I don't think it could be fundamental either. We'd again be left with the question why these symmetries... could there be a whole landscape?"<BR/><BR/>I'm in favour of extra spatial dimensions that are as large as the three in the universe experienced, any way. And I have a quite detailed empirical merlinwoodhttp://foranewageofreason.blogspirit.comnoreply@blogger.comtag:blogger.com,1999:blog-22973357.post-60502500906456090172007-06-15T08:01:00.000-04:002007-06-15T08:01:00.000-04:00Dear Bee & Stefan,You've been very patient, actual...Dear Bee & Stefan,<BR/>You've been very patient, actually.<BR/><BR/>Looking forward to your visit to New Jersey :)<BR/><BR/>Best,<BR/>-ArunArunhttps://www.blogger.com/profile/03451666670728177970noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-16649236869244857382007-06-15T04:42:00.000-04:002007-06-15T04:42:00.000-04:00Nige:If Bee didn't understand it she could have sa...Nige:<BR/><BR/><I>If Bee didn't understand it she could have said so in the first place instead of insulting my intelligence by claiming - falsely - that I'm somehow wrong when Bee missed the point, probably because she was busy with something more important.</I><BR/><BR/>I have explained repeatedly why you are not 'somehow' wrong but just wrong. I've explained more than once why several of your Beehttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-87457793408710151702007-06-15T04:26:00.000-04:002007-06-15T04:26:00.000-04:00Hi Stefan,I'm very sorry that the discussion went ...Hi Stefan,<BR/><BR/>I'm very sorry that the discussion went the way it did but I did my best to be clear and was still misunderstood.<BR/><BR/>I don't have a "private version of vector analysis". Maths is maths, it's not my private version.<BR/><BR/>If Bee didn't understand it she could have said so in the first place instead of insulting my intelligence by claiming - falsely - that I'm somehow nigehttps://www.blogger.com/profile/03402194253543690982noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-21870329778604277262007-06-14T20:49:00.000-04:002007-06-14T20:49:00.000-04:00Maybe in future I'll add a more detailed discussio...<I>Maybe in future I'll add a more detailed discussion of spherical symmetry when I write about it, and show how it is derived from general spherical coordinates.</I><BR/><BR/>Your welcome - but please, not in the comments of this blog. This is definitly not the place to propagate your own private version of vector analysis.<BR/><BR/>In fact, I could not follow in detail this thread over the laststefanhttps://www.blogger.com/profile/09495628046446378453noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-36039739359347243252007-06-14T12:56:00.000-04:002007-06-14T12:56:00.000-04:00"(you seem to implicitly assume without stating it..."(you seem to implicitly assume without stating it that the origin of your coordinates is the center of the symmetry.)" - Bee<BR/><BR/>I explicitly stated:<BR/><BR/>"The assumption that there's only one time dimension is the same as you would have if everything around you was radially symmetric, like living in the middle of an onion, where only changes as a function of radial distance (one nigehttps://www.blogger.com/profile/03402194253543690982noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-86304512389183434042007-06-14T10:59:00.000-04:002007-06-14T10:59:00.000-04:00Hi Damian,That's because only very little people c...Hi Damian,<BR/><BR/><I>That's because only very little people can fit inside those extra dimensions. </I><BR/><BR/>:-) I personally favor infinitely large extra dimensions. I love the KK idea but I don't think it could be fundamental either. We'd again be left with the question why these symmetries... could there be a whole landscape? Best,<BR/><BR/>B.Beehttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-52602038101790591242007-06-14T10:54:00.000-04:002007-06-14T10:54:00.000-04:00Nige: one uses spherical coordinates for spherical...Nige: one uses spherical coordinates for spherical symmetry because it makes the description much easier. Of course you don't HAVE to use them, but once you do, you have to do it properly - using a sensible coordinate transformation. <BR/><BR/><I>This relies on the fact that Spherical symmetry means that x = y = z = r.</I><BR/><BR/>I will repeat it one last time: spherical symmetry does not mean Beehttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-38330990719502373592007-06-14T10:38:00.000-04:002007-06-14T10:38:00.000-04:00For example of finding observable mass of universe...For example of finding observable mass of universe by integrating over radial distance:<BR/><BR/>M = {integral symbol}(4πr^2){rho} dr<BR/><BR/>Density, {rho}, increases with distance r in proportion to the factor<BR/><BR/>[1 – rH/c)^{-3}<BR/><BR/>this is caused by decreasing observable age of the universe we're seeing at earlier times (great distances).<BR/><BR/>The integral out to r gives nigehttps://www.blogger.com/profile/03402194253543690982noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-38842169998900775732007-06-14T10:11:00.000-04:002007-06-14T10:11:00.000-04:00"This is wrong. Correct is dxdydx = r^2 sin \theta..."This is wrong. Correct is dxdydx = r^2 sin \theta dr d\theta d\phi, where x,y,z, are the Euclidean coordinates."<BR/><BR/>No, in spherical symmetry r is defined as radial direction <I>which is equal to x, to y and to z.</I> The page you link to is for spherical coordinates, not spherical symmetry!<BR/><BR/>The equation<BR/><BR/>dxdydx = r^2 sin \theta dr d\theta d\phi<BR/><BR/>applies to the <Inigehttps://www.blogger.com/profile/03402194253543690982noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-34467904160150232012007-06-14T08:56:00.000-04:002007-06-14T08:56:00.000-04:00Dear Nigel,I never mentioned coordinate transforma...Dear Nigel,<BR/><BR/><I>I never mentioned coordinate transformations, which have nothing to do with the existence of spherical symmetry of gradients you object to. [...]<BR/><BR/>I don't understand why you keep repeating this endlessly, after I explained by your dismissal is totally vacuous.<BR/><BR/>The spherical symmetry of gradients has nothing to do with general relativity or with metrics, soBeehttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-22796504388586645762007-06-14T08:27:00.000-04:002007-06-14T08:27:00.000-04:00"I am not attacking you." - BeeYou seem to be beca..."I am not attacking you." - Bee<BR/><BR/>You seem to be because you falsely wrote <BR/><BR/>"It seems to me you slept through the GR session, you evidently have no idea how to make a coordinate transformation. Please look up every standard textbook on differential geometry to find out that I am correct."<BR/><BR/>I never mentioned coordinate transformations, which have nothing to do with the nigehttps://www.blogger.com/profile/03402194253543690982noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-66140628450260517522007-06-14T06:21:00.000-04:002007-06-14T06:21:00.000-04:00Nige: (your comments in italics)a) I am not attack...Nige: (your comments in italics)<BR/><BR/>a) I am not attacking you.<BR/><BR/>b) I am not making any false claims.<BR/><BR/><I>If you claim that Feynman is "arm-waving" then maybe you need to write your ignorant criticisms of him, not me.</I><BR/><BR/>c) I haven't said anything like Feynman being 'arm waving'.<BR/><BR/>d) Again I tell you that my argument with the Laplace operator was an example Beehttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-3680035628520616182007-06-14T04:42:00.000-04:002007-06-14T04:42:00.000-04:00"I have marked all your quotations in italics. Whe..."I have marked all your quotations in italics. Where you remark <BR/>This is correct, and what I was saying! you have wrongly attributed your own sentence to me." - Bee<BR/><BR/>Well in that case you maybe need to do something other than use italics when you write a formula, or it looks as if you are just emphasising it with italics.<BR/><BR/>"You should know that the electromagnetic fields can nigehttps://www.blogger.com/profile/03402194253543690982noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-67023228699897084052007-06-14T03:21:00.000-04:002007-06-14T03:21:00.000-04:00Dear Arun: thanks for your support... Should I eve...Dear Arun: thanks for your support... Should I ever be around New Jersey, I'll invite you for a dinner :-) <BR/>-B.Beehttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-20240347714283537342007-06-14T02:48:00.000-04:002007-06-14T02:48:00.000-04:00Nige: I am not confusing anything. In my first anw...Nige: I am not confusing anything. <BR/><BR/>In my first anwer assumed you were talking about spherical curves for which d\theta = d\phi = 0, and then dr^2 = ds^2. I apologize if that was not the case. <BR/><BR/><BR/>I have marked all your quotations in italics. Where you remark <I><BR/>This is correct, and what I was saying!</I> you have wrongly attributed your own sentence to me. <BR/><BR/>You Beehttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-65783123319366168792007-06-13T13:59:00.000-04:002007-06-13T13:59:00.000-04:00Bee says:I want to elaborate somewhat on these 'ea...Bee says:<BR/><BR/><I>I want to elaborate somewhat on these 'early' XDs since I noticed very little people actually read the original works by Kaluza and Klein.</I><BR/><BR/>That's because only very little people can fit inside those extra dimensions.Damien Brodericknoreply@blogger.comtag:blogger.com,1999:blog-22973357.post-51812337952692446052007-06-13T12:54:00.000-04:002007-06-13T12:54:00.000-04:00Arun,So you believe as Bee claimed that the equali...Arun,<BR/><BR/>So you believe as Bee claimed that the equality of gradients in all directions in a spherical space somehow disproves - or is replaced by - a metric? From someone who confuses ds^2 with dr^2 and whose arithmetic in claiming that dr^2 = dx^2 + dy^2 + dz^2 is equivalent to claiming that 1 = 1 + 1 + 1 since dr^2, dx^2, dy^2 and dz^2 are all equal for the spherically symmetric case nigehttps://www.blogger.com/profile/03402194253543690982noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-38303034450473840412007-06-13T08:11:00.000-04:002007-06-13T08:11:00.000-04:00Bee,Thanks! I'll have to think about what you wro...Bee,<BR/>Thanks! I'll have to think about what you wrote.<BR/><BR/>Nige,<BR/>You are utterly, butterly wrong. Nothing wrong with ignorance, provided it is accompanied with a willingness to learn. But you are too obtuse to accept a correction. I suggest with scant hope that you will heed it that you cease making a fool of yourself in public.Arunhttps://www.blogger.com/profile/03451666670728177970noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-37481343141638691032007-06-13T07:06:00.000-04:002007-06-13T07:06:00.000-04:00"I haven't talked about the divergence," - Bee.Bee..."I haven't talked about the divergence," - Bee.<BR/><BR/>Bee, you wrote above:<BR/><BR/>"If it was as you said, then the Coulomb force law in 3 dimensions wouldn't fall with 1/r^2 as it does, "<BR/><BR/><BR/>The Coulomb law in operator symbolism is:<BR/><BR/>divergence.E = charge density/permittivity<BR/><BR/>with force F_r = {charge acted upon} * E_r<BR/><BR/>So you need to learn that in vector nigehttps://www.blogger.com/profile/03402194253543690982noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-15458745342031921572007-06-13T03:32:00.000-04:002007-06-13T03:32:00.000-04:00Nige: would you please at least consider that what...Nige: would you please at least consider that what I say might be correct and look up a textbook. Alternatively, go and ask anybody who has learned differential geometry if you don't trust me. Again, your reasoning is just manifestly WRONG. As you know I am currently travelling, so I can't give you a page number, but for beginners you might want to look up Misner, Thorne, Wheeler or Weinberg's Beehttps://www.blogger.com/profile/06151209308084588985noreply@blogger.com