tag:blogger.com,1999:blog-22973357.post1058550139474715924..comments2023-09-27T07:44:19.769-04:00Comments on Sabine Hossenfelder: Backreaction: What is Dark Energy?Sabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.comBlogger265125tag:blogger.com,1999:blog-22973357.post-62143068434602964472019-12-05T08:38:24.160-05:002019-12-05T08:38:24.160-05:00PhysicistDave 6:22 AM, December 05, 2019
Dyson wa...PhysicistDave 6:22 AM, December 05, 2019<br /><br />Dyson was attempting big-picture thinking. Luke Barnes and the other Templeton-funded fine-tuners are telling blatant lies because they do not want physics saying their whacko beliefs are nonsense. That's it. That's all they want. $3 billion is being spent to try to stop rationalists laughing at Christians for being deluded morons with Steven Evanshttps://www.blogger.com/profile/13898046706669437332noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-88619865196367616262019-12-05T06:22:34.925-05:002019-12-05T06:22:34.925-05:00Steve Evans wrote to me:
>True, but irrelevant...Steve Evans wrote to me:<br /><br />>True, but irrelevant here. Here is one sentence to dismiss Luke Barnes' nonsense hypothesis of universal fine-tuning: it is completely unknown whether it is physically possible for the universe to be fundamentally different, or whether "other universes" exist.<br />...<br />>But Barnes also claims that his models (which are purely PhysicistDavehttps://www.blogger.com/profile/11111405959451703182noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-68610432275483029752019-12-05T03:31:08.059-05:002019-12-05T03:31:08.059-05:00PhysicistDave 10:21 PM, December 04, 2019
"A...PhysicistDave 10:21 PM, December 04, 2019<br /><br />"And if a scientist who is a Christian comes up with a plausible, testable scientific hypothesis, the hypothesis needs to be judged on its merits, "<br /><br />True, but irrelevant here. Here is one sentence to dismiss Luke Barnes' nonsense hypothesis of universal fine-tuning: it is completely unknown whether it is physically Steven Evanshttps://www.blogger.com/profile/13898046706669437332noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-34957831727902687712019-12-04T22:47:51.250-05:002019-12-04T22:47:51.250-05:00Phillip Helbig 4:24 AM, November 25, 2019
"V...Phillip Helbig 4:24 AM, November 25, 2019<br /><br />"Violence is the last refuge of the incompetent. Ad ad-hominem attacks in blog comments are the mark of a disturbed person."<br /><br />So what about someone who fantasises about murdering critics of his nonsensical book - disturbed person or not? <br /><br />Or does your definition of disturbed person just apply to people who have Steven Evanshttps://www.blogger.com/profile/13898046706669437332noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-91383589205427125232019-12-04T22:21:09.211-05:002019-12-04T22:21:09.211-05:00Steve Evans wrote to Sabine:
>And why link to ...Steve Evans wrote to Sabine:<br /><br />>And why link to Luke Barnes in your paper when he is clearly a mentally delusional, corrupt liar with an agenda? All the work that Luke Barnes is outputting now concerns *models* he has built to try desperately to support his mental delusions about baby Jesus, and have nothing to do with *reality*. You might as well quote Genesis as a serious scientificPhysicistDavehttps://www.blogger.com/profile/11111405959451703182noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-78767872053249920042019-12-04T22:04:31.370-05:002019-12-04T22:04:31.370-05:00Sabine Hossenfelder 11:38 PM, November 29, 2019
&...Sabine Hossenfelder 11:38 PM, November 29, 2019<br /><br />"Finetuning is also often used to quantify how much the parameters in our theories could be changed so that life as we know it would still be possible."<br /><br />In an article in the Sydney Morning Herald ("Bad news for the multiverse: it's still not likely"), Luke Barnes describes how his completely made-up Steven Evanshttps://www.blogger.com/profile/13898046706669437332noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-25131498903142740092019-12-04T16:36:55.274-05:002019-12-04T16:36:55.274-05:00This comment has been removed by the author.Tom Fuchshttps://www.blogger.com/profile/17646011875919892992noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-36371114284534590882019-12-04T03:33:21.158-05:002019-12-04T03:33:21.158-05:00So you're not biting, Dr H. Very wise. But I&#...So you're not biting, Dr H. Very wise. But I'm right. You are linking to models which are not intended to be models of physical reality, but are models of a La-La Land made by baby Jesus' papa in which burning bushes can talk. "Oh, hello there, Mr Burning Bush, how are you this fine day?". This is essentially what you are saying by linking to Luke Barnes' drivel in your Steven Evanshttps://www.blogger.com/profile/13898046706669437332noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-26209702137648742402019-12-03T23:43:56.804-05:002019-12-03T23:43:56.804-05:00Sabine Hossenfelder 11:38 PM, November 29, 2019
&...Sabine Hossenfelder 11:38 PM, November 29, 2019<br /><br />"Finetuning is also often used to quantify how much the parameters in our theories could be changed so that life as we know it would still be possible."<br /><br />But this idea of fine-tuning rests on pure assumptions that the universe could actually be fundamentally different and on assumptions about the possibilities of "Steven Evanshttps://www.blogger.com/profile/13898046706669437332noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-35477038296274364742019-12-03T21:32:59.087-05:002019-12-03T21:32:59.087-05:00This comment has been removed by the author.Tom Fuchshttps://www.blogger.com/profile/17646011875919892992noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-55679876142896290552019-12-03T18:46:05.597-05:002019-12-03T18:46:05.597-05:00similar, but different: Sachs-Wolfe is about CMB, ...similar, but different: Sachs-Wolfe is about CMB, but I'm describing an effect on photons from supernovae. <br /><br />The crucial point is: How do we know that space becomes flat far away from the center of gravity? (we did not measure! we only measure dark matter = more accelaration than we expect with the "flat space" formulae) How about space crossing the axis of being flat =>Angbarhttps://www.blogger.com/profile/02942045474103477791noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-1620593771350790652019-12-03T14:09:20.041-05:002019-12-03T14:09:20.041-05:00bud rap: Thanks for you clarifications (02 Decembe...bud rap: Thanks for you clarifications (02 December).<br /><br />Wrt black holes - stellar mass, or super-massive, or (likely) any other - it seems that there is no astronomical observation that could be made, even with projected technology a century into the future, which could test your assertions*. Is that about right?<br /><br />*possible exception: if a low-mass black hole were to come closeJeanTatehttps://www.blogger.com/profile/08737430572613792118noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-10968652632052524862019-12-03T04:43:59.105-05:002019-12-03T04:43:59.105-05:00Tom,
I assume you are referring to this page?
I ...Tom,<br /><br />I assume you are referring to <a href="http://math.ucr.edu/home/baez/physics/Relativity/SR/Rocket/rocket.html" rel="nofollow">this page</a>?<br /><br />I solved the elements of the relativistic rocket problem myself in ninth grade: it was the first time that I figured out something in physics that I had not seen in a textbook, and I was very proud of myself. It is indeed very PhysicistDavehttps://www.blogger.com/profile/11111405959451703182noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-66431506831454479802019-12-02T20:01:51.271-05:002019-12-02T20:01:51.271-05:00bud rap wrote to me:
>[Dave] Have you had clos...bud rap wrote to me:<br /><br />>[Dave] Have you had close personal contact with Sabine or Lawrence or Reimond or Jean... or me so that you actually know what we have "made an attempt at"?<br /><br />>[bud] My comment was based on the public record.<br /><br />There is nothing "on the public record" that gives you any idea whatsoever of what <b>I</b> have have "madePhysicistDavehttps://www.blogger.com/profile/11111405959451703182noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-60010467073256598802019-12-02T12:06:13.485-05:002019-12-02T12:06:13.485-05:00Jean,
It seems to me that, fundamentally, you hav...Jean,<br /><br /><i>It seems to me that, fundamentally, you have issues with certain parts of GR (or, perhaps, with how GR is used in certain parts of astrophysics and cosmology).</i><br /><br />That parenthetical clause is a good summation of my problems with some astrophysical models and ΛCDM generally. It is not GR that is at fault but its application to faulty qualitative models. In cosmologybud raphttps://www.blogger.com/profile/06948881286545517324noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-88628642189786476962019-12-02T06:16:44.705-05:002019-12-02T06:16:44.705-05:00Terry,
In summary:
The core of what we physicist...Terry,<br /><br />In summary:<br /><br />The core of what we physicists are doing involves <i>which</i> counter-terms are available and what parts of the total “energy” can and must be eliminated in order to get a form for the “energy” that works if we split the string in two. The physical symmetries of the theory <b>severely</b> limit how this can be done. <br /><br />(I think string theoristsPhysicistDavehttps://www.blogger.com/profile/11111405959451703182noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-81420721453221811432019-12-02T06:08:00.804-05:002019-12-02T06:08:00.804-05:00Ah, Terry! You still refuse to make any effort to...Ah, Terry! You still refuse to make any effort to understand what we physicists are doing.<br /><br /><i>We are not doing what Ramanujan did.</i><br /><br />You completely misunderstand.<br /><br />The fundamental issue is that when you write down the equations for a physical model and then want to compare the results to something in the real world (at least hypothetically real), you cannot justPhysicistDavehttps://www.blogger.com/profile/11111405959451703182noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-22687842908730806292019-12-02T02:54:59.237-05:002019-12-02T02:54:59.237-05:00Drl, I would also like to better understand your m...Drl, I would also like to better understand your motivation. Schrödinger wanted to “work backwards” to reconstruct the stress-energy tensor, but as Dave already said this does not give you the right molecules like QM does. <br />I guess Schrödinger was disappointed from QM because of its randomness and jumps – this just does not fit into the old Newtonian tradition of determinism and smooth Reimondhttps://www.blogger.com/profile/04669340425105889539noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-49345218105651189672019-12-02T02:38:32.496-05:002019-12-02T02:38:32.496-05:00“If it is the covariant derivative, then your firs...<i>“If it is the covariant derivative, then your first equation ...”</i> – I guess d/dxn is the partial derivative – see also Schrödinger <a href="https://books.google.de/books?id=XDDeVD_QZfcC&pg=PA102&lpg=PA102&dq=%22is+not+a+tensor-density.+But+we+will+come+back+to+this.%22" rel="nofollow">here</a> eq. 11.21, where the ‘gothicized’ T is coming from eq. 11.15, i.e. the one from the Reimondhttps://www.blogger.com/profile/04669340425105889539noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-6237825659870453872019-12-01T21:08:37.355-05:002019-12-01T21:08:37.355-05:00This comment has been removed by the author.Tom Fuchshttps://www.blogger.com/profile/17646011875919892992noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-53871577900592858842019-12-01T19:06:13.414-05:002019-12-01T19:06:13.414-05:00drl,
If I understand your notation correctly, t_,...drl,<br /><br />If I understand your notation correctly, t_,mm is just a constant times the metric tensor. The metric tensor certainly <i>is</i> a tensor, not a pseudotensor, sort of the granddaddy of tensors, in fact! And so t_mn would also be a true tensor.<br /><br />The covariant derivative of the metric tensor is, trivially, zero, of course.<br /><br />It's not clear to me if d/dxn PhysicistDavehttps://www.blogger.com/profile/11111405959451703182noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-54983773878205103842019-12-01T18:00:25.782-05:002019-12-01T18:00:25.782-05:00PhysicistDave,
Thank you again for all of your ex...PhysicistDave,<br /><br />Thank you again for all of your excellent feedback. In case you have not already seen it, here is an excellent Mathologer video regarding the dangers of switching too casually between real sums (1+2+3+… really does go infinity; this is not debatable) and Ramanujan summations (ℜ) (which characterize such series in interesting ways):<br /><br />https://www.youtube.com/Terry Bollingerhttps://www.blogger.com/profile/03915136249111338024noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-83948408865116962802019-12-01T12:31:57.783-05:002019-12-01T12:31:57.783-05:00Dave,
How do you know?
Have you had close person...Dave,<br /><br /><i>How do you know?<br /><br />Have you had close personal contact with Sabine or Lawrence or Reimond or Jean... or me so that you actually know what we have "made an attempt at"?</i><br /><br />My comment was based on the public record.<br /><br /><i>Again, you know nothing at all of the work I have done in the course of my life. Same for Lawrence, reimond, Jean, etc.<bud raphttps://www.blogger.com/profile/06948881286545517324noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-40787123188745561632019-12-01T11:58:05.371-05:002019-12-01T11:58:05.371-05:00Falker,
For all I can tell I approved all comment...Falker,<br /><br />For all I can tell I approved all comments you submitted. A reply from you to Dave did appear above starting with<br /><br />"Dave,<br /><br />Thank you!<br />I’m not familiar with these technicalities - unfortunately..."<br /><br />Is this the one that you referring to? If not, I am afraid it did not come through. Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-29387005941634527012019-12-01T10:41:50.124-05:002019-12-01T10:41:50.124-05:00I had posted a little reply message to Dave, but i...I had posted a little reply message to Dave, but it didn't show up. I don't know why. Not a big deal, it's just that you want to be polite but the system is not;-)Falkerhttps://www.blogger.com/profile/12364415222331194182noreply@blogger.com