tag:blogger.com,1999:blog-7315236707728759521.comments2023-11-28T16:52:43.327-07:00Dispatches From Turtle IslandAndrew Oh-Willekehttp://www.blogger.com/profile/02537151821869153861noreply@blogger.comBlogger5183125tag:blogger.com,1999:blog-7315236707728759521.post-20379632032972353532023-11-28T16:52:43.327-07:002023-11-28T16:52:43.327-07:00Thanks for the input.Thanks for the input.andrewhttps://www.blogger.com/profile/08172964121659914379noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-24416076048254373592023-11-28T16:51:16.308-07:002023-11-28T16:51:16.308-07:00Thanks for the heads up.Thanks for the heads up.andrewhttps://www.blogger.com/profile/08172964121659914379noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-72967500426457417102023-11-28T16:49:41.566-07:002023-11-28T16:49:41.566-07:00I appreciate the thoughtful comments from all of y...I appreciate the thoughtful comments from all of you, and have gotten a little break from saving widows and orphans, which had been taking up most of my time, but now I'm bogged down doing all of the administrative garbage involved in running a law firm that I ignored while doing the worthwhile stuff. Life is hell. See you soon.andrewhttps://www.blogger.com/profile/08172964121659914379noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-4813278716810965872023-11-22T00:52:31.173-07:002023-11-22T00:52:31.173-07:00Even if we must lower it to ~20 degrees, should th...Even if we must lower it to ~20 degrees, should that not mean that the "flux tube" effect between the wide binary enlarges the effective gravity? I'm not the expert, nor did I read Deur's papers closely, so correct me if I'm wrong.Maarten Havingahttps://www.blogger.com/profile/01483091922282647449noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-62363635794816715162023-11-21T13:24:59.643-07:002023-11-21T13:24:59.643-07:00Hi Andrew,
Nice to see you blogging about this int...Hi Andrew,<br />Nice to see you blogging about this interesting turning point in scientific history!<br /><br />I'd like to start a discussion on the effects of self-interaction for wide binaries. Suppose a graviton is coming from a point-like mass with an inclination of 30 degrees to the milky way disc plane. The most nearby other massive object is some 300000 AU (5 ly) further away (the avg distance between stars). The one after that 600000, and so on. If we want this graviton to be contained in the 2D structure of gravity around the disc, we can calculate the sum of deflection angles. For light these are 4MG/rc2 which is really tiny. The sum after several objects tends to a logarithm, and in the milky way with radius 50000 ly we can expect there to be around 10000 stars encountered in a straight line from the middle of the milky way. The sum of 1+1/2+...+1/10000 is around 10. In order for Deur's approach to work, which I certainly hope, the first deflection angle should therefore be on the order of 3 degrees, rather more since also larger angles should be captured. Let's put it on 7 degrees.<br />Doesn't this mean that for a wide binary some 15000 AU from each other that the deflection angle of one star on the other should be a factor 300000/15000 = 20 larger? Which is 140 degrees?Maarten Havingahttps://www.blogger.com/profile/01483091922282647449noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-55408367039826504742023-11-20T21:48:42.182-07:002023-11-20T21:48:42.182-07:00https://arxiv.org/pdf/2309.10404.pdf
[v4] Sat, 18...https://arxiv.org/pdf/2309.10404.pdf<br /><br />[v4] Sat, 18 Nov 2023 03:09:22 UTC (25,081 KB)<br /><br />a response to Banik et al. It will be available from Tuesday. Appendix B explains why the Banik et al. kinematic cuts don’t matter. Banik et al. made a false claim deliberately based on appearances of v^tilde without detailed calculations. A lot of people seem to be deceived by their v^tilde figures (in particular, their fig 19 and 21) as if they have a real truth. neohttps://www.blogger.com/profile/16769182614452171312noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-47039032589782526302023-11-19T20:27:33.443-07:002023-11-19T20:27:33.443-07:00Kyu-Hyun Chae
November 19, 2023 at 2:08 am
The a...Kyu-Hyun Chae<br />November 19, 2023 at 2:08 am <br /><br />The accepted version of https://arxiv.org/abs/2309.10404 has a response to Banik et al. It will be available from Tuesday. Appendix B explains why the Banik et al. kinematic cuts don’t matter. Banik et al. made a false claim deliberately based on appearances of v^tilde without detailed calculations. A lot of people seem to be deceived by their v^tilde figures (in particular, their fig 19 and 21) as if they have a real truth.<br /><br />Finally, please note that Hernandez and myself cannot respond to all the comments here mainly because we want respond formally with real results, some of which can be found in the new paper mentioned above. Since this is not a political issue, the answer cannot be found by exchange of words.<br /><br />https://tritonstation.com/2023/11/13/wide-binary-debate-heats-up-again/comment-page-1/#comment-21852<br /><br />debates rage on neohttps://www.blogger.com/profile/16769182614452171312noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-44000338109632492962023-11-16T08:00:23.770-07:002023-11-16T08:00:23.770-07:00Reminds me often told story where some young physi...Reminds me often told story where some young physicist brings in a model and VonNuemann said "with four free variables I can make an elephant, with a 5th I can wave it's trunk". Guyhttps://www.blogger.com/profile/15789570230699865921noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-60413449609360917012023-11-15T14:49:34.517-07:002023-11-15T14:49:34.517-07:00I would want to check this against the references ...I would want to check this against the references at the top of page 2, Stefani et al and Cionco et al, which are apparently more physical models of planetary influence on sunspot cycle, but somewhat stochastic. This author seems to be using pure stats to claim a deterministic relationship. Mitchellhttps://www.blogger.com/profile/10768655514143252049noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-56128511218713695912023-11-14T21:03:48.977-07:002023-11-14T21:03:48.977-07:00Arraut's paper is very good although I can'...Arraut's paper is very good although I can't speak to its correctness first hand. It is entirely classical and very much in the same spirit as Deur's work.<br /><br />The second paper explores relativistic GR modifications that give rise to MOND effects at the right scale as a quantum gravity effect. I can't speak to its correctness either. But it is also promising.andrewhttps://www.blogger.com/profile/08172964121659914379noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-13817319861087533092023-11-14T20:24:41.333-07:002023-11-14T20:24:41.333-07:00i'd like to see a blog on this and
arXiv:2...i'd like to see a blog on this and <br /><br /><br /><br />arXiv:2310.19894 <br /><br />MONDified Gravity<br /><br />Authors: Martin Bojowald, Erick I. Duque neohttps://www.blogger.com/profile/16769182614452171312noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-42678643275403632992023-11-14T19:19:37.502-07:002023-11-14T19:19:37.502-07:00I'll take a look at it.I'll take a look at it.andrewhttps://www.blogger.com/profile/08172964121659914379noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-64193049207962323242023-11-12T20:15:13.696-07:002023-11-12T20:15:13.696-07:00Stacy McGaugh says he's still in the middle ab...Stacy McGaugh says he's still in the middle about wide binaries, because Chae claims that when he repeats the analysis of Banik et al, the evidence for MOND increases...? <br /><br />https://twitter.com/DudeDarkmatter/status/1723888848952766798Mitchellhttps://www.blogger.com/profile/10768655514143252049noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-84095973905601704992023-11-12T19:03:39.642-07:002023-11-12T19:03:39.642-07:00arXiv:2311.05652 (gr-qc)
[Submitted on 8 Nov 2023]... arXiv:2311.05652 (gr-qc)<br />[Submitted on 8 Nov 2023]<br />The Tully-Fisher's law and Dark Matter effects derived via modified symmetries<br />Ivan Arraut<br />Download PDF<br /><br /> In any physical system, when we move from short to large scales, new spacetime symmetries emerge which help us to simplify the dynamics of the system. In this letter we demonstrate that certain variations on the symmetries of General Relativity at large scales, generate the effects equivalent to Dark Matter. In particular, we reproduce the Tully-Fisher law, consistent with the predictions proposed by MOND. Additionally, we demonstrate that the dark matter effects derived in this way, are consistent with the predictions suggested by MOND, without modifying gravity. <br /><br />Comments: 4 pages, Editor's choice at EPL<br />Subjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Theory (hep-th)<br />Cite as: arXiv:2311.05652 [gr-qc]neohttps://www.blogger.com/profile/16769182614452171312noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-6583031894363554242023-11-11T06:59:54.597-07:002023-11-11T06:59:54.597-07:00I read the Banik23 paper and it builds a towering ...I read the Banik23 paper and it builds a towering tower of models and assumptions. To the extent that a non-specialist can tell they all make superficial sense, and the paper was preregistered, so there wasn't a lot of model selection going on. He throws some accurate darts at some other Gaia DR3 papers. I think the folks finding positive MOND data are going to need to put on their big-statistician pants and pull out their slide rules.Guyhttps://www.blogger.com/profile/15789570230699865921noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-56909518933426026892023-11-10T07:47:17.939-07:002023-11-10T07:47:17.939-07:00See also https://arxiv.org/abs/2311.05525See also https://arxiv.org/abs/2311.05525andrewhttps://www.blogger.com/profile/08172964121659914379noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-36203003739718179332023-11-10T07:16:16.561-07:002023-11-10T07:16:16.561-07:00@Mitchell
Heuristically, because Deur is describi...@Mitchell<br /><br />Heuristically, because Deur is describing the self-interaction of big gravitational fields, and the gravitational fields are two stars in isolation aren't big enough for the self-interactions of those fields to be signifiant.<br /><br />Deur reproduces MOND in galaxies because the gravitational fields of gillions of stars in galaxies are vastly more significant in such large systems and acquire MOND-scale strength.<br /><br />Another heuristic observation is that the way that the somewhat non-intuitive way that self-interaction effects scale has similarity to how event horizons of black holes scale with mass, which isn't as one might expect, simply a function a mass within a certain volume of event horizon.<br /><br />You can look at the math in the link in this post to my previous blog post doing that math.<br /><br />MOND uses a simpler phenomenological formula to fit the data which fits pretty much all scales of galaxies. But MOND is too strong an effect in low mass handful of stars or less scale systems, and it is too weak an effect in very high mass galaxy cluster systems that also have a different geometry.andrewhttps://www.blogger.com/profile/08172964121659914379noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-90713976197455837382023-11-09T21:18:06.725-07:002023-11-09T21:18:06.725-07:00Why would MONDish binaries contradict Deur?Why would MONDish binaries contradict Deur?Mitchellhttps://www.blogger.com/profile/10768655514143252049noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-79740638470039082522023-11-09T14:45:12.813-07:002023-11-09T14:45:12.813-07:00Relevant:
https://www.youtube.com/watch?v=HlNSvrY...Relevant:<br /><br />https://www.youtube.com/watch?v=HlNSvrYygRc&ab_channel=Dr.BeckyRyanhttps://www.blogger.com/profile/07906194112935320590noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-40083655350124055632023-11-09T11:52:14.635-07:002023-11-09T11:52:14.635-07:00@GeorgeHerold
Try clicking on the "dark matt...@GeorgeHerold<br /><br />Try clicking on the "dark matter" tag on this blog. This covers both quantum gravity theories and dark matter particle theories.<br /><br />andrewhttps://www.blogger.com/profile/08172964121659914379noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-46269321127455040262023-11-09T08:45:46.362-07:002023-11-09T08:45:46.362-07:00Thanks Andrew, I'm an ignorant solid state exp...Thanks Andrew, I'm an ignorant solid state experimentalist. But MoND seems to be a hint to some type of quantum gravity(QG). When I look into QG theories I only see stuff about the high energy limits. Do you know of anyone thinking about the low energy limits? (Gravitons in the lowest energy state of the universe, interacting with each other and giving us something that looks like MoND.)George Heroldhttps://www.blogger.com/profile/10856527872293160233noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-25945899093826588702023-11-08T21:45:15.987-07:002023-11-08T21:45:15.987-07:00But it does show similarities with gravitweak unif...But it does show similarities with gravitweak unification theories, which is a pretty interesting line of inquiry. See also Woit's new paper "space-time is right handed."<br /><br />he mentioned also on his blog and mitchell porter<br />also <br /><br />"1. Introduction<br />If one wants to describe fermions coupled to gravity, the metric field does not suffice.<br />Rather, one needs to introduce frame fields, and with them the symmetry under frame<br />rotations, a spin structure and hence a local SL(2, C) symmetry. In this context, as the<br />fermions in the standard model are chiral, it is of special interest to consider chiral<br />formulations of gravity. One example are the variables introduced by Sen [1] and<br />Ashtekar [2, 3, 4] for gravity. The basic variables are a frame field eI and an so(3, 1)"<br /><br /><br /><br />Ashtekar could describe fermions coupled to gravity and " as the<br />fermions in the standard model are chiral, it is of special interest to consider chiral<br />formulations of gravity"<br />neohttps://www.blogger.com/profile/16769182614452171312noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-40062072679755736852023-11-08T20:40:10.978-07:002023-11-08T20:40:10.978-07:00 arXiv:2310.12114 (astro-ph)
[Submitted on 18 Oct ... arXiv:2310.12114 (astro-ph)<br />[Submitted on 18 Oct 2023]<br />Dissipationless collapse and the dynamical mass-ellipticity relation of elliptical galaxies in Newtonian gravity and MOND<br />Pierfrancesco Di Cintio<br />Download PDF<br /><br /> Context. Deur (2014) and Winters et al. (2023) proposed an empirical relation between the dark to total mass ratio and ellipticity in elliptical galaxies from their observed total dynamical mass-to-light ratio data M/L = (14.1 +/- 5.4){\epsilon}. In other words, the larger is the content of dark matter in the galaxy, the more the stellar component would be flattened. Such observational claim, if true, appears to be in stark contrast with the common intuition of the formation of galaxies inside dark halos with reasonably spherical symmetry. Aims. Comparing the processes of dissipationless galaxy formation in different theories of gravity, and emergence of the galaxy scaling relations therein is an important frame where, in principle one could discriminate them. Methods. By means of collisionless N-body simulations in modified Newtonian dynamics (MOND) and Newtonian gravity with and without active dark matter halos, with both spherical and clumpy initial structure, I study the trends of intrinsic and projected ellipticities, Sérsic index and anisotropy with the total dynamical to stellar mass ratio. Results. It is shown that, the end products of both cold spherical collapses and mergers of smaller clumps depart more and more from the spherical symmetry for increasing values of the total dynamical mass to stellar mass, at least in a range of halo masses. The equivalent Newtonian systems of the end products of MOND collapses show a similar behaviour. The M/L relation obtained from the numerical experiments in both gravities is however rather different from that reported by Deur and coauthors. <br /><br />Comments: 10 pages, 8 figures, submitted, comments welcome<br />Subjects: Astrophysics of Galaxies (astro-ph.GA)<br />Cite as: arXiv:2310.12114 [astro-ph.GA]neohttps://www.blogger.com/profile/16769182614452171312noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-65322092244593611792023-11-08T18:59:43.766-07:002023-11-08T18:59:43.766-07:00@DDeden
https://www.linkedin.com/pulse/could-mose...@DDeden<br /><br />https://www.linkedin.com/pulse/could-moses-have-led-exodus-from-indus-valley-bharat-jhunjhunwala<br /><br />Silly and crazy. The story of Moses is Sumerian and borrowed by the Jews with some slight twists from the prior Sumerian myth, however, which does play out on the Tigris-Euphrates Rivers.<br /><br />Baked bricks made with straw are ubiquitous rather than being a convincing geolocator.andrewhttps://www.blogger.com/profile/08172964121659914379noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-23347686363985954622023-11-08T18:51:29.531-07:002023-11-08T18:51:29.531-07:00https://arxiv.org/abs/2310.19729
https://arxiv.org...https://arxiv.org/abs/2310.19729<br />https://arxiv.org/abs/2310.19722<br /><br />Mildly interesting. I don't follow LQG all that closely, and its a bit technical and theoretical for me.<br /><br />But it does show similarities with gravitweak unification theories, which is a pretty interesting line of inquiry. See also Woit's new paper "space-time is right handed."andrewhttps://www.blogger.com/profile/08172964121659914379noreply@blogger.com