tag:blogger.com,1999:blog-22973357.post8683407513267643196..comments2023-09-27T07:44:19.769-04:00Comments on Sabine Hossenfelder: Backreaction: New gravitational wave detection with optical counterpart rules out some dark matter alternativesSabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.comBlogger17125tag:blogger.com,1999:blog-22973357.post-88166125116977438242017-11-05T01:37:34.885-04:002017-11-05T01:37:34.885-04:00On October 30, Green, Moffat, and Toth published a...On October 30, Green, Moffat, and Toth published <a href="http://arxiv.org/abs/1710.11177v1" rel="nofollow">a new preprint</a>, demonstrating that the preprint of Boran et al. grossly misrepresented Moffat's STVG alternative theory of gravity, and that STVG is consistent with the neutron-start merger GW170817/GRB170817A. (One the other hand, theories attempting to reproduce the behaviour of Anonymoushttps://www.blogger.com/profile/15729194602104030005noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-76522990982168796902017-10-26T11:19:21.252-04:002017-10-26T11:19:21.252-04:00@Axil, yes fuzzy/BEC dark matter still seems to be...@Axil, yes <a href="https://ncatlab.org/nlab/show/fuzzy+dark+matter" rel="nofollow">fuzzy/BEC dark matter</a> still seems to be in good shape regarding observation.Unknownhttps://www.blogger.com/profile/01006460812296046328noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-87439571401978189002017-10-25T14:42:59.281-04:002017-10-25T14:42:59.281-04:00Prof. Pierre Sikivie: "It has long been known...Prof. Pierre Sikivie: "It has long been known that axions produced by vacuum realignment during the QCD phase transition in the early universe form a cold degenerate Bose gas and are a candidate for the dark matter. More recently it was found that dark matter axions thermalize through their gravitational self-interactions and form a Bose-Einstein condensate (BEC). On time scales long Axilhttps://www.blogger.com/profile/07190120527431077518noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-71706877831123050532017-10-23T20:48:34.654-04:002017-10-23T20:48:34.654-04:00In addition to a dark matter particle detection, a...In addition to a dark matter particle detection, a way to see dark matter 'better' will be with better telescopes like the new Mauna Loa and James Webb scopes. Astronomy has been so successful in the past 100 years - every major step forward in capability solves and creates lots of new problems.<br /><br />Things one might see about dark matter - better more detailed maps of dm density (Tom Andersenhttps://www.blogger.com/profile/17562906116020498110noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-28771245794330799662017-10-23T07:03:50.343-04:002017-10-23T07:03:50.343-04:00Sabine, let me clarify/correct my comments about T...Sabine, let me clarify/correct my comments about TeVeS. It was not Moffat who originally pointed out that TeVeS results in stellar instability but rather <a href="https://arxiv.org/pdf/gr-qc/0703060.pdf" rel="nofollow">Seifert (2007)</a>. And its violation of local Lorentz invariance is mentioned on page 353 of the 2015 book <a href="https://www.amazon.ca/Gravity-Where-Do-We-Stand-ebook/dp/Anonymoushttps://www.blogger.com/profile/15729194602104030005noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-18644476052355920952017-10-23T03:34:11.930-04:002017-10-23T03:34:11.930-04:00@Rout
"However there is also a theory that da...@Rout<br />"However there is also a theory that dark matter doesn't exist in the first place and it is all a hoax and a scam."<br /><br />The theory that "X is a scam and does not exist" is very popular for many values of "X". However, supporting evidence that this theory is valid has historically been limited to only a handful of values of X. Also, values of X Rob van Son (Not a physicist, just an amateur)https://www.blogger.com/profile/12611755507524401026noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-38744773825672377272017-10-23T00:52:53.941-04:002017-10-23T00:52:53.941-04:00dlb,
This is an interesting question. I was think...dlb,<br /><br />This is an interesting question. I was thinking about this yesterday. If it's a particle, then detecting the particle will convince almost everyone that's it. If it's not a particle, I'm not sure what it would take. Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-39351553508009878782017-10-22T19:06:19.722-04:002017-10-22T19:06:19.722-04:00I would be interested in hearing follow ups on wha...I would be interested in hearing follow ups on what those supporting Moffat's modified gravity have to say about this data. Thanks for presenting it.Frank Hubenyhttps://www.blogger.com/profile/18058591172624203875noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-12336245933072533282017-10-22T19:01:53.065-04:002017-10-22T19:01:53.065-04:00@Rout: A "scam" is indeed always possibl...@Rout: A "scam" is indeed always possible since, however much we learn, there is still a possibility that our ignorance is still infinite in as much as removing a portion of the integers cannot exaust infinity - not even a countable one at that! Yet, for our world, equipped with such dreadful instrumentation what are the chances that we do not see what trully is there? Unless of course,Theophanes Raptishttps://www.blogger.com/profile/01269614280130174555noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-30844537459133358132017-10-22T15:19:54.686-04:002017-10-22T15:19:54.686-04:00I'm a long time reader of this blog, but almos...I'm a long time reader of this blog, but almost never post. I would like to thank you again for taking the time to summarize papers like this for us.<br /><br />I realize your blog is about quantum gravity phenomenology, and not dark matter or general relativity (if you know anyone who blogs at this level of expertise, I'd be delighted to know about them), but I have a question (hopefullydlbhttps://www.blogger.com/profile/00647687145267016748noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-46498055983121410792017-10-22T14:59:01.302-04:002017-10-22T14:59:01.302-04:00"In modified gravity, dark matter is not made..."In modified gravity, dark matter is not made of particles." In Milgrom's MOND, there is not necessarily an exclusion of all hypothetical dark matter particles. Also, MOND might be empirically valid even though Einstein's field equations are, after quantum averaging, 100% correct. How might this happen? There might be MOND-chameleon particles that have variable effective mass David Brownhttps://www.blogger.com/profile/10537922851243581921noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-2118751217591129292017-10-22T11:46:22.782-04:002017-10-22T11:46:22.782-04:00This is a very good analysis Sabine. However there...This is a very good analysis Sabine. However there is also a theory that dark matter doesn't exist in the first place and it is all a hoax and a scam. Nevertheless, a very good analysis.Bruce Routhttps://www.blogger.com/profile/07070314799576659579noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-18941736709904847752017-10-22T11:18:17.417-04:002017-10-22T11:18:17.417-04:00With all the new data resulting from LIGO detectio...With all the new data resulting from LIGO detections, the Nobel committee's choice is looking better and better, in retrospect.JimVhttps://www.blogger.com/profile/10198704789965278981noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-85477347068824931612017-10-22T10:28:39.265-04:002017-10-22T10:28:39.265-04:00Solve a problem? No, remove the problem.
"gr...Solve a problem? No, remove the problem.<br /><br />"<i>gravitational potential is described by the curvature of space-time</i>" and/or by Einstein-Cartan spacetime torsion, and mixed <b>[1,2]</b>. Torsion is chiral (a left foot) validated with opposite shoes (excluded from physics by Green's function).<br /><br />10^(-9) chiral anisotropic space-time torsion softens exact Uncle Alhttps://www.blogger.com/profile/05056804084187606211noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-30224307323443056792017-10-22T09:16:24.955-04:002017-10-22T09:16:24.955-04:00Unknown, that paper does not say anything about Da...Unknown, that paper does not say anything about Dark matter emulators. It however does do an independent calculation of Shapiro delay and we have cited that paper and mentioned that our calculation is complementary to that analysis. Shantanuhttps://www.blogger.com/profile/16322812456382858228noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-50008459948394435502017-10-22T08:18:28.301-04:002017-10-22T08:18:28.301-04:00Unknown,
How do you scoop a paper when you cite i...Unknown,<br /><br />How do you scoop a paper when you cite it? I don't understand what you mean.Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-39785723916276912692017-10-22T07:18:37.341-04:002017-10-22T07:18:37.341-04:00This comment has been removed by the author.Unknownhttps://www.blogger.com/profile/06031141191397448812noreply@blogger.com