tag:blogger.com,1999:blog-22973357.post1290204641011209126..comments2023-09-27T07:44:19.769-04:00Comments on Sabine Hossenfelder: Backreaction: Black holes declared non-existent again.Sabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.comBlogger72125tag:blogger.com,1999:blog-22973357.post-31914149021507865742016-03-25T10:47:28.692-04:002016-03-25T10:47:28.692-04:00It seems to me, the author has made several wrong ...It seems to me, the author has made several wrong assumptions, which lead to the calculated outcome (predictably). <br />She states, that <br />1. “the very last photon making it to future infinity and thus contributing to Hawking radiation, is produced just before an horizon forms.” <br />2. “The production of fluxes switches on gradually at the onset of collapse but most of it is produced on Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-22973357.post-56127006650539013612015-03-11T04:36:02.541-04:002015-03-11T04:36:02.541-04:00"virtual particles do in principle contribute...<i>"virtual particles do in principle contribute to the cosmological constant, yes. They contribute way too much, that's what's known as the cosmological constant problem"</i><br /><br />Anyone even remotely interested in such topics should read what is probably <a href="http://arxiv.org/abs/1002.3966" rel="nofollow">both one of the most important and one of the most overlooked Phillip Helbighttps://www.blogger.com/profile/12067585245603436809noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-2115652904056250442015-03-10T11:55:15.701-04:002015-03-10T11:55:15.701-04:00Stephen,
I'm not sure what you mean by 'r...Stephen,<br /><br />I'm not sure what you mean by 'real' mass and with saying that the cosmological constant is "massive". What does it mean that a constant is "massive"? Let me put it this way: virtual particles do in principle contribute to the cosmological constant, yes. They contribute way too much, that's what's known as the cosmological constant Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-77923764591126458452015-03-10T09:09:24.985-04:002015-03-10T09:09:24.985-04:00Hi Sabine,
I am curious. When you write that "...Hi Sabine,<br />I am curious. When you write that "black hole radiation is produced by the dynamics of the background", does this imply that virtual particle pair are influenced by gravity and thus have "real" mass. This makes no sense to me as it would imply a massive cosmological constant. What am I missing?Stephen Paul Kinghttps://www.blogger.com/profile/12854545182901504082noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-14818099915950627792014-10-05T08:30:19.152-04:002014-10-05T08:30:19.152-04:00/*..but the particle creation itself does not nece.../*..but the particle creation itself does not necessitate a horizon..*/<br /><br />You may consider the particles as a miniature quantum gravity black holes. They're just hold together with surface tension instead of gravity, but they've still event horizon at their surface. Therefore, once such a particle appears inside of strong gravity field, its Hawking radiation will take a place Zephirhttps://www.blogger.com/profile/06010623752049244967noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-73349287672892307452014-10-03T19:21:08.531-04:002014-10-03T19:21:08.531-04:00This is even more exotic from the same author. Evi...This is even more exotic from the same author. Evidence for multiverse. <br /><br />http://www.thesundaytimes.co.uk/sto/news/uk_news/Science/article1261602.ece<br /><br /><br />qsahttps://www.blogger.com/profile/08193989424656595346noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-84409659324691673212014-10-03T15:16:12.437-04:002014-10-03T15:16:12.437-04:00Perhaps you can correct me if I'm mistaken, bu...Perhaps you can correct me if I'm mistaken, but it appears to me that the statement of the Friedman equation in Eq. (IV.1) is wrong in the first preprint? It doesn't seem dimensionally correct either, and several of the equations that follow from it seem dimensionally wrong too. (Obviously hbar=1 in addition to c=G=1 allows you to convert any units to any units, but for the classical schrodingasdawghttps://www.blogger.com/profile/11146344773214303802noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-5218672574758904252014-10-03T14:22:06.083-04:002014-10-03T14:22:06.083-04:00i was assuming spherical symmetry in my previous p...i was assuming spherical symmetry in my previous posts, but of course i'm aware that for the spinning black hole the radius of the GR horizon can become much smaller and even if black hole do not actualy exist (for instance if the exponential metric is the correct one) astrophysicist can always play with a free parameter, the unknown spin of the object, to reduce the GR horizon radius in F henry-couannierhttps://www.blogger.com/profile/13933350696243790692noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-82209150168352539882014-10-03T07:18:41.386-04:002014-10-03T07:18:41.386-04:00Sorry , the neutron star stability limit would be ...Sorry , the neutron star stability limit would be significantly modified with an exponential metric but certainly not enough to be able to imagine that Sagittarius A^* might be a huge neutron star ... so we would have a collapsed object (much smaller than the volume delimited by the Schwarzschild horizon) but with no horizon, however even if it's not a singular at r=0 (quark star ?) the F henry-couannierhttps://www.blogger.com/profile/13933350696243790692noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-77583152665857764052014-10-03T06:21:07.371-04:002014-10-03T06:21:07.371-04:00"What Hawking is saying is essentially that h..."What Hawking is saying is essentially that he believes that a matter collapse only leads to a temporary apparent horizon but not to an eternal event horizon."<br /><br />OK , but probably the fact that this apparant horizon is expected to last for such a long time that it is not possible to make the distinction with a genuine horizon, is a very peculiar feature of GR ... in any F henry-couannierhttps://www.blogger.com/profile/13933350696243790692noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-29693524207901324192014-10-03T05:30:35.734-04:002014-10-03T05:30:35.734-04:00CIP:
As I explained in this earlier post, the obs...CIP:<br /><br /><a href="http://backreaction.blogspot.de/2014/01/if-it-quacks-like-black-hole.html" rel="nofollow">As I explained in this earlier post</a>, the observations are well explained by everything that behaves for a sufficiently long time like a black hole. There is nothing in this paper explaining whether this would be the case here, but it doesn't matter because the argument is Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-1640865651166933542014-10-02T23:27:53.643-04:002014-10-02T23:27:53.643-04:00Of course we have a lot of things in the universe ...Of course we have a lot of things in the universe which look like black holes, so if BH don't exist, what are they? CapitalistImperialistPighttps://www.blogger.com/profile/17523405806602731435noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-88529297095657834912014-10-01T12:48:50.141-04:002014-10-01T12:48:50.141-04:00What I find a little disturbing but inspiring is t...What I find a little disturbing but inspiring is that I cannot foresee what Bee will make the topic next, a reminder that for awhile I felt I was closer to knowing everything.<br />I missed whatever Leibniz talk was on her schedule, but that old dude is as essential as ideas of curvature and stresses, tensors and so on. Energy as physics probing the microscale that time so focused and amplified L. Edgar Ottohttps://www.blogger.com/profile/00525169618204198073noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-52804239264360682452014-10-01T10:47:11.902-04:002014-10-01T10:47:11.902-04:00Well said Neil. Remember your 156 billion light ye...Well said Neil. Remember your 156 billion light years wide and the hall-of-mirrors universe? Take a look at the HUDF, find a prominent galaxy, then look over to the left and down a bit. <br /><br />Yanick, re <i>any evidence to show that space itself just isn't energy?</i> Not from me. At the fundamental level, I just can't separate them. There's shear stress and pressure in the Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-22973357.post-27060887852695029962014-09-30T11:16:22.288-04:002014-09-30T11:16:22.288-04:00Hello,
Something that disturbs me a bit is that i...Hello,<br /><br />Something that disturbs me a bit is that i have always believed that our giant BH candidate at the center of our galaxy could not be bigger than its horizon: i believed that if it was the case people would already have observationnal evidence for that... Indeed as fas as i have understood if the theoretical result is correct, it would mean that not only there are no BH , but F henry-couannierhttps://www.blogger.com/profile/13933350696243790692noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-81480089417195304732014-09-30T10:50:21.354-04:002014-09-30T10:50:21.354-04:00Something that I haven't seen mentioned in all...Something that I haven't seen mentioned in all the coverage of this paper is that even if the assumptions that went into the calculation are correct (I have serious doubts), the solution they come up with has absolutely no effect on astrophysical black holes. The surface of the star still reaches an enormous redshift, and the entire process takes essentially forever as seen by an outside Anonymoushttps://www.blogger.com/profile/04016953821574199100noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-2497983875092578432014-09-30T08:12:13.240-04:002014-09-30T08:12:13.240-04:00But is it news or new twists, wrinkles. I mean by ...But is it news or new twists, wrinkles. I mean by standard particle models does the Higgs mass exists?<br />Of the 24 pips of backgammon where does the checker on the 25 bar go?<br />This unfolded cube of entangled back reactions?<br />In the end breaking science news has the upper hand in journalism no matter what is offered as spin.<br />The amazing thing is that this fact set is the very L. Edgar Ottohttps://www.blogger.com/profile/00525169618204198073noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-66189601003730464842014-09-30T00:09:22.704-04:002014-09-30T00:09:22.704-04:00On Huffington Post, along side news that butter is...On Huffington Post, along side news that butter is in fact good for you, comes word in bold headline:<br />"This Physicist Says She Has Proof Black Holes Simply Don't Exist"<br /><br />So the pinball hits the paddle and I can see why physicists should avoid the appearance of too much early enthusiasm for their discoveries.Don Fosterhttps://www.blogger.com/profile/04814669413022486958noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-82122867160370010412014-09-29T18:00:06.700-04:002014-09-29T18:00:06.700-04:00Yes Edgar, Bee is the update, that is why I thanke...Yes Edgar, Bee is the update, that is why I thanked her.<br /><br /><b>Bee</b>:<i>In their papers, Laura Mersini-Houghton and her collaborator Harald Pfeiffer have taken into account the backreaction from the emitted Hawking radiation on the collapsing mass which is normally neglected. They claim to have shown that the mass loss is so large that black holes never form to begin with.</i><br /><br PlatoHagelhttps://www.blogger.com/profile/00849253658526056393noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-46814761040632882702014-09-29T17:29:35.753-04:002014-09-29T17:29:35.753-04:00Plato Hagel,
I cannot say if its updated. I seemed...Plato Hagel,<br />I cannot say if its updated. I seemed to have passed a horizon leaving at least Hegel's reason which turns materialism on its head but I do not know when.<br />I cling to an idea a long time before I change it. But if there are no black holes physics seems dyslexic.<br />Sabine is the update. Lubos last three blog posts proves there are black holes needing updates on all L. Edgar Ottohttps://www.blogger.com/profile/00525169618204198073noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-24149350004438455632014-09-29T15:39:31.390-04:002014-09-29T15:39:31.390-04:00Hi Edgar,
Hagel.....not Hegel:)
What I like is t...Hi Edgar,<br /><br />Hagel.....not Hegel:)<br /><br />What I like is that Prof Susskind is speaking to problems that I see through all the conversations that have gone on and about abstract mathematics and how our own limitation provide room for a way to work for areas we do have problems with seeing. So theoretical has a defining point here.<br /><br />Prof. Susskind is very methodical and PlatoHagelhttps://www.blogger.com/profile/00849253658526056393noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-65668068623494580852014-09-29T12:14:57.594-04:002014-09-29T12:14:57.594-04:00Plato + Hegel
The Kugel or K (sphere group) is at...Plato + Hegel<br /><br />The Kugel or K (sphere group) is at once the most interesting and least interesting as far as physical laws go.<br /><br />Consider Plato's concept of a sphere before it is complicated by simple logic. For one thing as pairs (dialectics anyone?)<br /><br />At this foundational view the lecture fails from the start to predict the past (or future) beyond the L. Edgar Ottohttps://www.blogger.com/profile/00525169618204198073noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-86139487393251824432014-09-29T10:43:44.322-04:002014-09-29T10:43:44.322-04:00I guess Bee, one has to have an understanding of t...I guess Bee, one has to have an understanding of the <a href="http://youtu.be/iJfw6lDlTuA?t=6m36s" rel="nofollow">theoretical minimum</a>?<br /><br />Best,PlatoHagelhttps://www.blogger.com/profile/00849253658526056393noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-12494883245680449082014-09-28T22:49:10.485-04:002014-09-28T22:49:10.485-04:00Well, Robert, it is hard for me to disagree with t...Well, Robert, it is hard for me to disagree with that on the face of it so that is still the last word, plain and simple. The child in me remains like Aristotle or Darwin observing things around me as on the beach. Yet the focus, the fresh adventure, strives to think about it - some sense of unity to it all- if you mean our generation, or as we accumulate errors of thought or body I suppose we L. Edgar Ottohttps://www.blogger.com/profile/00525169618204198073noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-84762223966827416742014-09-28T21:02:50.652-04:002014-09-28T21:02:50.652-04:00Hi Otto,
Here is my prescription: study nature as...Hi Otto,<br /><br />Here is my prescription: study nature assiduously, not abstract theoretical models.Robert L. Oldershawhttps://www.blogger.com/profile/15396555790655312393noreply@blogger.com