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rjbeery

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Everything posted by rjbeery

  1. You're presuming that either the object in that image is a stable neutron star or a fully-formed black hole. A "frozen star" would still asymptotically red-shift light, it's just that the traditionally predicted effects of an event horizon would exist at r=0. This is one of those times that my BS-meter is going off. If the static solution gives a full accountability of the future then introducing a change in M does not change that fact. If I may be blunt, I believe you're just presuming that the Vaidya solution says something which bolsters your argument. You've even hedged your bet by saying You've thrown out what I believe to be a false resolution to my objection, and then you say This is intellectual insincerity. I raised an objection in the form of a logical contradiction in the OP. In an effort to respond to questions, I found three peer-reviewed papers which discuss my objection in detail (using the Schwarzschild metric), and agree with my objection. You throw out a comment about how the Vaidya solution resolves all problems, which you cannot prove but "may prove in the future", and until then we should just end the conversation. Is making a concession really that difficult for you?
  2. Accretion disks are still expected from a very compact, high mass area.
  3. The information paradox is resolved in this (and other) papers by claiming that the event horizon does not, ever, form, which is exactly what I've been saying. My objection to the original diagram used in the Hawking paper remains valid, and the idea that the Vaidya analysis solves this is false -- Vaidya black holes do not allow the infinite observer to see the event horizon in finite time, and that's the crux of the problem. If I were going to criticize anything about this and related papers, it's the fact that they are using Hawking "back reaction" to discuss the idea that the event horizon cannot form, but the rate of Hawking radiation is a function of the radius of the event horizon -- in other words, the black hole is a prerequisite for any back reaction of Hawking radiation to exist. This is why I'm careful to talk about "evaporating processes" without referring to Hawking radiation explicitly.
  4. I also work under the presumption that there is a single reality. I have a real problem (again, philosophical, but I believe that it has merit) with Kruskal coordinates and their supposed resolution to the so-called mathematical singularity problem at the event horizon.
  5. I understand the theory of studying "how {variable} changes with respect to {dimension 1} in the {dimension 2} direction". I can read Einstein tensor notation. I know the Schwarzschild metric pretty well. I understand Kruskal coordinates. This is neither here nor there, though, because I tend to analyze Physics on a more philosophical level. When the math "says something" I try very hard to understand what it's saying physically, and when I don't I try to find someone who does and ask them to explain it.
  6. The paper I referred to has addressed my issues and acknowledged the contradictions I believed to exist in the conventional model. It was a relief to find, actually, being published in a prominent journal, Nuclear Physics B, in 2016. My frustrations were doubled up in this thread because some posters' responses implied that 1) the issues I raised were trivially explained, 2) the physics community was well-aware of them, 3) the responders personally understood the explanations but, 4) the math was too complex to explain it to laymen. My BS-meter wouldn't stop blinking. Anyway, thanks for the back-and-forth on this.
  7. Agreed, which means that either 1) General Relativity is wrong, 2) some mysterious delimiter on the velocity of cosmic rays prevents them from reaching the critical energy required for a predicted micro black hole, or 3) the micro black holes evaporate before they can be detected. I'm working under the presumption of #3, and I feel it's fair to say that this is the same position held by most of the physics community today (as evidenced by the paper I linked to regarding the Large Hadron Safety Assessment Group). This is close, but regarding #1 -- the interior of a black hole cannot be described by the remote observer, and does not need to be. The infinite future is represented for a coordinate time observer B before mass crosses the event horizon. We have to take this literally. Pick a method of determining simultaneity, and then map those events of object A approaching the event horizon to the remote observer B; there will be events A that match to events B for any and all times/events for B from "now" until "eternity". Now, let the black hole evaporate, such that the black hole and A are simply gone and replaced by a new observer, C. Now, B and C can match events using our method of simultaneity, forever. In other words, If B were to describe what was happening in the region of the black hole at some certain time, he would claim that both A is asymptotically approaching it, and C is calmly residing there with no black hole in sight. I found this paper today, and, based on the abstract, it's making a similar argument: Parse this paragraph carefully. It says that it's assumed that an event horizon can form with Hawking radiation...but we have no model for it. Therefore we "turn off" Hawking radiation to allow the event horizon to form, and then "turn it on" to produce the graph that I used to show that a contradiction resides in this logic.
  8. Of course, and if the physical conditions were right then those things may come to be...or not. But the physical conditions for micro black holes are likely met continuously in our atmosphere. Obviously c applies to cosmic rays - when I said "no known mechanism might limit their incoming velocity" I meant limit it as a percentage of c such that they would be prevented from having sufficient energy to predict a micro black hole. Your second comment is baffling. Which assumption is false? Micro black holes do not produce cosmic rays -- they are produced by them. If you could summarize MY position on this, how would you do so?
  9. That's a distinction without a difference, and you have your logic backwards -- cosmic rays have no known nor plausible mechanism that might limit their incoming velocity as they enter our atmosphere. The energy required for a cosmic ray to collapse into a black hole isn't ungodly (due to their radius). To acknowledge cosmic rays but deny micro black holes is tantamount to declaring GR wrong. Possible, but I'm not here to convince others; I'm here to listen to and analyze objections.
  10. This is why I put the emphasis on micro black holes -- GR predicts them, yet the fact that we can't detect them implies (almost demands) that evaporation of some sort occurs. That this evaporation must occur prior to the event horizon existing, on logical grounds, is what I've been unable to convey in this thread.
  11. I'm referring to coordinate time (i.e. the infinite observer) when I make the statements below. In my experience there can be a tendency in forums to obfuscate through complexity, or at least unintentionally over-complicate a problem. Looking at the Schwarzschild solution for a black hole of radius zero should make it obvious that any sort of evaporation leads to a contradiction.
  12. Well if that's an argument then the singularity is necessary as well. 😜 There's no need to do this because my objection involving the event horizon using Schwarzschild coordinates only concerns the exterior region. All finite space and time have been accounted for. Every point (r=0, t<infinity) is represented, mathematically and physically, prior to the event horizon's creation. This has a literal, physical meaning. This mathematical fact does not vanish by changing coordinate charts or imparting angular momentum.
  13. This is a matter of fact, and I'm baffled that we're even on this subject. All of GR is designed to be coordinate invariant, and the ordering of events is obviously an absolute feature of physics. If different results are given in different analyses it's probably because they have altered the time and space definitions for mathematical convenience. An observer hovering just above the event horizon would witness the infinite future, but an infalling observer has his gravitational effects counter-balanced by his relative velocity, and the net result is a redshifting. If memory serves, he would see distant clocks ticking "at half speed" as he passes the event horizon.
  14. I'm not bothered by the notion of "no causal connection" but you cannot say that an event within the black hole "doesn't exist in the coordinate space". That's nonsensical. The entire point of this coordinate system is to give unique, well-ordered labels to events in spacetime.
  15. Wait a minute. That is literally the purpose of Penrose diagrams -- to follow causality through and beyond the event horizon. To say "it isn't meaningful" is the same thing as proclaiming that Penrose diagrams aren't meaningful.
  16. Then you agree that an observer residing in the upper part of Hawking's diagram (after the evaporation) has a coordinate time less than the time represented by any point residing at r=0 between the event horizon and the singularity below it on the graph?
  17. Some of these comments are presuming the existence of the event horizon, first, and then leaning on the definition of them as a defending explanation of them. Please refer to the diagram to see my objection. The formation of event horizons takes an infinite amount of coordinate time. We can map this using Penrose diagrams, where the top of the customary diagram represents the "infinite future". When we attempt to use a Penrose diagram to illustrate events after an event horizon has formed, we are now showing spacetime coordinates (events) which have already occurred, and have been accounted for. (r=0, t=100) is represented twice in the diagram, for example.
  18. Agreed, but I'm talking about a specific observer who is located at a point in space which "used to" contain a black hole. The black hole resides in the past of this observer. If you can't see the contradiction here, please refer to the diagram.
  19. The diagram is from page 219 of Hawking's "Particle Creation by Black Holes" paper. The causality issue is why Penrose diagrams are useful. I'm claiming that what Hawking did with them is not mathematically valid. The vertical axis is the time parameter, and either his diagram shows a black hole forming (and evaporating) in finite coordinate time, which is not supported by any mathematics of GR, or he is showing events that occur after the infinite future (i.e. higher on the vertical axis).
  20. It's the section in the past of our spacetime diagram where a theoretical black hole temporarily existed. The original way I showed the problem was this: The left vertical axis is the origin, r=0. This black hole is created and then eventually evaporates. Hawking wanted to represent the space r=0 after the black hole had dissipated, but you cannot normally do that with a Penrose diagram because timelike infinity is represented at the top. To see that this is a problem, consider the coordinate of the black hole completing its evaporation at t=100 in coordinate time. The point (r=0, t=100) is represented both at the event horizon formation and also after the black hole is gone.
  21. This is fair, we all appear to agree that finite black holes demand an "island" of spacetime which can be located in our past light cones, but whose interior contains points which are not. You both seem to feel that this is OK, and my feeling is that this "island" is no longer on a differentiable manifold when it becomes disconnected from the traditional future null infinity (the infinite future according to us).
  22. Being in my past is exactly the problem. It's directly contradicts the descriptive definition of event horizons and black holes. The problem isn't GR; it's GR + some process that makes black holes finite (in this case, evaporation). Event horizons and finite black holes are mutually incompatible, and since we agree that black holes require an event horizon then the very term "finite black hole" is an oxymoron.
  23. GR's treatment of gravity already accounts for stellar motions and accretion discs without requiring event horizons. It's entirely possible that black holes exist, but then it's also possible that the center of galaxies are full of unicorns and lemon ice cream. If GR has "a number of failings with regard to BHs" then you have no model whatsoever to predict them.
  24. From our perspective, the points beyond the visible universe are within the "black hole" that you're referring to, which is fine. That definition would be broken if we could somehow reach those locations at some point in the future, which we cannot (unless cosmic expansion reverses at some point?) That's the exact problem with "local" black holes. We can literally travel to the location of their existence and wait for them to evaporate. That entire region is now wholly within our past light cone. GR demands that spacetime is a differentiable manifold so we can't simply proclaim that this "remote island of spacetime" exists in our past but somehow has eluded existing in our causal past. It does put them in our past. The earliest reference to this concept that I can find is in Hawking's paper. Below is the graphic used, and a visualization of the problem (in green).
  25. One of the more common definitions of black holes is a variation on The above is pulled from here and is credited to Robert Wald. My issue is that this, and almost any, definition makes finite black holes a logical impossibility. In other words, any process (e.g. Hawking radiation, which I generically refer to as "evaporation"') that eventually eliminates the event horizon has, by the definition of black holes, negated that black hole's existence for all time, including the past. Evaporation and event horizons are mutually exclusive ideas. To make this point clear, imagine the hypothetical micro black holes (MBH) forming in our atmosphere due to cosmic rays. They form, let's say in our physics lab on some random night, and almost immediately decay (as declared by the authors of the LHC Safety Assessment Group paper): We come back the next morning and have equipment that recorded the MBH's existence. We can also verify that the MBH no longer exists. This clearly puts the entire history of this MBH in our causal past, and CERTAINLY in the causal past of future null infinity. That region in spacetime of our lab containing this theoretical MBH cannot have included an event horizon. This, of course, applies to black holes of any size and any arbitrarily long, but finite, evaporation time. We can always travel to the region in space where the black hole "used to exist" and declare that region to be completely within our past light cones, contradicting the notion that an event horizon ever existed there in the first place.
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