G Anthony Posted September 8, 2011 Posted September 8, 2011 Stephen Hawking retracted his paradoxical view that information must be lost when matter falls into a black hole. In place of this idea, his revised mathematics (validated many times by numerous workers) shows that information persists but is confined to the surface or "event horizon" of the black hole. "Hawking radiation" may then be emitted by such a black hole and the information becomes available again. The singularity that is predicted by general relativity (GR) results from extrapolation of GR to the logical extreme. But, it is still logical. The logic cannot be tickered with without destroying the whole ediface. The trouble with singularities is only that one cannot do anything more with them, mathematically. They are a dead end. One can still say that matter therein must be compressed to infinite density, though. But, what does this mean? If matter is compressed to infinite density, the gravitational field associated with its very existence becomes infinite as well. By GR, this means that as mass falls into a black hole, time itself must slow down whereupon its pace declines toward zero. The only weird thing about black holes is this effect. But, the very same thing is seen when temperature is reduced to near absolute zero when a perfect crystal is studied in the laboratory. One can only extrapolate along a straight line leading toward "zero" degrees Kelvin. One can never reach zero in the lab. The connection to black holes is direct. What this really means is that matter inside all black holes is still crashing down toward the "center of gravity" but it will never actually get there, not even after 14.72 bilion years. But, the center itself exists as the center of gravity as long as an event horizon can be defined. As such, it possesses a gravitational field that has a very unique profile of potential versus radius. The event horizon surface of a black hole is associated with a certain entropy linked to its surface area. It is also linked to a certain temperature which assures that information is still present and that Hawking radiation may be emitted therefrom. Such radiation may take hundreds of billions of years to significantly affect the mass that is retained in the black hole, however. But, this is just a detail. Search "Stephen Hawking entropy black hole". There is a class of thermodynamics called "black hole thermodynamics". Hawking and Beckenstein used quantum mechanics and statistical thermodynamics to define SBH, the total entropy of a black hole. So, the singular nature of a black hole is not just conjecture. It is fact, by general relativity. In order to dispute it, one must also dispute GR. This has huge implications to the hypothesis of "Dark Matter" and hypothetical "Dark Energy". See the thread "MOND, Prelude to Critique of the Universe" and the thread "Critique of the Universe" under Astronomy and Cosmology.
Realitycheck Posted September 8, 2011 Posted September 8, 2011 What do you mean "matter is crashing down to the center of gravity for all eternity"? It is plastered to other neutrons and electrons collapsed in an ultimately superdense heap. No disrespect intended. I mean, obviously, you seem fairly well on top of the subject, but it almost sounds like you're pushing 300 year old pushing gravity.
DrRocket Posted September 9, 2011 Posted September 9, 2011 Stephen Hawking retracted his paradoxical view that information must be lost when matter falls into a black hole. In place of this idea, his revised mathematics (validated many times by numerous workers) shows that information persists but is confined to the surface or "event horizon" of the black hole. "Hawking radiation" may then be emitted by such a black hole and the information becomes available again. The singularity that is predicted by general relativity (GR) results from extrapolation of GR to the logical extreme. But, it is still logical. The logic cannot be tickered with without destroying the whole ediface. The trouble with singularities is only that one cannot do anything more with them, mathematically. They are a dead end. One can still say that matter therein must be compressed to infinite density, though. But, what does this mean? If matter is compressed to infinite density, the gravitational field associated with its very existence becomes infinite as well. By GR, this means that as mass falls into a black hole, time itself must slow down whereupon its pace declines toward zero. The only weird thing about black holes is this effect. But, the very same thing is seen when temperature is reduced to near absolute zero when a perfect crystal is studied in the laboratory. One can only extrapolate along a straight line leading toward "zero" degrees Kelvin. One can never reach zero in the lab. The connection to black holes is direct. What this really means is that matter inside all black holes is still crashing down toward the "center of gravity" but it will never actually get there, not even after 14.72 bilion years. But, the center itself exists as the center of gravity as long as an event horizon can be defined. As such, it possesses a gravitational field that has a very unique profile of potential versus radius. The event horizon surface of a black hole is associated with a certain entropy linked to its surface area. It is also linked to a certain temperature which assures that information is still present and that Hawking radiation may be emitted therefrom. Such radiation may take hundreds of billions of years to significantly affect the mass that is retained in the black hole, however. But, this is just a detail. Search "Stephen Hawking entropy black hole". There is a class of thermodynamics called "black hole thermodynamics". Hawking and Beckenstein used quantum mechanics and statistical thermodynamics to define SBH, the total entropy of a black hole. So, the singular nature of a black hole is not just conjecture. It is fact, by general relativity. In order to dispute it, one must also dispute GR. This has huge implications to the hypothesis of "Dark Matter" and hypothetical "Dark Energy". See the thread "MOND, Prelude to Critique of the Universe" and the thread "Critique of the Universe" under Astronomy and Cosmology. About the only thing that you got right is that Hawking conceded his bet with Preskill. But even with respect to the bet things are not settled, for Thorne, who was also partt to that bet, has not accepted Hawking's rationale and has not conceded.
csmyth3025 Posted September 9, 2011 Posted September 9, 2011 ...The trouble with singularities is only that one cannot do anything more with them, mathematically. They are a dead end. One can still say that matter therein must be compressed to infinite density, though. But, what does this mean? ...If matter is compressed to infinite density, the gravitational field associated with its very existence becomes infinite as well. By GR, this means that as mass falls into a black hole, time itself must slow down whereupon its pace declines toward zero... ...What this really means is that matter inside all black holes is still crashing down toward the "center of gravity" but it will never actually get there, not even after 14.72 billion years. But, the center itself exists as the center of gravity as long as an event horizon can be defined. As such, it possesses a gravitational field that has a very unique profile of potential versus radius. Regarding black hole singularities you're making a statement that's an assumption on your part: "...One can still say that matter therein must be compressed to infinite density.." is an assumption. It would be more proper to say that as the volume of the mass asymptotically approaches zero, the density asymptotically approaches infinity. Simple mathematics will tell you that infinite kg/cm3 times zero cm3 equals zero kg. Black holes that are implied by indirect observation have very real (finite) mass. The "central massive object" in our own Milky Way Galaxy (Sagittarius A) - which is generally accepted to be a black hole - has an estimated mass of ~4 million solar masses: Two groups—in Germany and the U.S.—monitored the orbits of individual stars very near to the black hole and used Kepler's laws to infer the enclosed mass. The German group found a mass of 4.31 ± 0.38 million solar masses[1] while the American group found 4.1 ± 0.6 million solar masses. (ref. http://en.wikipedia....tral_black_hole ) One of the reasons the object at the center of this "central massive object" is called a singularity is that we don't know - and don't understand - the physical processes that take place at the extreme densities and pressures thought to exist in this compact region. Moreover, "...What happens inside the event horizon, stays inside the event horizon..." Conjectures about how things work inside the event horizon are just that - conjectures. Unless, of course, you have some experimental evidence you'd like to submit. When you say: "...So, the singular nature of a black hole is not just conjecture. It is fact, by general relativity....", you right. General relativity admits that its equations are not able to describe the physical nature of time, space, matter and energy at the center of a black hole. It's generally believed that a theory of quantum gravity is needed for that - a theory that we haven't yet been able to devise. All this means is that this compact region is outside the domain of applicability of general relativity. This is already known. Chris
BJC Posted September 10, 2011 Posted September 10, 2011 Stephen Hawking retracted his paradoxical view that information must be lost when matter falls into a black hole. some questions: 1) If the information is not lost but stored on the event horizon surface of the Black Hole --- then what is falling into the black hole? 2) As an object falls gravitationally that object becomes squeezed and accelerated. Both effects cause the object to increase in temperature. Since a Black Hole is aa massive gravitational object then objects should heat up , the Black Hole should heat up --- so why is a Black Hole so "cold" or more precisely why is the Hawking temperature so low. Susskind discussed this in his Topics in String Theory (lecture 5 and 6) but i am still unclear on the negative gravitational energy. I also assume Susskind discussed this in his lectures on Black Holes and Holography (Perimeter Institute, Lecture Series C07003) in addition to his popular book "The Black Hole Wars"
G Anthony Posted September 12, 2011 Author Posted September 12, 2011 (edited) I said 'So, the singular nature of a black hole is not just conjecture. It is fact, by general relativity. In order to dispute it, one must also dispute GR. This has huge implications to the hypothesis of "Dark Matter" and hypothetical "Dark Energy".' - - - - - - See the thread "MOND, Prelude to Critique of the Universe" and the thread "Critique of the Universe" under the Speculation category. I sincerely believe this and other moves to this category are far too easy and greatly overused. It is a form of censorship because confinement to Speculation is like banishment to Corsica. Napoleon was able to recover and return once, but not the second time. He was assassinated there by arsenic poisoning, it is said. By moving a thread to Speculation, some moderators must be hoping that the stuff they dislike (no hint by means of reply, no prior warning, notice or rationale is ever given - and there is no appeal) will just die there or be torn apart, eaten alive and poisoned with disrespectful replies. I may get banned for this remark, I would not be surprised. There is no such thing as totally free speech, it is all too true. But, there is more than just a hint of bias by some moderators. The thrust of my Stephen Hawking post is that there is more to black holes than meets the eye (pun intended). Since for all intents and purposes they must be considered to be point masses and therefore "singularities" in the logical and mathematical sense, we must not truncate the definition of "singularity" because the implications may be uncomfortable. A point mass singularity must also have a singular gravitational field. That is, the field must increase asymptotically with inverse distance to the "origin" or the center of gravity. This is the definiton of a hyperbolic gravitational potential field. Hyperbolas, in order to be hyperbolas, must asymptotically approach the graphical "ordinate" as well as the "abscissa". This means the gravitational acceleration will never fall all the way to zero, not even at "infinity". Parabolic Newtonian gravitational fields share this property, but their centripetal acceleration falls much much more quickly, as 1/r^2, as distance increases. Falling off only as 1/r, the hyperbolic field is substantively larger at large r - at and beyond the periphery of every galaxy. By the way, the "periphery" is self defining. So, the residual MOND acceleration value is essentially constant from galaxy to galaxy unless one moves beyond the boundaries of clusters and superclusters. In fact, it defines these boundaries. I do not defend MOND. I defend Milgrom. He is a pro. He has done meticulously careful work. His result deserves more respect. The respect that it deserves is not that he has discover4d MOND, but that he has pinpointed the hyperbolic black-hole field (HBH) effect. Cosmologists are always wrong, but never in doubt. - Lev Landau The gravitational fields of any supermassive black hole and its associated galactic disk are perfectly and precisely co-axial. This means that the gravitational fields will be indistinguishable from a distance, say, at and beyond the periphery of the disk. The fields merge into one, especially at the coaxial center. The fields must reinforce each other. So, the effective mass of a supermassive black hole at the center will not be just a few hundred to a few million suns, it will be a few tens of billion suns. So, when computing the gravitational acceleration at the periphery, one must assume at least M = 1011 solar masses. The major difference, therefore, is the assumption of the field being proportional to a hyperbolic 1/r term or to a Newtonian 1/r2 term. Let us not haggle details. Let us regard this as a postulate. Mordehai Milgrom is a pro. He is a careful worker. And, he is right. But, his demand for a revision of Newton's Law is not Kosher. And, Dark Matter dies. Dark Energy is dead too. Because when the hyperbolic field concept is applied to the global universe and it is postulated that this field must have existed PRIOR to the BB and must now be collapsing or transitioning to a Newtonian field, any and all evidence for dark energy is explained away. Dark Energy and Dark Matter were once rightly called hypotheses. They have now achieved the status of DOGMA. I would have thought that the care that I gave to composing those MOND and Critique posts (in Speculation) would red-flag to the reader that I have a brain larger than a poppy seed. My above point concerning 1/r versus 1/r2 is virtually self evident. If there is argument here, it is with GR and with the accepted etiquette of respect for a postulate, not with me. Edited September 12, 2011 by G Anthony
timo Posted September 12, 2011 Posted September 12, 2011 You are seeing yourself in the role of Napoleon being assassinated by poisoning because of your thread on an Internet forum being moved to a different section. What do you think might be the average reader's impression of you?
Realitycheck Posted September 13, 2011 Posted September 13, 2011 (edited) You really don't believe that a singularity must be absolutely pointlike, do you, or is it just one side of your brain telling you that it must fit a certain way? Ahh yes, for all intents and purposes. I thought giving it a finite, reasonable concrete value was a solution to a problem. Edited September 13, 2011 by Realitycheck
Phi for All Posted September 13, 2011 Posted September 13, 2011 By moving a thread to Speculation, some moderators must be hoping that the stuff they dislike (no hint by means of reply, no prior warning, notice or rationale is ever given - and there is no appeal) will just die there or be torn apart, eaten alive and poisoned with disrespectful replies. I may get banned for this remark, I would not be surprised. There is no such thing as totally free speech, it is all too true. But, there is more than just a hint of bias by some moderators Look, this is a science discussion forum on the web. We have to make a distinction between what is established science, and what is not established but may become established someday. Students need to know what they can take confidently to class, and what is more speculative in nature. When a thread is moved to Speculations, it's not because it's disliked, or wrong, or unpopular. It just means the idea has not yet passed the kind of review that establishes firm ground for further work. Can't you still like and support your idea but admit that it's not firmly established? Speculations is more like ice. It's not firm ground but you can still walk on it. It may not end up holding your weight, but that's why it's there, for testing ideas to see if they have merit. Yes, it's tough. Yes, your idea will be put through the ringer. Science is meant to be methodical and precise. It's not meant to take huge leaps without carefully testing each step. That's why established science can be trusted. And we would absolutely love it if one of our Speculation threads managed to prove worthy and become established. That's why we have the section, and most others don't.
ajb Posted September 13, 2011 Posted September 13, 2011 'So, the singular nature of a black hole is not just conjecture. It is fact, by general relativity. In order to dispute it, one must also dispute GR. This has huge implications to the hypothesis of "Dark Matter" and hypothetical "Dark Energy".' It is a fascinating result of Penrose, Hawking and others (there are several singularity theorems) that general relativity seems to insist on singularities. They are an integral part of general relativity. Disputing the physical nature of singularities is not necessarily disputing general relativity, but rather the domain of applicability and certainly points towards new physics. Most physicists believe that the singularities will not be realised in nature. In particular quantum effects will regulate this.
swansont Posted September 13, 2011 Posted September 13, 2011 I said 'So, the singular nature of a black hole is not just conjecture. It is fact, by general relativity. In order to dispute it, one must also dispute GR. This has huge implications to the hypothesis of "Dark Matter" and hypothetical "Dark Energy".' - - - - - - See the thread "MOND, Prelude to Critique of the Universe" and the thread "Critique of the Universe" under the Speculation category. I sincerely believe this and other moves to this category are far too easy and greatly overused. It is a form of censorship because confinement to Speculation is like banishment to Corsica. ! Moderator Note Topic merged with existing thread. You've been asked not to start up new threads on the same topic. Posting new threads to draw attention to topics in speculations is a violation of rule 5. Your posts are not being deleted and Speculations is as easily accessible as any other section, so you are using a definition of censorship with which I am not familiar. If you want carte blanche to post whatever you wish, start up a blog. While you are here, however, you are obligated to follow the rules
DrRocket Posted September 14, 2011 Posted September 14, 2011 It is a fascinating result of Penrose, Hawking and others (there are several singularity theorems) that general relativity seems to insist on singularities. They are an integral part of general relativity. Disputing the physical nature of singularities is not necessarily disputing general relativity, but rather the domain of applicability and certainly points towards new physics. Most physicists believe that the singularities will not be realised in nature. In particular quantum effects will regulate this. One possible alternative is Einstein-Cartan theory, in which one does not make the a priori assumption that spacetime is torsion-free. This results in a more complicated mathematical theory, but one in which the singularites may either disappear or take on a different character from GR. Unfortunately that is about the limit of my knowledge. In any case I think we both agree that focusing on the singularities in GR is not productive from a physical perspective. What makes a black hole is the event horizon, not the singularity.
ajb Posted September 14, 2011 Posted September 14, 2011 One possible alternative is Einstein-Cartan theory, in which one does not make the a priori assumption that spacetime is torsion-free. This results in a more complicated mathematical theory, but one in which the singularites may either disappear or take on a different character from GR. Unfortunately that is about the limit of my knowledge. I am aware of EC theory and other torsion theories, but like you am don't have any specialist or particularly deep knowledge of them. In any case I think we both agree that focusing on the singularities in GR is not productive from a physical perspective. What makes a black hole is the event horizon, not the singularity. Indeed. Lets not bring the idea of naked singularities into play...
Gary Anthony Kent Posted September 14, 2011 Posted September 14, 2011 About the only thing that you got right is that Hawking conceded his bet with Preskill. But even with respect to the bet things are not settled, for Thorne, who was also partt to that bet, has not accepted Hawking's rationale and has not conceded. Hawking did not retract? - i.e. He did not present a contradictory hypothesis? Does he not now propose that the information that points to matter which has fallen into a black hole still exists as a contribution to the total entropy of the black hole which exists as a sort of "image" on the"surface" of its event horizon? This information is NOT available again via Hawking radiation? What else did I get wrong? Kip Thorne's might be called the sour grapes of a sore loser. One possible alternative is Einstein-Cartan theory, in which one does not make the a priori assumption that spacetime is torsion-free. This results in a more complicated mathematical theory, but one in which the singularites may either disappear or take on a different character from GR. Unfortunately that is about the limit of my knowledge. In any case I think we both agree that focusing on the singularities in GR is not productive from a physical perspective. What makes a black hole is the event horizon, not the singularity. Quantum effects have already undermined this view. See Alan Guth's Inflation hypothesis. Also note Greene's book "the Fabric of the Cosmos", These fellows and many others are saying that it is impossible to make an artificial separation of the phenomena of the larger universe and quantum effects. The idea of singularity is fundamental to the concept of the black hole. Dismiss it at peril. The upshot of my whole thesis is that there must be a physical consequence of the black hole as a Schwartzchild singularity. I point out that GR predicts singularities and Michael Rowan Robinson has remarked that they should have hyperbolic gravitational field potential profiles. I only amplify these ideas to say that together these points account for Milgrom's scrupulously clean observations and, by association, the Dark Matter hypothesis. MOND is unnecessary. When applied to the whole universe a la Alan Guth, Milgrom's hyperbolic field observation (the only confirmational observable phenomenon that indicates the nature of a black hole as a singularity) implies, by simple short extrapolation, a hyperbolic field as a prerequisite to the BB. It would be the only thing that we could ever say about what came prior to the BB. The Universe Hyperbolic Field is essentially the same as the "Quintessence Field". The Universe Field transitions to a Universal Newtonian Field, thereby doing one or the other of two things: 1.) it releases potential energy that shows up as the kinetic energy inherent in the expansion of spacetime (stretching of spacetime should be considered kinematically to avoid confusion) OR 2.) subtle relativistic effects inherent in observations affected by hyperbolic field's collapse or transition must distort our perspective and give us the mirage of "acceleration" of the expansion rate, and by implication, of Dark Energy. My comments kill both Dark Matter and Dark Energy with one parsimonious stroke that also quashes MOND. What more can you ask for? Why Quibble? You must know by now, I hope, that I can answer any objection you may wish to lodge. But, that single item of the pre-existing hyperbolic field I mentioned does indeed start a new timeline. It brings John Wheeler's and Hugh Everett's Many Worlds Interpretation of quantum mechanics into more serious contention. Hey, what's wrong with that? Do we not all just love Strange Science? ! Moderator Note Topic merged with existing thread. You've been asked not to start up new threads on the same topic. Posting new threads to draw attention to topics in speculations is a violation of rule 5. Your posts are not being deleted and Speculations is as easily accessible as any other section, so you are using a definition of censorship with which I am not familiar. If you want carte blanche to post whatever you wish, start up a blog. While you are here, however, you are obligated to follow the rules Your Avatar image says it all. One possible alternative is Einstein-Cartan theory, in which one does not make the a priori assumption that spacetime is torsion-free. This results in a more complicated mathematical theory, but one in which the singularites may either disappear or take on a different character from GR. Unfortunately that is about the limit of my knowledge. In any case I think we both agree that focusing on the singularities in GR is not productive from a physical perspective. What makes a black hole is the event horizon, not the singularity. "Quantum effects have already undermined this view. See Alan Guth's Inflation hypothesis. Also note Greene's book "the Fabric of the Cosmos", These fellows and many others are saying that it is impossible to make an artificial separation of the phenomena of the larger universe and quantum effects. The idea of singularity is fundamental to the concept of the black hole. Dismiss it at peril..." See the rest of this comment in subsequent replies. You are seeing yourself in the role of Napoleon being assassinated by poisoning because of your thread on an Internet forum being moved to a different section. What do you think might be the average reader's impression of you? I did not say that. It's a metaphor, for Pete's sake. Look, this is a science discussion forum on the web. We have to make a distinction between what is established science, and what is not established but may become established someday. Students need to know what they can take confidently to class, and what is more speculative in nature. When a thread is moved to Speculations, it's not because it's disliked, or wrong, or unpopular. It just means the idea has not yet passed the kind of review that establishes firm ground for further work. Can't you still like and support your idea but admit that it's not firmly established? Speculations is more like ice. It's not firm ground but you can still walk on it. It may not end up holding your weight, but that's why it's there, for testing ideas to see if they have merit. Yes, it's tough. Yes, your idea will be put through the ringer. Science is meant to be methodical and precise. It's not meant to take huge leaps without carefully testing each step. That's why established science can be trusted. And we would absolutely love it if one of our Speculation threads managed to prove worthy and become established. That's why we have the section, and most others don't. I don't bother with Speculation. I don't have time. By Pareto's 80/20 rule, at least 80% of other readers do not bother either. This is why moves to this forum amount to "gentle" but effective censorship. That forum should be eliminated. Regarding black hole singularities you're making a statement that's an assumption on your part: "...One can still say that matter therein must be compressed to infinite density.." is an assumption. It would be more proper to say that as the volume of the mass asymptotically approaches zero, the density asymptotically approaches infinity. Simple mathematics will tell you that infinite kg/cm3 times zero cm3 equals zero kg. Black holes that are implied by indirect observation have very real (finite) mass. The "central massive object" in our own Milky Way Galaxy (Sagittarius A) - which is generally accepted to be a black hole - has an estimated mass of ~4 million solar masses: (ref. http://en.wikipedia....tral_black_hole ) One of the reasons the object at the center of this "central massive object" is called a singularity is that we don't know - and don't understand - the physical processes that take place at the extreme densities and pressures thought to exist in this compact region. Moreover, "...What happens inside the event horizon, stays inside the event horizon..." Conjectures about how things work inside the event horizon are just that - conjectures. Unless, of course, you have some experimental evidence you'd like to submit. When you say: "...So, the singular nature of a black hole is not just conjecture. It is fact, by general relativity....", you right. General relativity admits that its equations are not able to describe the physical nature of time, space, matter and energy at the center of a black hole. It's generally believed that a theory of quantum gravity is needed for that - a theory that we haven't yet been able to devise. All this means is that this compact region is outside the domain of applicability of general relativity. This is already known. Chris Quantum Gravity Theory is still under development. But gravity itself is not. Mordehai Milgrom has discovered the hyperbolic black-hole galactic gravitational field. This is all I am saying in that regard. Hawking has retracted his paradoxical view by advancing the opposite view. It is endorsed by many serious workers in the field whom I will not venture to contradict. Both of these points go to the issue of the existence of black hole singularities. One can stand on the dismissive parapet upon which one may then hoist himself upon his own petard. But, both black holes and singularities exist. Milgrom has proven it. "Macroscopic Quantum effects have already undermined the view that quantum theory and relativity are incompatible. See Alan Guth's Inflation hypothesis. Also note Greene's book "the Fabric of the Cosmos", These fellows and many others are saying that it is impossible to make an artificial separation of the phenomena of the larger universe and quantum effects. The idea of singularity is fundamental to the concept of the black hole. Dismiss it at peril..." See the rest of this comment in previous replies. We are all blithering idiots in comparison to Stephen. Too bad he is slipping away. But, he is not slipping away into Oblivion. Everything is NOT dust in the wind. Unless it is Golden Compass style dust. What do you mean "matter is crashing down to the center of gravity for all eternity"? It is plastered to other neutrons and electrons collapsed in an ultimately superdense heap. No disrespect intended. I mean, obviously, you seem fairly well on top of the subject, but it almost sounds like you're pushing 300 year old pushing gravity. Time virtually stops near the center of a black hole. Everything is still happening there. Time is Nature's way of keeping everything from happening all at once. Stop time and the same thing "happens". If I fall into a black hole (in conformity to the wishes of many) I shall scream my head off eternally. Along with everyone else. I shall never reach the limiting center of the hyperbolic asymptote. This is the meaning of an asymptote. I am not pushing 300 years old. I am not pushing gravity. Gravity is pulling me. "Everything is dust in the wind All we do crumbles to the ground but we refuse to see. Now, don't hang on Nothing lasts forever but the Earth and sky It slips away And all your money won't another minute buy" Se la vi "That's Life!" - Frank Sinatra I am aware of EC theory and other torsion theories, but like you am don't have any specialist or particularly deep knowledge of them. Indeed. Lets not bring the idea of naked singularities into play... Naked Singularities must be like Dark Energy. Living with either must be like living with a whore. Does this make one a pimp for either? some questions: 1) If the information is not lost but stored on the event horizon surface of the Black Hole --- then what is falling into the black hole? 2) As an object falls gravitationally that object becomes squeezed and accelerated. Both effects cause the object to increase in temperature. Since a Black Hole is aa massive gravitational object then objects should heat up , the Black Hole should heat up --- so why is a Black Hole so "cold" or more precisely why is the Hawking temperature so low. Susskind discussed this in his Topics in String Theory (lecture 5 and 6) but i am still unclear on the negative gravitational energy. I also assume Susskind discussed this in his lectures on Black Holes and Holography (Perimeter Institute, Lecture Series C07003) in addition to his popular book "The Black Hole Wars" Who said it is low? I prefer the Dark Energy Wars.
Spyman Posted September 15, 2011 Posted September 15, 2011 ...That forum should be eliminated... I think at least one of your two accounts, G Anthony & Gary Anthony Kent, should be eliminated. 9. Registering more than one account to yourself is not permitted without administrative approval. "Sockpuppet" accounts (those registered with the intent of using them to spread the original member's ideas, or for other malicious purposes) will be banned on sight, as well as those registered to evade a ban. http://www.scienceforums.net/index.php?app=forums&module=extras§ion=boardrules
ajb Posted September 15, 2011 Posted September 15, 2011 Naked Singularities must be like Dark Energy. Living with either must be like living with a whore. Does this make one a pimp for either? No idea what that means. If naked singularites don't exists then it must be explained why. For the case of naked singularities it does seem that under reasonable physical assumptions they are not permitted in 4d general relativity. But I don't think this a very rigid theorem and one can construct counterexamples, that is space-times with naked singularities, but these are very contrived. I would view singularites as the breaking point of classical gravity, you are pushing general relativity to it's limit. This is great for hinting at new physics, but great care will be needed in extracting physical phenomena that we could observe.
G Anthony Posted November 27, 2011 Author Posted November 27, 2011 (edited) Some good points posted elsewhere to which I must respond: Originally Posted by OnlyMe in scienceforums.net 26/11/11 > " 1) The infinitely deep gravitational wells and thus infinite gravitational potential of such is not consistent with experience. Infinite remains infinite despite the method of reduction. It is more likely that in practice a black hole does have volume and is not a point mass singularity. 2) We have no empirical evidence that the gravitational potential of a BH ever exceeds that requiring an escape velocity equivalent to . 3) There are many things described mathematically that we do not find in experience, observation and experiment. 4) By framing your argument based on the theoretical point singularity, you introduce the potential for, not only and infinite mass density, but also an associated infinite mass. Which could theoretically support the underlying conclusions. 5) It could be argued just as successfully that since GR describes space as dynamically interacting with matter/mass, and the Lense-Thirring or frame-dragging effect can be considered confirmed, that over time and regular orbital motions of the matter contained within a galactic system, the very weak interaction between matter and space responsible for the frame-dragging effect has a cumulative effect and that in mature galactic systems the involved space must be considered to be essentially inertially involved. 6) In such a circumstance, from within such a system the inertial aspect of the involved space would be unobservable, while from any frame of reference external to the galactic system it would be observed as a component of the orbital velocities of the involved galactic matter. This too could be argued to be not only consistent with GR but also with a view of Newtonian dynamics, where space is a dynamic component of the whole system. GR requires that space be dynamic and the Lense-Thirring or frame-dragging effect demonstrates that the dynamic nature of space cannot be limited to a cuvature we experience as gravitation. 7) The observed anomalies in the orbital velocities involving galactic rotation, are theirselves a problem of dynamics. A dynamic interaction from which the dynamic nature that GR bestows on space cannot be excluded from consideration. 8) No matter what trail we follow in an attempt to explain the involved anomolous observations, the inclusion of dark matter, MOND or viewing the whole as an inertial system composed of both matter and space, we are left with the same fundamental questions... What is inertia and gravitation and how are they related or connected? Personnally I believe the answer will lie in a hybrid of GR and QM. " < OM, thanks again for taking the time to compose your reply. My response: 1) At very least, the necessary experience is Milgroms raw observations. What other relevant hard experience do we have concerning purported actual black holes? The galactic rotation anomaly must be explained. Milgrom wants to modify Newtonian dynamics in a way that would vastly complicate general relativity. I want to introduce the simple expedient concept of the hyperbolic black-hole gravitational field effect, which preserves and even enhances GR. Which of us has the more extreme proposal? Infinite remains infinite despite the method of reduction. This means that infinities cannot be explained away (the ultimate reduction). The existence of infinities in the Math surely has meaning. Schwartzchild thought so. He did not attempt to explain his infinities away. Okay, there could be limits on the idea of infinity in this case. Perhaps there are quantum mechanical constraints such as the fact that pinpointing the center of a black-hole would violate the Heisenberg Uncertainty Principle. But, if a black hole compresses to a diameter as small as a Planck distance, it would serve the same purpose as an infinitely dense point mass. That is, there would be no way to tell that a black-hole was not infinitely dense. Milgroms observations indicate that it really does behave this way. Whether it may actually be so is a theoretical point that Schwartzchild has already considered. I know that infinites are anathema to mathematicians. Their squeemishness is misplaced in cosmology, however. What if it happens that it is actually more likely that a BH is a real point mass, as close as we can tell by QM, having as near to an infinite density that may be required to provide the proper effect (the real meaning of infinite). 2) Actually, this is irrelevant. We are speaking of the geometry of BHs and the influence this geometry must have on the structure of spacetime in the vicinity. The consequences are to be determined by observation and experiment. If the escape velocity does not actually exceed c nearer to the center of a BH, then there is no such thing as an event horizon anyway. Karl Schwartzchild would object. If the escape velocity may be exceeded only by a smidgen determined by the Heisenberg Principle, why not by something rather more than just a smidgen? We need only to suppose that the effective radius of a BH is small enough to produce the required effect, which we may then consider to approach that needed to give effectively infinite density. Effectively is the keyword. 3) The nausea experienced by some professional mathematicians upon contemplation of infinity is not matched by the feelings of some others who revel in the concept. In fact, there is a whole branch of mathematics devoted to it. I do not believe that professionals would devote their whole careers to studies that do not have even theoretical practical consequences. Math is beautiful, but is no 10. And, it is a whore. The mathematics of infinities engendered by the Schwartzchild analysis of GR serve as a flag signaling that there is something going on here. What we find in experience now does not equate to what may be found in the future. And, Milgroms observations are still extant. No revision of Newtons Law of Gravity is needed. No Dark Matter is needed either (Dark Matter is based on Milgrom). Just a liberal tweak upon the concept of what it really means to be a black hole is all that is required. Sometimes liberalism makes sense. 4) Speaking of infinite mass, one would have to refer to the whole universe, at minimum. What if BHs are wormholes leading to this very same universe, but from a different perspective? Might it not then have an effectively infinite mass? But this is all an unnecessary complication. The potential need not be realized. 5) Okay. Now we have another possible alternative to Dark Matter. 6) Well, of course. Do we not always observe external galaxies from afar? It seems far fetched that we should ever observe the Milky Way from beyond. So, your idea means that it should be futile to try to detect the effect in our own galaxy. But, is not GR all about the curvature of spacetime and the dynamic effects that we can expect from such a curvature. Remember, the vector and tensor math of GR is derived from techniques used in hydrodynamics. The dynamic nature of fluids has a frame dragging equivalent. In other words, you are saying that GR is dynamic, not static. Even Newtonian dynamics is really static in nature because it cannot treat transitions between states which are time dependent. Time dependent variations between fluid states is often referred to as turbulence. Is there turbulence in the behavior of spacetime? 7) You amplify your comment that frame dragging style wrinkles on the face of GR could explain MOND and explain away Dark Matter. What if BOTH these wrinkles and the giant scar of the hyperbolic field effect should apply? 8) Wonderful. Fundamental questions are what science is all about. But, the anomalies do indeed need to be explained. Good luck finding a valid hybrid of GR and Quantum. Instead of M Theory, maybe we can call it OM Theory. Thanks for taking the time to read this. Further response would be appreciated. 27/11/11 P.S. This reply is also in response to all the other objections expressed by some readers. I would love to see more responses that build on what I have said. I think at least one of your two accounts, G Anthony & Gary Anthony Kent, should be eliminated. 9. Registering more than one account to yourself is not permitted without administrative approval. "Sockpuppet" accounts (those registered with the intent of using them to spread the original member's ideas, or for other malicious purposes) will be banned on sight, as well as those registered to evade a ban. http://www.scienceforums.net/index.php?app=forums&module=extras§ion=boardrules The other account now belongs to my wife, who is not much interested in physics or cosmology. She likes my avatar. The account is not a sockpuppet as defined in the rules. Administrative approval may be forthcoming. I am aware of EC theory and other torsion theories, but like you am don't have any specialist or particularly deep knowledge of them. Indeed. Lets not bring the idea of naked singularities into play... Naked singularities are not what this discussion concerning MOND and Dark Matter is all about. Far from it. The Black-hole singularities referred to here are cloaked in spiral galaxy disks or other conglomerations of stars. Usually, they are surrounded by infalling stars that sometimes result in phenomena of their own like jets. Also, the central supermassive black hole in any spiral galaxy is too small to have this putative effect of MOND that mimics Dark Matter. They have masses of "only" a few million sols, at most. While the galaxies contain masses of over 200 billion sols. But, since the central black holes rotate congruently with the disk having a center of rotation that is coaxial with the disk's, their gravitational fields superpose. If this is not so, geometry is not valid. Superposed, the combined gravitational field would be sufficient to provide the effect. One need not have an actual singularity anyway. All that is required is that the compact diameter of a black hole is less than or equal to the Planck distance implied by the Heisenberg Uncertainy Principle. This is really all that we can ever postulate, in fact. ! Moderator Note Topic merged with existing thread. You've been asked not to start up new threads on the same topic. Posting new threads to draw attention to topics in speculations is a violation of rule 5. Your posts are not being deleted and Speculations is as easily accessible as any other section, so you are using a definition of censorship with which I am not familiar. If you want carte blanche to post whatever you wish, start up a blog. While you are here, however, you are obligated to follow the rules The references to my external site are mere references FYI for the reader. Do you mean that one may never quote material placed on one's own website? Confinement to "Speculation" is equivalent to effective censorship because, by Pareto'sa 8o/20 rule, at least 80% of all readers will avoid the Speculation category. I do. This category should be eliminated. Look, this is a science discussion forum on the web. We have to make a distinction between what is established science, and what is not established but may become established someday. Students need to know what they can take confidently to class, and what is more speculative in nature. When a thread is moved to Speculations, it's not because it's disliked, or wrong, or unpopular. It just means the idea has not yet passed the kind of review that establishes firm ground for further work. Can't you still like and support your idea but admit that it's not firmly established? Speculations is more like ice. It's not firm ground but you can still walk on it. It may not end up holding your weight, but that's why it's there, for testing ideas to see if they have merit. Yes, it's tough. Yes, your idea will be put through the ringer. Science is meant to be methodical and precise. It's not meant to take huge leaps without carefully testing each step. That's why established science can be trusted. And we would absolutely love it if one of our Speculation threads managed to prove worthy and become established. That's why we have the section, and most others don't. I wish your ideal of science was really true. But, don't kid yourself. You know that it is not. Give students a little more credit. We have to make a distinction? Why? You put too much faith in the peer review process and journal editors, who are only human (at least at present). I do not admit that the idea of the hyperbolic field effect is not firmly established. The solidity of the concept is what my posts are all about. Edited November 27, 2011 by G Anthony
G Anthony Posted December 23, 2011 Author Posted December 23, 2011 (edited) You really don't believe that a singularity must be absolutely pointlike, do you, or is it just one side of your brain telling you that it must fit a certain way? Ahh yes, for all intents and purposes. I thought giving it a finite, reasonable concrete value was a solution to a problem. The case r = 0 is different, however. If one asks that the solution be valid for all r one runs into a true physical singularity, or gravitational singularity, at the origin. To see that this is a true singularity one must look at quantities that are independent of the choice of coordinates. One such important quantity is the Kretschmann invariant which says at r = 0 the curvature blows up (becomes infinite) indicating the presence of a singularity. At this point the metric, and space-time itself, is no longer well-defined, but not undefined. For a long time it was thought that such a solution was non-physical. However, a greater understanding of general relativity led to the realization that such singularities were a generic feature of the theory and not just an exotic special case. Such singular solutions are now believed to actually exist and are termed black holes. The event horizon of a black hole is not really what defines it. It is defined by its singular mathematical nature. However, according to the Heisenberg Uncertainty Principle, the precise location of the center of a black hole cannot be known. Therefore, the matter in a black hole cannot actually be measured as infinitely dense nor its gravitational field as infinitely strong. But, mathematically, they may be treated this way. Edited December 23, 2011 by G Anthony
G Anthony Posted February 5, 2012 Author Posted February 5, 2012 (edited) The Hyperbolic Hyper-Massive Black-Hole Universe Hawking did not buy his own pronouncements regarding the disappearance of information into black holes. Instead, he and some others invented a whole new theory of black-hole thermodynamics. So in a sense, the black-hole event horizon is a real surface. It is sometimes called a "quasi-surface". The center of a black-hole is a physically real singularity. It is constrained only by the Heisenberg Uncertainty Principle. There is no such thing as quantum gravity (QG). How many papers are published in ArXiv on unicorns? By their standards, there should be dozens! So, any appeal to QG to put the Kibosh on black-hole singularities is therefore bogus. See The Hyperbolic Hyper-Massive Black-Hole Universe and Galactic Gravitational Field (HHBF), which is a paper written for the blog http://garyakent.wordpress.com that describes the e-Model for inflationary expansion of the universe. The hyperbolic hyper-massive black-hole gravitational field is a phenomenological postulate, that is, it is a tentative premise that should be confirmed by experiment or observation and need not wait for theoretical justification. In the case of galaxies and galactic clusters, there is already enough observational support for the galactic hyperbolic super-massive black-hole gravitational field (HSBF). The point is emphasized that Birkhoff's Theorem and other interpretive principles derived from general relativity cannot apply to any real black-holes. These rules presume that the massive bodies that are considered are always "unperturbed" and are perfectly "spherically symmetric". No real black hole meets these criteria. The rules are good only for approximate calculation, not for"precision cosmology". Besides, GR should not prohibit a gravitational field that declines as 1/r if a metric is found, similar to the Schwarzschild metric, using assumptions and boundary conditions wherein a singular black-hole is presumed at the outset. If such a gravitational field can be confirmed, the e-Model will serve as more evidence for the existence of our universe as part of a multiverse in meta-time. I appeal for collaborators to help find such a metric. Hugh Everett may one day be seen as a thinker on a par with A. Einstein. And, John Archibald Wheeler's suggestion concerning the quantum self-interference of probability density waves may be taken more seriously while Everett's declaration of the"reality of probability" as a sort of substance gains credence. Self-interference can explain the virtual absence of antimatter (AM) in our universe. AM would be confined to our virtual twin, which must exist according to the logical extension of Alan Guth's inflation hypothesis wherein a virtual particle came into existence from a hyper-excited false vacuum which came to exist precisely because of its ultra-high energy level. It would be seen as the deeper mechanism behind apparent "symmetry breaking" and unbalanced annihilation of fundamental sub-nuclear particles and antiparticles to give our universe with matter as the dominant form. The existence of an interference twin could also be helpful in explaining the hyperbolic field as the resultant of a superposition of states. As the real (to us) expression of a statistical process within the multiverse, we experience only the total sum, the superposed probability density form from which emerges probability, P --> 1. There are ways that such a superposition might affect the shape of a gravitational potential well. Gravity itself may be viewed as a probability vortex or wave in the Einstein Aether. There is much that has not been considered. Edited February 5, 2012 by G Anthony -1
StringJunky Posted February 5, 2012 Posted February 5, 2012 What's with the big bold font? You've made it harder to read and annoying not easier. Strange as it may seem, this type of presentation doesn't make your posts any more convincing than if you used normal font.
DrRocket Posted February 6, 2012 Posted February 6, 2012 Hawking did not retract? - i.e. He did not present a contradictory hypothesis? Does he not now propose that the information that points to matter which has fallen into a black hole still exists as a contribution to the total entropy of the black hole which exists as a sort of "image" on the"surface" of its event horizon? This information is NOT available again via Hawking radiation? What else did I get wrong? Kip Thorne's might be called the sour grapes of a sore loser. Your post is far too long and unintelligible to address line by line. You pretty much got everthing wrong, including the above, including the inane remark about Kip Thorne. You might want to take a closer look at Hawking's concession, which has some logical gaps, including the use of the Ads/CFT correspondence which itself is an unproved conjecture of Maldecena datting from about 1997. In short, you have no idea what in the hell you are talking about.
*puffy* japanisthebest Posted February 6, 2012 Posted February 6, 2012 Stephen Hawking retracted his paradoxical view that information must be lost when matter falls into a black hole. In place of this idea, his revised mathematics (validated many times by numerous workers) shows that information persists but is confined to the surface or "event horizon" of the black hole. "Hawking radiation" may then be emitted by such a black hole and the information becomes available again. The singularity that is predicted by general relativity (GR) results from extrapolation of GR to the logical extreme. But, it is still logical. The logic cannot be tickered with without destroying the whole ediface. The trouble with singularities is only that one cannot do anything more with them, mathematically. They are a dead end. One can still say that matter therein must be compressed to infinite density, though. But, what does this mean? If matter is compressed to infinite density, the gravitational field associated with its very existence becomes infinite as well. By GR, this means that as mass falls into a black hole, time itself must slow down whereupon its pace declines toward zero. The only weird thing about black holes is this effect. But, the very same thing is seen when temperature is reduced to near absolute zero when a perfect crystal is studied in the laboratory. One can only extrapolate along a straight line leading toward "zero" degrees Kelvin. One can never reach zero in the lab. The connection to black holes is direct. What this really means is that matter inside all black holes is still crashing down toward the "center of gravity" but it will never actually get there, not even after 14.72 bilion years. But, the center itself exists as the center of gravity as long as an event horizon can be defined. As such, it possesses a gravitational field that has a very unique profile of potential versus radius. The event horizon surface of a black hole is associated with a certain entropy linked to its surface area. It is also linked to a certain temperature which assures that information is still present and that Hawking radiation may be emitted therefrom. Such radiation may take hundreds of billions of years to significantly affect the mass that is retained in the black hole, however. But, this is just a detail. Search "Stephen Hawking entropy black hole". There is a class of thermodynamics called "black hole thermodynamics". Hawking and Beckenstein used quantum mechanics and statistical thermodynamics to define SBH, the total entropy of a black hole. So, the singular nature of a black hole is not just conjecture. It is fact, by general relativity. In order to dispute it, one must also dispute GR. This has huge implications to the hypothesis of "Dark Matter" and hypothetical "Dark Energy". See the thread "MOND, Prelude to Critique of the Universe" and the thread "Critique of the Universe" under Astronomy and Cosmology. ...my friends at school are reading this and i just simplified it for them... when stuff falls in a black hole... it never reaches the bottom...eh... i didn't really do details..
guenter Posted February 9, 2012 Posted February 9, 2012 ...my friends at school are reading this and i just simplified it for them... when stuff falls in a black hole... it never reaches the bottom...eh... i didn't really do details.. Be careful, using "Anthony" as a reference, see the comment of DrRocket! The proper time for an object to fall from the event horizon of a black hole with 3 billion sun masses e.g. to its center (the singularity) is about 13 hours.
MigL Posted February 10, 2012 Posted February 10, 2012 Well I guess its time to add my two cents... When a relatively massive star reaches the end of its sustainable fusion process, it eventually undergoes gravitational collapse. The remaining material which cannot be ejected by a massive stellar explosion, is more or less in free fall towards the geometric centre of the former star, now a black hole. Einstein's equations have the peculiar consequence that the stellar material can continue to exist forever in a state of free fall without ever reaching the bottom. This can be nearly visualised with a Penrose diagram. The space/time in the region of the black hole is so strongly curved that space and time become interchanged. If you are an outside observer, you see the stellar collapse slow down and come to a stop because the direction of time inside the black hole is 'perpendicular' to the direction of time as seen externally, i.e.the only thing in your future once inside the black hole, is a direction ( the geometric centre ).The experiences and observations of the infalling and outside observers are vastly different ( to say the least ). This is due to the purely classical nature of GR. Stephen Hawking came along and introduced a bit of QM and Thermodynamics into this classical picture of black holes, much the same as Max Planck did with his quantization of black body radiation in 1900.. Planck's equation E=hv was a long way from QM which took at least another 25-30 yrs and 50-60 for QED. Similarily Hawking has given us S=kA, where S=entropy, A=area and k is a constant, but like Planck's itt is only a modest beginning. Entropy is very similar to heat capacity and is measured in cal/deg while area is in cm^2. Hawking's constant k, then has a value of about 10^41 cal/deg/cm^2. This is a very large proportionality constant, and since entropy is a measure of randomization, this shows the degree to which any infalling material / energy / information is randomized. So yes, I will agree black holes have a temperature and therefore radiate, and so, if small enough will evaporate and eventually finish with a gamma ray explosion, during our universe's lifetime. But no, I don't agree that information could possibly be conserved after that degree of randomization.
guenter Posted February 10, 2012 Posted February 10, 2012 Migl, I recommend to careful distinguish Free-fall coordinates, whereby the time coordinate is proper time, from any other coordinates, otherwise there is confusion. The picture of the frozen star, you mentioned, refers to the far distant Schwarzschild observer.
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