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Found this article today, and felt it is a better/shorter name for it; if they are indeed the same thing. - Roy Boy 800 01:10, 13 August 2005 (UTC)
If QM-based ideas like gravastars and dark energy stars are now beginning to proliferate, perhaps it's time to start thinking about a reorganisation: perhaps three main crosslinked pages: (1) NM's "dark stars", (2) GR's "black holes" and (3) QM's modified "radiating black hole" predictions. Then perhaps it might be natural to crosslink "gravastar" and "dark-energy star" pages to that new "QM black hole" page. It's a shame that there doesn't yet seem to be an accepted generic name for a "QM-modified black hole". ErkDemon 02:24, 19 August 2005 (UTC)
A "QM-modified black hole" could be crosslinked with Hawking. That would at least make a bit of a distinction.
Tom
07:32, 24 August 2005 (UTC)
I've stripped out most of the last edit as combination of POV and technical inaccuracy issues, e.g.
" It should be noted that dark stars are totally theoretical objects, whereas significant evidence supports the existance of black holes in the actual universe. "
Actually, both black holes and dark stars are theoretical, if you look at unsolved problems in physics, you'll see the existence of GR black holes listed. The thing that confuses people is that since GR is the standard theory of gravitation, we now refer to an object that would be a black hole according to GR, as a black hole. This does not mean that we have discovered that these objects really do have the special properties that make GR black holes "different", it just means that everyone got understandably bored writing "black hole candidate" in full every time.
What evidence would let us verify that the "novel" GR properties for black holes are real? Well, the two defining properties of a GR black hole that earn it its name are (1) the existence of a central singularity, and (2) the total absence of radiation through the r=2M surface.
Since
Stephen Hawking's 2004 change of opinion, he now reckons that horizons ought to radiate [reradiate information], and that classical theory must be modified or otherwise "fiddled with" to produce that result. If he's right, GR black holes, in the original sense of the word, don't exist in our universe.
ErkDemon
01:24, 29 August 2005 (UTC)
You are very confused here.
Your biggest confusion is between the ideas of black holes radiating and black holes leaking information. Black hole radiation depends on quantum mechanics and was predicted by Stephen Hawking in the 1970's. Hawking's change of opinion in 2004 is about black holes leaking information. Ken Arromdee 04:04, 30 October 2005 (UTC)
So it's true that GR black holes don't exist--but no scientist claims that they do, and hasn't since the 1970's. It isn't news. Scientists who talk about black holes don't mean GR black holes, they mean black holes that are similar to GR black holes but with quantum effects added.
Ken Arromdee
04:04, 30 October 2005 (UTC)
What is the reference for the sentence indicated in bold here?
QM’s description of black holes is different to GR’s – they are again “dirty” and “smelly”, but although it is agreed that they have about the same amount of dirt and smell as dark stars, it is not yet agreed whether the dirt is “old” or “new”, or exactly what a QM black hole ought to smell of
This sentence sounds very suspicious to me. For one thing, smaller black holes emit more Hawking radiation (smell). But if two dark stars both have escape velocity of the speed of light, the *larger* dark star will produce more radiation (since it has more surface area for matter to produce indirect radiation).
Also, why would the amount of "dirt" be the same? The amount of "dirt" around a dark star would depend on the composition of the dark star and not just on its mass. Ken Arromdee 21:36, 27 October 2005 (UTC)
Yep, iffy! A proper qualification (attempted below) would probably be too long-winded, so perhaps it's better just to snip it out. "Agreed" was too strong a word considering the vagueness of "about the same" (I was thinking about the membrane paradigm when I typed that, but that doesn’t quite justify the sentence). Very probably misleading. Consider it gone. Cheers. ErkDemon 05:37, 31 October 2005 (UTC)
under Newtonian mechanics, the surface of a compact high-gravity body doesn't have a particular reason to correspond to the r=2M surface. For a compact spherical object built from material with a given density, the r=2M radius increases proportionally with the mass, but the radius of the actual physical object only increases with the cube root of the mass. So while (as you say) the radiation has the same difficulty leaving the r=2M surface for "dark stars" of all sizes, one also has to take into account the additional difficulty of radiation leaving the dark star and climbing up to the r=2M surface in the first place. For material of a given density, increasing the size of the body increases this distance between the body's surface and the r=2M surface up above it.
You are quite right about the dependency on composition! This exercise still hasn’t reckoned in what the supposed density of a Newtonian dark star's material ought to be (realistically) and how much it ought to emit in the first place as a baseline figure before we take into account the reduction due to gravity and the increase due to indirect radiation effects through an atmosphere. I figure the best one can do as a first approximation (when comparing NM dark stars with GR black holes), is to start with a very generic prediction, move away from specifics and assume an idealised gas or dust cloud, without a well-defined surface. As with GR, the gas is going to compact as you pile up more material, but where GR makes the inward radiation pressure on a self-supporting body go to infinity and beyond as the radius shrinks past r=2M, with the NM relationships, the inward radiation pressure never becomes infinite for a self-supporting body of any finite size. You certainly expect compression, but (without getting into specifics of materials and atomic structure) don't have an obvious reason to expect total collapse, because you have at least some outward radiation pressure acting all the way down to the core. The GR argument of zero outward force resisting collapse inside r=2M does not apply to dark star models.
Since this is technically an acoustic –style metric, the further we go in idealising the interior of a dark star to get away from specifics about the exact material involved, the further we move towards an abstract statistical mechanical description, of how indirect radiation through a horizon ought to work in general, and since QM's Hawking radiation effect has now been generalised to the case of acoustic metrics, dark star radiation would seem, technically, to be a case of Hawking radiation (in a non-GR context), and would seem to follow the same basic statistical rules.
Unfortunately, I don’t know of any published study that explicitly compares the phenomenology of the "QM black hole" predictions with the "NM dark star" predictions. When I asked around a few years back there wasn't anything anyone could cite me to say that the two things were in any way distinguishable. The best I could find were studies of the statistical behaviour of a hypothetical conventional radiating surface at r=2M, in the context of the black hole membrane paradigm, which found that once you assigned the horizon surface an appropriate temperature, you could assume that wholly conventional radiation effects were in play, and generate the "spooky" descriptions of QM (e.g. nominal pair production outside the horizon) by playing games with the coordinate systems being used to generate the description. So the properties of (idealised) dark star radiation outside the horizon would seem to correspond, statistically, to the properties of QM black hole radiation, if one can just justify getting the right value for the "horizon temperature", and since QM can calculate this temperature using very general arguments, an idealised dark star model (obeying the same basic laws of thermodynamics, entropy, etc) ought to be at least in the same ballpark. (Maybe even identical, who knows.)
Perhaps a full comparison of the idealised "dark star" phenomenology against the predictions of QM for black holes might have to wait until the community have decided exactly what QM ought to be predicting, at the moment there still not complete agreement about whether the current QM predictions can be taken at face value, or need modifying to prevent a clash with GR (-> black hole information paradox), so perhaps there's not yet an 100% agreed QM reference model for dark star models to be compared against.
Anyhow, the above arguments are probably too long and hand-wavy to belong in a Wiki article, so I think it's simplest if I just snip the offending text rather than find a way of rewording it to be less misleading. Thanks for pointing out the prob. ErkDemon 05:37, 31 October 2005 (UTC)
See, the black hole membrane paradigm, as discussed in the Thorne book, on Wiki, and in references provided by them. ErkDemon 04:35, 7 January 2006 (UTC)
No, the statement is correct, Hawking radiation is a little more subtle than your post suggests. According to QM, an observer near the event horizon of a black hole sees the region to be occupied by particles that do not exist for a distant observer. Quantum mechanics deals with this by saying that the particles are deemed to be "virtual" for the distant observer and cannot be sensed directly, whereas for the nearby observer the particles are "real". If the near observer decides to bat one of these particles out to the distant observer to prove that the things are real, we say that the physical acceleration has converted a "virtual" particle into a "real" one ("Unruh radiation", "acceleration radiation"). This has been discussed at some length by Thorne and others, who have established that for observers hovering outside the event horizon, QM effects superimposed on a GR background make the region outside the horizon look exactly as if it is illuminated and populated by a completely conventional radiating surface at r=2M. This result is a few decades old (the black hole membrane paradigm). Kip Thorne's book (cited) tackles most of these topics pretty well, if people are bothered to read it. I didn't see the need to offer more specialised references here supporting the characteristics of Hawking radiation, virtual particles, Unruh radiation and so on, because Wiki already has dedicated pages on all those topics, and this is, after all, supposed to be a page about dark stars and their characteristcs, not an in-depth lecture on modern quantum theory.
Thorne: " In 1975, Wheeler's recent student William Unruh, and independently Paul Davies at King's College, London, discovered (using the laws of quantum fields in curved spacetime) that accelerated observers just above a black hole's horizon must see the vacuum fluctuations there not as virtual pairs of particles but rather as an atmosphere of real particles, an atmosphere that Unruh called "acceleration radiation." This startling discovery revealed that /the concept of a real particle is relative/, not absolute; that is, it depends on one's reference frame. …
… What the freely falling observers see as particle pairs converted into real particles by tidal gravity, followed by evaporation of one of the real particles, the accelerated observers see simply as the evaporation of one of the particles that was always real and always populated the hole's atmosphere. Both viewpoints are correct; they are the same physical situation, seen from two different reference frames. "
Thorne: " … the two paradigms give precisely the same predictions for the outcomes of all experiments or observations that anyone might make outside a black hole – including all astronomical observations made from Earth. "
I've also removed the "in brief" section. These sections are bad ideas because they suggest, to the unwary reader, that science once accepted dark stars, then rejected them because of relativity, and now is close to accepting them again. This could give the misleading impression that modern ideas of quantum mechanics are a move towards a pre-relativity world. Ken Arromdee 01:10, 7 November 2005 (UTC)
if people removed the merge part, then why is it not removed from BOTH pages? 69.22.224.249 21:56, 21 December 2005 (UTC)
I've been asked by User:Ken Arromdee to take a look at the disputed parts of this article, but am having a great deal of trouble sifting out what exactly is being disputed in the lengthy debate above. If the two of you would be willing to put a point-form list of points of contention below this comment, that would help a lot. To be clear, I'm not trying to act as any kind of arbiter, but will simply (as asked) state my views on the points of contention, where I'm capable of doing so (I like to think that I'm aware of the limits of my areas of knowledge). If things look sufficiently muddy, I'll link the page from Wikipedia:Pages needing attention/Physics and Wikipedia talk:WikiProject Physics, but from what I can see of the discussion above, it appears to be mostly a conflict of editing styles as opposed to irreconcilable differences over content. User:ErkDemon, is it ok with you if I take a look at this, or would you prefer that it just be put on PNA/P and WPP? -- Christopher Thomas 23:46, 8 January 2006 (UTC)
I really know nothing about this but a number of sites, such as Enchanted Learning use the term "dark star" for any star that has stopped or doesn't emit light, including black dwarfs and brown dwarfs. Could someone please offer some form of explanation? I plan on asking the school physics teacher, but disambiguation by an expert would be more reliable. I'll check with astronomy professors at the university if no one can offer a suitable explanation, but that might take a while. Thanks. DUCK 17:29, 21 February 2006 (UTC)
"Since observations all confirm the relativistic version, a dark star could not exist."
Which observations exactly? With no direct reference, validity of that statement is just that bit vague...
The following statement is not completely actuate in the intro due to what is understood about Hawking Radiation "The key difference being that in addition to being, dark, the black hole is completely cut off from the surrounding universe." There is a low level of communication between the universe and a black hole in the form of Hawking Radiation. I would content that the statement is not even needed since the article does not talk about this point and since the previous statement covers what is in the article "Such objects in modern understanding would be more properly described as black holes." Thoughts? Fcsuper 05:40, 21 July 2007 (UTC)
I have mixed feelings about this article: I originated it, so I feel that I have some responsibility for it, but I'm trying not to edit "controversial" physics pages, because it's obviously felt by some here that I'm not the right person to be doing that ... the article seems to collect junk edits that need changing, but nobody else seems to be fixing them ... my positions on this topic seem to be minority views, but then again, I seem to be the only active participant here who's actually read the source material.
I also notice that the people who watch and maintain the " black hole" page removed the link that points here, so the consensus there seems to be that this page isn't wanted. The talk page also seems to have generated far too many arguments. So I think that perhaps the correct thing to do is to turn this page into a redirect that points to black hole, and be done with it, and avoid all the bad feeling. ErkDemon 23:04, 31 July 2007 (UTC)
I've replaced the light-bending paragraph, because it didn't seem to make much sense as it was, and nobody else had fixed it. I don't know where that strange-looking "r=4M" business came from. Oops, I forgot to sign in. Today's edit was me. ErkDemon 01:32, 7 August 2007 (UTC)
We need to rename and reorganize these articles: there is a third astronomical term, "Dark Star". At the moment, this current article is not well-named - as in physics and astronomy classes the term "dark star" is not commonly used for Newtonian black holes. This current article needs to be renamed "Newtonian black holes", or something like that. Then, we should use the title "dark star" for this newly hypothesized category of super-huge star, powered by neutralino interactions.
In summary:
Current situation: Two articles, and one is simply missing
Proposed renaming
Let's start discussing this. We now have two articles with similar names, for three types of astronomical objects. This is confusing not only to lay readers, but even to scientists. RK ( talk) 16:24, 21 December 2009 (UTC)
I've seen the term "dark star" used to refer to Newtonian black holes. It's not in use today, but is important for historical reasons.
With regards to the articles, this type of situation happens all the time. The usual solution is to use a disambiguation page. Dark star gets moved to Dark star (Newtonian mechanics), Dark star (dark matter) stays where it is ( Dark matter star redirects to it, at present), and Dark energy star stays where it is. A new article, Dark star (disambiguation) is created, pointing to all of these concepts in the usual manner. A new article, Dark star, is created, which redirects to the disambiguation page.
Does this solution seem reasonable to everyone? -- Christopher Thomas ( talk) 07:05, 23 March 2010 (UTC)
As there's been no objection in the week or so since this first came up, and some lukewarm support, I've moved the page. I'm now in the process of tweaking the Dark Star disambiguation page, fixing links to dark star and talk:dark star, and so forth. If there are any problems remaining past the end of March, it means I missed something; feel free to either fix it or notify whoever's performing housekeeping for the relevant pages/templates/etc. -- Christopher Thomas ( talk) 05:45, 31 March 2010 (UTC)
There was also a German scientist who independantly discovered Dark stars but I forget his name. I think he should be added. 8digits ( talk) 13:07, 26 January 2012 (UTC)
Johann Georg von Soldner, he accepted that light could bend under Newtonian physics but I am not sure whether he ever came up with a Dark Star. BernardZ ( talk) 15:08, 1 April 2014 (UTC)
Also Johann Georg von Soldner, in 1801, calculated the bending of light rays grazing the Sun’s disk, using classical mechanics and a hypothetical light velocity 300,000 km/sec. This is after John Michell and Pierre-Simon Laplace had already done their work on Dark stars and Pierre-Simon Laplace appears to have already given up with the idea in Exposition Du Systeme Du Monde 2nd Edition in 1796.
What I did is add him slightly into the article BernardZ ( talk)
In Newtonian universe things FTL is possible, so mass maybe able to escape so there is no event horizon and it may still be unstable measured in billions of years as it is losing mass.
As there is no event horizon it would create a naked singularity.
Thoughts BernardZ ( talk) 14:55, 1 April 2014 (UTC)
Newtonian physicists thought that the sun radiation was powered by a gravity collapse. Similarly, a Dark star would be emitting light/energy but this energy would be trapped inside. Energy does not produce gravity under Newtonian physicists, would the gravity strength would be reducing? If so the Dark star would grow in size, maybe become unstable as its gravity force turns to energy. BernardZ ( talk)
A dark star would be subjected to classical thermodynamics so it temperature to an outside observer is exactly the same as a black hole. This although interesting this is getting into original research. What do you think??? BernardZ ( talk)
If you say something needs to exceed the speed of light you should follow it with "which isn't possible". It takes infinite energy to even reach the speed of light. Infinite means all the energy there is and then some because infinite can't be quantified. So more than infinite is absurd. Jackhammer111 ( talk) 05:52, 29 April 2018 (UTC)
I was reading through the article and it seems that it’s only theorized and needs to be found. Is it even possible for it to exist? 174.247.241.135 ( talk) 01:31, 20 February 2022 (UTC)
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Found this article today, and felt it is a better/shorter name for it; if they are indeed the same thing. - Roy Boy 800 01:10, 13 August 2005 (UTC)
If QM-based ideas like gravastars and dark energy stars are now beginning to proliferate, perhaps it's time to start thinking about a reorganisation: perhaps three main crosslinked pages: (1) NM's "dark stars", (2) GR's "black holes" and (3) QM's modified "radiating black hole" predictions. Then perhaps it might be natural to crosslink "gravastar" and "dark-energy star" pages to that new "QM black hole" page. It's a shame that there doesn't yet seem to be an accepted generic name for a "QM-modified black hole". ErkDemon 02:24, 19 August 2005 (UTC)
A "QM-modified black hole" could be crosslinked with Hawking. That would at least make a bit of a distinction.
Tom
07:32, 24 August 2005 (UTC)
I've stripped out most of the last edit as combination of POV and technical inaccuracy issues, e.g.
" It should be noted that dark stars are totally theoretical objects, whereas significant evidence supports the existance of black holes in the actual universe. "
Actually, both black holes and dark stars are theoretical, if you look at unsolved problems in physics, you'll see the existence of GR black holes listed. The thing that confuses people is that since GR is the standard theory of gravitation, we now refer to an object that would be a black hole according to GR, as a black hole. This does not mean that we have discovered that these objects really do have the special properties that make GR black holes "different", it just means that everyone got understandably bored writing "black hole candidate" in full every time.
What evidence would let us verify that the "novel" GR properties for black holes are real? Well, the two defining properties of a GR black hole that earn it its name are (1) the existence of a central singularity, and (2) the total absence of radiation through the r=2M surface.
Since
Stephen Hawking's 2004 change of opinion, he now reckons that horizons ought to radiate [reradiate information], and that classical theory must be modified or otherwise "fiddled with" to produce that result. If he's right, GR black holes, in the original sense of the word, don't exist in our universe.
ErkDemon
01:24, 29 August 2005 (UTC)
You are very confused here.
Your biggest confusion is between the ideas of black holes radiating and black holes leaking information. Black hole radiation depends on quantum mechanics and was predicted by Stephen Hawking in the 1970's. Hawking's change of opinion in 2004 is about black holes leaking information. Ken Arromdee 04:04, 30 October 2005 (UTC)
So it's true that GR black holes don't exist--but no scientist claims that they do, and hasn't since the 1970's. It isn't news. Scientists who talk about black holes don't mean GR black holes, they mean black holes that are similar to GR black holes but with quantum effects added.
Ken Arromdee
04:04, 30 October 2005 (UTC)
What is the reference for the sentence indicated in bold here?
QM’s description of black holes is different to GR’s – they are again “dirty” and “smelly”, but although it is agreed that they have about the same amount of dirt and smell as dark stars, it is not yet agreed whether the dirt is “old” or “new”, or exactly what a QM black hole ought to smell of
This sentence sounds very suspicious to me. For one thing, smaller black holes emit more Hawking radiation (smell). But if two dark stars both have escape velocity of the speed of light, the *larger* dark star will produce more radiation (since it has more surface area for matter to produce indirect radiation).
Also, why would the amount of "dirt" be the same? The amount of "dirt" around a dark star would depend on the composition of the dark star and not just on its mass. Ken Arromdee 21:36, 27 October 2005 (UTC)
Yep, iffy! A proper qualification (attempted below) would probably be too long-winded, so perhaps it's better just to snip it out. "Agreed" was too strong a word considering the vagueness of "about the same" (I was thinking about the membrane paradigm when I typed that, but that doesn’t quite justify the sentence). Very probably misleading. Consider it gone. Cheers. ErkDemon 05:37, 31 October 2005 (UTC)
under Newtonian mechanics, the surface of a compact high-gravity body doesn't have a particular reason to correspond to the r=2M surface. For a compact spherical object built from material with a given density, the r=2M radius increases proportionally with the mass, but the radius of the actual physical object only increases with the cube root of the mass. So while (as you say) the radiation has the same difficulty leaving the r=2M surface for "dark stars" of all sizes, one also has to take into account the additional difficulty of radiation leaving the dark star and climbing up to the r=2M surface in the first place. For material of a given density, increasing the size of the body increases this distance between the body's surface and the r=2M surface up above it.
You are quite right about the dependency on composition! This exercise still hasn’t reckoned in what the supposed density of a Newtonian dark star's material ought to be (realistically) and how much it ought to emit in the first place as a baseline figure before we take into account the reduction due to gravity and the increase due to indirect radiation effects through an atmosphere. I figure the best one can do as a first approximation (when comparing NM dark stars with GR black holes), is to start with a very generic prediction, move away from specifics and assume an idealised gas or dust cloud, without a well-defined surface. As with GR, the gas is going to compact as you pile up more material, but where GR makes the inward radiation pressure on a self-supporting body go to infinity and beyond as the radius shrinks past r=2M, with the NM relationships, the inward radiation pressure never becomes infinite for a self-supporting body of any finite size. You certainly expect compression, but (without getting into specifics of materials and atomic structure) don't have an obvious reason to expect total collapse, because you have at least some outward radiation pressure acting all the way down to the core. The GR argument of zero outward force resisting collapse inside r=2M does not apply to dark star models.
Since this is technically an acoustic –style metric, the further we go in idealising the interior of a dark star to get away from specifics about the exact material involved, the further we move towards an abstract statistical mechanical description, of how indirect radiation through a horizon ought to work in general, and since QM's Hawking radiation effect has now been generalised to the case of acoustic metrics, dark star radiation would seem, technically, to be a case of Hawking radiation (in a non-GR context), and would seem to follow the same basic statistical rules.
Unfortunately, I don’t know of any published study that explicitly compares the phenomenology of the "QM black hole" predictions with the "NM dark star" predictions. When I asked around a few years back there wasn't anything anyone could cite me to say that the two things were in any way distinguishable. The best I could find were studies of the statistical behaviour of a hypothetical conventional radiating surface at r=2M, in the context of the black hole membrane paradigm, which found that once you assigned the horizon surface an appropriate temperature, you could assume that wholly conventional radiation effects were in play, and generate the "spooky" descriptions of QM (e.g. nominal pair production outside the horizon) by playing games with the coordinate systems being used to generate the description. So the properties of (idealised) dark star radiation outside the horizon would seem to correspond, statistically, to the properties of QM black hole radiation, if one can just justify getting the right value for the "horizon temperature", and since QM can calculate this temperature using very general arguments, an idealised dark star model (obeying the same basic laws of thermodynamics, entropy, etc) ought to be at least in the same ballpark. (Maybe even identical, who knows.)
Perhaps a full comparison of the idealised "dark star" phenomenology against the predictions of QM for black holes might have to wait until the community have decided exactly what QM ought to be predicting, at the moment there still not complete agreement about whether the current QM predictions can be taken at face value, or need modifying to prevent a clash with GR (-> black hole information paradox), so perhaps there's not yet an 100% agreed QM reference model for dark star models to be compared against.
Anyhow, the above arguments are probably too long and hand-wavy to belong in a Wiki article, so I think it's simplest if I just snip the offending text rather than find a way of rewording it to be less misleading. Thanks for pointing out the prob. ErkDemon 05:37, 31 October 2005 (UTC)
See, the black hole membrane paradigm, as discussed in the Thorne book, on Wiki, and in references provided by them. ErkDemon 04:35, 7 January 2006 (UTC)
No, the statement is correct, Hawking radiation is a little more subtle than your post suggests. According to QM, an observer near the event horizon of a black hole sees the region to be occupied by particles that do not exist for a distant observer. Quantum mechanics deals with this by saying that the particles are deemed to be "virtual" for the distant observer and cannot be sensed directly, whereas for the nearby observer the particles are "real". If the near observer decides to bat one of these particles out to the distant observer to prove that the things are real, we say that the physical acceleration has converted a "virtual" particle into a "real" one ("Unruh radiation", "acceleration radiation"). This has been discussed at some length by Thorne and others, who have established that for observers hovering outside the event horizon, QM effects superimposed on a GR background make the region outside the horizon look exactly as if it is illuminated and populated by a completely conventional radiating surface at r=2M. This result is a few decades old (the black hole membrane paradigm). Kip Thorne's book (cited) tackles most of these topics pretty well, if people are bothered to read it. I didn't see the need to offer more specialised references here supporting the characteristics of Hawking radiation, virtual particles, Unruh radiation and so on, because Wiki already has dedicated pages on all those topics, and this is, after all, supposed to be a page about dark stars and their characteristcs, not an in-depth lecture on modern quantum theory.
Thorne: " In 1975, Wheeler's recent student William Unruh, and independently Paul Davies at King's College, London, discovered (using the laws of quantum fields in curved spacetime) that accelerated observers just above a black hole's horizon must see the vacuum fluctuations there not as virtual pairs of particles but rather as an atmosphere of real particles, an atmosphere that Unruh called "acceleration radiation." This startling discovery revealed that /the concept of a real particle is relative/, not absolute; that is, it depends on one's reference frame. …
… What the freely falling observers see as particle pairs converted into real particles by tidal gravity, followed by evaporation of one of the real particles, the accelerated observers see simply as the evaporation of one of the particles that was always real and always populated the hole's atmosphere. Both viewpoints are correct; they are the same physical situation, seen from two different reference frames. "
Thorne: " … the two paradigms give precisely the same predictions for the outcomes of all experiments or observations that anyone might make outside a black hole – including all astronomical observations made from Earth. "
I've also removed the "in brief" section. These sections are bad ideas because they suggest, to the unwary reader, that science once accepted dark stars, then rejected them because of relativity, and now is close to accepting them again. This could give the misleading impression that modern ideas of quantum mechanics are a move towards a pre-relativity world. Ken Arromdee 01:10, 7 November 2005 (UTC)
if people removed the merge part, then why is it not removed from BOTH pages? 69.22.224.249 21:56, 21 December 2005 (UTC)
I've been asked by User:Ken Arromdee to take a look at the disputed parts of this article, but am having a great deal of trouble sifting out what exactly is being disputed in the lengthy debate above. If the two of you would be willing to put a point-form list of points of contention below this comment, that would help a lot. To be clear, I'm not trying to act as any kind of arbiter, but will simply (as asked) state my views on the points of contention, where I'm capable of doing so (I like to think that I'm aware of the limits of my areas of knowledge). If things look sufficiently muddy, I'll link the page from Wikipedia:Pages needing attention/Physics and Wikipedia talk:WikiProject Physics, but from what I can see of the discussion above, it appears to be mostly a conflict of editing styles as opposed to irreconcilable differences over content. User:ErkDemon, is it ok with you if I take a look at this, or would you prefer that it just be put on PNA/P and WPP? -- Christopher Thomas 23:46, 8 January 2006 (UTC)
I really know nothing about this but a number of sites, such as Enchanted Learning use the term "dark star" for any star that has stopped or doesn't emit light, including black dwarfs and brown dwarfs. Could someone please offer some form of explanation? I plan on asking the school physics teacher, but disambiguation by an expert would be more reliable. I'll check with astronomy professors at the university if no one can offer a suitable explanation, but that might take a while. Thanks. DUCK 17:29, 21 February 2006 (UTC)
"Since observations all confirm the relativistic version, a dark star could not exist."
Which observations exactly? With no direct reference, validity of that statement is just that bit vague...
The following statement is not completely actuate in the intro due to what is understood about Hawking Radiation "The key difference being that in addition to being, dark, the black hole is completely cut off from the surrounding universe." There is a low level of communication between the universe and a black hole in the form of Hawking Radiation. I would content that the statement is not even needed since the article does not talk about this point and since the previous statement covers what is in the article "Such objects in modern understanding would be more properly described as black holes." Thoughts? Fcsuper 05:40, 21 July 2007 (UTC)
I have mixed feelings about this article: I originated it, so I feel that I have some responsibility for it, but I'm trying not to edit "controversial" physics pages, because it's obviously felt by some here that I'm not the right person to be doing that ... the article seems to collect junk edits that need changing, but nobody else seems to be fixing them ... my positions on this topic seem to be minority views, but then again, I seem to be the only active participant here who's actually read the source material.
I also notice that the people who watch and maintain the " black hole" page removed the link that points here, so the consensus there seems to be that this page isn't wanted. The talk page also seems to have generated far too many arguments. So I think that perhaps the correct thing to do is to turn this page into a redirect that points to black hole, and be done with it, and avoid all the bad feeling. ErkDemon 23:04, 31 July 2007 (UTC)
I've replaced the light-bending paragraph, because it didn't seem to make much sense as it was, and nobody else had fixed it. I don't know where that strange-looking "r=4M" business came from. Oops, I forgot to sign in. Today's edit was me. ErkDemon 01:32, 7 August 2007 (UTC)
We need to rename and reorganize these articles: there is a third astronomical term, "Dark Star". At the moment, this current article is not well-named - as in physics and astronomy classes the term "dark star" is not commonly used for Newtonian black holes. This current article needs to be renamed "Newtonian black holes", or something like that. Then, we should use the title "dark star" for this newly hypothesized category of super-huge star, powered by neutralino interactions.
In summary:
Current situation: Two articles, and one is simply missing
Proposed renaming
Let's start discussing this. We now have two articles with similar names, for three types of astronomical objects. This is confusing not only to lay readers, but even to scientists. RK ( talk) 16:24, 21 December 2009 (UTC)
I've seen the term "dark star" used to refer to Newtonian black holes. It's not in use today, but is important for historical reasons.
With regards to the articles, this type of situation happens all the time. The usual solution is to use a disambiguation page. Dark star gets moved to Dark star (Newtonian mechanics), Dark star (dark matter) stays where it is ( Dark matter star redirects to it, at present), and Dark energy star stays where it is. A new article, Dark star (disambiguation) is created, pointing to all of these concepts in the usual manner. A new article, Dark star, is created, which redirects to the disambiguation page.
Does this solution seem reasonable to everyone? -- Christopher Thomas ( talk) 07:05, 23 March 2010 (UTC)
As there's been no objection in the week or so since this first came up, and some lukewarm support, I've moved the page. I'm now in the process of tweaking the Dark Star disambiguation page, fixing links to dark star and talk:dark star, and so forth. If there are any problems remaining past the end of March, it means I missed something; feel free to either fix it or notify whoever's performing housekeeping for the relevant pages/templates/etc. -- Christopher Thomas ( talk) 05:45, 31 March 2010 (UTC)
There was also a German scientist who independantly discovered Dark stars but I forget his name. I think he should be added. 8digits ( talk) 13:07, 26 January 2012 (UTC)
Johann Georg von Soldner, he accepted that light could bend under Newtonian physics but I am not sure whether he ever came up with a Dark Star. BernardZ ( talk) 15:08, 1 April 2014 (UTC)
Also Johann Georg von Soldner, in 1801, calculated the bending of light rays grazing the Sun’s disk, using classical mechanics and a hypothetical light velocity 300,000 km/sec. This is after John Michell and Pierre-Simon Laplace had already done their work on Dark stars and Pierre-Simon Laplace appears to have already given up with the idea in Exposition Du Systeme Du Monde 2nd Edition in 1796.
What I did is add him slightly into the article BernardZ ( talk)
In Newtonian universe things FTL is possible, so mass maybe able to escape so there is no event horizon and it may still be unstable measured in billions of years as it is losing mass.
As there is no event horizon it would create a naked singularity.
Thoughts BernardZ ( talk) 14:55, 1 April 2014 (UTC)
Newtonian physicists thought that the sun radiation was powered by a gravity collapse. Similarly, a Dark star would be emitting light/energy but this energy would be trapped inside. Energy does not produce gravity under Newtonian physicists, would the gravity strength would be reducing? If so the Dark star would grow in size, maybe become unstable as its gravity force turns to energy. BernardZ ( talk)
A dark star would be subjected to classical thermodynamics so it temperature to an outside observer is exactly the same as a black hole. This although interesting this is getting into original research. What do you think??? BernardZ ( talk)
If you say something needs to exceed the speed of light you should follow it with "which isn't possible". It takes infinite energy to even reach the speed of light. Infinite means all the energy there is and then some because infinite can't be quantified. So more than infinite is absurd. Jackhammer111 ( talk) 05:52, 29 April 2018 (UTC)
I was reading through the article and it seems that it’s only theorized and needs to be found. Is it even possible for it to exist? 174.247.241.135 ( talk) 01:31, 20 February 2022 (UTC)