Talk:Cosmic censorship hypothesis

message: the article says "In 1991, John Preskill bet against Stephen Hawking and Kip Thorne that the hypothesis was true. He won the bet (for an encyclopedia of the winner's choice) due to the discovery of the special situations just mentioned."
now, those things mentioned above provide counterexamples to the hypothesis.  so if Preskill bet that the hypothesis was true, then those counterexamples lost him the bet, so which is it?  did he win the bet, or did he bet that the hypothesis was false?
Or am I just being stupid and reading this wrong? 
Lethe 00:29, Jun 16, 2004 (UTC)
:I think I edited it to its current version, and I got my information from the bet itself:
:http://www.theory.caltech.edu/people/preskill/info_bet.html
:I think your version is right.  Maybe I had the conjecture switched around in my head.  Double check it.  - Omegatron 01:54, Jun 16, 2004 (UTC)
::Well, it seems to me that the bet described in the article is only indirectly related to the bet in the link.  ostensibly, one is about the existence of naked singularities, and the other is about information loss in Hawking radiation.  i think they really are the same bet, or at least related, but the precise description in which they are the same is beyond me.  Something like this: if the cosmic censorship principle holds, then a singularity must be surrounded by a true event horizon, past which no information can flow.  thus a pure quantum state must evolve to a thermal state when it Hawking radiates.  If, on the other hand, we want to preserve unitarity in our quantum theory, we should require that a pure state evolve to a pure state, which i guess would imply that it's not a true event horizon, as we understand them from classical GR (this is the part i am foggy on).  So i guess in some sense this would a sort of weak violation of the Cosmic Censorship Principle.  
::So Preskill bet that the cosmic censorship principle was false in the original bet in 1991, and then in 1997 he bets that it is true that pure states evolve to pure states.  I don't know the history, but this is what i infer from the article text and the bet that is currently up on Preskill's webpage.  It would be helpful if we could find a link to the original 1991 bet, to get this all straightened out.
::Incidentally, I think Preskill is going to win again (and there is some evidence that he has already).  perhaps we should add some stuff to the article to reflect some news about the 1997 bet.
:: - Lethe 12:49, Jun 16, 2004 (UTC)
:::Compared to you, I know nothing about it.  Definitely add some more information if you know it.  Here is the site with the bets, however.  I'm still good for somethin':
:::http://www.theory.caltech.edu/people/preskill/bets.html - Omegatron 13:56, Jun 16, 2004 (UTC)
::::OK, actually that linked pretty much cleared everything up for me.  Basically, there are two bets, one about information loss, and one about the nonexistence of naked singularities.  the first one is still open, the second one was won by Preskill, and then reformulated to make it less susceptible to technicalities, and is open again.  While there may be some vague relationship between the two concepts that i alluded to above, i don't really understand that connection, and perhaps there isn't one.  Therefore the information loss bet doesn't belong in this article (but certainly deserves its own article!) Lethe 21:24, Jun 16, 2004 (UTC)
A perfect Stephen Hawking quote: "God abhors a naked singularity", in other words, were humans able to witness the birth of the universe as per the "Big Bang" theory, it would be the best example of a naked singularity.  —Preceding unsigned comment added by 96.50.10.211 (talk) 04:11, 19 May 2010 (UTC)
thread_title:  True or False? 

message: I think we should make explicit the two different version of the Cosmic censorship principle
:There you go with an initial revision. -- Schnee 23:07, 16 Jun 2004 (UTC)
thread_title:  Strong vs. Weak 

message: Can someone explain how the existence of a naked singularity may lead to a loss of causality, existence of closed timelike curves or other such things? And, for that matter, is that the existence of a naked singularity *might* lead to it, or *would* it definitely? Thank you. ^_^ -- Schnee 16:01, 17 Jun 2004 (UTC)
replies: text: I second this request.  Perhaps it's just my layman's lack of understanding of the nature of singularities, but a clearer explanation of why there would be a loss of causality would be nice, because it doesn't seem obvious from the text. -- Tsuji 03:00, 21 May 2007 (UTC)
thread_title:  Closed timelike curves etc. 

message: Naked Singularity says:
:Computer simulations of the collapse of a disk of dust have indicated that these objects can exist, and thus the Cosmic censorship principle (stating that singularities are always hidden) does not hold. Stephen Hawking lost a bet about this question.
I'm not sure what to make of that; it seems to be related to the following from this article:
:Computer models of gravitational collapse have shown that naked singularities can arise, but these models rely on very special circumstances (such as spherical symmetry). These special circumstances need to be excluded by some hypothesis.
For a casual reader without a background in physics (such as me), the way the articles are worded at the moment is suboptimal, though; Naked Singularity seems to imply that we do know (or at least are reasonably sure) that naked singularities do in fact exist in the universe, while this article makes it seem like the fact that they arise in the aforementioned computer models is a technical issue that only stems from the fact that the current models are still overly simple, and that we do NOT know whether naked singularities do exist "in the wild" or not. Can someone who has a background in physics please clear that up and reword the articles accordingly? Thanks a bunch. :) -- Schnee (cheeks clone) 20:56, 18 August 2005 (UTC)
thread_title:  Is it false now? 

message: I've restored the paragraph about determinism.
First of all, classical GR in the absence of naked singularities is at least locally deterministic. See Wald, for example. 
References to quantum mechanics don't make much sense in context of this article, because cosmic censorship hypothesis is essentially a classical concept. 
Finally, saying that QM is non-deterministic is not accurate. If we know the wave function and the hamiltonian of the system at any given moment of time, we can predict its evolution. 
See  for a brief discussion of determinism in GR. --Itinerant1 22:27, 19 June 2006 (UTC)
replies: text:  Maybe a qualifying statement, like "statistically deterministic" would be helpful. While on quantum level it's non-deterministic (not fully deterministic is still non-deterministic), the emergent macroscopic properties are fully predictable to within statistical error. 83.14.232.226 (talk) 09:39, 23 October 2015 (UTC)
replies: text:  I added ",as described by the general theory of relativity," as a clarification tho the paragraph about determinism. I also added a reference to a nice book chapter about determinism in physics by John Earman. He analyzes how deterministic the various physical theories really are and concludes: "In Newtonian theories determinism is hard to achieve without the aid of various supplementary assumptions that threaten to become question-begging. For special relativistic theories determinism appears so secure that it is used as a selection criterion for “fundamental fields.” GTR, under the appropriate gauge interpretation, is deterministic locally in time; but whether it is deterministic non-locally in time devolves into the unsettled issues of cosmic censorship and chronology protection." Thawn (talk) 10:50, 4 December 2015 (UTC)
thread_title:  Determinism 

message: Is quantum behavior the result of an "event horizon" surrounding something of zero mass, just as an event horizon surrounds the black hole of "infinite mass"?  12.41.40.20 18:00, 4 January 2007 (UTC)
thread_title: Quantum

message: Isnt it in the nature of quantum mechanics, (and einsteins physics as well) that location and speed cannt be observed at the same time. We never know where and at how many places a quantum particle apears (even looking at it would change its position, think of the boudble split experiment). So how can one still think of a universe which is deterministic ?   —Preceding unsigned comment added by 82.217.115.69 (talk) 08:42, 6 October 2008 (UTC)
thread_title:  Quantum mechanics 

message: There is an "it has been suggested that ... merge" box on the main page, but no corresponding setion on the talk page.  Where is the discussion?  68.144.80.168 (talk) 16:04, 25 June 2008 (UTC)
thread_title:  page says merge / merge box removal 

message: Please?  And delete this when done...  — Preceding unsigned comment added by 84.231.0.235 (talk) 16:21, 18 October 2012 (UTC)
replies: text: See null infinity. 67.198.37.16 (talk) 06:52, 18 November 2023 (UTC)
thread_title:  future null infinity -- entry