Talk:White hole

Proposed move

• White hole → White Hole (physics) —(Discuss)— There is another page about a television episode (White Hole) and the only difference between the titles is the capitalization on the 'h' —24.177.76.237 22:12, 24 March 2007 (UTC)

Fixed by moving White Hole to White Hole (Red Dwarf episode). It has far fewer pages linking to it than this page does, and this is the usual naming convention used for episodes of television series (including several other Red Dwarf episodes). Links to White Hole are being updated accordingly. --Christopher Thomas 06:38, 25 March 2007 (UTC)

white hole violate thermodynamics

Would a white hole violate thermodynamics any more than a black hole would? Who said anything would have to actually be falling out of it? - Leperous

If black holes converted matter et al to pure energy (very high temperatures), would a white hole work within the bounds of the 2nd law of thermodynamics if the energy was converted to space?

Could white holes, in creating space, account for the apparent, accelerating expanding universe?

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I believe that the law of thermodynamics being broken is the second which is about entropy. Which to my knowledge means that things tend to become less ordered. Not more ordered. A black hole destroys ordered objects a white hole would order objects ... Think about a complex system ... maybe even one with life popping out of a white hole being made of nothing. Wow ... kind of godlike huh? Before reading your questions I posted below that could a system of decreasing entropy exist in the area that would correlate to the part beneath the event horizon of a black hole? This would certainly be an exotic. But it is my opinion that black holes / white holes are exotic in nature anyway. --Tommac2 (talk) 19:19, 10 December 2007 (UTC)

Strange edit

For a second time User:Noz92 did a complete replacement [1] of the article, I reverted again for these reason:

• old content, includeing referencesm was deleted
• new content not very layman-friendly
• it's Schwarzschild, not Swartzchild. If you don't know this, there a some doubts about your qualifications to edit this article

Pjacobi 15:49, 2005 Jan 22 (UTC)

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Can somebody who speaks Japanese check the edit by 166.121.37.7. The old link was an actual article while the current one looks like the notice of no article yet. --Laura Scudder | Talk 00:09, 19 Apr 2005 (UTC)

more content

Added some more to justify why people believe in white holes in the first place. I think maintaining energy conservation for the whole universe (thought of as a closed system) is the main reason. The Big Bang theory essentially proposes that the universe was created from a white hole , but that doesn't mean that there must still exist other smaller white holes in our universe. Penrose (Emperor's New Mind) discusses the controversies of white holes in some depth. Might have to read that again ! Mpatel 08:30, 22 May 2005 (UTC)

I appreciate the work various people have done to motivate belief in the existence of white holes, but overall the article seems to suggest that there's *not* much reason to think they exist, so it would be nice if someone could make the original motivation clearer. Who first postulated their existence? What motivated the original suggestion? Mathematical fallout from accepted theory? Explanation of some phenomenon? Simple symmetry with black holes? Also, has the idea's fortunes waxed and waned over time? Is it a divisive topic, or merely an off-hand suggestion? Thanks. — B.Bryant 00:11, 30 May 2005 (UTC)

Reason for removing the 'Hitchhiker's Guide to the Galaxy' edit

I've noticed a few times on WP that people mention things along the following lines: 'in the science fiction series blah blah blah, ... one character falls into a wormhole and blah blah blah'. It might be OK to mention stuff like that in non-scientific articles, but in the middle of scientific ones is a little out of place. Perhaps a little section on science fiction is appropriate in the scientific article (especially for controversial ideas like wormholes) - something like the article Alcubierre drive (if I remember correctly). Mpatel 08:26, 8 Jun 2005 (UTC)

Big Bang

The article had suggested that the Big Bang was simply a white hole, as they both share the characteristic that they 'spew out matter'. This assertion is a bit silly, as the Big Bang did a lot more than spew out stuff. It created time, space, matter and energy.

Realised by anyone who knows roughly what the Big Bang theory is; the assertion that the Big Bang 'was' a white hole (or very similar to one) is better than saying that 'some have suggested that the Big Bang was created by a white hole', which is even sillier than the previous version, as you're saying that space, time, matter and energy were created by an object that supposedly resides in our universe - circularity (all this without giving any references). Give a reference (or an authority on the subject who made this claim) and you can keep what you wrote. ---Mpatel 16:43, 14 Jun 2005 (UTC)

"keep what you wrote"

I am tired now, so please don't take this the wrong way, but I do not appreciate your tone. I am not trying to do anything 'my way' as it were, I just feel that the old wording was wrong. The current wording is hardly ideal either. "The dubious nature of white holes takes on a new twist when it is realised .. " is not encyclopedic wording. -- Ec5618 01:43, Jun 15, 2005 (UTC)

Whether you appreciate my tone or not is irrelevant - my only gripe is that if you say, 'some people believe/think etc. ...' then you must give a reference, according to WP. The current wording is not ideal, I agree with you on that point, but I think it's better than what was written. Like I said, you can keep what you wrote provided you give an authoritative reference. ---Mpatel 09:43, 15 Jun 2005 (UTC)

I still don't appreciate your tone, and I'll ask you, directly this time, to do something about it. Now, dubious is a value statement, as is new twist in which both 'twist' and arguably 'new' are POV. When it is realised suggests that any logically thinking person will eventually realise this, which is not a message you'll want to be sending. If a reader does not 'realise' this, he'll disagree with or doubt the validity of the intire article.

'Some scientists have realised'. -- Ec5618 10:30, Jun 15, 2005 (UTC)

Well, your 'tone' isn't much better either (if you think it's possible to define a 'tone' online). I'll say it again, according to WP, you have to give a reference if you're making a claim, for example, that some scientist said something (you have to say which scientist(s)). The words 'twist' and 'new' are POV individually, but if you put them together in the context of the present article, there's nothing POV about the combination. It is a new twist because that's exactly what it is. I think it's clear we're not getting anywhere with this, so how about we come to an agreement and not include either of our suggestions (at least until we can clear up the argument) ? ---Mpatel 11:07, 15 Jun 2005 (UTC)

I'll apologise for my tone then.

Most of the sources I have found accent the idea that a White hole is currently no more than a mathmatical anomaly, and that this anomaly is found in mathmatical calculations using normal space/time as a starting point. While a layman might conclude that the similarities between a white hole and the Big Bang are uncanny, these similarities seem to be only skin deep.

[2] | [3] -- Ec5618 12:56, Jun 15, 2005 (UTC)

This was primarily taken from a video interview with Dr. Michio Kaku, who also referenced Stephen Hawkings ideas with baby universes. The idea that a white hole "is" the big bang seems to be incorrect. The white hole definition is better defined as the product of the big bang occuring, which some think is just a colliding of membranes, one of which had a black hole on it at the center of the collision.

Lots of ideas have been revised as well as the general understanding of some of the laws of thermodynamics... especially when you now have to think 11 dimensionally. Not saying that the laws have changed, but there can be new interpretations and clarifications that can arise due to the addition of extra dimensions.

Given the fact that "no matter" and "no universe" existed on the membrane our universe exists on, the idea that a white hole created time space and everything else here is plausible. Time, as viewed from someone that "existed" here before the existence of this universe, is due to the movement initially given to and instilled into this universe, is it not? The white hole is the "sticky" new end of the transfer of matter from one membrane to the next.

A few references... http://www.space.com/scienceastronomy/white_hole_030917.html http://education.guardian.co.uk/academicexperts/story/0,,1419424,00.html

I think this is the video where he touches on it. http://vids.myspace.com/index.cfm?fuseaction=vids.individual&n=2&videoid=641879988

--Outcomer 17:48, 4 September 2006 (UTC)

In the 'Recent Developments' section I vaguely recognised the words and it turns out that most of that paragraph is a direct copy and paste of the first part of the introduction from this paper : http://arxiv.org/pdf/gr-qc/0611054 . I don't know exactly what Wiki's attitude is towards copy and pasting from published papers, but I imagine it's better to not do that, do it in your own words and then use the paper as a reference. AlphaNumeric 02:08, 20 January 2007 (UTC)

It depends on the copyright licensing of the work but even if it is free the article should still have "This article incorporates text from yada yada" like is done in Autumn leaf color just below the references section. --WikiSlasher 06:37, 20 January 2007 (UTC)

Once again, I did not use that paper to write that section of the article. I came up with the wording myself after watching an interview of Dr. Michio Kaku and reading the references I wrote above. If it resembles that article, then it is by chance. I cited where I got it from in the references. WATCH THE VIDEO BEFORE YOU CLAIM PLAGIARISM AND DELETE THE ARTICLE. --Outcomer

Couldn't time have always existed? The universe's just keeps repeating it self? and maybe space already existed. Like the areas beyond all the galaxies at this point. And a white hole could throw out energy and matter to create the rest of the universe.

The Big Bang wasn't an explosion, it was a rapid expansion of super compressed energy. That should be changed in the article. —Preceding unsigned comment added by 199.126.42.145 (talk) 01:31, 9 September 2007 (UTC)

energy conservation problem of black holes?

Somehow an energy conservation problem of black holes has emerged in this article. Can the author of this sentence please provide references? Otherwise I'll delete it. --Pjacobi 18:00, 2005 Jun 26 (UTC)

Done. --Pjacobi July 9, 2005 13:41 (UTC)

It was in the article that I linked when I made that revision. In fact everything stems from that article. Whoever erased everything that was added, please follow up with some of the latest information from Steven Hawkingm, Michio Kaku and possibly Brian Greene. The theory goes that our universe is actually a white hole. Two membranes collide which cause matter on one of the membranes (which has centralized itself in a small section of the membrane due to a black hole forming) to be transfered to the next... creating a "wormhole" which is sort of like what we witness when we place our fingers together when we have glue on one of them. When we pull them apart, the glue is transfered but there is also a strand which gets stretched between the two fingers. The white hole of the worm hole is then really just the product of the membrane collision, its the after math of the collision. The instant of the collision is the big bang. The white hole is the universe being formed on the other membrane.

Part of my original energy conservation rant I was going to erase. The first part. The second part, was accurate however, and is how it is viewed now. It completely justifies the law. From reading the original article, the first authors stated that some argue the white hole theory goes against the second law. However, it does not. Some theorize now that this universe will die with lots of black holes. All matter eventually ends up being involved in a reduction of entropy, or the organizing of itself in a black hole, instead of being spread out through space. This goes against the second law. White holes and the collision of membranes solves that and says that the matter is then spread out even more, not only in this universe but also on an external membrane.

Actually the energy conservation problem was brought up in the article before I clarified it. My clarification was removed as well...

--Outcomer 17:22, 4 September 2006 (UTC)

Bubble universe

the universe should not be called as UNIverse but instead be called MULTIverse. There is NOT only 1 big bang that happen. It is possible that there is a parrallel universe somewhere! another universe made up mostly of anti-matter. Do you know the granfather paradox? Although going back in time does not affect the future, it affects the parrellel universe. So in parallel universe or in other bubble universe, it is possible that whiteholes exist there, instead of blackholes.

if any one got other doubts please post here.

Bubble universes have nothing to do with the Grandfather paradox... those are separate "existences" not universes... —The preceding unsigned comment was added by 68.119.88.132 (talk • contribs) on 06:47, 8 April 2007.

Edits of User:Whiteholes

I've reverted (again) a change of User:Whiteholes [4]. Our current knowledge implies that collapsing antimatter will form black holes, not white holes. Please give your sources. --Pjacobi 08:14, 13 September 2005 (UTC)

Get this clear

a star that collaspe in our part of the universe is purely made up of hydrogen and helium carbon etc. and if this star collaspe, it will form a black hole for example "cygnus-x". And NOT a white hole. but in other bubble universe, the star itself is made up of anti-hydrogen, anti-helium, anti-carbon etc. and NOT neccessrily be matter. It will be anti-matter. Anti-matter is the opposite of matter. White holes is the opposite of black holes. So it is only logical to say that an anti-matter star collaspe into a white hole and a star made up of matter will collaspe into a black hole. If you don't even know this, i suggest you do up more reading before posting here again.

You're wrong. A hypothetical antimatter universe is not a world in which everything is opposite. People in such a world would not come to life if they were shot. Things would not fall up. Black is not white.

Yes, a black hole is the theoretical opposite of a white hole. That doesn't mean they are made up of something else. It doesn't mean they can only exist in other 'bubble' universes. Where are you getting your information? -- Ec5618 15:26, 13 September 2005 (UTC)

Related question: the article states a white hole is the time reversal of a black hole. Isn't the time reversal of a black hole also a black hole? In classical physics, the time reversal of a gravitating object is also a gravitating object, not an anti-gravitating. In general relativity, the Schwarzschild metric and the like are time-symmetric. Am I out to lunch? -Dan 20:39, 18 November 2005 (UTC)

You're close. As none of the metric coefficients depend on t, the Schwarzschild metric is clearly invariant under both translation and reversal in t. But t is not timelike everywhere; it becomes spacelike within the event horizon, and r becomes timelike. The metric is not invariant with respect to reversal of r, and so the behaviour within the event horizon depends on which direction we choose as 'future.' If we choose the direction of decreasing r as 'future,' we have a black hole, where we can no more avoid travelling towards the singularity at r=0 than we can avoid moving forwards in time in everyday life. Make the opposite choice, and we have a white hole. Does that clear things up? ~ Tsumetai 20:32, 14 December 2005 (UTC)

Recollapse?

It strikes me as unlikely that a white hole could collapse -- a white hole is a gravitational mirror, a perfect reflector (but not retroreflector) for all incoming material and light, as its boundary is a barrier of infinite potential energy. Neglecting anything emitted from the hole (which would very likely be moving at escape speed relative to anything already present), a large amount of matter collected around a white hole would congregate into a sphere, not growing because of its own gravity and not shrinking because of the (negative) gravity of the hole. There might conceivably be a way to pack enough matter onto it that the matter collapsed into a black hole outside the white hole, but this is distinct from the white hole somehow collapsing. Of course, on that note, how does a white hole react to normal gravity? Would a black hole near to a white hole suck it in, or be repelled itself, or simply annihilate (possibly leaving a weaker hole of one variety or the other)? --Tardis 19:34, 15 December 2005 (UTC)

If I understand correctly, a white hole acts gravitationally like a concentration of negative mass, suggesting that the hole would repel and be repelled by normal matter, but doublecheck with the lurking physicists before taking that statement as being correct. Surrounding it with a shell of normal matter such that the net mass present is greater than zero would give you something that could collapse, but models of situations involving negative mass tend to do strange things, so again, ask a physicist. --Christopher Thomas 08:09, 22 March 2006 (UTC)

Revisions to the article

I've made substantial revisions to the article in an attempt to clean it up. One point bothers me - most discussions of white holes state that they emit matter, but if they're a vacuum solution, this isn't necessarily true (any more than a black hole is required to be consuming matter as a part of its existence).

It would also be handy to have clarification on whether or not they act like they have negative mass (preferably with references cited, so this information can be added to the article). The article presently gives the impression that a white hole has positive mass. --Christopher Thomas 09:01, 22 March 2006 (UTC)

Do you.....

Do you even think that whiteholes even exist? I don't think they exist. They can't as entropy can only increase not decrease!!!!!!!!!!!!!!!!!!!!! —This unsigned comment was added by 219.74.160.43 (talk • contribs) on 04:27, 26 March 2006.

• It would violate the law of thermodynamics, but it could theoretically exist mathematically if you ignore thermodynamics. Since a white hole has not been observed, I'd say they don't exists, but I'm not a scientist. --Frenchman113 00:53, 30 March 2006 (UTC)
  • When I first read this subject, I considered the Big Bang might be a form of White Hole. Maybe I am right, maybe not.

If you observe a black hole or a white hole as being a closed system, then your generalization that white holes can't exist is wrong. Black holes would "appear to lower entropy" and white holes would "appear to increase entropy"... but only in the disorganization viewpoint of entropy. In actuality if Brane cosmology is correct, then both black holes and white holes increase entropy, as matter in one universe is constantly being redistributed to other newly formed universes and perhaps old universes.... eventually it will be so spread out that the multiverse freezes. —The preceding unsigned comment was added by 68.119.88.132 (talk • contribs) on 06:52, 8 April 2007.

White holes can not exist because nothing is created, nothing is destroyed, everything is transformed. There would be no where for white holes to get matter from, and they couldnt get matter from black holes because they compact it and add to their mass. —Preceding unsigned comment added by 199.126.42.145 (talk) 01:27, 9 September 2007 (UTC)

Disputed tag

This whole section talking about entropy seems to fundamentally misunderstand entropy and give too much weight to the "greater entropy is greater disorder" metaphor. High entropy in systems dominated by electrochemical interactions corresponds to states with uniform distributions of particles, but enropy in systems dominated by gravitational interactions operates very differently. In systems dominated by the both attractive and repulsive electromagnetic force, these forces cancel out over long ranges, and there are a large number of equivalent states with uniform distributions of particles. Because gravity is always attractive, forces add up over long ranges, and there are a large number of equivalent states with clumps of particles (and relatively few equivalent states with uniform distributions of particles). "Disorder" is only useful as an intuitive measure of how likely a particular state is. Disordered states are numerous and more complicated to distinguish from each other; ordered states are more rare and uniquely identifiable.

Anyways, my point is that independant of the existence of white holes or their thermodynamic properties, the statements "If anything, black holes by themselves without an exit point violate the second law. Black holes are points at which entropy is reversed. The entropy that exists in our solar system is greater than that of which is in a black hole, which continues to lower entropy by engulfing and trapping everything within its grasp." are false. In particular I imagine you'd be hard pressed to find a physicist who thought that black holes lower entropy.

In fact the consensus is that black holes are objects of maximal entropy. I quote Entropy#Entropy_and_cosmology: If the universe can be considered to have generally increasing entropy, then - as Roger Penrose has pointed out - an important role in the increase is played by gravity, which causes dispersed matter to accumulate into stars, which collapse eventually into black holes. Jacob Bekenstein and Stephen Hawking have shown that black holes have the maximum possible entropy of any object of equal size. This makes them likely end points of all entropy-increasing processes, if they are totally effective matter and energy traps. Hawking has, however, recently changed his stance on this aspect. I'm not sure what precisely Hawking changed his stance regarding, but regardless it seems clear to me that black holes are regarded as having quite high entropy.

Disclaimer: my knowledge of these subjects comes almost solely from pop-sci books such as The Fabric of the Cosmos and A Brief History of Time, and from Wikipedia itself. I am not educated in the finer mathematics of these theories. Bradkittenbrink 06:43, 29 August 2006 (UTC)

A large amount of dubious material was added to this article over the past few months. I haven't gotten around to vetting it myself yet. If you want this to be done more quickly, maybe ping a few of the GR types over at Wikipedia:WikiProject Physics. --Christopher Thomas 06:53, 29 August 2006 (UTC)

Although the shock-wave metric business isn't complete crap, it still gets relatively too much coverage for something quite on the speculative side (even for an already speculative topic such as white holes), and the 2nd law discussion wanders way of course. I'm going to just toss the latter discussion for a start, but the bottom line is probably that the article needs expansion. 192.75.48.150 14:00, 29 August 2006 (UTC)

My understanding was that black holes are now thought to be objects of maximal entropy, only given the fact that they perhaps lead to another universe where the matter could be transfered and therefore spread out. "To an observer" in the "immediate sense", they "seem" as if they are in fact lowering entropy. That was all my contribution was trying to say.

Not only that, but isnt also true to say that gravity, since it is now thought to come from another membrane, or at the very least from somewhere outside of our universe, is therefore an outside force, which when accumulating around our own matter and eventually causing black holes to form, is in fact a reverse of entropy in our universe, since it is the product of an outside force?

--Outcomer 17:29, 4 September 2006 (UTC)

The reason the entropy of a black hole was originally postulated was thermodynamic considerations, and the mechanism of Hawking radiation lent it credibility. It is not dependant upon the existence of D-branes or other universes, which are still speculative theories (more so than Hawking radiation, that is). 192.75.48.150 18:51, 5 September 2006 (UTC)

Although I am not an expert on thermodynamics (6 years of biology/chemistry, and now pharmacy school), my understanding is that if black holes are releasing thermal radiation, then you can assume there is an increase of entropy? What I was trying to point out, was that although to the observer they appear to reverse entropy as far as dispersal goes, they are in fact sending their matter elsewhere... which could show itself here as a release of energy... going from being ordered in the singularity to disordered in the extra dimension / baby universe?

--Outcomer 04:34, 7 September 2006 (UTC)

Law violation

I'm not a physicist but it says that the existence of white holes that are not part of a wormhole is doubtful as they appear to violate the second law of thermodynamics (entropy etc.) is this right or should it be the first law of thermodynamics (energy conservation and that)? —The preceding unsigned comment was added by WikiSlasher (talk • contribs) 06:36, 4 December 2006 (UTC).

Wow that was quick. —The preceding unsigned comment was added by WikiSlasher (talk • contribs) 06:37, 4 December 2006 (UTC).

Ah it was HagermanBot that added the unsigned template so fast. --WikiSlasher 06:40, 4 December 2006 (UTC)

->I think second is correct. Meaning that things are moving from non-ordered to ordered. A black hole would make disorder from order and white hole would be ordering. Think of it, you start with energy and spew out solar systems, galaxies, suns, earths maybe even planets with life forms on them. Kind of godlike --Tommac2 —Preceding unsigned comment added by 207.45.240.18 (talk) 19:24, 10 December 2007 (UTC)

Recent Changes

Multiple people have called the recent developments section either bogus due to no references or plagiarized. This is incorrect. Look in the references section for the video on Dr. Kaku's web page before you begin hacking away at a decent article.

--Outcomer

The relevant sections of WP:RS and WP:NPOV can be summarized as follows:

• References for articles must be "reliable sources". For scientific articles, this usually means publications in peer-reviewed journals that are considered reputable by most scientists. A video presentation doesn't meet this requirement. The sources it's based on might; if so, they're what should be cited as "references" (with the video being under "external links").

• Neutral articles should not give "undue weight" to ideas that aren't commonly accepted. For scientific articles, this means that the article should mostly describe mainstream science's view of the topic, and that space given to fringe views should be in proportion to the degree to which that view is held by scientists as a whole (generally judged by the number of different groups publishing about it and citing papers about it in reputable journals). Brane cosmology itself is arguably a fringe view. The idea that white holes are produced as a result of brane collisions is a subset of _that_. To keep the section, you'll have to dig up enough reputable papers about it to demonstrate that it's a widely-considered (even if not accepted) view.

Google has pretty decent indexing of scientific publications, even if all of them aren't viewable online. If many different research groups talk about white holes being the result of brane collisions in reputable journals, it'll probably keep its own section. If only this researcher or his group talks about it, it might get one sentence, if other people cite him. If nobody's cited it, it didn't make a big enough splash to even be in here. Good hunting. --Christopher Thomas 21:42, 8 March 2007 (UTC)

Video interviews of one of the pioneers of string theory isn't good enough? wow. Didn't Hawking also come to the same conclusion as Kaku in regards to Brane cosmology? Not really sure if there are any papers regarding this idea of wormholes being the "glue between the fingers" viewpoint of black holes and white holes and matter transfer from brane to brane.

--Outcomer

Correct, videos by one of the pioneers of string theory aren't good enough. Peer-reviewed publications are required, as they're the only thing with real weight in the scientific community, and yes, I _am_ a scientist. It won't be that hard to do the search, and I'm sure Prof. Hawking and Prof. Kaku have published about the topic, so do the type of search I suggested above, and then alter the section according to the guidelines in WP:NPOV. The section is already flagged as needing appropriate references, so if none appear, it's likely that an editor will remove or greatly reduce it. --Christopher Thomas 16:29, 11 March 2007 (UTC)

I am a scientist as well... and I know that peer reviewed publications are what you want primarily when referencing things... HOWEVER, they are not the only things that carry weight to them. If there is no primary literature, and instead only a tertiary source, then that has to suffice. And if there is some form of primary literature, but no peer reviewed articles, that has to suffice as well. If a subject is lacking in resources, you take what you can get. You don't just say "Hmmph... there are no peer reviewed articles.... so oh well, I'll just pretend that this subject doesn't exist, and there isn't an ongoing debate about it." In medicine, of course you want to find as many peer reviewed primary sources that you can when making recommendations... But with rare diseases that lack extensive research, you don't just tell the patient "I'm sorry... the only thing I found was a bit of tertiary information on the disease... I can't treat you".

Regardless of that disagreement, I have found an article which should correlate with what Dr. Kaku was talking about.

Dymnikova IG, Dobosz A, Fil'chenkov ML, Gromov A. Universes inside a Lambda black hole. [Journal Paper] Physics Letters B, vol.506, no.3-4, 10 May 2001, pp. 351-61.

--Outcomer

The recent developments section is a mess, IMO. I've added a couple of { { fact } } tags. If the references exist, please add them. The last sentence, about a possible link to the cosmological constant/dark energy, seems particularly suspect to me.--76.81.164.27 21:32, 14 June 2007 (UTC)

Once again, if anyone can find Dr. Kaku's papers on this it would be nice. Before you claim the content is SUSPECT, watch his interview on the subject. HE IS THE ONE THAT SAID THIS STUFF ABOUT DARK MATTER/DARK ENERGY. THE VIDEOS HAVE BEEN PROVIDED. Until someone finds his papers (I HAVE TRIED, BUT HAVE NOT FOUND ANY) on this subject, the videos will have to do. And don't say they can't be used, because Dr. Kaku isn't going to make stuff up. And read my comments above if you want to argue about what's an acceptable source when obviously NO ONE CAN FIND ANY... yet all the top physicists are talking about it.

Before users edit things and turn stuff upside down, you need to look through all sources cited at the bottom of the page... this includes watching videos that users have provided as sources.

--Outcomer

Please clarify "recent developments"

Is the section titled "recent developments stating that everything the layman calls our universe is in fact a white hole? And is this white hole contained inside a black hole? It would help if someone gave a source to this information. —The preceding unsigned comment was added by Eternalmatt (talk • contribs) on 23:36, 24 March 2007.

Again, look in the references... its there! If anyone can find Dr. Kaku's papers on this stuff it would be nice... or Dr. Hawkings. —The preceding unsigned comment was added by 68.119.88.132 (talk • contribs) 06:43, 8 April 2007.

Again, find references that are refereed journal papers to demonstrate that this view satisfies WP:RS and notability requirements. --Christopher Thomas 21:03, 9 April 2007 (UTC)

Again, this is not the only form of reference required for topics as controversial as this. Besides, looking on that reliable sources link, the second sentence stands out: "This page is a guideline, not a policy, and is mandatory only insofar as it repeats material from policy pages." Guidelines is the key word. Rules and guidelines are different.

Only if there is a specific reason to ignore a guideline in a specific article, explained and defended on the talk page, should they be ignored. In great majority of cases, a guideline SHOULD be followed. The basic points are in the WP:V policy anyways. However, in this particular case, Im inclned to interpret the policy as considering that video a MARGINALLY acceptible reference - its by an established expert in the relevant field, and his works have been previously published in reliable third party publications (i.e. he published sci papers in the relevant sci field before). And this is the phrasing of the criteria for acceptence of self-published, non-peer revieved online sources such as the video in question, as outlined in the WP:V policy. The fringe theory section of the reliable sources gudeline seems to be talking about the really far out conspiracy theories, not something as bland as a normal albeit marginal physics theory, so I do not think this would qualify as fringe in the sense that word is used in that guideline. And i dont understand how notability could be questionable since it seemed that in previous discussion, the author was already accepted as a significant authority on the topic. In any case, the article on notability is rather explicit - Notability guidelines give guidance on whether a topic is notable enough to be included in Wikipedia as a separate article, but do not specifically regulate the content of articles, which is governed by other guidelines such as those on using reliable sources and on handling trivia. The particular topics and facts within an article are not each required to meet the standard of the notability guidelines. , so this policy has no relevance at all in this discussion. Nevertheless, though I dont have the will to do anything about this, I still must agree, the "recent developments" section reads abysmally, IMO it really needs to be greately improved upon.--83.131.148.241 00:51, 11 August 2007 (UTC)

I'm deleting the Recent developments section, since it has a "citation needed" tag, and my inderstanding is that WP users are encouraged to delete unsourced claims if they think they're wrong. Putting a link to a video in the references section just doesn't cut it. It seems clear from the talk page that there is a consensus that there was a problem with this section, and only one user keeps pushing it. It's incumbent on that user to build a change in consensus by doing a better job of documenting the claim.--76.81.180.3 18:09, 25 August 2007 (UTC)

Not cool.Dr. Kaku does have a paper. Why doesn't someone add it so we can keep that section?

Besides I added a citation and someone removed the link to it... It's still in the references section. Learn to read the entire discussion before you start deleting things. You shouldn't just delete information that quick. Especially when we all know the info was taken right from Dr. Kaku's mouth. Just because we can't find his papers, doesn't mean you delete the info. There is another reference there! Silly. I added the superscript reference number to the end of the paragraph. Not sure how to actually link it to the references section (hyperlink I mean).

BUT SOMEONE FIND HIS PAPERS ON THIS SUBJECT. ONE REFERENCE IS ALREADY THERE. SOMEONE FIND OTHERS. Stop debating this and get it done. —Preceding unsigned comment added by 68.119.86.169 (talk) 01:10, August 29, 2007 (UTC)

I assume his idea of white holes is incorrect by simple reasoning. If a blackhole on the other side contains a new univese for which it turns out to be a whitehole (big bang event). Then all universes would have such an origin. Lets assume it for a moment, such universe would have no origin to explain particle creation, because there was always a universe before it. If there was indeed such time-loop for universes it would mean it would repeat for ever. If that was true, also our universe is just a result of such repeating. However our universe contains many blackholes, so it would mean every universe would contain endless baby universes. But such a system would end up almost empty since you cannt devide universes for ever into sub universes. Well it might be possible but then the chance that our universe would contain anything would be close to zero, and thats not how our universe looks like. Or do i hit some kind of paradox here ? 82.217.143.153 (talk) 11:27, 1 April 2008 (UTC)

The use of membranes as the point of matter transfer solves some of the endless loop paradox... but then again, when dealing with extra dimensions, some things that seem paradoxical to us due to our 3D nature are actually solved in extra dimensions. —Preceding unsigned comment added by 70.150.134.2 (talk) 19:00, 31 May 2008 (UTC)

Just an idea that popped into my head

I know, random chatter isn't appreciated on discussion pages, so I apologize if this is a tangent. But does anyone else think it may be possible that a theoretical white hole might also be the same thing as a naked singularity? Without an event horizon, information would still be intact and visible if one had the ability to extrapolate from infinite density. I'm no physicist, and I may be BS-ing, but I thought it was an interesting concept. Perhaps someone with a better understanding of the subject could shut me up? The Great Attractor 01:14, 13 June 2007 (UTC)

I have posted a few times on this page also with a similar thought. Basically my thought is that a white hole would mirror a black hole in reverse time ... ( take a movie of the black hole and play it in reverse ) ... what may be some of the things one would see ... the destruction of a star would appear like a star forming from nothing ( anti - spaghettification and popping out of the white hole.

Also a few other thoughts that I had about it.

What would the event horizon look like?

Would a white hole have an anti-gravitational force?

What frame of time would a white hole be in? ( if a black hole is almost at time rest because of its mass would that mean that a white hole is very sped up because of its anti-mass anti-gravity?

Could there exist an exotic state of decreasing entropy?

Would things travel at faster than light? If a blackhole pulls back time / space so fast that light cant escape then reversing that would mean that light coming out of a white hole would travel at greater than the speed of light because of the pushing out of time / space. --Tommac2 —Preceding unsigned comment added by 207.45.240.18 (talk) 19:32, 10 December 2007 (UTC)

contradicts itself

The article appears to contradict itself. The lead states that black holes and white holes are the same thing, but the Origin section says "The existence of white holes that are not part of a wormhole is doubtful, as they appear to violate the second law of thermodynamics." I've added a contradiction tag.--76.81.180.3 18:07, 25 August 2007 (UTC)

This is only in relation to Hawking radiation. It states that it is implied, not that it actually is, which is clarified further down in the paragraph, here: "Hawking's semi-classical argument is reproduced in a quantum mechanical AdS/CFT treatment[3], where a black hole in Anti De Sitter space is described by a thermal gas in a gauge theory, whose time reversal is the same as itself."

As such it does not appear to contradict. - Imperator ^Talk 17:46, 27 August 2007 (UTC)

The current mainstream view in light of AdS/CFT is indeed that white holes and black holes are the same. This point of view, however, was not suggested until Hawking figured out the radiation and entropy laws. The remainder of the article describes various scenarios where white holes were part of the classical description of space time. Since the full quantum description of black holes is still somewhat controversial, it is not clear in what circumstances exactly a black hole will act as a "white hole", in the sense that it will emit sensible objects, and not just thermal radiation. —Preceding unsigned comment added by Likebox (talk • contribs) 21:39, 31 August 2007 (UTC)

DO white holes mathmatically resemble black holes in reverse time?

Would / could a white hole look mathmatecally behave, appear as a black hole in reverse time? Since this would break the second law of thermodynamics could it be possible that an exotic condition such as the sigularity of black / white holes which already blur some conditions create a system where things tend to decrease in entropy? I guess my suggestion here is that a white hole mathmatecally would be a black hole in reverse time and between the singualarity and the event horizon there is an exotic system that naturally tends towards a decrese in entropy. Reverse-spaghettification. Spewing out stars and galaxies. --Tommac2 (talk) 19:11, 10 December 2007 (UTC)

White holes not only resemble black holes in reverse-time, they are defined that way. The important thing to note is that a time-reversing operation does not turn an attractive thing into a repulsive thing. The reason is that forces are accelerations, and acceleration is sometimes counterintuitive--- if you have a ball accelerating toward the Earth and you time-reverse its path, you still have a ball that is accelerating toward the earth. If it was falling and picking up speed, now it is rising and losing speed. Both motions are caused by an attraction to the earth. Repulsion would be rising and picking up speed, or falling and losing speed.

Since black holes are entirly defined by their gravitational effects, and both black holes and white holes attract objects, black holes and white holes are identical except for the horizons. Black hole horizons ostensibly "absorb", and white hole horizons "emit". A black hole singularity is in the future (you will see it if you fall in) while a white hole singularity is in the past (you remember it if you fly out). This distinction exists classically, but it is a nagging problem, because you have a classically time-reversal non-symmetrical object which every ounce of physical intuition says should be the same thing under time reversal.

After Hawking clarified the thermodynamic properties of black holes, he gave a convicing argument that black holes are the same as white holes except for thermodynamics. He used a physical argument, which is discussed in the article, and I think his conclusion is well accepted nowadays. You are right that whenever thermodynamics is involved, reversing in time can violate physical law. The decrease in entropy that you are talking about is the one associated with the black hole spitting out stuff instead of absorbing it.Likebox (talk) 22:03, 10 December 2007 (UTC)

: Thank you, the acceleration piece is nice. But I have one more question. This attraction by the white hole is post event horizon ( is this called something else for a white hole )? If a white hole is emitting then doesnt that mean that it is accelerating / pushing? At least inside of the event horizon I would assume that things are traveling at faster than the speed of light ... or rather that time space is being effected in such a way that things appear to move faster than light. I would guess that the escape velocity of that being emitted would be great enough to re-escape the attracting force.

Apologies for chopping up your comments, but I wanted to adress them in order. This stuff was very controversial until AdS/CFT and the answers are still not univerally accepted.

The inside of the event horizon is described by two different regions of the black hole solution. While intuitively there is only one point at any value of r, the radial direction becomes a time direction inside the horizon, and the usual intuition fails. There are two copies of the interior in the (maximally extended) Schwartzchild solution. One of these regions describes infalling objects--- the future of any point is at smaller values of r, and objects which are in this region are going to hit r=0. The second region has a future which points towards larger values of r, and objects in this region come from r=0 and are going to be spit out.

Which region is physical, the ingoing or outgoing? Both? That's a question whose answer is hard to determine mathematically, because it depends on whether ordered stuff like observers can come out of the singularity into the outgoing region. But physical intuition makes everybody agree that observers are not going to shoot out of the singularity into the outgoing region and then out the horizon. This means that the only the ingoing region is accessible to observers. So that's why people say black holes only absorb. But the classical solution admits arbitrary emissions, even though everybody agrees that these emissions are not physical.Likebox (talk) 23:01, 11 December 2007 (UTC)

: I guess what is confusing me the most is that black holes do not emit stuff. If they are time reversal opposites but both have equal gravitational fields one would think that a white hole would absorb things that were close to it and black holes would push away some stuff that was close to it. I guess if we assume that the gravitational pull of a white hole could pull something in but when past the event horizon it getting popped back out. But then a white hole would be the same thing as a black hole. Can black holes be the same as white holes? Could a black hole also be emitting matter maybe on a sub-atomic level? Basically it would attract whatever is near it and emit sub-atomic particles at exactly escape velocity? This doesnt need to happen at the same time but possibly in the future. Does the mass of a black hole increase as it absorbs?

This paragraph gets to the point of the Hawking radiation. The radiation is the stuff that is emitted from the black/white hole. This is the stuff that is coming out, and it comes out thermally and it only comes out quantum mechanically. The radiation has no past--- but it looks like it is coming from the past region. In principle, Hawking radiation could emit a human being or a car stereo, but the probability is very small.Likebox (talk) 23:01, 11 December 2007 (UTC)

Agreed that the chance that a car stereo is emitted is low, however is the chance of something ordered coming out ( something that resembles the stuff going in ) probable? Or does the second law of thermodynamics hold up? Tommac2 (talk) —Preceding unsigned comment added by 207.45.240.18 (talk) 19:36, 21 December 2007 (UTC)

: OK so if what you say is true, then I think one could deduce that the stuff that would be emitted from a white hole must be traveling at a speed greater than that of light in order to escape the event horizon. Everything that is emitted from a white hole must have enough velocity to escape the gravitational pull of a black hole. Since light is not moving fast enough then stuff must be moving faster than light.

: If that is the case then what is the reference frame of time on the emitted object? But I guess that would only be until it hit the event horizon which would be defined by the point at which the emitted stuff was traveling at exactly the speed of light.

This is a confusion which comes from the fact that the space-time inside the black hole the radial direction is the time direction. You can be moving outward (toward larger r) without going locally faster than light, because the outward direction could be your future.Likebox (talk) 23:01, 11 December 2007 (UTC)

: The stuff being spit out one would think would need to be more ordered than the stuff that it came from. Also would there be reverse spaghettification? If there is not a decrease in entropy then I would think the matter emitted would have to be very sub atomic. However if it is a true time reversal then ordered matter is coming out. --Tommac2 (talk) 03:25, 11 December 2007 (UTC)

The last point about the spaghettification--- that's stuff that happens near the singularity. The stuff that comes out is always hawking radiation, and its thermal, so it is coming out in a maximal entropy state. It's what you would guess would come out of a singularity.Likebox (talk) 23:01, 11 December 2007 (UTC)

Just wanted to add that while the above is the standard lore, I personally think that the picture is incomplete. Maybe objects can survive the singularity-region and be reemitted more or less whole after passing through the outgoing region. I suspect that this can happen for objects falling into charged or rotating black holes, because there the singularity is (at least naively) hard to hit, and infalling objects (at least classically and in the absence of perturbations) are reemitted. but I'm not 100% sure, and anyway it's OR.Likebox (talk) 23:22, 11 December 2007 (UTC)

White Hole vs Big Bang

I was watching a special on the Big Bang ( part of The Universe series ). As they spoke it seemed all of the claims they made could also be applied to a white hole.

From my understanding they claimed that people found out that the universe was expanding and logically they were able to calculate when the universe was a singularity. They claimed that the entire universe was once a point smaller than an electron.

Then they discussed that seeing that the universe is expanding crushed the idea of a steady state universe.

However could the proof of the big bang be the same proof as a white hole / black hole pairs and indeed a steady state universe?

What are the differences of the big bang and a big white hole?

--Tommac2 —Preceding unsigned comment added by 69.249.66.67 (talk) 04:51, 22 March 2008 (UTC)

A black hole is not just an object that does not emit radiation, but an object with extremely high gravity, so that no radiation can escape, though particles may cross the event horizon from the outside. Think of a movie showing a particle that crosses the event horizont of a black hole. If the movies runs backward (time-reversed) one can see a particle leaving the object, that is a white hole, since no matter can cross the event horizon from outside but from inside. From CPT symmetry we know that neither black nor white holes really exist. --84.59.46.253 (talk) 19:49, 27 October 2008 (UTC)

No, there is tons of radiation (in the form of Gamma ray) being emitted from black holes... I think you meant light >.< 68.185.167.117 (talk) 14:39, 26 November 2008 (UTC)

No radiation escapes from inside a black hole (ie, from inside the event horizon), neither light nor gamma rays, except for the theoretically predicted Hawking radiation (which is as yet unconfirmed due to severe observational difficulties, though widely accepted as probable). The gamma rays observed come from regions believed near, but always somewhat outside the event horizon. Wwheaton (talk) 20:47, 26 November 2008 (UTC)

Citation required

The sign of the acceleration is invariant under time reversal: This does not require a citation.

Physically: If you throw a particle up from your hand, it slows down and stops, then it falls back down into your hand, the acceleration is downward. If you reverse the movie, the particle goes up from your hand, slows down, stops, then falls back down into your hand. The acceleration is still down.

Mathematically: d^2x/dt^2 is the same for the curve x(t) and x(-t). That's because it's dt^2 on the bottom.

The reason people are confused about this is because they have some Aristotelian model in their heads where Force equals velocity. The velocity changes sign under time reversal.

The time reversal of an attracting object is an attracting object. There is no citation required, because it is manifestly obvious, and can be checked by thinking.Likebox (talk) 23:13, 24 November 2008 (UTC)

This page is very hard to understand

Could someone write an introduction that is easier to understand for all that are not a physicist? "Theoretical time reversal", "acceleration is invariant", "behavior at the horizon"... uh?

C'mon, guys, Wikipedia serves a much larger population than academics. I'm an engineer and I barely made through the first paragraph, and while I'm curious to understand what is a white hole, this article was of no help to me. Some volunteer to write an easier introduction, please?

Thanks a lot! Fbastos7 (talk) 20:33, 20 June 2009 (UTC)