Talk:Universe

Exists -> Existance

I noticed that the Exists link goes to Existential quantification, but I wonder if Existence would be a better link?

Lead sentence

The Encyclopedia of Astronomy defines the Universe as, “Everything we can detect, see, feel, know, or that has ever had any effect on our region of space. It encompasses all of SPACETIME, not just out to the visible horizon, and includes all particles, fields and interactions.”

The current statement is ok, but it seems to be changing rapidly because, ironically, there is not a universal definition of the Universe. Maybe we could use the ideas from the definition given above to formulate a better lead.

The concept of "spacetime" is confusing to some individuals such as myself. So why just keep it simple as it is right now? After all many theories and concepts about the Universe are mind bottling most of the time.Matthew Goldsmith 23:32, 18 February 2011 (UTC)

Andrew Colvin | Talk 00:22, 9 June 2010 (UTC)

At least it's not suffering from the "Your universe or mine?" problem (see my comment above). - DVdm (talk) 08:24, 9 June 2010 (UTC)

It does suffer from that - far more than what is presently in the lede - by being limited to what "we" (humans, I presume) can detect or observe. The ordinary meaning of "universe" includes even stuff we do not & perhaps never will observe (or know about). It also leaves us hanging about what "our region of space" means. It also might be taking the unusual view that future time is included - I say might because, while overly technical for a general purpose encyclopedia, "It encompasses all of SPACETIME' is also vague --JimWae (talk) 08:34, 9 June 2010 (UTC)

Hm, you stopped reading after the first sentence. The we-phrase is only part of the story. The remainder is covered by the phrase "It encompasses all of SPACETIME, not just...". The first sentence is the John-Doe part, to be completed by the second sentence, which is the technical part. Taken together, it looks perfect for the job. I think that is a viable solution of the problem that I mentioned earlier. DVdm (talk) 09:18, 9 June 2010 (UTC)

So what would be a good proposal for a better lead sentence? I see the point about the "we" part. That could be removed and changed to what we know, including what we do not know. However, is that really the universe? I presume that if we were not here to observe the universe, it would still be here. Help construct a better lead without the sociocentric or worldview of what “we” know. Andrew Colvin • Talk 01:27, 11 June 2010 (UTC)

What is really the universe doesn't really matter (NPI). We just have to decide which source we take and repeat what it says. We can take a dictionary or we can take an encyclopedia, but I would prefer a specialized enc. over a generic dict. We could say that the Encyclopedia of Astronomy defines the Universe as etc... just like the bolded statement. We can keep the we-part, since the non-we part is covered by the spacetime part. If we do that; we should replace "SPACETIME" with spacetime though. DVdm (talk) 10:07, 11 June 2010 (UTC)

There is another definition from the Encyclopedia of Astronomy and Astrophysics that reads as, “The sum of everything that exists and of which we can be aware; the entirety of space. There is a semantic difficulty in talking about the universe; on the one hand, we define it to be ‘everything’, but it may be (a) that our universe is finite, yet unbounded; (b) that the accessible universe is only a small part of a much larger entity, most of which we cannot observe; or (c) that there exist other universes of which we are not ‘aware’.”

I like the previous definition and I agree that the SPACETIME should be lowercased. I think it was caps by paste from the dictionary to tell you to look up Spacetime in the same book. Similar to a link here on Wikipedia. Maybe some of this new definition could be molded with the other one to form a stronger and more explanatory definition. Andrew Colvin • Talk 06:22, 12 June 2010 (UTC)

There's a problem in including "the entirety of space" in the universe. We cannot be sure if the author means "space" to be "3 dimensional space" or "outer space". If 3D space is intended, it makes it seem as if by adding "space" to the "contents" of the universe, we are listing some additional entity that is not already covered. The same problem applies to adding "spacetime". We have over 40 sources that do not include "space" or "time" or "spacetime", and only a very, very few that do. There is no need to include "spacetime" among the contents of the universe. What would be left out by not including it in the list? Perhaps something along the lines of "everything ever located anywhere within space". (The use of "ever" would thereby also include objects from times past.)--JimWae (talk) 06:51, 12 June 2010 (UTC)

This is harder than I thought it would be to define the Universe. Maybe we could take a different route still including much of the first definition I gave with the addition of something along the lines of, “the product of the big bang…”? Adding the big bang into the equation would allow for anything that we do not know of to be included in the universe. I perceive the universe to be just the place that we reside as a result of the big bang. Anything outside of the product of the big bang would have to be considered speculative or as described lower in the article, a multiverse. Thoughts? Andrew Colvin • Talk 21:38, 12 June 2010 (UTC)

I like the second Encyclopedia of Astronomy definition above. Remember that most readers will be nontechnical people who merely want an ordinary definition which they can understand. Rather than coming up with a long, complicated lead sentence that is overly inclusive and confuses people by covering all the esoteric possibilities, it states the most common definition and in the second sentence enumerates the more esoteric types of "universes" that aren't covered by the common definition. The existing lead para also takes this approach and I think is pretty good --Chetvorno^TALK 03:07, 14 June 2010 (UTC)

How is this for a definition?

The Universe is the sum of everything that exists and of which is the ample product of the big bang. The Universe comprises the totality of everything that exists visibly, and beyond the visible horizon. It includes all particles, fields, and interactions making up the structures observed today and in the past.

There is a semantic difficulty in defining the Universe. The word Universe is usually characterized as encompassing everything, however it may be (a) that our Universe is finite, yet unbounded; (b) that the accessible Universe is only a small part of a much larger entity, most of which we cannot observe; or (c) that there exist other Universes of which we are not aware.

I am not sure if Universe needs to be capitalized each time and I am not sure if the wording is clear enough. Suggestions and modifications welcome! Additionally, this would replace the first and half of the second paragraph in the lead. Andrew Colvin • Talk 03:31, 14 June 2010 (UTC)

My feeling is that the term "Big Bang" should not be included in the first sentence; the term "universe" was used before the Big Bang theory, and is not dependent on it; in addition nontechnical readers won't know what it is. I'm also kind of bothered by the emphasis on the term "visible" although I understand the importance of including the parts beyond the visible horizon. Just my two cents --Chetvorno^TALK 19:08, 14 June 2010 (UTC)

Dodecahedron Multiverse

This keeps being added to the article and often removed. Is it worthy to be part? Andrew Colvin • Talk 20:16, 13 June 2010 (UTC)

if you see my links that i have posted it has a lot of evidence that points out that the universe is a dodecahedron.THE WMAP probe sent by nasa was analyzed by a team of french cosmologist-topologist and it was found to be true. here more studies

http://en.wikipedia.org/wiki/Talk:Universe#no_mention_of_dodecahrdron_multiverse

his book: http://books.google.com/books?id=LLIGTaVATCYC&printsec=frontcover&dq=jean+pierre+luminet&cd=2#v=onepage&q&f=false manchurian candidate 05:57, 14 June 2010 (UTC)

I am, to a certain extent, sure that it is a possibility that the universes topology is dodecahedral and that is well worth mentioning, however that prospect must be taken with skepticism at the present moment. Reason being that just because of Jean-Pierre Luminet’s expertise on the subject does not mean that it is correct. Before assuming that he is correct ask yourself a few questions. Likely, Luminet is a credible author and scientist; however, does he have a consensus? Is the idea of a dodecahedron topology of the universe a widely accepted theory? Are their peer-reviewed papers and scientific journals on the subject?

Please present us with a bit more credible information about the subject and it may become more accepted for its inclusion in the article. I noticed that reading the back cover of the book you provided states, “…where possible topologies of the universe…” This I assume means that the dodecahedron universe is a possibility, not a fact or theory.

In no way is this help in any way hostile, it is just the reason for the removal of the material and the reason for exclusion. Andrew Colvin • Talk 07:23, 14 June 2010 (UTC)

there is again no proof of multiverse so why do we have many world hypothesis.the thoery of evolution is a theory but it widely used as evolution.the theory of a molten earth is a theory but it is widely said as moltern earth. i am not posting the dodecahedron multiverse as my or jean pierre idea.the NASA WMAP mission prooves it.i have given soo many links.if you care to read all the links which has all the raw scientic data which points to a finite dodecahedron universe then it should be mentioned.IF the NASA WMAP mission was never launched this theory would never exist. this topic should have a seperate page imo and in the mean time it should be a sub part of the multiverse.

also plz read this http://en.wikipedia.org/wiki/Poincar%C3%A9_dodecahedral_space#Poincar.C3.A9_homology_sphere In 2003, lack of structure on the largest scales (above 60 degrees) in the cosmic microwave background as observed for one year by the WMAP spacecraft led to the suggestion, by Jean-Pierre Luminet of the Observatoire de Paris and colleagues, that the shape of the Universe is a Poincaré sphere.[1][2] In 2008, astronomers found the best orientation on the sky for the model and confirmed some of the predictions of the model, using three years of observations by the WMAP spacecraft

the WMAP mission found this and this is proof that atleast we need to have this theory in this topic.

manchurian candidate 13:17, 14 June 2010 (UTC)

The possibility is interesting, but we are not here to publish exciting new results. To get this included at this level in this article, it is important that independent third-party sources take notice of this idea. That has not happened yet. It will now be removed. ScienceApologist (talk) 16:26, 14 June 2010 (UTC)

WHAT there is ample source of independent news sources.national geographic is one http://news.nationalgeographic.com/news/2003/10/1008_031008_finiteuniverse.html bbc http://news.bbc.co.uk/2/hi/science/nature/3175352.stm

"Astronomers from the US and France suggest that space itself is not big enough to support such waves.

A small, cosmologically speaking, finite Universe, however, made of curved pentagons joined together into a sphere, would fit the observations. "

now are you happy

let me ask you why is there a wiki page of a suns twin star nemesis http://en.wikipedia.org/wiki/Nemesis_%28star%29 when there has been not a single shred of evidence? scientists hypothesize that since earth goes through a extinction event every 26 mya so there must be a brown dwarf hidden in the oort clound. this dodecahedron model has been talked after WMAP probe was launched in 2001.it is via through the WMAP obervatory we known the about this model and and you dont want to add a iota of line?Also i have added the planck obervatory data.it is a improvement of the WMAP and the full structure of the multiverse would by known by its CMB by end of 2012.if you really want to remove it and remove nemseis star crap which has no proof manchurian candidate 16:55, 14 June 2010 (UTC)

I think we have made our points very clear Manchurian… Andrew Colvin • Talk 18:37, 14 June 2010 (UTC)

I agree. Wikipedia's NPOV states that an article must give "due weight" to "significant viewpoints" from reliable sources. "...articles should not give minority views as much or as detailed a description as more widely held views; generally, the views of tiny minorities should not be included at all" even if they are held by reliable sources. The dodecahedron proposal is one among many papers on the shape of the universe. It doesn't merit its own section. I removed it. --Chetvorno^TALK 18:41, 14 June 2010 (UTC)

great censorship at its best.i guess the nemesis article has more scientific proof than the dodecahedron model.at least add some 5-6 lines of this model in the multiverse article.why be so agasint this model?

why cant you have it named as a dodecahedron multiverse.why not reomve stupid article of nemesis.plz tell me why the nemesis articles needs to stay in wiki and not this. also for those who think its only third party.plz read this journal http://arxiv.org/ftp/physics/papers/0509/0509171.pdf

they have presented all the data in a scientific manner.I am a humanities student so i dont know didly squat.perhaps you can agree with thier inferences.

Perhaps there is some misunderstanding here. I, and probably others, have no objection to including the dodecahedron universe proposal in Wikipedia. It just doesn't belong in this article. Why don't you create a new article for it? Like the Nemesis (star) example you cite. That's where it belongs. It's just that if all of the hundreds of serious universe models that have been proposed were included in this article, it would be too long. --Chetvorno^TALK 18:41, 15 June 2010 (UTC)

the thing is that unlike other theories proposed by scientist like bubble multiverse etc this model has some scientific basis aka WMAP probe and the planck probe.we can have a separate page but i cannot do it.I dont know the command tools to create a page link it etc.but i really want this thoery to be mentioned in this page.by 2012 we will know for certain as the full details will be released.the prelim details will be released by dec 2010 and according to the url link i have posted above the scientists say the if the Q=>1.01 then the model would be proved. 59.95.131.16 (talk) 03:58, 16 June 2010 (UTC)

Manchurian:

1. first, I don't see any mention of a 'multiverse' in any of the links you provided. This seems, in fact, to be a model of a single universe with finite volume achieved by closure of opposing facets.
2. second, at present this is a model with interesting but weak supporting evidence. it does not even seem to be a major accepted theory, though it may be gaining credibility in the discipline. You seem to want to present it as a foregone conclusion, which over-emphasises its place in the scholarly discourse.

However, I think the solution to this problem may be to create a new section in this article called Shape of Universe which lists out the current and historical theories about the shape of the universe - including this one - along with supporting and refuting evidence. It would be a nice addition to the article regardless, and would help balance this addition so that it wasn't over-emphasized. do you think you could do some research and start fleshing out a section like that? --Ludwigs2 05:44, 16 June 2010 (UTC)

MC, I've read the arxiv paper you linked, and you are overlooking several important things:

• This is an arxiv paper. That means it has not been published in peer-reviewed literature of the type required by the WP:RS policy. This is a preprint - an early draft of a paper that the author hopes will get accepted by a prestigious journal, but has not yet been accepted to any such.

• The author's assumption that the universe has positive curvature is from the "1.02 +/- 0.02" figure he cites. The "+/- 0.02" figure is for one standard deviation. The expected value of omega is almost exactly 1 (indicating a nearly-flat universe), per the flatness problem. Most cosmologists interpret the WMAP data as confirming that the universe is very nearly flat. To confirm otherwise, you'd need to be several standard deviations away from 1, to have confidence that you aren't just seeing statistical fluctuations. A distance of between 4 and 6 standard deviations is considered "statistically relevant", depending on what you're trying to measure (detecting new particles usually requires being 6 sigma away from your noise).

• The author computes matchings for dodecahedral, octahedral, and tetrahedral spaces. All of these will produce some statistical matching of facets due to random chance. The author has to demonstrate that the matches are good enough that this is extremely unlikely to happen by chance. He hasn't done this. The range of curvature values his own models predict are 1.009, 1.015, 1.025; these are within one sigma of the WMAP data, but so is the 1.000 assumed by most cosmologists. He claims a Polish team's matching circle analysis gives 1.010 +/1 0.001, but he doesn't show any of his work deriving this number. He certainly didn't find that level of confidence from the WMAP data.

Long story short, the author's "careful analysis of the power spectrum" ends up seeing patterns where there probably aren't any. It's still an interesting idea to study, but so far the most plausible interpretation of the WMAP data is that it confirms flatness. You're going to need a much, much stronger case for non-flatness and for power spectrum oddities before anyone calls it "proof" of any given finite topology for the universe.

What you can say from this and other papers is that cosmologists have studied the idea that the universe has finite size, and have looked for the imprint of this in the microwave background. Nobody's turned up strong evidence for it, though. --Christopher Thomas (talk) 06:14, 16 June 2010 (UTC)

I will try to find out the polish team data on the internet.his articles have his email address.maybe you all can email him and ask him about other socentist confirming this thoery so we can better create the articel. All i know that the poincare dodecahedron is mentioned in the dodecahedron page,the jean pierre luminet page and the comsmology homology page.I have already written in the article that it needs to be verified and planck probe will give us prelim data in dec 2010 so i guess by 2011 we would know more and by dec 2012 all the data would be available.imo this article atleast warrants to have a topic in the main universe article.we can shorten the article but it is imporatant. manchurian candidate 11:34, 16 June 2010 (UTC)

I think this section clearly belongs in Shape of the Universe, not here. By the way, Manchurian candidate, you can sign your posts by typing 4 tildes (~~~~) after them. --Chetvorno^TALK 15:54, 16 June 2010 (UTC)

Yes, per WP:SUMMARYSTYLE, we can wax lyrical about topology theories in Shape of the Universe, but in this article we need to summarise that article's content, not repeat it all. This is a new and little recognised theory so it does not deserve placement in this main article. Fences&Windows 16:45, 16 June 2010 (UTC)

Ah, I had no idea that we had a separate article on the shape of the universe. there you go.

@ Manchurian: please talk a look at wp:cheatsheet which will give you tools you can use for editing articles and talk pages effectively. --Ludwigs2 17:20, 16 June 2010 (UTC)

why did you remove the pic and the word dodecahedron mltiverse.atleast bring those back. 59.95.130.218 (talk) 06:16, 18 June 2010 (UTC)

the shape of the unvirse is a total irony.there is no mention of the dodecahedron model.

i am adding this line and it is getting removed by a ego Hungary person. add tthe data gathered from jean pierre luminet about universe being a finite and shaped like a dodecahedron . manchurian candidate 17:10, 18 June 2010 (UTC)

Please do not treat Wikipedia as a game to make a WP:POINT. Try to establish talk page consensus before you add this or similar content to this article. DVdm (talk) 18:03, 18 June 2010 (UTC)

The term "dodecahedron multiverse" does not appear in the paper you cite. Using the word "multiverse" seems to be your own idea. That sort of thing is forbidden by the WP:NOR policy.

The purpose of Wikipedia is to summarize the views of well-established, well-accepted sources of information, not to publish new or cutting-edge information. In the context of science articles, the relevant policies are WP:RS, WP:UNDUE, and WP:FRINGE. The idea that the shape of the universe might be measured is noteworthy and has been widely published -- and is already mentioned in the article. Your favourite authour's idea about what that shape ends up being, on the other hand, has not yet been published in peer-reviewed journals and is not accepted as being any better than the many other proposals in that regard. As such, it doesn't merit a mention in the Universe article, and at best merits a very short mention (along with the other options proposed with similar confidence by their proponents) in the shape of the Universe article, and possibly a paragraph at the page about the paper's authour.

If you continue to re-insert this material against the advice of all of the other editors on this page, after all of the policies have been explained to you, then what you're doing is called "edit warring". Per the WP:EW policy, it'll get you blocked if you continue doing it. You seem to want to contribute constructively, so please restrain yourself to contributing within Wikipedia's rules. There are places where you can push cutting-edge proposals more strongly; Wikipedia isn't one of them. --Christopher Thomas (talk) 19:03, 18 June 2010 (UTC)

The sensible place to discuss details seems to me to be Talk:Shape of the Universe. Whatever consensus lead develops there can be used to update this article. i'll just mention that information that is presently missing is a summary of the recent (3-4 years) peer-reviewed Aurich et al. work favouring the 3-torus model. A few minutes on ArXiv.org will get to the open-access versions and peer-reviewed publication details. i'll do it myself if i find a few minutes some time...

There is no "multiverse" concept in the cosmic topology literature - these deal with standard FLRW models. Boud (talk) 22:31, 18 September 2010 (UTC)

latest info about dodecahedron multiverse http://arxiv.org/abs/1011.3706 Concentric circles in WMAP data may provide evidence of violent pre-Big-Bang activity http://www.technologyreview.com/blog/arxiv/26132/?ref=rss

can you plz add a dodecahedron model and some data— Preceding unsigned comment added by manchurian candidate (talk • contribs)

If it was you who added this content again against consensus and in logged-out mode as 122.161.71.196 (talk · contribs), note that I have removed the section again and left a warning on your talk page. DVdm (talk) 13:34, 18 December 2010 (UTC)

Article's first two paragraphs contradict one another

The first paragraph states that the universe is everything that exists.

The second talks about the possibility of other universes.

This is patently a contradiction. I suggest that the original definition should be brought into line with the modern definitions given below, which emphasise that a universe is everything within 'your' spacetime which is in some sense causally bound to everything else in this universe. This allows for a multiverse comprising of individual, 'disconnected' universes, as the second paragraph talks about. —Preceding unsigned comment added by 86.140.67.71 (talk) 15:13, 21 June 2010 (UTC)

Your proposed definition wouldn't cover one of the main "multiverse" models, the bubble universe theory, which consists of multiple non-causally connected universes. The existing definition isn't a contradiction. Keep in mind that most readers of this page are nontechnical people merely looking for the most common, understandable definition. Many esoteric universe models have been proposed. Rather than coming up with a long, confusing, overinclusive first sentence that covers all the exotic possibilities, the existing intro gives a definition that covers the most common meanings of the term "universe", and in the second sentence mentions the more exotic models not covered in the first sentence. I think this is a much better approach for a general-use encyclopedia article. --Chetvorno^TALK 17:40, 21 June 2010 (UTC)

I don't think it's particularly technical. If somebody is reading this article, they are certainly going to be interested in the idea that there may be other universes, and hence the universe is very far from 'everything that exists'.

At the very least this article shouldn't contradict itself; that will only confuse people who read it.

"The Universe comprises the totality of everything that exists"

and

"some cosmologists have speculated that the "Universe" we know of is just one of many disconnected "universes""

are patently not compatible statements.

I think I will edit the article very slightly so that it at least points out that these definitions are not compatible with each other, which would be better than the present state in which the contradiction is treated as if it isn't there. —Preceding unsigned comment added by 86.140.67.71 (talk) 15:08, 24 June 2010 (UTC)

• The commonest present def is that the "universe" is "everything that exists...". Some people have speculated that there might be things that exist that we can never access, nor observe, nor ever know about in any way. Some who engage in such speculation refer to these other speculative "worlds" as other "universes", some call each other word a "multiverse", & some use "multiverse" for the collective "everything". (i.e. Not even every such speculator agrees that the term "universe" could not still be applied to "everything..." in this context.) There will always be speculation that perhaps there is something more that can (or, more weakly, "has") never be/been observed nor known about. The existence of some such other worlds (by definition) will always remain speculation. There may come a time when we observe a "world" so separate from ours that we may wish to give it a separate name. A decision then about how to continue to use the word "universe" might be a real choice that is eventually made. There will still be a sense in which some word (and that word could continue to be "universe") is used to refer to everything that exists. For now, it is quite appropriate to say that in current actual usage, "universe" signifies everything. Those who speculate about other inaccessible "worlds" may sometimes use the word "universe" in a more limited sense to make a point - but not even all of those agree on how to use the word. Some have proposed a more limited meaning for "universe" based on speculation that there are other "worlds" extremely inaccessible from our "world" (i.e. more extremely inaccessible than the presently accepted "edge" of "our" universe). Many words do not have a unique meaning - especially not when language is being stretched to make a point about speculative ideas. --JimWae (talk) 19:14, 24 June 2010 (UTC)

I'll agree that there is a real problem here. It is not so much that the paragraphs contradict each other as they are just not clear and not well supported. My suggestion is to introduce the concept of the "observeable universe" as distinct from the universe as "everything that exists." This way we can introduce theories about what the universe might have looked like prior to the big bang and explain that such states are beyond the "observeable universe" but but may well be part of the broader universe. Let's face it, modern cosmological theory is full of notions of big bangs as commonplace in the "big universe" and that we are simply stuck within a single "observeable universe" beyond which we can only theorize. If these theories are correct these other places are no less real, no less existant, and therefore part of "everything that exists". Thus ideas of multiverse models can be introduced in a clearer way. The "universe" is everything that exists - even that which we cannot observe. The "observeable universe" is everything that we have the potential to observe and that is covered by current theories of big bang, inflation and so on. —Preceding unsigned comment added by 151.191.175.204 (talk) 14:09, 29 June 2010 (UTC)

I think we need to be guided by actual usage of the term. The first sentence adequately covers everyday usage, as "everything that exists". The succeeding sentences need to cover usage in cosmology, where it differs from "everything that exists". Although in cosmology "other universes" always refer to regions unobservable in principle and undetectable from ours, not all unobservable regions are called separate universes. In the Big Bang model, the parts beyond the speed-of-light horizon, outside the observable universe, are still considered as part of our "universe", so this conforms to the everyday usage. However in bubble universe theories, a very active area, the non causally-connected bubbles are usually described as multiple "universes". Another alternate usage is in oscillating universe theories, where the (unobservable) consecutive iterations between successive "crunches" are often described as separate "universes". I think we should avoid generalizations and just describe how the word is used. --Chetvorno^TALK 01:24, 30 June 2010 (UTC)

Pie Chart

I added up the numbers on the pie chart in the article, and the sum of the numbers was only 99.83%. So what, is the other .17% black holes, the absence of anything at all? Could somebody try to fix this? Pawsrent (talk) 21:44, 30 June 2010 (UTC)

The pie chart (and the NASA version on which it was based) is a combination of several sources of data, with varying amounts of precision in each. Missing or excess percentages probably fall into the error bars in the larger values. A more intuitive description would be to say that the universe is about 5% baryonic (normal) matter, 25% dark matter, and 70% dark energy, with the baryonic matter breakdown being about 80% free hydrogen and helium, 12% stars, 7% neutrinos, and less than 1% heavy elements, but these are rather rough numbers.

To get better numbers, and draw more accurate charts, you'd need to track down relatively recent papers describing the universe's composition. The dark matter article, for instance, cites one that gives 4.6% baryonic matter, 23% dark matter, and the remainder (about 72%) dark energy, but notice that the dark matter figure isn't known as precisely as the baryonic matter figure (so there could be slightly more or less dark matter, with a correspondingly different amount of dark energy).

I hope this answer is useful to you. --Christopher Thomas (talk) 22:23, 30 June 2010 (UTC)

Undue emphasis on Anthropic Principle in introduction?

Almost half of the introduction (the last 2 paragraphs) is taken up by an unsourced description of the Anthropic principle, and a dubious paradox in some bubble universe theories. I believe neither of these topics is within mainstream views of cosmology, and they are off-topic for this article. I certainly don't feel they belong in the introduction, and probably not in the article at all. Comments? --Chetvorno^TALK 06:42, 2 July 2010 (UTC)

Not only does it dominate the lede, but it appears nowhere in the body of the article. The lede is supposed to be an introduction to the article - not present ideas never revisited. It looks like the entire 2 paragraphs need to find a new home somewhere in the body.--JimWae (talk) 07:05, 2 July 2010 (UTC)

looking again, it seems the anthropic principle is there because of the discussion about whether the constants and laws are uniform throughout the universe. That part is revisited in the body, but is still over-examined in the lede.--JimWae (talk) 07:09, 2 July 2010 (UTC)

The "bubble universe" paragraph refers to the idea of chaotic inflation, which is taken seriously as a hypothesis (though not considered proven by any stretch). The idea is that there's no reason to assume that the inflationary field (which is a mainstream assumption) collapsed at the same time everywhere. If its collapse was instead a stochastic (random) process, you'd a) end up with multiple normal-looking universe regions that weren't in causal contact with each other, and b) always have some part of the universe in which cosmic inflation continued to operate. More speculative versions of the hypothesis use a metastable vacuum state (false vacuum) rather than cosmic inflation, with decay to "normal" vacuum being the process that spawns universe regions like ours. It's quite possible that both hypotheses are correct (if cosmic inflation is the result of a metastable vacuum state). We won't find out for sure for quite a while (the estimated energy scale is at least the GUT scale).

Anon's argument fails because it boils down to "in some places it stops, therefore it's not true", which fundamentally misunderstands the conjecture (all that's needed is for it to _not_ stop _somewhere_, to produce an arbitrarily large number of normal-universe-like spaces). --Christopher Thomas (talk) 08:39, 2 July 2010 (UTC)

I removed the anon's additions to the lead -looked like a POV argument to me, and certainly too detailed and specific for a lead section. I am not convinced that the remaining sentence about the bubble universe theory belongs in the lead either, but it was already there before the anon's addition, so I gave it the benefit of the doubt and left it in. Gandalf61 (talk) 10:35, 2 July 2010 (UTC)

The original purpose of introducing the bubble universe theory in the intro was to give an example of alternate definitions of the term "universe" in which multiple universes were possible. I think that is a necessary part of the intro. That got deleted with the unnecessary, extraneous bubble universe stuff. I'm going to put it back. --Chetvorno^TALK 17:28, 2 July 2010 (UTC)

Anthropic principle "untestable"?

Did not Fred Hoyle successfully test AP with his prediction of the unknown energy level of carbon nuclei during stellar synthesis against the odds based on the application of said AP? That's how theories are tested, by using the model/principles to predict how a phenomenon or process behaves, which he did - successfully, so much so it changed his outlook. I bring this up as editor Gandalf61 insists AP is untestable. This just doesn't square with the facts, does it? In addition, John Leslie provides a list of predictions implicit in Carter's SAP; this too is shrugged off as if to dismiss it's validity. It should be noted Leslie's views on AP have been cited by Francis Collins in his book where he strongly argues in favor of AP. I find it convenient to categorize Leslie's views as unimportant (while a top scientist is borrowing his thoughts on the subject) so as to categorize the theory as "untestable." The SETI program is another clear case of testing Carter's WAP, not to mention the Mars Exploration Rover Mission. This observation was likewise slapped down as "nonsense" by the same editor. In any case, it seems Fred Hoyle's successful testing of AP alone should invalidate the "untestable" theory. Thoughts? 97.106.241.66 (talk) 18:58, 3 July 2010 (UTC)

You have been repeatedly adding or changing material against consensus (as demonstated by the fact that many different users have been reverting your changes). You've been warned about doing this with other articles on your talk page. Stop doing it. Instead, after the first reversion of material you want to add, come to the talk page and try to convince other people to add it back. Adding it back yourself is edit warring, which is against wikipedia policy. --Christopher Thomas (talk) 19:18, 3 July 2010 (UTC)

Please try to stay on topic. If you wish to speak about this there are more appropriate places to do so. I'm sure there's a wiki policy somewhere against changing/hijacking a subject.

For those interested, did not Fred Hoyle successfully test AP with his prediction of the unknown energy level of carbon nuclei during stellar synthesis against the odds based on the application of said AP? See above. 97.106.241.66 (talk) 19:39, 3 July 2010 (UTC)

Your are misunderstanding what the AP is. The AP is a simply logically true statement about observations, namely that any observation has an observation bias due to the fact that the observer has to exist. This not something your can empirically test or not, because it is simply true.

Fred Hoyle was not testing the AP, since his prediction was not dependent on it. His prediction simply followed from the abundance of carbon found in the universe. His surprise however was at how small the parameter space of possible "universes" is in which there is enough carbon to form carbon based life. This obervation is known as "fine-tuning" not as the anthropic principle.TimothyRias (talk) 20:02, 3 July 2010 (UTC)

Thanks for your thought Timothy. Hoyle explicitly applied AP arguments in his prediction, and the literature explicitly states this (fine-tuning is the underlying 'principle' observed in universal constants, yes). The citation from Encyclopaedic Dictionary of Astrophysics, p. 185 says, "A paper of his made an interesting use of the Anthropic Principle" and about his prediction states, "those energy levels, while needed in order to produce carbon in large quantities, were statistically very unlikely." This is in stark contrast to your sense that the prediction "simply followed" etc., etc. It perhaps only looks 'simple' after the fact, which is just an unsourced POV anyways, but mathematically it was "very unlikely." POV doesn't trump "statistics."

While I agree that there are relatively few predictions from what I understand (I'm no expert of course), it still makes predictions (cf. Leslie, Collins), and if those predictions are proven wrong, the theory can be falsified. I believe Stephen Hawking has made use of AP as well for predicting, calling it "essential" in quantum cosmology, see "Quantum Cosmology, M-theory and the Anthropic Principle" (January '99). He mentions that AP is not favored among many physicists for being "messy and vague" and it has "little predictive power" (as opposed to "NO predictive power," note the contrast made here when he says that Cosmology has "NO predictive power" - so AP makes some, maybe not a lot, but it's a start.) and states, "I sympathize with these feelings, but the Anthropic Principle seems essential in quantum cosmology." He then offers a remedy declaring, "One can make the Anthropic Principle precise, by using Bayes statistics." Bayes statistics involves predicting things, and this is how Hawking sees AP being applied in quantum cosmology in his lecture. Again, "statistics" are not overthrown by popular POVs on WP - or are they? 97.106.241.66 (talk) 21:44, 3 July 2010 (UTC)

• Some forms of the anthropic principle can be reduced to "Our universe must be such that life like our own can exist in it", which is a tautology.
• Stronger forms of the anthropic principle make the stronger claim "Any universe must be such that life like our own can exist in it". Since we cannot, by definition, observe any other universe apart from our own, this claim is untestable.
• Leslie's "tests" are odd (why should the anthropic principle predict only carbon-based life ?), vague and not mainstream science.
• Bayesian inference can't be applied because we have a single observable (our universe) and no way of knowing the marginal probability distribution of the universe's parameters. In other wrods, we cannot know what a "random" universe would look like.
• If I see a black cow, can I conclude that all cows are black ? If I observe the cow many times from many different view points and note that it always looks black, does this strengthen the case for all cows being black ? The weak forms of the anthropic principle are equivalent to saying "whenever I look at this black cow it will appear to be black". The strong forms of the anthropic principle are equivalent to saying "this cow is black therefore all cows are black". And your "tests" are equivalent to saying "the more times I look at this cow and confirm that is black, the more likely it is that all cows are black". Gandalf61 (talk) 08:51, 4 July 2010 (UTC)

Some forms of the anthropic principle can be reduced to "Our universe must be such that life like our own can exist in it"... You can reduce it to that if you want to, but AP goes quite a bit farther than that. We're in a unique position where we are afforded insights into nature like studying the light spectrum of the corona during a total solar eclipse, a remarkable 'coincidence' in itself, leading to deeper inquiries/discoveries in science; this 'coincidence' is also necessary to stabilize ocean tides, protect earth from space debris, providing a fairly stable environment to be able to thrive and make these same unique discoveries. Moreover, this entire area of research is an intellectual domain exclusive to humans, not monkeys or giraffes or swine, microbes etc., they don't make records, invent technology, formulate theories, debate or study the universe like we do, hence "Anthropic" principle. As far as scientists have observed, this knowledge is restricted to Man..carbon-based life, but the intellect and the principles transcend materialism, for it governs the material world. That's why the hard science of math (statistics) are used primarily to validate it, it too is immaterial and transcends the universe (or a multiverse). Hawking was correct to turn to it to test AP, and Hoyle's prediction was remarkable because of the statistics also.

"Stronger forms of the anthropic principle make the stronger claim "Any universe must be such that life like our own can exist in it." Since we cannot, by definition, observe any other universe apart from our own, this claim is untestable." Yes, but that is a strawman argument. You're assuming that is the only way to test the theory, and I've already provided you with others smarter than you or I who have given ways to test (via prediction- Leslie) or do not use a form of SAP where imaginary universes must exist (like Hawking). Carter's SAP is mentioned in the article because he was the first to introduce AP in a fairly comprehensive way, though others before had the same working ideas (like Rev. Bayes himself). In addition, since the principle is based on scientific observations of constants which can be broken down into raw mathematical functions, computer models can test the 'fine-tuning.' This is similar to how the big bang model is investigated.

Leslie's "tests" are odd (why should the anthropic principle predict only carbon-based life ?), vague and not mainstream science. So you want to argue a point based on ignorance and an opinion? I don't think it's odd, and the theory is restricted (in this case) to carbon-based life because that is what man is composed of in the matrix of universal constants governing his biology, chemistry, physics, etc down to the quantum level. Others like Barrow and Tipler have their own tweaked version which is not limited to carbon-life. Oh and it doesn't get anymore "mainstream" than Hawking I'm afraid, and he was using it in a predictive manner that is not "vague" that was the point of his lecture I cited.

Bayesian inference can't be applied because we have a single observable (our universe) and no way of knowing the marginal probability distribution of the universe's parameters. In other wrods, we cannot know what a "random" universe would look like. Well, dudes like Hawking disagree with you vis-a-vis Bayes statistics, perhaps not with the particular model you use, no he opposes a 'multiverse' with the principle of economy, and fortunately we can cite Hawking too in the wiki article, we can't cite you - so who holds more weight? So I must reject the strawman. Further, random universe models can be generated with advanced computer systems plugging in varieties of observable constants that hold our known universe together. This has been going on for quite some time now.

Your other argument is immensely flawed and demonstrates you don't understand the fundamentals of AP. We're talking about a huge list of constants that can be tweaked every which way and work as an incredibly complex elegant symphony - you're talking about "black," whereas AP talks about light waves, speed of light, frequency, wavelength, polarization, electromagnetic radiation, EM spectrum, absence of light, space-time, and so many variables that come together, hence the statistical significance goes up. But hey, you don't need to be right on WP to have your way, all you need is enough people to agree with you. George Soros could fund an army of activists to troll WP and say the Moon is made of cheese, and someone could show good science against it but would lose simply because they're out numbered. That's the dilemma here I think. In fact, I would even say it goes on in academic circles, sadly Hoyle knew all about the political corruption among his peers and likely lost a Noble Prize because of it, but I digress. 97.106.241.66 (talk) 18:52, 4 July 2010 (UTC)

You can weight the cow, measure the length of its tail, calibrate the colour of its eyes, and collect a thousand statistics about it. Isn't it amazing that you have found a cow that has just these exact statistics out of all the many possible combinations that could exist ? That can't be coincidence can it ? Surely all cows must be the same ! No matter how many variables you measure, because you are observing the same cow/universe all the time, you are not gathering any more evidence about cows/universes in general. BTW, nice touch of conspiracy theory at the end of your rant - because everyone disagrees with you, that just shows you must be right, doesn't it ? Gandalf61 (talk) 23:17, 4 July 2010 (UTC)

Your juvenile example has nothing to do with universal constants that cannot be tweaked without severely if not completely demolishing the known universe and destroying the observer (changing the cow's weight, eye color or tail length will not destroy it - did you know that?) nor does it bear on providing the perfect environment to observe the high precision of said constants and highlight the tailored position required to do so. I can't say I'm surprised you don't understand this issue seeing as how you even missed the reason for giving an example illustrating how anyone can stick baloney on WP as long as enough like-minded supporters back it with their unlearned opinions, emotions, or political agenda in the case of Soros, infamous for funding myriad front groups and so makes a convenient example. It isn't a "theory" that numerous groups have been caught doing similar activities right here on WP - is that shocking? As I said, Hoyle came face to face with it in his profession, Einstein talked about it as well but on a more global scale. It helps to be informed on history so you know how the world actually works. Oh and the reason why I'm alone on this is because I'm the only one not just asserting my own opinions/ideas. So? being distinguished is automatically bad? Groupthink and mediocrity is good right? Take a look at my previous responses vs. yours and others.. I'm the one plying you with citations, quotes and facts and in return I get sophomoric cow examples? Crying out loud, the control freaks who paTroll this place never even bothered to include a section for AP to begin with - I wonder why! This place is a joke! I'm done speaking here -- please hold the applause. 97.106.241.66 (talk) 05:26, 5 July 2010 (UTC)

You have an incredibly big mouth for someone who keeps confusing the AP and fine-tuning. The AP does not say that the universe in fine-tuned in any way, it just provides a possible explanation (or rather something to keep in mind) when you do observer fine-tuning in the universe. The AP is simply something you can proof by logic, on the otherhand showing that the universe is fine-tuned does not sat squat about the AP.TimothyRias (talk) 08:17, 5 July 2010 (UTC)

Hey, everybody, WP:CIVIL. My (amateur, uninformed) feeling is that the Anthropic principle is simply not highly enough regarded in mainstream cosmology to merit a place in this article. Can we maybe have a vote on this? --Chetvorno^TALK 01:39, 6 July 2010 (UTC)

Straw poll on anthropic principle and fine-tuning

In the interests of 1) clearly measuring consensus and 2) keeping things civil, I'm taking User:Chetvorno's suggestion and starting a straw poll on how the fine-tuning problem and the anthropic principle should be presented in the article.

Please indicate which of the following options you prefer:

• this version by TimothyRias (talk · contribs)
• this version by 97.106.241.66 (talk)
• Neither version (please clarify in a comment)

(Delta between TR and IP versions: here.)

Consensus doesn't necessarily reflect truth, but it does reflect a decision on the part of Wikipedia editors, per WP:CONS. A straw poll attempts to measure consensus in an informal way. The formal way to do it is an article RFC, which is a longer but more formally binding process. --Christopher Thomas (talk) 19:21, 5 July 2010 (UTC)

Votes

Please indicate which of the options above you endorse ("neither" is a valid option). Comments should be in the next section, not here.

• Endorse version by User:TimothyRias. --Christopher Thomas (talk) 19:21, 5 July 2010 (UTC)
• Endorse version by User:TimothyRias. Reyk _YO! 11:15, 6 July 2010 (UTC)
• Endorse version by User:TimothyRias. Gandalf61 (talk) 09:55, 7 July 2010 (UTC)
• Endorse version by User:TimothyRias. --PLUMBAGO 12:34, 7 July 2010 (UTC)
• Weakly endorse User:TimothyRias version. --Chetvorno^TALK 17:37, 7 July 2010 (UTC)

Comments

Please place comments here, rather than among the votes.

• Can you fix the link to the IP's version? Currently it goes to their contributions. Reyk _YO! 23:18, 5 July 2010 (UTC)

  Done; Thanks for the heads-up. The diff link was still correct, thankfully. --Christopher Thomas (talk) 00:29, 6 July 2010 (UTC)

• I lean slightly more toward the version by User:TimothyRias because it is a little more thorough. However, I would strongly prefer to see the remark about Fred Hoyle's atheistic beliefs and the impact therein be removed. It seems too editorial in nature.—RJH (talk) 15:31, 6 July 2010 (UTC)

  If I'm reading the diff correctly, that was in the IP's version, not TR's version? --Christopher Thomas (talk) 19:03, 6 July 2010 (UTC)

  Ah... yes. Sorry. In that case then I think I was leaning a little more toward the IP version because of detail. No offense intended to M. Rias of course.—RJH (talk) 19:33, 6 July 2010 (UTC)

  My version is purposefully very short. It is a summary style paragraph linking to fine-tuned universe where there is room to discuss the various subtleties around the subject. The IPs contribution on the other hand is very much a POV push.TimothyRias (talk) 05:31, 7 July 2010 (UTC)

  Mmm, well a possible issue there is that your version doesn't really appear to be a summary of the Fine-tuned Universe article. It only includes selected parts.—RJH (talk)

  I think it covers all the major points from that article: "observed fine tuning" "dispute about that observation", "explanation through AP and multiverses, probabilistic nature of QM etc." If you feel that any major points from that article are missing please free feel to add them in a succinct way . The only thing I can think off not currently mentioned is the link with ID and creationist viewpoints. If you see possibility to add a good neutral mention of that, that could be an improvement. I'll be the first to admit that my version is not perfect, but I do think that it is a lot more constructive way of moving forward than the POV push of the IP. TimothyRias (talk) 16:26, 8 July 2010 (UTC)

  Okay. Thanks.—RJH (talk) 21:39, 12 July 2010 (UTC)

• The TR version seems preferable to me for a couple of reasons. Firstly, it better describes the situation concerning the fine-tuning and AP to my mind; largely by separating them. Secondly, the IP version seems written from a POV that seems to want to play-up fine-tuning. That might be wrong, but the wording and topics covered do not appear NPOV. Thirdly, the IP version contains too much detail for an overview article on certain points (e.g. Fred Hoyle; and this ties to my point on POV). Cheers, --PLUMBAGO 12:34, 7 July 2010 (UTC)

Size and age

The universe age is 14 bln years, and it's size 92 bln (46 bln from the centre each direction) - it means that it had to expand with over 3 times of light speed - not possible acording to Einstein's theory. If the size is 92 bln the age must be more then 46 bln years, and if the age is 14 bln then the size can be no more then 28 bln. 82.1.4.100 (talk) 10:54, 23 August 2010 (UTC)

Please sign your talk page messages with four tildes (~~~~)? Thanks.

You have applied a local calculation to a global situation. The theories of the universe are modeled with general relativity in which the speed of light over long distances is "not constant". In the presence of mass that speed only has that property locally, i.e. over short distances, as expressed in special relativity. DVdm (talk) 11:04, 23 August 2010 (UTC)

The speed of light in a vacuum is a limit on the movement of material objects and radiation within space. It is not a limit on the expansion of space itself.

For example, consider an ant walking on a rubber band. Suppose the ant can not walk faster than one centimeter per second. However someone grabs the rubber band and stretches it by a factor of three (so that one centimeter becomes three centimeters) over a period of one second. The ant started at a certain place (the "center" of the universe) and walked one centimeter in the second. However, after the first half second the ant has moved at least half a centimeter, so in the second half second that half centimeter has stretched to at least 3/4 centimeter while the ant has moved at least another half centimeter. Thus the ant has traveled at least 5/4 centimeter. In other words, he has moved faster than his maximum walking speed because the rubber band is carrying him along as well. JRSpriggs (talk) 14:48, 23 August 2010 (UTC)

To quote the relevant paragraph of observable universe:

The age of the Universe is about 13.7 billion years, but due to the expansion of space we are now observing objects that are now considerably farther away than a static 13.7 billion light-years distance. The diameter of the observable universe is estimated to be about 28 billion parsecs (93 billion light-years), putting the edge of the observable universe at about 46-47 billion light-years away.

I've adjusted the "size" section of this article to better express this. --Christopher Thomas (talk) 19:20, 23 August 2010 (UTC)

This is of course nonsense. Faster than light expansion has been introduced along with dark matter and dark energy to prop up a failing theory. The BBT has passed its sell by date. A universe infinite in time and space makes sense and fits the facts without fiddle factors. And have you heard about the inverse square law? Thats why the night sky is dark and the temperature of all those infinte suns shining down on us is exactly the same as the so called echo of the Big Bang! Its a pity the Pope decided to endorse the Big bang Theory, but then Rome has been wrong many times before. —Preceding unsigned comment added by 89.243.44.208 (talk) 17:52, 16 January 2011 (UTC)

Accompanying Image

I think the image attached to this article is useless here. Its attachment to this article, without explanation or title, implies that this image is an image of "the universe." It is of cosmic microwave background (CMB) radiation, not of the universe (this comment of mine is part of the universe, and is not in that image). It lends no immediate explanatory service to the article and is rather confusing. Would someone like to defend its inclusion, before I remove it? —Preceding unsigned comment added by Wdjunkin (talk • contribs) 17:32, 7 December 2010 (UTC)

CMB radiation represents the boundary of the observable universe (or more properly the visible universe, but we don't yet have the technology to map the neutrino background or gravitational waves from before the time the CMB photons were emitted), and is the largest possible distribution of matter/energy we can map at present. Also, fluctuations in density observable in the CMB radiation are thought to be the seed of later large-scale structure formation, and of course the CMB is the closest we can get to an "image" of the Big Bang which is thought to have birthed our universe. So, I think it's as good a picture as any to represent the "universe" (also note that some cosmology texts use it as a cover image--see here for instance). Hypnosifl (talk) 22:46, 26 December 2010 (UTC)

Age and Size of the Universe

Size, age, contents, structure, and laws

p. 1 The region visible from Earth (the observable universe) is a sphere with a radius of about 46 billion light years

p.4 The most precise estimate of the universe's age is 13.73±0.12 billion years old,

Given that the speed of light is an absolute, hwo can these two statements be reconciled? Starting form a singularity, how can any particle be more than 2 x the age of the Universe (i.e., the distance if they travel away from each other in a more or less straight line?

141.189.205.1 (talk) 15:01, 17 February 2011 (UTC)Tom Campbell

There is a detailed discussion of this in our observable universe article. Basic explanation is that not only are distant objects receding from us, but the space between us and them is also expanding at the same time. Gandalf61 (talk) 15:19, 17 February 2011 (UTC)

In fact distant objects are (on average) not receding from us at all, and it is only the space expanding between us and them that causes them to appear to be receding.TR 16:50, 17 February 2011 (UTC)

Yes, I stand corrected. I should have said that the edge of the observable universe is receding, and at the same time the space between us and it has also expanded, and hence it is more than 13.7 billion light years distant. Gandalf61 (talk) 16:58, 17 February 2011 (UTC)