# Talk:Universe/Archive 3

## Regarding the spoken Version

The spoken version of this article is NOT computer generated, but human read by myself. Marmenta (talk) 04:03, 5 February 2012 (UTC)

## The Universe is NOT everything that exists

Sorry I tried to create an account but couldn't. So I commit to staying with this for however long it takes and will be open on this, I will do the research and the maths and help the project but:

The Universe is not everything that exists and Websters is incorrect in this, that this is obvious to me is a fundamental weakness of wiki. I will help fix this starting now as well.

We are now speaking openly about Multiverses and about gravity being unwrapped beyond the 'observable' Universe. So the 'Universe' is becoming the everyday 'observable universe' meaning 'non observable universe' is something else.

So we are growing into a nomenclature issue. In that the world, used to be the universe, but the universe is not, in everyday usage, now believed to be all that exists.

It seems to me that baryonic matter and associated non baryonic matter that is affected by the observable universe (or the inverse), is what we call now the universe.

So to be partially clear. Before the big bang is not the Universe (am I right), wrapped forces with no interaction in the observable universe are not in the universe. Dark matter interactions with other forces that are unwrapped in dark matter mulitverses but don't exist in any observable fashion in our universe are not in our universe.

So a better definition would be that the universe is all that exists and is observable, but that things that interact with our universe but are not observable (i.e. cannot be quantified in force interactions) are not in our universe, because their interactions are in our exoverse or mutliverse, but if a higgs boson has 80% of its interactions in another universe then it is not fully in our universe. OK and to lighten the tone, this does not include David Letterman. I know this is arcane but I am good (very very very good at maths), but lazy and I do believe that only about 200,00 people of all the people who have ever existed will understand this post. I also believe that the David Letterman element will reduce it to 50,000. However that is the wrong 50,000, how do we fix that there problem Pierse?

I suggest that the Universe is not all that exists, and we bound it in the same way that we bounded Ptolemy's map, as a definition of the extent of existence that was exceeded by our knowledge. Three quarks for Muster Mark. — Preceding unsigned comment added by 83.70.227.155 (talk) 01:02, 9 June 2012 (UTC)

Interesting, but it really doesn't matter. We don't include original research, nor information for which we cannot find a reliable source. You were right to ask here on the Talk page, though--thank you. — UncleBubba T @ C ) 01:41, 9 June 2012 (UTC)
The idea of a "multiverse" is already discussed in this article. --Christopher Thomas (talk) 03:34, 9 June 2012 (UTC)
Do you have a source for all this? Pass a Method talk 11:33, 9 June 2012 (UTC)
The multiverse hypotheses (they are not "theories") have been around for years. In a way, they are like religion--since, to date, they cannot be observed. Even the magazine article Pass a Method cited used words like "may", "possibly" and "potential". Sure, some smart folks might find a way to prove the existence of parallel universes but, to be reported here, it needs to be a fact, covered by reliable, secondary sources.
Also, the mention of "various multiverse theories" should read "various multiverse hypotheses", since multiverse research hasn't yet risen to the level of "theory", or general acceptance, as in Theory of Gravity or Music Theory. — UncleBubba T @ C ) 20:19, 9 June 2012 (UTC)
For better or worse, theory and hypothesis should be used as they are from the sources, if any.—Machine Elf 1735 00:59, 10 June 2012 (UTC)
None of this matters. the WORD universe means 'ALL in ONE' or 'turned into one' where the ONE is a representation ove EVERYTHING so the universe is by definition EVERYTHING. anyone that says that the universe is not everything does not understand the entomology of the word. so here it is :) http://www.etymonline.com/index.php?allowed_in_frame=0&search=universe&searchmode=none Δρ∈rs∈ghiη (talk) 13:15, 27 August 2012 (UTC)
Language changes over time. Your claim about the word "universe" is exactly the same as claiming that there can't be anything smaller than an atom, since atoms are indivisible by definition. That was the original meaning of the word atom, but it no longer is. Now atom means something along the lines of "smallest chemical building block" or somesuch odd definition. The path of the word universe has been the same. From the original "all that is" to the current "that place where we live". — Gopher65talk 13:47, 27 August 2012 (UTC)
Getting back to the original subject of this thread, are we satisfied with the coverage of multiverses in this article? I feel that, with a section already devoted to the hypothesis, the article has quite enough about multiverses, and would probably be even better off without Tegmark's idle computations of the probability of doppelganger universes 1010115 meters away; a pretty trivial addition even in this arcane field. --ChetvornoTALK 14:42, 27 August 2012 (UTC)

## The difficulty of defining universe

First of all I'm not sure of this has ever been discussed and didn't bother looking in the archives first. The reason I added "known existence" is because of the ideas of multiverses and alternate dimensions. In this view, our universe is just one of many and not the totality of all existence. Technically, would these other universes and dimensions not be considered to "exist" or are they simply not part of our existence? However, adding "known" may also discount things we have never directly observed but which we hypothesize may exist within the universe such as dark matter, dark energy, exotic matter, etc. Has any consensus ever been reached on a definition? Cadiomals (talk) 21:10, 21 September 2012 (UTC)

There are as many definitions of "universe" as there are people discussing it. By all means dig through the archives; I'm sure you'll find quite a few fascinating positions. Constant adjustment, adding of caveats, removing of caveats, tweaking, and so forth is why the lede eventually settled back on to a dictionary quote for its first sentence. The second sentence (at the time of my edit) noted other variants of the definition and gave citations for those too; the first definition wasn't presented as the only one, no worries.
Rather than returning to the old days of constant changes, let's cut to the chase and have an RFC about what the lede's first-paragraph text should be, and ping the various relevant wikiprojects to ensure sufficiently broad coverage. I'll even do the legwork for setting it up, if you want. Does this sound like a reasonable approach to the two of you who have been adjusting it so far? --Christopher Thomas (talk) 22:32, 21 September 2012 (UTC)
I tried removing the weasely "commonly defined as" and it was reverted. All articles are about the common definition. The only purpose of those words is to be weasely. Saying "<topic> is commonly defined as <definition>" is just a stupid way of saying "<topic> is <definition>". If there are variations on the definition then list them after the first sentence. Bhny (talk) 22:54, 20 November 2012 (UTC)
As has been repeatedly emphasized above, there are a huge number of different definitions of "universe". If all of them were listed after the first sentence, the intro would be longer than the current article. Using "commonly defined as" is not weaselly, it's used in such situations to limit the lead section to the most notable definition(s), leaving less important ones to be covered in the article. --ChetvornoTALK 01:11, 21 November 2012 (UTC)
"commonly defined as" isn't used in well written articles. Bhny (talk) 03:15, 21 November 2012 (UTC)
And there's nothing wrong with writing an article about a single definition of the topic. There can always be another article "Universe in context of Multiverse" or whatever. If we really need to be inclusive then the definitions have to be in the lead. It can't have absurd waffle like "Definitions and usage vary..."! That tell doesn't help anyone. Bhny (talk) 03:25, 21 November 2012 (UTC)
Since the article has a whole section covering various variations of the definitions of the concept of "universe" and their nuances, and the lede should reflect the content of the article, the "commonly defined as" phrase is completely warranted. It communicates to the reader that this definition is not set in stone and that the article will also cover variations. Note, that since a lot of the variations are rather subtle it is not viable to have separate articles on each variation.
Also, blanket statements like "XXX isn't used in well written articles" are not used in well argued discussions. ;-)
TR 10:15, 21 November 2012 (UTC)

## Τα όρια του σύμπαντος

Τα όρια του σύμπαντος

Αν πάρουμε ως δεδομένο ότι το γνωστό-άγνωστο σύμπαν έχει όρια αυτά τα όρια θα ήταν η απόλυτη τιμή ψύξης -273,15 C στην περίμετρο του,η οποία δεν έχει καταγραφεί πουθενά εώς τώρα στην αστροφυσική. Αυτά τα όρια εάν κατέρρεαν στο χωροχρονικό συνεχές με μιά μορφή εναλλασόμενης ή συνεχές συχνότητα αυξανόμενης ενέργειας τότε μοναχά δεν θα είμασταν εξαρτημένοι στον χωροχρόνο μας επειδή το υλικό-άυλο φώς αντανακλά και συνάμα φθείρει τα τείχη των -273,15 C.

Ουσιαστικά όμως εάν αμβλύνεται το σύμπαν μέσω της ίδιας ενέργειας που το διακατέχει τότε αμβλύνονται και τα όρια ..

Το ερώτημα όμως που μένει αναπάντητο είναι υπάρχουν όρια στα τείχη?

Η φυσική και η αστροφυσική μας αναφέρει πώς υπάρχουν όρια σε ότι περιορίζεται στο χώροχρονο και βάσει αυτού του χωροχρόνικου σύμπαντος δύναται να καταρρεύσουν και τα όρια των τειχών του..

Όμως άραγε πώς θα ήταν η ζωή μας χωρίς την εξάρτηση του χώρου? Βάσει της σύγχρονης φυσικής αυτό θα λεγόταν θάνατος ή κατάργηση των ύλικο-άυλων ενεργειακών σωμάτων. Με μιά άποψη θα έλεγα πώς η ζωή μας θα ήταν άπειρομεγενθυμένη στον άπειρο χώρο μας μέσα στον χρόνο επειδή το σύμπαν ρέει και έρεε για κάθε μορφή ενέργειας ενώ συνάμα δεν έπαψε ούτε και παύει ποτέ να υφίσταται απο την άπειροαρχή της δημιουργίας αυτού.. — Preceding unsigned comment added by 94.64.26.155 (talk) 18:47, 21 October 2012 (UTC)

Your talk about—best I can tell—"The Limits of the Universe" really doesn't belong here. This Talk page is for discussion of the universe ARTICLE, not the universe itself. Also, please remember this is the English Wikipedia; discussions should generally be in English, not Greek.
Thanks! — UncleBubba T @ C ) 19:51, 21 October 2012 (UTC)

## unintentional

My recent edit was an accident. I did not even know I had visited the page--JimWae (talk) 04:38, 15 December 2012 (UTC)

The universe is mysterious Bhny (talk) 17:36, 15 December 2012 (UTC)

## 93 billion light years in diameter - really?

The statement that the Universe "is believed to be at least 93 billion light years in diameter" is not a factual statement about the universe; the statement that the Universe "is at least 93 billion light years in diameter" is not adequately supported by the reference (or anything else); neither statement belongs in the article. Dr5t3v3 (talk) 08:38, 2 January 2013 (UTC)

The reference literally states: "Today diameter of the observable universe is estimated to be 28 billion parsecs (about 93 billion light-years)."TR 12:22, 2 January 2013 (UTC)

Exactly - estimated by who? Is there a citation? The reference is not a research article, or research of any form. It is pure opinion. Dr5t3v3 (talk) 02:42, 14 January 2013 (UTC)

The source is a textbook, which is a perfectly acceptable reliable source. Textbooks rarely give citations for the facts they present. That does not make the facts they present "pure opinion". Given the time frame, the estimate in the book is probably based of the WMAP 5 year data.TR 15:23, 14 January 2013 (UTC)

Within the Big Bang model, how can the diameter of the universe be greater than about 27.5 billion lightyears (i.e., radius = age of universe from centre at speed of light)?? Unless expansion occurred faster than the speed of light???--Jeffro77 (talk) 04:09, 25 February 2013 (UTC)

It did. See Inflation (cosmology). — HHHIPPO 07:34, 25 February 2013 (UTC)
I think you probably mean cosmic expansion rather than inflation - inflation was a specific phase in the very early universe. The key point is that the light or other radiation that we observe from the furthest visible objects (which ultimately means the cosmic microwave background radiation) was emitted 13.7 billion years ago, but during that time the universe has expanded so those objects are now about 46.5 billion light years distant, giving the observable universe a diameter of approximately 93 billion light years. So, yes, the space between us and the most distant objects is expanding at a rate that is numerically greater than the speed of light (although the two quantities are not really comparable). Gandalf61 (talk) 11:57, 25 February 2013 (UTC)
Thanks. I also had a read of Faster-than-light#Universal expansion earlier.--Jeffro77 (talk) 12:05, 25 February 2013 (UTC)

## Interesting point to add...

I'm not able to come up with a way of phrasing this that would seem to fit into this article, but I have found an interesting point that may be worth mentioning:

http://news.yahoo.com/higgs-boson-particle-may-spell-doom-universe-152236961.html

The point of the article is that new research on the Higgs Boson seems to suggest that the Universe may eventually collaps in on itself, or ultimately be destroyed billions of years in the future. Again, I think this may be worth noting. Additionaly sources will be needed. -Poodle of Doom (talk) 19:15, 19 February 2013 (UTC)

It's not that it will collapse in on itself in the classical sense, it's that a nucleation point could form, inside which the universe would to jump to a lower, more stable energy level. The nucleation point would expand outward at the speed of light, so a single "tear" wouldn't be enough to "destroy" the universe as we know it. — Gopher65talk 00:27, 20 February 2013 (UTC)
Still, wouldn't this be something relevant to add to the article? At that, you can see that my understanding of this isn't necessarily enough to add the point to the article. -Poodle of Doom (talk) 03:14, 20 February 2013 (UTC)
I'm no expert in theoretical physics, but is this related to False vacuum#Vacuum metastability event? And since this page already links to Ultimate fate of the universe anyway, maybe this point should be mentioned in either one instead of here. Reatlas (talk) 07:41, 20 February 2013 (UTC)
Yeah. My understanding of this work is that if we're in a false vacuum (probably are), a nucleation event is more likely than previously thought. — Gopher65talk 22:51, 20 February 2013 (UTC)
Yeah, the placemeant of the newly found info in the above mentioned articles would be better. However, I think it should be lightly alluded to here. -Poodle of Doom (talk) 05:02, 22 February 2013 (UTC)

## Unsolved problems

The sentence "Physicists remain unsure about what preceded the Big Bang model and also the ultimate fate of the Universe" in the lede has multiple issues:

• What preceded the Big Bang model is not the question here, it's what preceded the Big Bang.
• It remains unclear if the second part (and also...) refers to what preceded or to unsure about.
• Physicists is unclear: some of them? all of them? How about non-physicists, are they sure?
• The question is actually a bit broader: it's not only what preceded the Big Bang, but first of all if preceding is a well-defined concept at all at that point.

The previous version, "What preceded the gravitational singularity before the Big Bang and the ultimate fate of the Universe remains an unsolved and speculative problem in physics", was in some respects better, but also had its issues:

• Talking about a gravitational singularity before the Big Bang is a bit questionable.
• Problems are not speculative, answers are.
• It would be nice to link to List of unsolved problems in physics, but that page doesn't mention the preceding the Big Bang part.

Here's a suggestion for another rephrasing: "What, if anything, preceded the Big Bang, and what will be the ultimate fate of the universe remain unsolved problems in physics." Any thoughts? — HHHIPPO 17:51, 14 May 2013 (UTC)

I disagree.
• If we remove "model" we are not being specific enough
• "Physicists" as worded gives a general perspective
• Gravitational singularity is unproven
• We should speak about physicists not physics. Pass a Method talk 19:18, 14 May 2013 (UTC)
The sentence is poorly constructed at best, misleading at worst. It needs to be reworded. 04:11, 15 May 2013 (UTC) — Preceding unsigned comment added by Gopher65 (talkcontribs)
1. Why is it unspecific? What else could it be confused with? Using the phrase "big bang model" is like prefixing every use of gravity and evolution with "the theory of".
2. Physics is an academic discipline, which physicists study. How exactly is "physicists" more general than "physics"?
3. Has been removed.
4. This is the same as number two. Reatlas (talk) 14:53, 15 May 2013 (UTC)

I broke it into 2 sentences. I think it reads much better. I removed "model" as this is logically wrong. What preceded the "Big Bang Model" was another model (Solid State?). Bhny (talk) 15:22, 15 May 2013 (UTC)

I can live with the new version, but still think physics would be better than physicists: it's not only physicists who wander about this question and are unsure what's the answer, it's also laypeople. So the statement is at least incomplete. If one interprets physicists as meaning all physicists, then it's also wrong: there are physicists who also are creationists and they feel pretty sure they know the answer. Of course one could also interpret it as some physicists, that's the 3rd problem: ambiguity. Unsolved problem in physics avoids all that. There's a reason we have an article List of unsolved problems in physics, but not List of things physicists are unsure about.
P.S.: Bhny, I guess you mean steady state, not solid state ;-) — HHHIPPO 18:38, 15 May 2013 (UTC)
haha yes Bhny (talk) 20:18, 15 May 2013 (UTC)

## Semantics: the "Universe" vs. a "universe"

This isn't a big deal, but I think it would be a good idea just to throw in a line about how the Universe is a proper noun that is capitalized if one refers to the universe in which we live. This contrasts with a "universe" which is a hypothetical or model cosmological object, such as the theory of there being more than one universe. PirtleShell (talk) 22:07, 15 May 2013 (UTC)

## Just a small mistake

It's actually, nothing, and I'm really sorry, I must come off as a miss "know-it-all", but I just want to tell you that, you've made a mistake with the translations. To be precise, in the "etymology, synonyms and definitions" section, in the third paragraph, where you say "Related terms were matter, (τὸ ὅλον, tò ólon, see also Hyle, lit. wood) and place (τὸ κενόν, tò kenón)." you are a little bit wrong. "τό κενόν" in greek, actually means "the vacuum" and it was used to describe... well, non other but the vacuum of space. What you're looking for is "χώρος" which is the exact translation of "place" (in physics)
Again, sorry to bother you :) — Preceding unsigned comment added by 109.242.93.193 (talk) 19:00, 26 May 2013 (UTC)

## "universe" common usage means EVERYTHING, so no "multi-verses"

i think whoever talks about multiple universes is violating the spirit of the word, since it is designed to indicate everything. those other aspects would merely be a subset of the universe, and referring to them as 'other universes' is a horrible description. — Preceding unsigned comment added by 108.184.252.247 (talk) 22:20, 4 June 2013 (UTC)

I kind of agree but unfortunately our opinions don't matter and we just have to go with our sources Bhny (talk) 22:48, 4 June 2013 (UTC)
Yes, like it or not, the word "universe" may be losing its connotation of "everything" and becoming associated with "our" contiguous section of spacetime, governed by our physical laws and the Big Bang theory. If other "universes" are a serious possibility, we need a word to distinguish them from our "universe", hence "multiverse". This is not an unusual situation in science, when names lose their original meaning. Before modern astronomy, didn't the term "Earth" or "World" originally mean "everything", just like "universe"? Now it just means our planet, one among many. --ChetvornoTALK 09:32, 26 June 2013 (UTC)

## "the observable universe, is about 93 billion light years in diameter"

Are you all sure about that? The universe is just 14.3 billion years old so I believe there is a typing or magnitude error in this article. As for the uni-verse vs. multiverse I've made a note with the term multiverse and I believe there's a mistake in vocabulary of some kind. — Preceding unsigned comment added by 84.198.212.162 (talk) 19:32, 27 July 2013 (UTC)

Due to general relativity, space can expand faster than the speed of light. The light from the farthest objects we can see left the objects within the age of the universe, 14.3 billion years ago, yet due to expansion the objects are now much farther apart than 14.3 billion light years. See Universe#History of the Universe and Observable universe. --ChetvornoTALK 20:13, 27 July 2013 (UTC)
The observable universe is approximately 93 billion light years/28 billion parsecs in diameter. That puts the visible distance from the observer to the most distant point at 46-47 billion light years away. From observable universe, "According to calculations, the comoving distance (current proper distance) to particles from the CMBR, which represent the radius of the visible universe, is about 14.0 billion parsecs (about 45.7 billion light years), while the comoving distance to the edge of the observable universe is about 14.3 billion parsecs (about 46.6 billion light years),[1] about 2% larger."
As for multiverse and universe, a multiverse holds multiple universes, according to some theories. Our universal laws of physics may not apply to that which exists outside of our universe.Wzrd1 (talk) 20:27, 27 July 2013 (UTC)

## Edit Request.

Done

I made a simple fix as per your ideas. Do you additional specific edit requests? Bhny (talk) 20:15, 31 July 2013 (UTC)
As the IP editor pointed out, the original sentence was jibberish. But the new sentence wasn't really any better, mostly because it's probably not possible to explain what "observable universe" means in a single short sentence. I simplified the sentence so that it is now technically correct. The term observable universe is better expanded upon in the appropriate section (and further expanded beyond that in its sub-article) rather than us attempting to squish an entire textbook's worth of explanatory material into the introduction. — Gopher65talk 23:57, 31 July 2013 (UTC)
looks good, I'll mark this as done Bhny (talk) 03:50, 1 August 2013 (UTC)
Tweaked this a bit. There is parallax, unapparent without precision instrumentation which ancients lacked. Student7 (talk) 22:20, 4 August 2013 (UTC)

## Capitalisation

We need to establish a consensus whether "the [u|U]niverse", when it refers to our universe, is to be capitalised or not, and add an edit comment or perhaps even better a note visible to all explaining the established convention (house style) at Wikipedia. Considering that a lot of article titles such as Age of the universe use the lower-case convention, I propose we go with this one unless there are serious objections to this. I'm not attached to any specific solution, I just desire consistency and a consensus to help avoiding constant back-and-forth. --Florian Blaschke (talk) 18:56, 19 August 2013 (UTC)

I don't care one way or the other either, but I've always been told - including in astronomy classes - that it was Universe (ours) and universe (general use). But conventions change over time, so who knows what the current convention is. — Gopher65talk 00:44, 20 August 2013 (UTC)
I'm not sure either. In a similar context, try My country (Country?), right or wrong.... Same sort of thing IMO. There has to be a rule already existing for this sort of thing. Student7 (talk) 14:15, 26 August 2013 (UTC)

## Capitalization redux

The results of the recent move requests at Talk:Age of the universe, Talk:Shape of the universe, and Talk:God becomes the universe lead me to resurrect the proposal above that the word universe be lowercased in the body of this article. Note that it was brought up in those discussions that the Style Guide for NASA History Authors and Editors specifies that universe should be lowercase and that the word is also lowercase in the American Astronomical Society's list of keywords. Deor (talk) 13:05, 21 October 2013 (UTC)

I still say it depends on the context. Not only whether you're talking about "the Universe" or "a universe", but whether or not you're specifically referring to our universe using its implied name (the Universe). I liken it to how you can refer to your father as "my dad", but still call out to him "hey Dad!" Whether or not the word is capitalized is contextual; it needs to be looked at on a sentence by sentence level. — Gopher65talk 15:08, 21 October 2013 (UTC)
Yeah - I'm with Gopher on this, but simply because that's the way they taught me to deal with proper nouns that can also be generic many years ago at grammar school. But if the guys who devote masses of time to this kind of thing have debated it, and NASA, god bless 'em, agree, then who am I to stand in the way of change? Seriously, we should do whatever the convention is, even if old dinosaurs like me find it a little jarring. Whatever we do we should do it consistently, though... 15:46, 21 October 2013 (UTC)

## The human fish

“Just as a fish may be barely aware of the medium in which it lives and swims, so the microstructureofempty space could be far too complex for unaided human brains”. - Lord Rees — Preceding unsigned comment added by 178.197.229.5 (talk) 01:06, 17 January 2014 (UTC)

## The Universe includes You

Deciding about mentioning of the self as part of the Universe (defined as totality of existence). There is bias on the matter, as many think that the Universe is just about the astronomical model.

### Discussion

This page about the Universe is currently missing an essential part. I added it and it got removed.

The Universe [...], including yourself

If anyone feels that his presence in the Universe is not real, or not relevant to the topic, let's talk about it. This page is about the Universe at Whole, as totality of existence, and not just about some limited models (theories/descriptions) of it.

The exclusion of the Self from the Universe is a common flaw of perception/interpretation that I feel we should signal explicitly. The interplay between the subjective Self and the objective Universe is the key to a more profound understanding. Relativity once accepted, makes all other theories dependent on their purpose (including astronomy).

In a broader sense, in its current form, this article gives the wrong impression that the Universe is ambiguously out there somewhere, in the galaxies that only astronomers see, or in the Physics lab where bosons are experimented or in some mathematicians mind where complex equations make sense.

Extremind (talk) 09:19, 27 September 2013 (UTC)

This article is about the astronomical concept of universe, it's scope does not include psychological, religious, or New Age definitions. --ChetvornoTALK 10:22, 27 September 2013 (UTC)
Totally agree with comments from Chetvorno above. Regards to all, David J Johnson (talk) 16:44, 2 October 2013 (UTC)
Well yes, if we're doing that "agree" thing, I agree too. Including yourself, huh? How about including my cat, or my pocket fluff?

This is not a place to correct your personal "feeling" that "The interplay between the subjective Self and the objective Universe is the key to a more profound understanding." I'm not sure where that place would be, but I doubt that it's anywhere on an encyclopedia. 16:56, 2 October 2013 (UTC)

What would you rather say the purpose of an encyclopedia is, other than expanding the reader's consciousness? If your cat is equally important to that goal as a totally generic (and totally specific in the meanwhile) yourself, take your chance and make your plead to include it as well. Although you should at least prove that your cat (or your fluff) actually exists, first. I am not sure if you place thinking above feeling or if you are that special kind of man who speaks unbiased of all things as they really are, but your polemic tentative on this matter shows quite a personal perspective, I would say. Extremind (talk) 19:41, 3 October 2013 (UTC)
The introductory phrase suggests that this article is rather about the ontological concept of Universe. Surely you are not suggesting that astronomy monopolizes the whole concept for itself, are you? Astronomy (as it is clearly mentioned as just just one of the models) did not invent the concept and neither does it exhaustively cover it. There are infinite aspects of the Universe that lie between the scales of macrocosm and microcosm, wouldn't you say? Extremind (talk) 19:41, 3 October 2013 (UTC)

I suggest we'd first agree on a definite set of criteria for evaluating this matter. How about truthfulness and relevance, for example? Does anyone know that his presence in the Universe is not real, or not relevant? Dare I emphasize that the very presence of the reader themselves is the basic premise of an encyclopedia? Extremind (talk) 19:41, 3 October 2013 (UTC)
WP:NOR Bhny (talk) 20:36, 3 October 2013 (UTC)
If you really want to play this game, I'll play: no, a reader's presence in the universe is not relevant to the existence of a Wikipedia article on the nature of said universe. Whether or not the alleged "you" who is reading the article existed, the universe would be, for the most part, basically the same. "Yourself" references a single individual (the person reading the words at any given moment). That one individual is not of significant importance to the concept of "universe", and certainly not any more significant than any other person. For example, would you accept the sentence, "The Universe [...], including yourself and Miley Cyrus." I would argue that neither "my" (the implied reader) nor "Miley Cyrus" are important enough for mention here. In policy terms, this falls under WP:UNDUE--mention of any single specific person, even by pronoun reference, is not due for this topic. Otherwise, theoretically, we'd go into every single article of this type and add something similar. For example, Earth includes the line "The planet is home to millions of species of life, including humans". Would you change that to say, "The planet is home to millions of species of life, including humans, one of which is you. And Miley Cyrus." I should hope not. The problem isn't original research, it's about deciding exactly what level of detail belongs in this article, and, sadly, "you" aren't (ain't? isn't?) at the level. Qwyrxian (talk) 07:54, 4 October 2013 (UTC)
I am not playing any game here. I am trying to improve this article by making it more precise. Rhetoric is definitely not my thing. It fails to be constructive. I am not exactly sure what your point is. Your suite of analogies has some degree of inadequacy that I wish to mention, so that we stick to the fair side of any play and avoid any inappropriate inferences.
• The reader's presence is the only raison d'etre of any Wikipedia article, even to Wikipedia in general, I would say. Do you know any other?
• Yourself is not just a pronoun, as you tend to suggest by your reductive analogy with an alleged Miley Cyrus. Yourself is not just one individual, as you may also reductively suggest, and not even just a class of individuals, but it stands for quite an indefinite set of classes (humans, observers, wikipedians, scientists, extraterrestrials - just to name a few of the postures that your self might identify with). It references the concept of self and it implicitly involves the actual presence of the reader/observer/you. It is strange how some people place more emphasis on the existence of a word in a wiki page than on their own existence in the world. We may ask the Universe if you are significant to it at all, I am sure we can think of ways.
• Adding a word to this article is not a beginning of an avalanche to adding anything more to anywhere else. In your mind, maybe you are setting a precedent, but it is not the case. I would not change the page about the Earth, because I see no point, but your exaggeration is no argument for not improving a page of the Universe, where I see perfectly fit.
• This article is not about the most part or the basic part of the Universe at all. It is about the totality of it. Yes, the totality may be hard to grasp. But the totality of existence (as it is) leaves absolutely no doubt to any alleged me/you. It seems to me that you are not making a difference between what is (existence) and what you think (the alleged possibility that I, a reader might not be, for instance).Extremind (talk) 12:04, 8 October 2013 (UTC)
My view is that this article is primarily about the astronomical definition of the Universe. With the latest discussion we are getting into "new age" and individual (personal) aspects of the subject. I'm afraid that to go into this scenario is giving WP:UNDUE to a fringe theory. I suggest that the article should remain broadly as it is. Regards to all, David J Johnson (talk) 19:25, 4 October 2013 (UTC)
David, your point of view is already stated (and enforced by your action also), there is no need to repeat it.
• You might be confusing the totality of existence with the astronomical descriptions of the outer space. If it were not the case, this article would have a _astronomy suffix in the address bar, but it doesn't. Astronomy is just a model of the Universe and is correctly listed as such.
• Moreover, you may misplace your concerns from this talk page on the change that I have proposed. "The article should remain broadly as it is". Definitely. Let's not forget that we are not discussing a radical change, like you may want to suggest. We are talking here about adding one single word: yourself
• I am not sure why you bring up this New Age theory that I know nothing about, except if you want to make yourself a defender of a supposedly Obsolete theory. I care less for theory than for significance. There is nothing new agey about my/human presence in the Universe. And there is nothing questionable about it. My presence is a consequence of uncountable factors that have lead to my manifestation as it is.
As far as I’m concerned, there's still no reason to exclude yourself from this article, except some personal bias on the matter. Extremind (talk) 12:04, 8 October 2013 (UTC)
I was wondering whether there might not be some definition in philosophy or mathematics that has a definition that includes the observer that might go into Universe (disambiguation). To my surprise, I stumbled across this: Quantum_mind–body_problem#Decoherence_and_modern_interpretations. Your thoughts? Student7 (talk) 17:33, 7 October 2013 (UTC)
Nice catch. I would gladly agree with the alternative that this existing article be suffixed with _astronomy or _cosmology and a clean article of the Universe be abstracted further to treat the Universe as totality of existence in more nuanced aspects, linking down to all other theories. Extremind (talk) 12:04, 8 October 2013 (UTC)
I'm agreeing with David Johnson and Chetvorno and others. From personal observation, I am so cool that I am out of this world, so the universe does not yet include me (it tries), so I think sticking with the astronomical view is preferred.--Tomwsulcer (talk) 12:18, 8 October 2013 (UTC)
After you carefully observe the definition of Universe (as totality of existence) as well as some basics on logic, you might adjust your conclusion to either 1: you exist and are part of it; or 2: you don't exist, and neither your absurd point of view exists, case which I will kindly ask you to let the forces of Universe do what they need to do here, okay? And this is valid for all of you unexisting people. Get a sense of existence first and only then write about it. 79.119.101.176 (talk) 09:50, 21 October 2013 (UTC)
Extremind, you need to stop pushing your nonsensical unsourced addition against consensus. Be satisfied. The article defines the universe as the "totality of existence"; that obviously includes each of us. --ChetvornoTALK 16:31, 21 October 2013 (UTC)
According to WP:Consensus, I am the consensus here, even though you are many. In determining consensus, consider the quality of the arguments, the history of how they came about, the objections of those who disagree, and existing documentation in the project namespace. The quality of an argument is more important than whether it represents a minority or a majority view. The arguments "I just don't like it" and "I just like it" usually carry no weight whatsoever. Many pretexts, games, jokes and rhetoric have been invoked against reasoning, but no valid argument so far. This is just not about me or you or Miley Cyrus. Please cast your misunderstanding somewhere else. Wikipedia is just too important to shelter ignorance. Extremind (talk) 09:55, 23 October 2013 (UTC)
One person alone cannot simply say "I have consensus, all of the other people commenting are wrong." We have put forward many many valid arguments. The fact that you do not accept them does not mean that you get to declare that you are correct. The simple fact is that the person reading the encyclopedia is of no greater importance than any other thing in existence...arguably of quite less importance.
The only way I could possibly imagine you swaying the current very strong consensus would be for you to introduce a substantial number of reliable sources that defined the universe in the same way you wish to define it. Do you have any such sources? Remember, that's really our goal--to reflect what sources say, not what our own philosophies/opinions say. Qwyrxian (talk) 11:25, 23 October 2013 (UTC)
You might mistake the pretexts to cover up a bias for valid reasoning, but that's fine, I guess, for someone who does not practice relativity. You might also confuse importance with something else (like probably... scale?). When you realize what importance is and who gives the importance (the subject, maybe?), look up for yourself the sources that you need. For the moment, I am more efficient in other activities than to force my way through Wikicracy. There is a time for everything. Extremind (talk) 07:32, 28 October 2013 (UTC)
• this is an encyclopedia article, not a philosophical commentary. "including you" is in contradiction to WP:TONE, WP:VALID, WP:OR, WP:NOT and pretty much every other policy and guideline and has no place in this article. -- TRPoD aka The Red Pen of Doom 11:10, 23 October 2013 (UTC)

§ Thank you all very much for your input. It is sad for me to accept the current misrepresentation of the Universe on Wikipedia, but it's been a pleasure knowing your viewpoints. Extremind (talk) 07:32, 28 October 2013 (UTC)

The Universe won't bother, either. Maybe that's what you were searching for, explaining the difference between our subjective minds and the real world outside of our minds: http://philoctetes.free.fr/parmenidesunicode.htm --178.197.229.5 (talk) 01:17, 17 January 2014 (UTC) Forgot to mention: The 6 senses being the interface between our inside world and the outside world: sound, sight, touch, smell, taste and balance. Senses do make sense, right? --178.197.229.5 (talk) 01:27, 17 January 2014 (UTC)

## Universe

I would like to add some information in the "Universe" section. In 1875 Swami Dayanand Saraswati wrote a book called "Satyarth Prakash" it means Light of Truth. The chapter 8 is " Creation Sustenance and Dissolution of Universe" Please read the book which is also in Wikipedia and can be found using Google. JRBhagat (talk) 18:57, 3 February 2014 (UTC)

## Long or Short Scale?

Quote: "The observable universe is about 46 billion light years in radius" Is this in short scale or long scale? Long_and_short_scales --Taltamir (talk) 17:02, 6 February 2014 (UTC)

Short scale. This should not cause problems for anyone from the English speaking world. Asians may have problems. In other words, "billion" is one thousand million and therefore standard in this encyclopedia. Student7 (talk) 21:23, 7 February 2014 (UTC)

## Semi-protected edit request on 21 February 2014

Marlon Eros/Jesus/Yahweh=Owner of the Universe>

Aeros1971 (talk) 20:58, 21 February 2014 (UTC)

Declined. Not a useful request. Mindmatrix 21:03, 21 February 2014 (UTC)

## The age and size of the universe

How is it possible to detect stars from 100 billion light years away if the Universe is only 13 billion years old? How can anything out there in the Universe be beyond where light traveling since the Big Bang has yet to reach? Is it possible for two objects to be become separated in space by more than the distance light could have traveled? 71.212.228.6 (talk) 20:50, 6 February 2014 (UTC)

I suggest you look to the definition of the observable universe article. But let me explain it further.
It's true that we can only see objects 13.8 billion light years away at the present because of the finite speed of light. But it's a common misconception that "observable universe" means what part of the universe we can see at the present when its true meaning is what part we can see at some point of the infinite future.
I know its confusing that the observable universe is somewhere 46 to 47 billion light years in radius. But it is actually a mark. Metric expansion of space redshifts photons of light to lower energies. The mark, 46-47 billion light years, is actually the point where a photon beyond it gets so redshifted that it will no longer be detectable here on Earth. For example, a supernova happened 36 billion light years away. We are not able to see it today, given the age of the universe, the signal is still 23 billion light years away. But again, observable universe does not deal with the present, it is given to the point of infinite future. Because the supernova is inside the mark, in the future, we are able to detect it, because the photon is not yet so redshifted to the point of undetectability.
But consider a supernova happens 53 billion light years away. That is beyond the mark. You may think we can see it after 53 billion years. Well, no. Even if we wait for 54 billion years, 106 billion years, 1 trillion years, a googol (10100) years, and even a millinillion (103003) years, we will never be able to detect the supernova. Why? It's because it's outside the mark! Anything beyond the mark will never be able to be detected even to the point of infinite future.
You may be confused, how can objects expand superluminally (faster-than-light) without breaking the laws of physics? Einstein's general relativity says nothing can be faster than light. Well, people misunderstood the definition.
It does not say "anything". It says "anything that curves spacetime" can never be faster than light. Matter has weight and curves spacetime, so we will never go beyond c (the speed of light). But spacetime is different, it has no weight and does not curve itself. So it can expand beyond c. It only carries matter away with it, so we can see galaxies travelling away from us faster than c.==Johndric Valdez (talk) 22:16, 1 March 2014 (UTC)==
The light's been travelling for 13 thousand million years but the Universe has been expanding in the meantime so the point from which the light came is now more than 13 gigalight-years away. Jimp 10:04, 13 March 2014 (UTC)

## Finite Vs Infinite

To imply the universe is infinite, means the Universe or everything that we are referring to is in fact not Everything and thus we are allowing ourselves to be contradictory rather than "non contradictory" aka "Finite".

The laws of physics work because they are based upon finite non contradictory quanta. Thus the Universe can only ever be Finite, no matter how much of it we will never know about it.

Yes the universe presents infinitely, but that's only possible by way of some unknown division aka assumed "Infinite" division. — Preceding unsigned comment added by 120.148.16.19 (talk) 22:20, 27 January 2014 (UTC)

Do you have a citation to support this? There are other citations which refute it and state the (this) universe is geographically infinite. Both positions should be in article. Student7 (talk) 19:05, 1 February 2014 (UTC)
I don't know what you're on about. The Universe may be finite or it may be infinite in terms of space. Space is curved. The curvature may be such that the Universe is curved in on itself (like the surface of a sphere) in which case it is finite in size. Otherwise it's infinite. Matter and energy may be quantised but there may be a finite or infinite number of these quanta. Jimp 10:11, 13 March 2014 (UTC)

## An infinite universe?

“The size of the Universe is unknown; it may be infinite.””

“…the Big Bang model suggests that at some moment all matter in the universe was contained in a single point, which is considered the beginning of the universe.”

If it is infinite, then it always must have been infinite so going back in time would not result in a point-like beginning? Antonquery (talk) 01:44, 20 May 2014 (UTC)

Zero times infinity can be zero. This exactly what happens if you evolve the universe back in time according to general relativity. Please also note that wikipedia talk pages are not the place to ask questions. They are here to discuss improvements to articles.TR 12:47, 20 May 2014 (UTC)
Well, if the creation of an infinite universe (and ditto matter and energy content) cannot be completed within a finite time, then the big bang should still be going on as we speak. If, on the other hand, its dimensions and hence its matter/energy content is finite, but there is nothing outside of it to whom or what its exact size, its matter and energy content can matter –its density, the value of k– then its magnitude also cannot matter as seen from within, and hence not affect the fate of the universe. Antonquery (talk) 08:22, 22 May 2014 (UTC)
Antonquery was not asking a general question, he was bringing up an apparent contradiction between two statements in the article, which is within the scope of this page. As I understand it, the two statements are not contradictory, but the paradoxical reason is buried in the Solving Einstein's field equations section and perhaps should be addressed more prominently in the article. If the curvature of the universe is zero or negative (k = 0 or -1), at any time after the Big Bang the universe has infinite size; given any number of kilometers d you can find two points in the universe which are separated by a greater (spacelike) distance than that. As time t goes on, the (spacelike) distance between any two points in the universe is constantly expanding. Conversely as you look back further in time, the distance between any two points gets less. What happens at the Big Bang itself is undefined, but as the time approaches the Big Bang, the distance between any two points or objects approaches zero. The universe is infinite but all distances approach zero. This indicates a breakdown of the concept of distance at the instant of the Big Bang, a singularity in the metric.
The article does attempt to address this by saying: "A common misconception is that the Big Bang model predicts that matter and energy exploded from a single point in space and time; that is false. Rather, space itself was created in the Big Bang...." But perhaps it should be explained better. --ChetvornoTALK 22:49, 20 May 2014 (UTC)
Given his posting history, it is more like he was just asking a question. (This is not the first time I have answered one of his questions.) Nonetheless, you are right that somebody asking a question might indicate something is unclear about the article.TR 10:36, 21 May 2014 (UTC)
Yeah, I guess if a reader wants a more detailed explanation he can also refer to other articles, such as the Metric expansion of space article. --ChetvornoTALK 17:50, 21 May 2014 (UTC)
My problem is that if the universe creates itself out of nothing, then everything inside of it, including space and time, should add to nothing, cancel –which is not unlike how the sum of all debts and credits on Earth is always zero. In that case the universe isn't just unobservable from the outside (which is the same as saying that mass, energy, space and time aren't defined outside of it): it then is that extraordinary, paradoxical 'thing' which has no external physical reality but only exists as seen from within. While its unobservability wouldn’t matter if particles have been provided with properties shortly into the bang so their properties are privately owned quantities, only the cause of interactions, if in a self-creating universe particles must create themselves, each other, then particles, particle properties must be as much the cause as the effect of their interactions. In that case it is no longer legitimate to consider the universe as an ordinary object which has particular properties and evolves as a whole, in time. If it cannot have particular properties as a whole as ‘seen’ from the outside, then it also cannot not have particular properties and be in any particular state as a whole as seen from within.Put differently, if the universe, among many kinds of particles, would contain only a single electrically charged particle, then it wouldn’t be able to express its charge –in which case it cannot be charged itself. A property, any property then must be something which lives within particle interactions. So if we speak about the properties of an object, we implicitly assert that there is an environment in which they can be expressed in interactions. In speaking about the properties of the universe, we in fact state that it owes its properties to something outside of it: that it has been created by some outside intervention -so the Big Bang hypothesis is a naïve, essentially religious tale, never mind the observational ‘evidence. Antonquery (talk) 02:58, 22 May 2014 (UTC)
As TR said, this is not the place to discuss general questions about the universe. Guess you were right, TR. --ChetvornoTALK 05:11, 22 May 2014 (UTC)
Does it matter much where it is discussed if the answer affects the text page: whether the statement “The size of the Universe is unknown; it may be infinite” should be changed or not? Antonquery (talk) 08:22, 22 May 2014 (UTC)

## "commonly defined" weasel words

I've tried unsuccessfully before to remove the weasel words "commonly defined" from the first sentence. I think our current definition is good but far from a common one, and it is now a lie to say "commonly defined". Also it is weasely and against WP:REFERS. The standard structure of the first sentence of a good article is usually <topic> is <definition>. If there are two or more definitions then we should just list them or find a simple definition that covers them all. As it is now we are just inferring that there are other better, less common, definitions that we won't tell you about. Bhny (talk) 04:19, 31 May 2014 (UTC)

## Totality of existence

There is a difference between universe as totality of existence and other terms mentioned (cosmos, world, nature, ...), and it could be that this difference is enormous considering various philosophical, religious and even pyhsical (multiverse) theories about existence. — Preceding unsigned comment added by 93.103.74.8 (talk) 17:21, 22 December 2013 (UTC)

For this article, Physics/Astronomy/Quantum Physics "own" the article name plus the article multiverse. Other definitions may be construed but would need to be qualified. Universe (religion) or Universe (philosophy), that sort of thing. There is no ambiguity here, nor room for further disciplines. Student7 (talk) 18:50, 26 December 2013 (UTC)
If so, then the first 'phylosophical' statement in the article doesn't belong here. — Preceding unsigned comment added by 93.103.74.8 (talk) 20:44, 1 January 2014 (UTC)

The first sentence of this article presupposes naturalism, making it a philosophical statement. This is why I find it difficult to take Wikipedia seriously at times. It's obvious that the sentence was construed this way to push an agenda. Science is a methodology by which we can observe, study, and predict physical phenomena (e.g. planets, stars, etc.). Therefore, one would have to presume there is nothing but physical reality in order to state that the universe (a physical manifold) is the totality of all existence. 24.128.244.108 (talk) 03:13, 10 March 2014 (UTC)

Then your problem is not with Wikipedia but with encyclopedias in general, because virtually all encyclopedias define it that way.
If your claim is true, then I suppose I would take issue with those other encyclopedias as well. They would be just as misleading and biased with their definition of universe. Is your claim true though? Even if it were, that's not a good argument to continue the ignorance. Is it? In any case, I noticed you didn't touch upon the main point I was driving at with my comments. That being said, according to http://www.britannica.com/EBchecked/topic/139365/universe the universe is "the whole cosmic system of matter and energy of which Earth, and therefore the human race, is a part." A much better first sentence for the definition of universe, I must say. Notice how the definition doesn't presuppose naturalism in the opening sentence. 24.128.244.108 (talk) 04:42, 10 March 2014 (UTC)

This is exactly what I came here to post. I think that adding the qualifier "The Universe is commonly defined as the totality of physical existence" would solve most of these philosophical problems with that opening sentence. Wikipedia is a document of the human experience of life, and I think it's inappropriate to completely ignore the metaphysical/spiritual realm of existence that an overwhelming majority of human beings believe in -- whether you may agree or disagree. Pinkpills (talk) 08:33, 29 May 2014 (UTC)

Inserting religious dogma in this article is no more appropriate than going around and inserting, "but science says this is stupid" in every article on religious topics. — Gopher65talk 13:42, 29 May 2014 (UTC)
Totally agree with Gopher65's comments above. This article is no place for religious dogma. David J Johnson (talk) 13:59, 29 May 2014 (UTC)
You two are the first that have brought up religion. As far as I can see the change made had nothing to do with religion, but more with logic and philosophy. To highlight the problem with the old first sentence consider the following: Mathematics exists. But is mathematics part of the universe as commonly defined? Probably not. Adding the word "physical" to the first sentence nicely clarifies in what sense the word "exist" is used.TR 16:44, 29 May 2014 (UTC)
Then may I respectfully suggest that you re-read Pinkpill's comments above, which is furthering the religious theme - as is the rest of their contributions to Wikipedia. David J Johnson (talk) 16:59, 29 May 2014 (UTC)
My I respectfully ask that you actually respond to arguments? Whatever his motivation, his change was an improvement for the reason I mentioned above.TR 20:14, 29 May 2014 (UTC)
I have responded to the "arguments", you are the only editor who thinks that Pinkpills changes are an improvement. Further you have no reason to engage in a personal attack in your comments when you make an edit. You need to abide by Wikipedia conventions in future. Unlike yourself, I have no intention of entering a edit war with you. I'm happy to wait for other editors response to the matter. As far as I'm concerned - case closed. David J Johnson (talk) 20:43, 29 May 2014 (UTC)
I agree with Gopher65 and David J Johnson; the qualification "physical" is not needed. --ChetvornoTALK 20:58, 29 May 2014 (UTC)
Although not strictly necessary, it does help to provide context for the definition. As I noted above, the current first sentence can be construed to include abstractions (like mathematics) that would not normally be considered "part of the universe". In this sense having the qualification "physical" is somewhat helpful. I have yet to see anybody here provide an argument why have that qualification would detract from the article.TR 21:14, 29 May 2014 (UTC)
I recently read a bit about this, and, fascinatingly, it isn't known whether math exists as a construct within our universe, or if it exists independently of our universe in a greater multi/metaverse, or if it exists independently of any universe, as a kind of sea of probability. It's an interesting subject:). But because it isn't known (or even "leaned" either way, as far as I can tell), we can't really make a claim like that in the opening sentence. — Gopher65talk 00:42, 30 May 2014 (UTC)
It's not a claim about physicalism, MUH, etc., it helps distinguish the topic of this article from Universe of discourse, for example.—Machine Elf 1735 02:50, 30 May 2014 (UTC)

──────────────────────────────────────────────────────────────────────────────────────────────────── The first sentence is extremely bad but adding "physical" to it makes it worse. Where is the reference for this? Bhny (talk) 04:08, 30 May 2014 (UTC)

Why ask for a reference for something supposedly "redundant"? It's not btw, but what people seem troubled about is that it's too specific in the sense given at the "physical universe" article: that it would exclude the supernatural. However, that seems ok to me because this article doesn't actually cover the supernatural, fictional universes, mathematical universe (mathematics), etc.—Machine Elf 1735 06:16, 30 May 2014 (UTC)
It is frustating to try to discuss, when people do not explain why they think something is "redundant" or "makes things worse". It makes building consensus hard.TR 08:00, 30 May 2014 (UTC)
"Physical" is redundant because the universe is everything that exists and non-physical things don't exist. Saying "physical" also weirdly implies the existence of non-physical things outside of the universe. But that is only my opinion and doesn't matter! If the references say "physical" then we use physical. "Why ask for a reference" seems a crazy question to me. Bhny (talk) 19:30, 30 May 2014 (UTC)
Perhaps redundant given the "Physical cosmology" sidebar, but I agree the "commonly defined" part's pure weasel.—Machine Elf 1735 05:15, 31 May 2014 (UTC)
"Saying "physical" also weirdly implies the existence of non-physical things outside of the universe." — That is exactly my problem with that phrasing. It's nonsensical. — Gopher65talk 12:24, 31 May 2014 (UTC)
I like this debate I got going here. I still stand by my wording. "Saying 'physical' also weirdly implies the existence of non-physical things outside of the universe." Not exactly, but close: it implies the possible existence of non-physical things outside the universe. This is where the question of neutral POV comes in. To a naturalist, the physical universe is all there is, end of story. But neutral does not mean "naturalist". The definition should be fair to the very large majority of people who believe in "higher" realms of whatever kind. That isn't nonsensical at all; it's simply a different opinion than yours. So I still think we need to be careful how we define the Universe, and calling it the totality of physical existence works for most beliefs. But maybe there is an even better way to word it.Pinkpills (talk) 12:37, 31 May 2014 (UTC)
The reason it is nonsensical is because - by definition - the universe contains everything physical and non-physical that can impact our existence. The only reason to insert the word "physical" there is as a weasel word to try and imply that there are non-physical things that exist inside the universe, but also non-physical things that exist outside the universe. You've now entered the realm of wide imagination. This addition is necessary only if your personal beliefs include things that are so far outside the known laws of physics that no reasonable addition to those laws could cover your beliefs. What's ruled impossible by that line of reasoning? Not much. FTL? Nope, we can imagine laws that would cover that. Might not be true, but it could be. "Higher planes of existence"? Might exist. May well not, but meh. "Aliens killed my cattle!"? They're almost certainly not here, but they aren't precluded from existing or being here. Telepathy? Doesn't seem likely, but we can certainly imagine that new physical laws could be uncovered that would allow previously unthought of types of long distance communication. Miracles/curses? Well, maybe something exists that alters the laws of probablity somehow? Doesn't seem likely, but maybe. That covers almost every belief system, and it's all included inside the word "universe". What's precluded though? As I said, not much. Some older mythologies can no longer exist (hollow Earth, glass spheres, etc). But for modern mythologies? Pretty much just one: an all seeing, all power, all knowing, omnipresent God. That is precluded. That is impossible. That cannot exist within our universe.
So, as I originally stated waaaay up at the top of this topic, putting the word "physical" in there is inserting religious dogma into this article. And not even general religious dogma, but rather support for a specific subset of Abrahamic religions. This is not a religious article. It is not the place for mythology. There are articles that are all about such topics. That is where statements like that should go. — Gopher65talk 14:38, 31 May 2014 (UTC)
I have to go to work now, so no edits for a while, but I hope that didn't sound overly harsh. It was intended to get an idea across, not be mean. — Gopher65talk 14:42, 31 May 2014 (UTC)

### Edit Warring

Well, with the exception of obvious vandalism I don't engage in more than 1 revert of someone's content. I don't like edit warring. So hopefully we have enough people chime in on this that a consensus is possible. — Gopher65talk 03:45, 30 May 2014 (UTC)

## Universe and reality

The universe is certainly part of reality--but is it the totality of reality? The opening paragraph of this article seems to indicate that it is. In particular, I'm talking about the sentence, "Similar terms include the cosmos, the world, reality, and nature." First, I find this sentence redundant because universe was already clearly defined before it. It's redundant as far as that's concerned unless the editor is making an attempt to lump "universe" in with "reality," as though the universe and reality were synonymous. Perhaps they are and perhaps they aren't. The terms are certainly synonymous to the naturalist, but that isn't a neutral position. 24.128.244.108 (talk) 06:05, 6 June 2014 (UTC)

It doesn't say the "universe" is synonymous with "reality", Different terms have been used in history and in everyday discourse to discuss the concept we now call the "universe" For example the word "World" was used extensively in Western philosophy to mean "universe" (particularly before it was understood there were other "worlds"). Some of the terms from the sentence are also used in dictionary definitions of "universe". We've had a lot of discussion on this page already about the philosophical meaning of "universe". I think it's fine the way it is. --ChetvornoTALK 08:33, 6 June 2014 (UTC)

The opening paragraph defines the universe as a physical manifold which is true; that's what it is. However, at the end of the paragraph a laundry list of words are used and we're told that these are all similar to what the universe--a physical manifold--is. One word in the list is "reality." But reality encompasses absolutely everything that is real or actual, which would include even the supernatural (e.g., God). The problem with this is the supernatural is by definition a category of being that transcends the universe or nature. So there's a glaring problem here unless one holds the belief that there is no such thing as a category of being outside of nature, that naturalism is true, that the universe IS reality, and not merely a stratum of reality. 24.128.244.108 (talk) 09:07, 6 June 2014 (UTC)

And that is why it says "similar" and not "equivalent", i.e. there is overlap in how the terms are used, and within a certain POVs (but not others) they could even be used as synonyms.TR 09:19, 6 June 2014 (UTC)

Similar how though? Reality encompasses everything that is real or actual. The universe encompasses all physicality. So in what way is "reality" and "universe" similar? Calling these two words similar is like calling the set of natural numbers and the set {1, 2, 3} similar. I guess they're similar in the sense that they're both sets, but that's not worth noting. I don't think these two words are similar in any way or to be more modest: in any meaningful way. For the sake of my next point, let's say they're similar. How similar are they? That isn't explained at all, which makes things confusing and ambiguous for the reader. There are people reading the opening paragraph, being taught that the universe is spacetime or all physicality, and then they go on to read that this is similar to reality. But when one investigates this claim by clicking on reality they find that reality is much bigger than the universe--or at least there is the possibility that it is.

There seems to be something fishy going on here. One problem is many of the editors here at Wikipedia don't have any formal training in the topics that they're editors for--so one see them doing silly things like comparing "reality" with "the universe." A person with a little training in science and philosophy wouldn't make such a mistake in a so-called encyclopedia that is supposedly neutral, unless they were purposely trying to push a certain viewpoint like naturalism. 24.128.244.108 (talk) 09:42, 6 June 2014 (UTC)

## Recent addition to introduction on multiverses

There seems to be an incipient edit war over the addition of a paragraph to the introduction saying that the terms "multiverse" or "many universes" are unscientific. --ChetvornoTALK 04:51, 1 September 2014 (UTC)

I agree with with all your points, in fact I think it's quite over the top, thank you.—Machine Elf 1735 19:58, 1 September 2014 (UTC)

I have never understood why, if universe is defined as everything, "multiverse" isn't an oxymoron. 97.64.209.102 (talk) 21:04, 10 October 2014 (UTC)Terry Thorgaard (talk) 21:05, 10 October 2014 (UTC)

This situation happens over and over again in science; when the definition of a concept gets expanded due to scientific discoveries, new words (neologisms) have to be invented to distinguish the new meaning from the old meaning. In the history of Western philosophy the word "World" used to have a similar meaning to "Universe". Then the early astronomers discovered the stars and planets in the sky were not supernatural beings but physical objects ("worlds") like the Earth, so the word "World" slowly shifted in meaning from "everything there is" to mean "planet", one among many. So a new word was needed for "everything there is" and the word "Universe" came into use, which has come to mean our contiguous spacetime. If it turns out there are multiple universes, the word Universe is going to likewise shift in meaning to mean "one among many", and a new word will be needed for "everything there is", hence "multiverse". --ChetvornoTALK 23:30, 10 October 2014 (UTC)

## A wrong use of "infinite"

This article states "The size of the Universe is unknown; it may be infinite." Yet it also states " Observations of supernovae have shown that the Universe is expanding at an accelerating rate." Now I'm no Einstein but I know that if the Universe had a beginning in the big bang and we are now 13.8 billion years in, It must be really big, but by definition cannot be infinite, because infinity is defined as "without limit". Please this is really simple and I was thinking about how it didn't make sense after reading. It can't be infinite regardless of how quickly it has been expanding for 14 billion years.

What is actually happening is a non-terminating process, space is continually growing larger, Yet it's not infinite because each individual light year, or mile, or foot, or inch etc. is finite and is achieved in a finite number of steps or time. Rather, the expansion of the universe "Approaches infinity". Yet, it cannot currently be infinite, not even in speculation (according to the previous mentioned facts of this article).

In fact, nothing in our universe can currently be infinite because time itself had a beginning in the big bang and terminates up to this very moment. For some physical property of our universe to have "no limit" and have a beginning at some point... time itself would have to stop completely - Only then will you never reach an end. The absence of time is true infinity.

Infinity is an abstract concept that cannot be observed in nature. Thanks. I hope this gets cleared up.

ps: This applies to the observable and unobservable universe. Carb0nshell (talk) 06:32, 30 August 2014 (UTC)

That isn't presently known. Available evidence gently *suggests* that the universe is spacial finite (maybe, or maybe just our local bubble is spatially finite...could go either way), but it doesn't say much about whether or not it is temporarily finite or infinite. Remember, something only has to be infinite in one direction (ie eg, a number life from 0 to infinity) to be infinite. So even if the universe could be said to have had a conventional beginning - a singularity popped into existence and instantly expanded - and it could still be just like that number line. It could have had a set beginning, go on forever, and be infinite in the direction of the future. And in that case it would be infinite, just like that number line. — Gopher65talk 12:35, 30 August 2014 (UTC)

I think you [(Carb0nshell)] are mistakenly thinking of the universe as a simple expanding sphere. Read this: Shape_of_the_universe- "According to cosmologists, ... the shape of the universe is infinite and flat, but the data are also consistent with other possible shapes". Bhny (talk) 13:27, 30 August 2014 (UTC)
A spatially infinite universe does not necessarily follow from the non-detection of curvature in the local universe. The article you link to actually talks about that a bit. Basically, if we detect the local universe to be "flat", that tells us nearly nothing about the shape or size of the universe. It's only if we detect curvatures that we can really start to speculate. This is (among other reasons) because any shape universe will appear flat if it is much larger than our local observable universe. All we can really say from our current measurements is exactly what this article says: "The size of the Universe is unknown; it may be infinite." That is literally the entirety of our (relatively certain) knowledge in this area. — Gopher65talk 15:40, 30 August 2014 (UTC)
Sorry by "you" I meant Carb0nshell, who may be using a balloon metaphor for the expanding universe. Bhny (talk) 19:25, 30 August 2014 (UTC)
The universe has been expanding for billions of years. We could mentally freeze this current moment in time and measure all of the finite miles back to the center. If we did this, we would get a concrete number, not infinity.
Also, remember: The future hasn't yet happened. Our timeline terminates, or ends, or stops at the most recent moment of present time. (its constantly being pushed froward, as time moves on). Infinite would mean the future already existing. Otherwise we only "approach" infinity with each passing second. Of course time is not infinite in the past direction - having an origin with the Big bang. So time has a beginning, and an end - that's constantly moving closer to infinity - yet it isn't infinite because it isn't complete. The number line is a good example of a complete infinity. Time - unlike the number line - is moving. Carb0nshell (talk) 09:25, 31 August 2014 (UTC)
Shape shouldn't matter here if the universe is somehow changing in any way through time. shape-wise, or really in any respect, then it can't be infinite. Carb0nshell (talk) 09:35, 31 August 2014 (UTC)
Carb, if you wouldn't mind, please put your comments at the bottom of all the other ones. It just makes it easier to follow the flow of conversation:).
As to your comment, I want you to ignore the universe for a moment, and we'll talk about infinities in general, since you seem to misunderstand the term.
Imagine this: you have an infinite set of numbers. This set, in fact: {0, 1, 2, 3, 4, 5... ---->}. This is the set of natural numbers. It starts at 0 and just keeps going forever. So it's an infinite set. Ok so far? Everyone has trouble with infinity. It's a weird concept.
Ok, so we have this infinite number set. You take out a single number, let's say "13", and you say, "ah hah! 13 is not an infinity! Therefore this isn't an infinite set of numbers!" ...Well 13 certainly isn't infinite, but that isn't the point. You can always extract a single number, or in fact any finite set like {13, 14, 15}, say, and that finite set will, of course, be finite. It will be finite because you specifically defined it as finite when you extracted it:). But just because you can pull out individual non-infinite numbers from that infinite set, that doesn't have any bearing on the set itself. The set of natural numbers is still infinite. It still goes on forever. For our purposes here, infinite basically means "goes on forever in at least one direction". In the case of the set of natural numbers, it has a definite beginning (either 0 or 1, depending on which you choose to start with), but it doesn't have an ending. It is only infinite in one direction.
So what does this have to do with the universe? Well, you said (paraphrased), "ah hah! The universe is 13 billion years old! That means it isn't infinite!" Well... no. That just means that you pulled out one number of an infinite set. Of course that particular number (that particular age) isn't infinity large, but it couldn't be. That's just not how infinities work. — Gopher65talk 15:23, 31 August 2014 (UTC)
You are also questioning the size of the spacial dimensions of the universe, claiming that it can't be infinite, because it started a finite time in the past. This is not the case. A universe could *poof* into existence and be infinitely large, or it could *poof* into existence and be a finite size. Universes are weird things. They don't follow the same rules as you and me, or as a balloon that you're blowing up.
I know scientists will say, "the universe expands like a balloon filling with air", but that's just an analogy. A really, really bad analogy, which gives people a lot of wrongheaded ideas about the universe.
I also think you're making the (very common) mistake of thinking of the Big Bang as an explosion which blew 'stuff' outward. If you make that assumption, then it totally makes sense that the universe would *have* to be finite, right? Because the explosion has been going on for 13.8 billion years, and no matter how fast the stuff is exploding outward, it is still finite in size.
But that's another really, really, really inaccurate analogy. That one isn't so much inaccurate as it is flat out wrong. The Big Bang didn't explode. And from the inside, even expansion is hard to see. Oh it "expanded", but an infinite object can still expand (see, infinities are weird, aren't they), either locally or as a whole. Just think about some points on our number line from the comment above: {12, 13, 14}. {40, 41, 42, 43}. {60, 61, 62, 63}. {1000000, 1000001, 1000002}. Each individual point on the number line, both present and future, is growing larger. But the number line as a whole is infinite. Weird, right? That's not an exact analogy either, but I don't think there are any exact analogies for the universe;).
I'm not sure I can properly explain to you exactly why the universe might be infinite (it's complicated), but I hope I've been successful in helping you see some of the flaws in your logic. — Gopher65talk 15:38, 31 August 2014 (UTC)
I have one last comment about how freaking weird the concept of infinity is. Imagine the set of natural numbers again. We'll use the version without 0 this time, for simplicities sake. {1, 2, 3, 4, 5, 6... ---->}. Now, imagine a second number line where we count by twos instead of by ones. {2, 4, 6, 8, 10, 12... ---->}. Both sets go to infinity. They're both infinite. But the second set, the one that counts by twos, is twice as large as the first set. No really, the second infinity is (provably) 2x the size of the first infinity. This isn't a trick. It really is. You see, infinities are never ending, but that doesn't mean they're all the same. Some infinities are... bigger... I guess, than others. We don't really have words to describe that. Bigger doesn't really work there, does it? But that's the way it works. One last time: infinities are weird;). — Gopher65talk 15:45, 31 August 2014 (UTC)
Our arguments all boil down to the structure of time. If the future is some construct that already exists out there, just waiting for us to arrive at its pre-built location, then your logic could work. I don't think most people see time as pulling random numbers off of an infinite number line, but rather as the inevitable progression into the future with the passing of present events into the past. Maybe, however, we do need to give science more time before changing this article. Pun intended.— Carb0nshell (talk) 19:40, 1 September 2014 (UTC)
No, cosmologists don't see time like that. Time is a dimension like the spacial dimensions, and like them had its origin at the Big Bang. The Big Bang is a singularity, a "coordinate" at which time and space lose meaning. Since all world lines originate at the Big Bang there is no meaning to the time "before" the Big Bang. That is also why the Universe could have always been spacially infinite, and yet have a beginning, in opposition to your argument, Carb0nshell Think of a movie of the Universe expanding, played backwards. The distance between any two objects, such as galaxies, gets smaller, until at the Big Bang the distance between any two objects goes to zero. ANY two objects, no matter how far apart they originally were. ALL distances go to zero. So the Universe could be spacially infinite a moment after the Big Bang. You can't apply normal intuition about distance and time to the Big Bang itself, it is inconsistent, like dividing by zero. --ChetvornoTALK 20:47, 2 November 2014 (UTC)

To address the very first comment in this section: The universe could quite possibly be infinite in extent even though only a finite amount of time has passed since the Big Bang. Even in 1-dimensional space (a line), the velocity field dx/dt = x2 results in particles going off to infinity in a finite amount of time. (And like that field, we know that masses are moving away from us faster, the farther away they are from us.)Daqu (talk) 13:59, 21 November 2014 (UTC)

## Confusion between a number and a function

In the Multiverse section, this sentence appears:

"Tegmark calculated our nearest so-called doppelgänger, is 1010115 meters away from us (a double exponential function larger than a googolplex)."

But this statement confuses a number— which is what 1010115 is — with a function, which 1010115 is not.Daqu (talk) 14:06, 21 November 2014 (UTC)

## Not infinite

I have researched the universe a topic and in my research it say that the universe is expanding so therefore it can not be defined as infinite.

Fun facts. The universe as far as we know has no edge an is not expanding from a singular point in space.

If I am wrong about any of there things I am talking about I would like to know what and why it is wrong. — Preceding unsigned comment added by ZeroKool00 (talkcontribs) 09:06, 27 September 2014 (UTC)

This was just discussed in the section two sections up from this one (and many, many times before this). Long story short, we don't even know what shape the universe is (current evidence points toward a "saddle" shaped, or infinite universe). Until we know the shape of the universe, we can't tell if it is spatially finite or infinite. Also, the universe may be temporarily infinite in one direction (the future). — Gopher65talk 12:48, 27 September 2014 (UTC)
I agree. In addition, ZeroKool00, a spacially infinite universe can still be expanding. Expansion just means the distance between any two sufficiently separate objects, such as clusters of galaxies, is increasing. --ChetvornoTALK 15:09, 27 September 2014 (UTC)
In addition, a spatially finite universe can also be expanding. (Imagine a balloon inflating.)
But I have no idea what the comment "Until we know the shape of the universe, we can't tell if it is spatially finite or infinite." Isn't the infinitude, or finitude, of the universe something that is one aspect of its shape? Or was something different meant?
Furthermore: Fun fact — a shape that is uniformly expanding is expanding from every point (not from no point). That means you can choose any point you like, and everything else will be expanding away from it. Again, imagine an inflating balloon.Daqu (talk) 21:10, 2 January 2015 (UTC)

## Fine tuning and the anthropic principle

The section on fine tuning contains the text:

"As such the conditional probability of observing a Universe that is fine-tuned to support intelligent life is 1. This observation is known as the anthropic principle and is particularly relevant if the creation of the Universe was probabilistic or if multiple universes with a variety of properties exist (see below). However, the observation that the chemistry of life may have begun shortly after the Big Bang, 13.8 billion years ago, during a habitable epoch when the Universe was only 10–17 million years old, may differ, in part, with the anthropic principle.[62][63]"

So, I don't understand how the possibility that the early universe had conditions conducive to life changes the conditional probability from 1 that the universe could support intelligent life. Maybe @Drbogdan can add an brief explanatory clause to the last sentence? Thanks, still wondering how we all got here, Grandma (talk) 19:57, 6 December 2014 (UTC)

I really want to get rid of that fine tuning section. Totally irrelevant in that section Tetra quark (talk) 17:26, 8 January 2015 (UTC)
Well, if the universe had a habitable period in a time when we'd previously decided that nothing should have been alive, that likely means that the only reason we see the universe as being "fine tuned" to allow us to exist is because we have both a narrow point of view of what can exist, and a very self-centered view of what conditions need to be like for life to exist. I wouldn't say it contradicts the weak anthropic principle, I'd say it strengthens it, if anything. — Gopher65talk 16:16, 9 January 2015 (UTC)

## Does the word universe have a capital "U"?

I see the capital U being used sometimes, but not all the times, so we should make a decision Tetra quark (talk) 22:43, 6 January 2015 (UTC)

For the sake of having a centralized discussion, here's the link to the same topic at Wikipedia talk:WikiProject Astronomy, also recently started by Tetra quark.   ~ Tom.Reding (talkcontribsdgaf)  01:35, 16 January 2015 (UTC)
I don't expect to get any replies here but thanks Tetra quark (don't be shy) 01:40, 16 January 2015 (UTC)
IIRC the last time this was brought up the consensus was no, but with the caveat that it's context dependent. Simply put, sometimes it should be capitalized, and other times not. In the article, it should mostly be lower case. — Gopher65talk 12:33, 16 January 2015 (UTC)
While I generally favor consistency of use within any given wiki article, chasing after consistency of this issue (U or u for Universe, the Earth or just Earth, etc.) across all wiki articles is probably a waste of time. People tend to take unhelpful strong opinions on these kinds of things, and usually to no positive effect in the end. Isambard Kingdom (talk) 13:04, 16 January 2015 (UTC)

As presented earlier, my own preferences atm may be summarized as follows:

Copied from "Wikipedia talk:WikiProject Astronomy#Capitalize the "U" in "universe" or not?":

FWIW - if not already considered, a relevant reference for the discussion *may* be the "Style Guide for NASA History Authors and Editors" at the following link => http://history.nasa.gov/styleguide.html - especially? => "Astronomical Bodies: Capitalize the names of planets (e.g. Earth, Mars, Jupiter). Capitalize moon when referring to Earth's Moon, otherwise lowercase moon (e.g. the Moon orbits the Earth, Jupiter's moons). Do not capitalize solar system and universe." (and more? - see link) - in any case - Enjoy! :) Drbogdan (talk) 17:11, 18 January 2015 (UTC)

Hope this helps in some way - Enjoy! :) Drbogdan (talk) 20:30, 18 January 2015 (UTC)

## Capitalization of universe

There is currently a discussion about the capitalization of Universe at Wikipedia talk:Manual of Style/Capital letters § Capitalization of universe. Please feel free to comment there. sroc 💬 13:14, 19 January 2015 (UTC)

## Discussion of capitalization of universe

There is a request for comment about capitalization of the word universe at Wikipedia talk:Manual of Style/Capital letters#Capitalization of universe - request for comment. Please participate. 00:50, 4 February 2015 (UTC)

## Semi-protected edit request on 17 February 2015

In the Contents section, it looks like the critical density is used as the baryon density from the NASA reference. Could this be checked and corrected if incorrect? <http://map.gsfc.nasa.gov/universe/uni_matter.html>

Emuspace (talk) 22:22, 17 February 2015 (UTC)emuspace

Not done: Edit request templates aren't used for such purpose. When (if) you're ready to request the change, then you can use this template. Edgars2007 (talk/contribs) 00:08, 18 February 2015 (UTC)

The comment is correct; I corrected it. —Alex (ASHill | talk | contribs) 01:02, 18 February 2015 (UTC)

Perhaps the lead of the Universe article should be much shorter and more concise than the one at present (18 January 2015) - and more like the one not too long ago (2 January 2014) - or even - more like a dictionary definition like those below:

In any case - Hope this helps - Enjoy! :) Drbogdan (talk) 21:33, 18 January 2015 (UTC)

Thank you, Drbogdan. I would like to see a lead for Universe that 1.) is a fair summary of the existing content, 2.) points the way to a more balanced depiction of the concept of "universe", by which I mean not focused on just astronomy/astrophysics, 3.) is encompassing of other physical disciplines, including particle physics, 4.) is encompassing of the wider scientific community, including chemistry and life sciences, 5.) is encompassing of philosophical interpretations of the concept of "universe" (capitalized or otherwise). And, because it might become an issue, I just note that this discussion is not necessarily about cosmology pre se. Isambard Kingdom (talk) 01:10, 19 January 2015 (UTC)
We can choose to limit the scope of the article as an editorial decision. :-) Certainly I would prefer not to see philosophical material here (rather than at an article like Universe (philosophy)), except to the degree that it is relevant to our current understanding and its historical antecedents. Sunrise (talk) 21:41, 19 January 2015 (UTC)
The lead is about the right size, so it should not reduced to a single sentence. It should have a sentence on philosophy added, but the other topics wanted by Isambard Kingdom, should first be written about in the article, otherwise there is nothing to summarise in the lead. I think a philosophical section is fair enough, though I suspect what is in there now is not the most relevant to the topic. Where is the source for material for article/s on Living universe, chemical universe, or particle universe? We do have fictional universe though. Graeme Bartlett (talk) 21:53, 19 January 2015 (UTC)
Graeme, I don't know the answer to all your questions, but let me offer partially informed responses: First, in general, it is good that a *finished* article have a lead that is perfectly consistent with the body. I don't, however, know if this article will ever be truly finished, so I would suggest that, as a work in progress, some allowance for things like chemical universe and life in the universe can and should be included in the lead, if only in anticipation of what can and should be included. Although I'm a scientist, I'm a bit concerned that some wikipages take on a momentum of their own, partly depending on which first community first contributed the content. Honestly, the word "universe" is so inclusive it needs, yes, to be flexible for its notion in lots of fields. Now, a bit more specifically, the notion of life in the universe (which assumes conditions tame enough to enable chemistry), how much is out there, how it evolves, is a quite an interesting subject. I think it needs to have a bit of space here (and there is brief discussion of chemistry and life, together with citations to articles that look quite interesting). Otherwise, why have other topics, like stars and galaxies? Those are important too, but not more important than life. The article does have content about particle physics (see section on "laws") and this needs to be "democratically" represented in the lead. Okay, just thoughts. Isambard Kingdom (talk) 22:15, 19 January 2015 (UTC)
I also note that the formation of molecules affect the opacity of the universe. But I might be wrong about this. Isambard Kingdom (talk) 21:50, 22 January 2015 (UTC)
BRIEF Followup - the formation of molecules (see Molecular cloud?) may affect the opacity of the Universe I would think; more clearly, however, seems Cosmic dust (and/or Interstellar dust) may affect such opacity - ( possibly relevant => http://arxiv.org/abs/1409.5738 ) - if interested, molecules in space are in several Wikipedia articles, including => Astrochemistry; Cosmochemistry; List of interstellar and circumstellar molecules; Template:Molecules detected in outer space - Enjoy! :) Drbogdan (talk) 22:38, 22 January 2015 (UTC)
FWIW - Brief Note re Life in the universe => relevant Wikipedia articles, if not already aware, include: Abiogenesis; Astrobiology; Biogenesis; Biological immortality; Evolution; Extraterrestrial life; Interplanetary contamination; Life; Panspermia - as well as - Life in the universe itself - and many other related articles - hope this helps in some way - Enjoy! :) Drbogdan (talk) 15:05, 20 January 2015 (UTC)
Astroecology. Isambard Kingdom (talk) 20:06, 25 January 2015 (UTC)
I agree. I think the 2 January 2014 version is much better than the present version (although the length is about the same in the two versions). The article overwhelmingly treats the scientific concept of the Universe, so as long as that's true, the lede should reflect that. I'm not sure it really makes sense to spend much effort in this article on non-scientific aspects of the Universe; it seems to me like that would be better split out in a different article. I'll work on restoring the better, older version of the lede, unless there's objection. —Alex (ASHill | talk | contribs) 14:40, 18 February 2015 (UTC)
YES - updating the lede of the Universe article to the "2 January 2014" version seems like an excellent idea - and - has my full support - hope this helps in some way - Enjoy! :) Drbogdan (talk) 15:44, 18 February 2015 (UTC)
Done. I've incorporated changes over the last year that I think were helpful, but the lede is now much closer to the 2014 January 2 version than it was before. Here's the diff from 2014 January 2 until now.
I've also moved the manifold in two dimensions image back down to the Big Bang section. I did that partly because I disagree with another editor's argument that the image is more welcoming than the image of the CMB from the cosmology template but mostly because I think it doesn't show the whole Universe; it would be more appropriate for the lede of an article on the beginning of the Universe than on Universe. Also, it's a somewhat complicated, technical image, which I don't think is quite right for the lead image of a broad article (the most broad topic on all of Wikipedia, I'd argue, since it's by definition all-encompassing!). Instead, the image of the cosmic microwave background in the cosmology template is the closest thing we have (or are every likely to have) to a single, pretty image that accurately shows the whole Universe in a model-independent way. —Alex (ASHill | talk | contribs) 16:32, 18 February 2015 (UTC)
Note that there's currently nothing about philosophy or anything else; a sentence in the lede summarizing what's in the body of the article wouldn't hurt. Though I'd ask that any new content go in the body, not the lede. —Alex (ASHill | talk | contribs) 16:43, 18 February 2015 (UTC)

Any thoughts on the sentence "Related terms include the cosmos, the world, reality, and nature."? Particularly the last three I really don't think are at all "similar" (the wording in place both as of before I rewrote the lede and as of 2014 January 2 until I changed it to "related" just now) to Universe. And world is linked to world (philosophy), which is quite a different context than the scientific context of the rest of that sentence. That difference may be interesting and worth including in the lede, but I'm not sure how to do so. Suggestions? —Alex (ASHill | talk | contribs) 19:42, 18 February 2015 (UTC)

Done - agree & share your concerns - edited article w/ following summary => "rm text - seems better - and more consistent with the physical, rather than abstract, context - per concerns on talk - *entirely* ok w/ me to rv/mv/ce of course" - Enjoy! :) Drbogdan (talk) 21:27, 18 February 2015 (UTC)

## Notification of request for comment

An RfC has been commenced at MOSCAPS Request for comment - Capitalise universe.

Cinderella157 (talk) 03:23, 22 March 2015 (UTC)

An image of the Hubble Deep Field was recently added before the cosmology infobox. Should it be there? A nearly-identical image is already in the contents section of the article. I think that having this image above the infobox is ugly, and I also think that the image of the cosmic microwave background in the infobox is a better image to represent the whole universe; it's the closest thing we have (or probably will ever have) to a single image of the Universe. I won't make the change myself, as I've been in several edit conflicts with this particular editor recently about a lead image on this page (among other things) and don't want to start another without some consensus first. —Alex (ASHill | talk | contribs) 14:50, 5 March 2015 (UTC)

I agree, we shouldn't have two nearly-identical images in the article. I'm not all that opposed to an introductory image of galaxies, as I think that would more effectively express what the article is about to nonastronomers than the cosmic microwave background image you referred to, but for sure it shouldn't be that image. --ChetvornoTALK 18:23, 5 March 2015 (UTC)
Well, the deep-sky image in the lead is shown again down in the section on "contents". So at least one of them should be deleted. Isambard Kingdom (talk) 23:12, 10 March 2015 (UTC)

To address aesthetic concerns, and partly motivated by the (tiresome) discussion as to whether or not "universe" should be capitalized, I figured if, as many assert, the universe is actually an astronomical object, then it deserves an info box. I inserted one. Please consider if this address concerns raised here, and please consider adding content to the info box. Thanks, Isambard Kingdom (talk) 17:20, 13 March 2015 (UTC) Also, note that I have inserted the image in the info box that @Ashill found attractive. As for whether or not the info box withstands wikiopinion, I don't know. At the very least, I hope it generate some thought. Isambard Kingdom (talk) 01:20, 23 March 2015 (UTC)

## Case Change

I think someone should change Ultimate fate of the Universe into Ultimate fate of the universe.— Preceding unsigned comment added by 96.52.34.191 (talk) 00:16, 30 April 2015 (UTC)

Unfortunately there is a long, as yet unresolved, discussion about capitalization of the word universe. You can see a sample of it at Wikipedia talk:Manual of Style/Capital letters#Request for comment - Capitalise universe. Until that is closed satisfactorily, it is best if no changes are made. 00:41, 30 April 2015 (UTC)
I do think that the article would benefit from a well-cited footnote about usage and capitalization (similar to Solar System). Such a footnote could benefit from the sources found in the discussion at WT:MOSCAPS, though it would of course be content and thus subject to WP:V, unlike the MOS discussion. That would probably make it easier to write, since coming to one conclusion would not be desirable, unlike in the MOS. In particular, Google (or whatever) searches counting usage aren't reliable sources but are somewhat relevant in the MOS discussion. —Alex (Ashill | talk | contribs) 14:02, 1 May 2015 (UTC)
I prepared a footnote discussing capitalization. I tried hard to be neutral and to stick to sources; I deliberately erred on the side of being too inclusive since it's easier to cut. I listed the five journals (Science, Nature, MNRAS, ApJ, and AJ) for which the capitalization patterns are very clear, even though only MNRAS has a source explicitly stating the policy. I don't think there's any doubt about their policies and I think their inclusion is illustrative, but interpreting what they do is strictly original research, so there's an argument that they shouldn't be there. I self-reverted because this has been the subject of so much discussion without a consensus at the MOS, but is including a note along these lines helpful here? Here is the version with the footnote. —Alex (Ashill | talk | contribs) 15:40, 1 May 2015 (UTC)
Alex, I appreciate the spirit of you communication, here and on this issue. However, given everything else that needs to be addressed in this article and all other articles about the universe, it is my opinion that this issue of capitalization is very far down on the list of priorities. Also, I imagine that is one of those things about which some people will never be happy. Isambard Kingdom (talk) 16:04, 1 May 2015 (UTC)
@Ashill: I think your footnote is well written and fair, but I think it is such inside baseball as to be unencyclopedic. On the other hand, I sometimes look things up on Wikipedia to help decide how to capitalize them. I'm of mixed opinions, but I think it's best to leave it out. As a side note, adding it then self reverting is a clever way of looking at an idea; kudos for that. 17:31, 1 May 2015 (UTC)
My thought is both that I find the capitalization somewhat interesting and that the number of editors (particularly editors who haven't been involved previously) who tweak this is an indication that readers are interested (to the extent that those who edit pages they haven't edited before are reflective of our readership). So I think that compiling sources that do address this and reporting what they say is a useful and encyclopedic thing to do. That said, the paucity of sources that actually address this question may be an indication that it's not encyclopedic and worth including. So I too am of mixed minds but lean towards thinking it's helpful. —Alex (Ashill | talk | contribs) 16:47, 4 May 2015 (UTC)
One of your two sources for 'Some sources capitalize "universe" when used as the name of the particular universe which contains Earth' doesn't say that. Gleiser proposes we capitalize for the observable universe but don't capitalize the greater expanse which includes both the observable and unobservable universe ... in other words both the Universe and the universe contain Earth; containing Earth has nothing to do with Gleiser's capitalization proposal. And what you call "major astronomical journals" leave out the big-circulation ones -- Astronomy or Sky + Telescope seem to avoid capitals. As for Nature, it's easy to find "universe" on nature.com, and although "Universe" is indeed more frequent I fail to see the explanation that it's done because it's "when used as the name of our universe", that looks like an assumption. Peter Gulutzan (talk) 03:18, 2 May 2015 (UTC)
I agree that some tweaks could be made to the example wording I suggested. I didn't say "on nature.com"; I said in the journal Nature. (But I Googled "site:nature.com universe" and found that all snippets on the first two pages of the Google search results did capitalize "universe" in contexts where it is used as a name -- the one exception was actually a link that redirected on to a different site.) Astronomy and Sky & Telescope aren't journals; they're magazines. I think that my interpretation of the capitalization practices in the five journals I listed is uncontroversial and I used sources for generalizations ("the word 'universe' is most commonly not capitalized"), but as I stated, it is technically original research since I only know of one source (the MNRAS typesetters guide) that says explicitly "journal X does/does not capitalize 'universe' in certain contexts."
But my intent here was to make a suggestion in concept which can be tweaked. There doesn't appear to be consensus for the concept, so quibbling over the details is unnecessary unless that changes. —Alex (Ashill | talk | contribs) 16:47, 4 May 2015 (UTC)
You can find the definition of the word journal in Webster's dictionary or Oxford dictionary. Peter Gulutzan (talk) 20:17, 5 May 2015 (UTC)

──────────────────────────────────────────────────────────────────────────────────────────────────── In reading the Wikipedia article in more detail, I note the sentence "According to one common terminology, each "soap bubble" of spacetime is denoted as a universe, whereas our particular spacetime is denoted as the Universe,[32] just as we call our moon the Moon." (The cited ref does explicitly support this statement. It doesn't use the soap bubble metaphor or the Moon bit.) So this is mentioned in the article, albeit in a place I certainly didn't think to look for it. —Alex (Ashill | talk | contribs) 19:34, 4 May 2015 (UTC)

## Creation

Seems a bit odd to me that the section on Creation mentioned a finnish poem about a giant egg and a few other creation stories (Maoris etc) but no mention of the belief of most people in the world of a creator God? Eg from Abrahamic religions etc? What do others think? I'm sure that the typical "don't include God in any serious discussion" atheist scientist doesn't see the need for this but this is an article about.. well the universe.. and what portion of humans believe that the Abrahamic God had something to do with the universe? Or is wikipedia just a scientific journal on such things? djambalawa (talk) 04:34, 6 May 2015 (UTC)

Make the edits you think need to be made. Isambard Kingdom (talk) 08:27, 6 May 2015 (UTC)
The Abrahamic creation myth is mentioned in the creation myth section. It is not given any special prominence because that's not what this article is about. There are a number of articles that center around both the Abrahamic creation story and every other one you can think of (and many you can't), this just happens not to be one of them. — Gopher65talk 12:47, 6 May 2015 (UTC)
I don't believe it was mentioned when I wrote the comment. Also saying "It is not given any special prominence because that's not what this article is about" is a bit silly I think - so you are saying that the article about the Universe isn't anything about the Universe's origins? And this particular origin belief is believed by 4.4 billion people (numbers taken from wikipedia Christian and Islam articles). djambalawa (talk) 01:47, 7 May 2015 (UTC)
It was there when you wrote the comment, but it was subtle; I didn't see it after looking for it until Gopher65 pointed it out. I added the words "Judeo-Christian" but otherwise that section hasn't been modified since your comment. If you think changes should be made, be BOLD and do it instead of talking about it in the abstract. —Alex (Ashill | talk | contribs) 01:53, 7 May 2015 (UTC)
Although I am an atheist scientist (wink), I entirely agree that this creation myth should be mentioned as well. I added the adjective "Judeo-Christian" to the mention of the Genesis creation narrative because every other creation myth listed in that sentence mentions the civilization or faith it comes from. I (embarrassingly) don't know whether Genesis is part of the Islamic faith, so if it should be "Abrahamic" instead of "Judeo-Christian", please change it. Genesis creation narrative says Jewish and Christian, so I followed that. —Alex (Ashill | talk | contribs) 14:27, 6 May 2015 (UTC)
Thanks - although I think half a line mentioning this when 4.4 billion people (over 60% of us) believe this is how the universe originated is pretty lame I guess I shouldn't complain until I have a go at doing something better myself.. djambalawa (talk) 01:51, 7 May 2015 (UTC)
Ok I had a go at editing it myself - please be gentle - I'm not a great writer. djambalawa (talk) 02:40, 7 May 2015 (UTC)
Thabks for providing an edit to discuss. The premise is uncited and needs to be (and Wikipedia is not a reliable source and thus can't be used as a reference). Even if there are 4.4 billion Jews, Christians, and Muslims, we would definitely need a source for the claim that they all believe in the Genesis creation story. I highly doubt that that's true. —Alex (Ashill | talk | contribs) 03:11, 7 May 2015 (UTC)
I didn't say that they believe in the Genesis creation story - only that they believe that the Abrahamic God is responsible for the origins of the universe djambalawa (talk) 03:55, 7 May 2015 (UTC)
OK, same objection. —Alex (Ashill | talk | contribs) 13:01, 7 May 2015 (UTC)
Going back to the initial objection for a moment (I have no objection to adding "Abrahamic" or "Judeo-Christian", whichever turns out to be more accurate): the reason this article doesn't mention these beliefs in detail is because this is an article about the astronomical properties of the universe. You shouldn't spend paragraph after paragraph describing super-symmetry and the inflation model in the Genesis article, and you shouldn't spend significant time discussing Genesis here. It's not appropriate because that's just not what those articles are about. You don't talk about almonds very much in the apples article, and you don't talk about sheep in a fruit fly article. *Shrugs* They're just different subjects. — Gopher65talk 13:51, 7 May 2015 (UTC)
While I agree that we don't need too much duplication from other articles, that the presentation of this article presently has a tilt toward the astronomical should not preclude a more balanced and appropriate presentation. Isambard Kingdom (talk) 14:08, 7 May 2015 (UTC)
I strongly agree in general and tend to be suspicious of claims that religion should be injected into largely-scientific articles. But although I have some quibbles with the newly-added text (especially the uncited assertion that a majority of the Earth's people believe that a god created the Universe and the unstated but clear implication that that view is just as valid as the prevailing evidence-based view), I think the extra context for the following paragraph is reasonable and an improvement to the article. It could be trimmed a bit, and the "wheels in motion" statement is awkward (and also uncited). The universe is a concept that has well-sourced meaning in both scientific and non-scientific contexts, and I don't think that ignoring that is the right approach. (Genesis has no scientific meaning, and super-symmetry has no non-scientific meaning, so the analogy isn't quite fair.) —Alex (Ashill | talk | contribs) 15:00, 7 May 2015 (UTC)

## Rotation

I always felt that as planets, solar systems, and galaxy's all rotate that the universe is not only sphere shaped as all things a certain size seem to be but also rotates as well. if we could figure out the speed of the rotation of the Universe we could figure out a universal time based on this rotation the same way a as a day is.--Guyver92 (talk) 06:13, 8 May 2015 (UTC)

Kurt Godel and rotating universes: [[1]] Isambard Kingdom (talk) 09:59, 8 May 2015 (UTC)

There's a long history to that question [2], [3], [4]. Rotation of the universe would violate the cosmological principle and Mach's principle. It would also require the abandonment of the cosmological inflation hypothesis, part of the Big Bang, since inflation would damp out the rotation. Godel's model is noncausal (it would be possible for particles to go back in time and for the world lines of objects to be timelike loops). The evidence for rotation seems to be observations of small asymmetries in the number of galaxies rotating in each direction about various axes, which could of course be a random statistical fluke. Measurements of the CMB put an upper limit of 10−15 rad/yr on the rotation. This is not to say the issue is settled, but I think the answer of most cosmologists to the question of whether the universe is rotating would be "no" [5]. --ChetvornoTALK 15:42, 8 May 2015 (UTC)

## Infinite Universe?

I think the phrase in the introduction "may be infinite" needs to be further qualified. The prevailing view is that the universe is finite and currently expanding. There are many things that "may" exist that is not included because it is too speculative. The view that the universe is infinite is bordering on being speculative in light of the current prevailing scientific opinion. I understand that the "certainty" surrounding whether the universe is finite or not is less certain than say the Earth revolving around the Sun, but I do think that the sentence should read something to the effect of: "The size of the whole universe is not known but is currently understood to be finite. Some, though, believe that the universe may be infinite." Also, bear in mind that saying the universe is infinite is illogical based on what is said two sentences later that the universe is expanding and the rate of expansion is increasing. An infinite universe, which by its definition occupies everything into infinity, cannot expand.

NOTE: "The size of the whole universe is not known" could also be subject to further qualification. There is an emerging view based on calculations of expansion from the time of the Big Bang that the size of the universe is somewhat more than 2x the observable universe.

On a separate note, I also have an issue with "the Universe has been governed by the same physical laws...for all time." It is far from clear that this is the case at the moment of and immediately following the Big Bang (Planck Epoch).140.247.0.131 (talk) 14:38, 2 April 2015 (UTC)

What we can know is what we can observe, but we can also admit that we don't observe everything. On the issue of whether or not the universe is or is not "infinite", or whether or not something that is infinite can also expand, I suggest you read Brian Greene's book which is cited after the phrase "may be infinite". Do you have a citation backing up your assertion that "the prevailing view is that the universe is finite" or are you just commenting on the observable part of the universe? Isambard Kingdom (talk) 14:56, 2 April 2015 (UTC)
140.247.0.131, here are some sources that the universe may be infinite [6], [7], [8] and some that explain how an infinite universe can expand: [9], [10], [11], [12] --ChetvornoTALK 15:48, 2 April 2015 (UTC)
See metric expansion of space, which does a decent job (in the lede) of explaining that it's space in the Universe that is expanding, not the Universe itself. We could perhaps make that more clear in the Universe article, although the wording in the lede is carefully chosen to say exactly that. —Alex (Ashill | talk | contribs) 16:06, 2 April 2015 (UTC)

I think writing that space in the Universe is expanding and writing the Universe is expanding are the really same subject. Space in the Universe expanding is how the Universe expands, in my mind. The metric expansion of space article, does explain the Universe is not expanding into some other space, and cannot be viewed as by an outside observer, which I think is the main point.Jcardazzi (talk) 14:40, 30 May 2015 (UTC)jcardazzi

## Scope of article

To be explicit about something that's come up tangentially in a few other places, what should the scope of this article be? A recent set of edits incorporated the philosophical meaning into the lede. (I think the content as it is should be in the body, not the lede, but that's a side point.)

I don't really think that the scope of the article should be limited to just the scientific meaning of the Universe, but discussion of the philosophical meaning of the word (including mathematics) is really talking about a very different thing than the discussion of the astrophysics, so it's a little hard for me to see how to make the article coherent. Making the topic of the article every meaning of a word that really does have quite distinct meanings in different disciplines seems to err a bit too much on the general side. —Alex (Ashill | talk | contribs) 19:16, 29 May 2015 (UTC)

My opinion: The article does not need to try to cover every meaning of the word "universe". Similarly, the article does not need to try to summarize all astronomical aspects of the universe. The Universe article is not a specialized article. It is a general article. Specialized subjects can be taken up in specialized articles (that is the beauty of an encyclopedia). What the Universe article should be is a fairly accurate panoramic discussion of what is meant by "universe" across a wide range disciplines. Not easy. I know. And I don't even pretend to be able to do that. So, how to proceed? I think we need to encourage participation in the article's development, especially from editors capable of delivering non-astronomical content (because we seem to have quit a lot of that already). How do we encourage this involvement? Isambard Kingdom (talk) 19:32, 29 May 2015 (UTC)
My feeling is the article already has an appropriate amount of "panoramic" discussion of the meaning of Universe in non-astronomical contexts, in the Synonyms and definitions, Historical models and Philosophical models sections. It is important and valuable, and maybe it could be better written. But I think most readers come here for the astronomical concept. --ChetvornoTALK 21:48, 29 May 2015 (UTC)
Perhaps, then, the thing to do is encourage editors with expertise in religion, history, philosophy, etc. to consider those sections in this article and try improve the existing content. Isambard Kingdom (talk) 21:53, 29 May 2015 (UTC)
What do you think is missing, or needs to be improved? --ChetvornoTALK 22:21, 29 May 2015 (UTC)
Well, notions that the universe encompasses all kinds of things: life, ideas, thoughts, emotions; abstract things like philosophy and mathematics. Plus, I'm sure, lots of other things that are not astronomical. By the way, I don't think people necessarily arrive at this page looking for things astronomical. I don't claim to be qualified to fix the article. Isambard Kingdom (talk) 22:28, 29 May 2015 (UTC)
That definition of "universe" is synonymous with "everything," which is an existing and distinct article. Remember that as an encyclopedia not a dictionary, we have one article per subject not one article per word. VQuakr (talk) 00:32, 30 May 2015 (UTC)
That article everthing is certainly well written. Funny too! Isambard Kingdom (talk) 01:19, 30 May 2015 (UTC)
if the redlink is sardonicism, you are over my head. VQuakr (talk) 07:47, 30 May 2015 (UTC)

I think the scope of this article should be the the Universe as a subject in Astronomy/Physics. Text at the top should describe the subject and refer readers to other articles for subjects on other meanings of the word. Thank you,Jcardazzi (talk) 22:39, 2 June 2015 (UTC)jcardazzi

## An issue with the definition

The 'totality of existence' is a rather facile definition. Not only is that taking the position—in violation of WP:NPOV—that physicalism and atheism are correct, but it's also ignoring the fact that many viewpoints in mathematical philosophy regard non-physical abstract objects (sets, numbers, etc.) as existing as well. This is compounded by the fact that the sources cited for that definition are mere dictionaries(the Encyclopedia Britannica entry of "universe", which was also cited, does not regard it is the "totality of existence"), which are certainly not reliable for a topic clearly requiring a specialized, scholarly definition.JDiala (talk) 01:42, 15 April 2015 (UTC)

So, are you saying the definition is too inclusive or not inclusive enough? Although this Talk page constantly goes round and round about it, there has been a sort of consensus that the definition should be limited to the astronomical concept, and should not include philosophical or religious concepts such as God, or abstractions (ideas, numbers, etc.). In agreement with that, I feel 'totality of existence' is a little too inclusive. --ChetvornoTALK 02:12, 15 April 2015 (UTC)
In recent years I notice the definition has switched back and forth between versions of 'totality of existence' and the more limited 'totality of spacetime', which would more clearly exclude the philosophical stuff like God. I think I prefer the latter. --ChetvornoTALK 02:12, 15 April 2015 (UTC)
It is too inclusive. Spacetime is sufficient for a simple definition. JDiala (talk) 02:38, 15 April 2015 (UTC)
At the risk of igniting another endless "lede" discussion, how does everybody feel about switching back to a lede that defines the Universe as the "totality of spacetime and all it contains" as it was in January [13]? --ChetvornoTALK 20:23, 16 April 2015 (UTC)
If you haven't noted it, do see the discussion above; the current wording in the lede was in place in January 2014 and was largely restored in January 2015. However, I'd be fine replacing "existence", since it's a bit fluffy and metaphysical (though I disagree that there are any NPOV issues, and I think dictionaries are the best sources for definitions like this). I think the dictionary definitions at the beginning of the discussion above are helpful, particularly the Oxford and Merriam-Webster ones. How close can our wording be without being plagiarism? "Totality of spacetime" doesn't seem as clean to me as "the sum of everything that exists" (Oxford) or "all of space and everything in it" (Merriam-Webster). —Alex (Ashill | talk | contribs) 21:40, 16 April 2015 (UTC)
I think we need to avoid something that is exclusively astrophysical.Isambard Kingdom (talk) 21:42, 16 April 2015 (UTC)
How about this (which was also used in the january version): We use the "spacetime" definition in the lede, but add the sentence: "The term is also used more broadly for concepts such as the cosmos, the world, reality, and nature." further down in the lead section. That way we indicate the broader meanings to the word are strictly separate from the "astrophysical" definition. --ChetvornoTALK 22:09, 16 April 2015 (UTC)
I suggested removing that sentence in February, with my reasoning in the discussion above. I now see that those terms are discussed in the article itself, which does argue for including them in the lede. However, I think the context they were in before (immediately after the contents of the Universe) isn't quite right. I also note that there's no mention of the fairly extended section about historical models in the lede. Perhaps we should add a new paragraph to the lede that goes into historical models, etymology, and synonyms? The lede could probably benefit from some discussion of the difference between the scientific/astrophysical entity (what I'd call the Universe, though that's controversial from a grammatical point of view but I think very useful from a meaning point of view) and the more philosophical concept of the universe (which those terms are more related to). —Alex (Ashill | talk | contribs) 14:28, 17 April 2015 (UTC)

──────────────────────────────────────────────────────────────────────────────────────────────────── After thinking about the relationship between the lede and the article, I've boldly reordered the article to be

1. Etymology
2. Synonyms
3. Historical concepts
4. Chronology
5. Properties and laws
6. Shape
7. Theoretical models

(Synonyms and Historical concepts were between shape and theoretical models, which broke up the modern scientific description.) I ordinarily prefer to leave historical models and synonyms to the end, but I think this is appropriate for this particular article, since the word "universe" does have significant non-scientific meaning. It also flows better, particularly since the historical models section ends with "The modern era of physical cosmology began in 1917, when Albert Einstein first applied his general theory of relativity to model the structure and dynamics of the Universe.", which flows very nicely into the modern scientific description. —Alex (Ashill | talk | contribs) 14:39, 17 April 2015 (UTC)

@Ashill: You have not given a convincing reason as to why dictionaries should be used to define what "universe" is(note that it doesn't matter what you "think"; you require an argument based on Wikipedia policy), nor have you (or Isambard Kingdom) explained why an astrophysical definition is not preferable. Cosmology is the scientific study of the universe, and is a sub-category of astrophysics. This is a scientific article. Why, then, should our definition not be based on the mainstream view of experts on the subject (rather than dictionaries)? In the above discussion neither of the several sources linked describe the definition of "universe" as "the totality of existence". Are they less reliable than dictionaries? I suggest you may need to read through WP:RELIABLE. — Preceding unsigned comment added by JDiala (talkcontribs) 23:45, 30 April 2015 (UTC)
@JDiala: Dictionaries are absolutely reliable sources for simple definitions. What makes you think otherwise?
The cited Webster's New College Dictionary definition (#1) is "the totality of all the things that exist; creation; the cosmos", which mostly supports the current definition (though maybe "existence" has a subtly different meaning that "all things that exists"). And the second sentence ("This includes planets, stars, galaxies...") makes it very much astrophysical. But as I stated above, I'm not wild about the "existence" bit either.
Rewriting the sentence without plagiarizing one of the sources is a bit difficult, since they've found most of the ways to say the same thing. A suggestion: "The Universe is all of time, space, and its contents. This includes planets, stars, galaxies, the contents of intergalactic space, the smallest subatomic particles, and all matter and energy, the majority of which are most likely in the form of dark matter and dark energy."
Though I generally do prefer to keep scientific and non-scientific stuff in separate articles, this article does have a fairly extended set of sections with well-sourced and (I think) relevant content. The lede should reflect that instead of being entirely focused on the modern scientific aspects as it currently is.
As to "think": I do try to use words like "think" on talk pages to distinguish my opinion from what sources say. What editors think is absolutely relevant in editorial decisions about what to include in an article and which sources are relevant (within policy); Wikipedia isn't written by automatons. I suggest that you read the box at the top of the guideline you linked to: "This page documents an English Wikipedia content guideline. It is a generally accepted standard that editors should attempt to follow, though it is best treated with common sense, and occasional exceptions may apply. Any substantive edit to this page should reflect consensus. When in doubt, discuss first on the talk page." I think that what editors think is very relevant to using common sense. —Alex (Ashill | talk | contribs) 13:56, 1 May 2015 (UTC)
@Ashill: A simple definition may suffice for a simple topic--say, Pizza--but not for "Universe". An overly simplistic definition, evident in the case of this article, can be an imprecise one. If plagiarism is an issue, why not the following definition from the July 2014 version: "The Universe is all of spacetime and everything that exists therein, including all planets, stars, galaxies, the contents of intergalactic space, the smallest subatomic particles, and all matter and energy."? Notwithstanding the non-scientific stuff included in the article, I am still not convinced that the lead should encompass these non-scientific views. Consider, for example, life. The lead sentence is clearly totally scientific, even though there is a large amount of non-scientific discussion on the issue of life (ie. meaning of life). Moreover, since practically all of the sources describe and discuss the universe scientifically, should Wikipedia not do the same? If this is a major point of contention, why not have a separate sentence or a separate paragraph discussing broader, non-scientific conceptions of the "universe". JDiala (talk) 00:48, 2 May 2015 (UTC)
I think there's more miscommunication than disagreement here. Our proposed definitions are, as far as I can tell, nearly identical. The main difference is that I prefer to split it up into two sentences to avoid a run-on. I'm not suggesting incorporating the historical models and etymology into the definition in the first paragraph of the article; I'm suggesting adding a fourth paragraph to the lede that summarizes those sections of the article. —Alex (Ashill | talk | contribs) 02:03, 2 May 2015 (UTC)
Okay fair enough. If we're largely in agreement, shall we make a change? JDiala (talk) 23:58, 3 May 2015 (UTC)
OK, I've done this. I used "time and space" instead of "spacetime" because none of the sources with definitions actually say "spacetime". —Alex (Ashill | talk | contribs) 16:26, 4 May 2015 (UTC)
Alex, thank you for these thoughtful edits. Isambard Kingdom (talk) 14:48, 17 April 2015 (UTC)
I agree, looks great. A nice simple clear definition. Agree "space and time" is better than the technical word "spacetime". Nice job. --ChetvornoTALK 18:49, 4 May 2015 (UTC)

Proposed Definition update-add "contents" per the sources The Universe is all of time and space and its contents, [8][9][10][11] which includes the planets, stars, galaxies, the contents of intergalactic space, the smallest subatomic particles, and all matter and energy, the majority of which are most likely in the form of dark matter and dark energy.[12][13]Jcardazzi (talk) 00:06, 2 June 2015 (UTC)jcardazzi

Okay with me. --ChetvornoTALK 00:20, 2 June 2015 (UTC)
Per which source? None of the four cited sources include the word "contents". Though Merriam Webster does say "and everything in it including stars, planets, galaxies, etc", but that's already covered (almost verbatim) in the next sentence. I prefer keeping the first sentence concise. —Alex (Ashill | talk | contribs) 01:05, 2 June 2015 (UTC)
I think Ashill is being too technical here. We don't necessarily need dictionary-like definitions, and we don't need a lead that strives for consistency with such verbatim distinctions ("contents"). It is okay if the lead is a sensible summary of the content of the article. Isambard Kingdom (talk) 06:44, 2 June 2015 (UTC)

Sorry,sources: per Meriam Webster: "the universe : all of space and everything in it including stars, planets, galaxies,

per American Heritage: All space-time, matter and energy, including the solar system, all stars and galaxies, and the contents of intergalactic space, regarded as a whole.

per Oxford: All existing matter and space considered as a whole; the cosmos.

per oxford Advanced: The universe: the whole of space and everything in it, including the earth, the planets and the stars

When I read the definition "The Universe is all of time and space", I wondered "what about the contents? why are the contents not included in the Universe?" the Universe's matter and energy, et al. The next sentences explain after the definition the Universe includes matter and the contents, but the contents are not in the 1st sentence definition. Thank youJcardazzi (talk) 03:03, 2 June 2015 (UTC)jcardazzi

I can only echo what Isambard Kingdom and Jcardazzi said. Adding "and its contents" surely does not require an explicit source, and if it does Jcardazzi's is sufficient. --ChetvornoTALK 10:16, 2 June 2015 (UTC)
I didn't mean to say that "and its contents" isn't OK, just that Jcardazzi's argument that it is better "per the sources" is clearly false (based on the currently-cited sources). My substantive objection is that it turns a simple, clear, and complete topic sentence into a run-on. What about "The universe is all of time and space. This includes its contents: planets, stars, galaxies, intergalactic space, the smallest subatomic particles, and all matter and energy, the majority of which are most likely in the form of dark matter and dark energy."? —Alex (Ashill | talk | contribs) 12:50, 2 June 2015 (UTC)

I used a synonym of "contents" for the different words in the cited sources, which refer to the contents of the Universe in different words, "whole of matter and energy", "totality of known..objects:, "totality of all space and time,all that is, has been, and will be." (the 3rd definition seems too vague and mystical to me). I don't think adding "and it's contents" makes the 1st sentence a runon sentence, the sentence goes from 8 to 11 words. Leaving the contents out of the universe seems incomplete to me. None of the current sources state the Universe is only space and time, with no contents.

Current sources cited: yourdictionary.com:The universe is the whole of all matter, energy, planets, galaxies and space

dictionary.com the totality of known or supposed objects and phenomena throughout space; the cosmos; macrocosm.

Introductory Astronomy & Astrophysics (4th ed.): The totality of all space and time; all that is, has been, and will be.

Thank you Jcardazzi (talk) 13:20, 2 June 2015 (UTC)jcardazzi

Again, all of that is in what is currently the second sentence of the lede. You propose merging that second sentence into one long run-on. I prefer a short, first sentence; the second sentence is already on the long side. —Alex (Ashill | talk | contribs) 13:29, 2 June 2015 (UTC)

Hi, I do not propose merging the 2nd sentence. I propose the below text, for consistency of terms and definitions. Reasons: 1. None of the sources cite the universe is only all of time and space. 2. The WP article https://en.wikipedia.org/wiki/Outer_space describes space (outer space) as a void, between celestial objects, and excludes the objects from "space".

Proposed text: The Universe is all of time and space and its contents. The Universe includes planets, stars, galaxies, the contents of intergalactic space, the smallest subatomic particles, and all matter and energy. The majority of matter and energy most likely is in the form of dark matter and dark energy. Thank you, Jcardazzi (talk) 22:33, 2 June 2015 (UTC)jcardazzi

This new proposed text is not what you proposed above (which did merge the two sentences). It's an improvement. I think that space has a subtly different meaning when combined with time that does imply everything in it, but I'm fine including contents in the first sentence if it's split up like this (though I still prefer just "all of time and space" in the first sentence). I'd change the second "The Universe" to "This", but otherwise go for it. Breaking up the second sentence as you suggest is a definite improvement. —Alex (Ashill | talk | contribs) 23:29, 2 June 2015 (UTC)

## Recent edits

I've moved, merged some sections, sorted and updated the lede, put Universe into italics. If someone wants to comment on these changes, go ahead. prokaryotes (talk) 11:30, 2 June 2015 (UTC)

I have a few concerns.
1. The new lede is much more technical (going into details of Euclidean space, manifolds, and Minkowski space in ways that should be in the body, not the lede; using "R(t)" – especially without definition – is also too technical). Moreover, the broad description of the observable universe, including its size and ultimate fate, are moved to a separate section ("Characteristic"). This is particularly inappropriate because that text describes content that's later in the article; we shouldn't have a second, non-lede section that summarizes content elsewhere in the article (per WP:LEDE).
2. The completely rewritten Definition section is awkwardly short (though what it replaces was pretty bad as well, consisting of choppy, short subsections) and uncited.
3. I made an argument above as to why I like having the historical models section before the modern scientific description; I still think that, though not strongly.
4. Putting "Universe" in italics seems inconsistent with MOS:ITALICS and standard English usage; why the change? —Alex (Ashill | talk | contribs) 13:24, 2 June 2015 (UTC)
Definition section - I've removed the italics. —Alex (Ashill | talk | contribs) 13:40, 2 June 2015 (UTC)
• The definition section was separated, i did not changed the text there, its the remaining parts now. It should be extended. Lede - I will try to make it less technical. Italics, because some words were in italics, some not. I don't care if it is in Italics, or not. Maybe merge all theories and models, than separate them by historic and modern. prokaryotes (talk) 13:44, 2 June 2015 (UTC)
Italics are used, in this article, when discussing the word "universe" as opposed to discussion of the actual "Universe". These are matters of style only, and, so, less important than content. Isambard Kingdom (talk) 13:47, 2 June 2015 (UTC)
They are now, after I removed the italics. They were used for every occurrence of the word universe. —Alex (Ashill | talk | contribs) 13:51, 2 June 2015 (UTC)
Right, and I'm fine with that reversion, but prior to this round of edits, italics were used in the definition/etemology section to emphasize the word "universe" as a word only. Not arguing, just saying. Isambard Kingdom (talk) 13:58, 2 June 2015 (UTC)

Thanks Prokaryotes. A fresh overhaul, such as this, might help jumpstart progress on this article. I think we could still use input on the "Historical Models" section. One thing, my understanding is that the notion of a "model" is kind of new in the history of science, and that ancient scientists either perceived their "models" as actual reality. I believe that Gilbert perceived his terrella as actual "Earth's" (though I'm happy to be corrected). Or, more practically, as simply a means to an end. So, again just my understanding, at first Copernicus was more concerned about practical prediction of the motion of the planets and Sun for purposes of calendar production; whether or not his heliocentric theory was "real" was of secondary concern. On a completely different note, I'd like to see the equations (there are just a few) removed from the article, as I see them as not balanced relative to the whole of the article's content. My thoughts, Isambard Kingdom (talk) 13:27, 2 June 2015 (UTC)

Before Copernics, namely Philolaus should be mentioned, Copernicus mentions him too. See also Nicolaus Copernicus#Predecessors. I renamed the Historic model section to Historic development. prokaryotes (talk) 13:55, 2 June 2015 (UTC)
P, if you feel qualified to add that content (Philolaus), then please do. Isambard Kingdom (talk) 14:02, 2 June 2015 (UTC)

There are a few newly-added sections (dark matter and dark energy) that are straight copy and pastes of the ledes of their respective articles. Summary style is certainly appropriate for this article, but it's not clear what the benefit of this is. The content was already covered (more briefly) in the Contents section, obviously with links to the specific articles. Why duplicate the content again? (I deleted the dark matter section, but thought I'd bring it here before deleting more.) It looks like the particle physics section is largely the same. —Alex (Ashill | talk | contribs) 14:43, 3 June 2015 (UTC)

Dark matter and energy make most in the universe, and the content in the respective sections is only liek 2 paragraphs and elsewhere only mentioned briefly. These topics deserve a sub section entry. prokaryotes (talk) 14:51, 3 June 2015 (UTC)
It's obviously true that they're most of the contents of the Universe, but I really don't see what is gained by duplicating the content. I think that keeping the focus of this article on how things fit together on large scales is much better. An already-large and unwieldy article has gotten much larger (it was about 100K yesterday, about the WP:TOOBIG rule-of-thumb size when it "almost certainly should be divided", and is now 130K). The particle physics details strike me as worse than dark matter and dark energy; instead of short sections, they're quite lengthy sections that go deep into detail that really isn't relevant for the Universe as a whole (or at least the relevance isn't made clear). Particle physics is obviously important for the early evolution of the Universe, but the entire Particle Physics section (as it currently stands) contributes nothing to understanding the early Universe. —Alex (Ashill | talk | contribs) 15:01, 3 June 2015 (UTC)
What do you suggest is missing in the particle section, when you say it is not covering the early universe? The content also mentions that it is not only related to the early universe. I agree that the article should not be bigger. I thought maybe merging the philosophic and astronomy section, and could be trimmed. Some parts in the particle section could be trimmed, but repeating basic info helps to communicate a complex topic. prokaryotes (talk) 15:08, 3 June 2015 (UTC)
I see that there's one paragraph in each section about the lepton epoch, the hadron epoch, and the photon epoch; that's good. It's the rest of each of those sections that isn't on topic. I think it goes beyond repeating the basic info needed to communicate the topic, particularly since the repetition of basic info looks to me like it's 4–6 times as long as the relevant info in these sections. I'll try to trim. —Alex (Ashill | talk | contribs) 15:30, 3 June 2015 (UTC)
Alex, i think you done a good job, except for removing the particle model removal. If we have an article on the universe and a section on models, than the Standard model belongs there. The part really was tiny, please readd, thanks. prokaryotes (talk) 16:34, 4 June 2015 (UTC)
Are you talking about this edit? I didn't remove anything; I just moved it to what I think is a more sensible and less-redundant place. —Alex (Ashill | talk | contribs) 17:47, 4 June 2015 (UTC)
If we have a section on models, then we need to list the particle physics model there too. Or remove the model section, and just outline the BB event. This is important because both models are considered Standard Models, thus it is a bit confusing when you only find the BB SM under Models. Or just add a sub section with a link to the SM page. prokaryotes (talk) 05:33, 5 June 2015 (UTC)
Thanks Ashill for your edits, i think the article is now in a good shape. prokaryotes (talk) 18:18, 9 June 2015 (UTC)
I also think the article looks very good. Maybe it can be nominated for article of the day or something? Isambard Kingdom (talk) 18:27, 9 June 2015 (UTC)
It was nominated as a Good Article a couple months ago and is still pending review: WP:GAN#PHYS. (There's a large backlog.) My guess is that it may well pass the Good Article review (depends very much on the individual reviewer). I think it would have a very hard time passing a featured article nomination; if you're talking about the article being a front page nominee, featured article status is the first step. Though I do think the article is significantly improved (and wasn't bad to begin with), there are still a number of improvements that could be made (and are on my mental list, which I'm slowly making progress on). —Alex (Ashill | talk | contribs) 18:49, 9 June 2015 (UTC)
Alex, there are a couple of equations in the article (Solving Einstein's equations, Geometry). Can these be taken out? I feel that in all the mix of material, these equations, while possibly interesting, are not balanced with the rest of the material. Just my thoughts. Isambard Kingdom (talk) 18:54, 9 June 2015 (UTC)
I too think that equations do not necessarily have to be in this article, but before removal they should be added (if not already) to the related sub article. prokaryotes (talk) 19:03, 9 June 2015 (UTC)
That's on my mental list to tackle. Need to think about whether the content they convey should be in the article in text; when I looked at it, it seemed probably. —Alex (Ashill | talk | contribs) 23:44, 9 June 2015 (UTC)

## contents- what about ordinary energy?

regarding: "The Universe is composed of dark energy, dark matter, and ordinary matter." Why is ordinary energy not mentioned? for example: light, heat, radio waves et al. If dark energy is specifically mentioned, should ordinary energy be mentioned to be consistent? Thank you,Jcardazzi (talk) 23:14, 9 June 2015 (UTC)jcardazzi

Ordinary energy (meaning electromagnetic radiation) is a tiny fraction of the energy density of the present Universe. Add up the contributions of dark energy, dark matter, and ordinary matter to the mass–energy of the Universe, and <0.1% is left over. And essentially every source lists those three as the dominant constituents of the Universe, so we'd be going against the sources to include radiation. The article correctly notes that radiation was the dominant component during the photon epoch, most of the first 380,000 years. —Alex (Ashill | talk | contribs) 23:43, 9 June 2015 (UTC)

Hello Ashill, ordinary energy being <0.1% of the universe is still greater than zero, and is a content of the universe, per all sources I checked. Plus, ordinary energy is an important and necessary content to humans. For example: If the sun stopped emitting light and heat, all humans would die. If there was no electricity, there would be no electronics, no computers, no wikipedia.

Ordinary energy, while not dominant, is worth stating, I believe. I suggest a revision: "The Universe is composed of dark energy, dark matter, and ordinary matter and energy."...Ordinary energy is less than 0.01% of the content of the Universe. Thank you,Jcardazzi (talk) 12:00, 10 June 2015 (UTC)jcardazzi

This image (part of Dark energy) https://commons.wikimedia.org/wiki/File:DMPie_2013.svg should be updated then too? prokaryotes (talk) 12:09, 10 June 2015 (UTC)
If that image were updated, there would be no change. The sliver that is radiation is thinner than the thin lines that separate the significant constituents. At the highest resolution PNG rendering (2000 pixels), ordinary energy would take up less than half a pixel.
Radiation is discussed a good bit in the chronology section, as it was dominant during the photon epoch. A radiation section in Contents would probably be good. To the introduction to the Contents section, I think that appending something like this to the paragraph would be better than including radiation in the list of significant constituents: "At present, electromagnetic radiation is a small portion of the mass–energy density in the Universe, but it was the dominant form of mass–energy during the photon epoch." But that just duplicates content that is (appropriately) in the chronology section.
(Note that "ordinary energy" is not a commonly-used phrase; I think that "radiation", "electromagnetic radiation", or "light" are all better.) —Alex (Ashill | talk | contribs) 13:48, 10 June 2015 (UTC)

## The Universe as a sentient sense organ

It is strange that nobody involved in religion, or anyone interested in religious thought and who has helped compile this article, to date, has thought of the Universe itself as actually being the physical neurons connecting themselves together in God's brain? Or quite possibly it isn't that surprising, given the subject matter, although the person who wrote the movie script for Men in Black was quite near to doing it. And he could have been on anything, not just dopamine. Anonymous (talk) 13:31 2 may 2015 (UTC) — Preceding unsigned comment added by 31.51.13.202 (talk)

This sounds like the panpsychism concept. It probably belongs on the Cosmology article, since that covers philosophical viewpoints. Praemonitus (talk) 17:24, 19 June 2015 (UTC)

It could be that the as per the multivers theory we are actually a cell or even just a atom or particle of the One Above All (the one true god a being that is both good and evil. yes i am a fan of marvel comics.) as true perspective distance of the universe is next to impossible to determine as it is constantly expanding. --Guyver92 (talk) 06:06, 8 May 2015 (UTC)

## Magnetic effects on cosmic scales

@Ashill, I think I'm okay with your reverting my edit here: [14], but let me ask for some clarification. Galaxies can have their own dynamos, what with the electrically conducting plasma of stars and gas acting through motion to generate large-scale magnetic fields. Sounds interesting to me, but I don't know for a fact that a galactic dynamo can have a (dynamic) back-reactive effect on the structure of a galaxy -- thus qualifying under the "cosmological length scales" discussed in this part of the article. Let me know. A possible nuanced edit of the article might avoid confusion from people like me who know enough to get confused. Isambard Kingdom (talk) 16:23, 26 June 2015 (UTC)

Also, note the role of magnetic fields in jets (even large ones): Astrophysical jet. The term cosmological scale "level of galaxies and larger-scale structures" might need some adjustment to fix this. Isambard Kingdom (talk) 17:14, 26 June 2015 (UTC)

Yes, galaxies can produce dynamos and have magnetic fields in the interstellar medium (in fact, that's largely what I study professionally and thus something I avoid on Wikipedia ;) ) which may well impact what galaxies look like, but the magnetic fields don't control the formation of cosmic structure; the electromagnetic forces are much smaller than gravity on those scales. So magnetic fields may affect what galaxies look like (though even there, probably only as a secondary effect except on observational tracers like polarized radio emission that are very sensitive to magnetic fields) but probably don't affect what the Universe looks like. So I think just glossing over it is appropriate here. Magnetic fields may be created in jets but probably don't control jets. —Alex (Ashill | talk | contribs) 17:29, 26 June 2015 (UTC)
Understood, I also don't edit Wikiarticles on what I actually do! Isambard Kingdom (talk) 17:31, 26 June 2015 (UTC)
But that whole paragraph should be referenced better.... —Alex (Ashill | talk | contribs) 17:45, 26 June 2015 (UTC)

## History section

I notice that the classical Chinese school of thought regarding the universe, dating as far back as the 4th century BCE is not mentioned here, why is that?

The Chinese term for Universe is 宇宙, the first character meaning all of space, infinite and without bounds, and the second meaning all of time, without beginning nor end.

The classic saying goes:

“四方上下曰宇，往古来今曰宙。”

The four directions and up and down are called yu, from ancient to modern is called zhou, thus the universe yuzhou (宇宙） is the totality of all space-time.

Though I understand that other cultures have other ideas regarding what the universe really is, this seems to be a rather gaping omission in this article.

71.202.100.77 (talk) 12:00, 28 June 2015 (UTC)

Interesting. I don't know how or if foreign language issues like this are handled (I can't read more than about a dozen Chinese characters). Ideally, we have a citation to a reference article that discusses (say) ancient Chinese notions of space and time, and everything that existed, exists, or will exist. Isambard Kingdom (talk) 17:02, 28 June 2015 (UTC)
Some interesting articles:
1. Gernet, J., 1993-94. Space and time: Science and religion in the encounter between China and Europe, Chinese Science, 11, 93-102.
2. [15]
3. [16]


Isambard Kingdom (talk) 17:15, 28 June 2015 (UTC)

Done. Isambard Kingdom (talk) 14:31, 9 July 2015 (UTC)

## What fraction atoms?

In response to a few recent edits on this article, I'm wondering if there is an estimate of the mass fraction of the Universe that is composed of electrically neutral atoms (not ions, not free electrons). It would be interesting to put this into in this article. Isambard Kingdom (talk) 03:41, 25 June 2015 (UTC)

I would think that would be a difficult question to answer accurately. See for example. Praemonitus (talk) 16:40, 23 July 2015 (UTC)

## Big Rip

The article only briefly mentions the Big Rip scenario in the GR section. A new study gives further info, model of cosmic stickiness favors 'Big Rip' demise of universe prokaryotes (talk) 08:28, 2 July 2015 (UTC)

At this point the result is just a paper study.[17] It will need to predict verifiable results that can be tested. Praemonitus (talk) 16:43, 23 July 2015 (UTC)
The last intro paragraph of Dark Energy is based on a paper from 2007 with the Big-Rip scenario. This might be overemphasizing of that theory. prokaryotes (talk) 04:43, 13 August 2015 (UTC)
Recent science https://scholar.google.de/scholar?as_ylo=2015&q=cosmology+big+rip&hl=en&as_sdt=0,5 it appears that some studies end up with a BR and some don't. prokaryotes (talk) 04:53, 13 August 2015 (UTC)

## Solving Einstein's field equations

This section should be either sourced and written in a less hypothetical style, or moved to a relevant page, or just removed from this article. It adds nothing significant, without RS. Section was tagged long enough. Anyone disagree? prokaryotes (talk) 20:57, 12 August 2015 (UTC)

I think I'm in favor of removing that section, but I'd be interested to know what @Ashill and @Amble think about this. Isambard Kingdom (talk) 21:47, 12 August 2015 (UTC)
The last paragraph has some info on the fate of the universe, this could be merged with things like Big Rip. prokaryotes (talk) 23:44, 12 August 2015 (UTC)
Yeah, when I've given this article a proof-read in the past, I thought that that section had just enough content that really is directly relevant to the Universe that I didn't feel it could be cut. It needs a dramatic trim or rewrite, but there's some content that can stay, probably in a less mathematical style. That said, the math probably can't and shouldn't be completely removed. It's probably the most difficult part of the article to fix, which is why it was last on my (and presumably others') priority list. (I think that most if not all of the section is correct and readily-citable, though it's not currently cited. But it's still excessive detail for this broad an article.) —Alex (Ashill | talk | contribs) 00:02, 13 August 2015 (UTC)
Okay, i guess then it is relevant. However we should add some sort of citations then. Also i opt for a new article which evolves around the fate of the universe or universal field theory. Ahh there are articles for this. So please trim then. Basically the intro of the section should briefly delve into why there is a problem with an important theory - should mention the cosmological constant. also this articlw Solutions of the Einstein field equations, is based on old literature references - no inline, we should use more and newer - accessible sources. prokaryotes (talk) 00:57, 13 August 2015 (UTC)
(edit conflict) You know, I just read through the section carefully, and I actually think it's quite well-written and focused on applications of the field equations to understanding the Universe. I found it a useful summary that I'm not sure I've seen written down so nicely in once place before. I did some copy editing, but I'd actually keep it largely intact. It does need citations, but I'm essentially certain that it's all correct. It is in some sense a more mathematical and consolidated description of things that are mentioned elsewhere in the article. However, it only has one equation, and that equation is necessary for discussing R and k, fundamental parameters that are discussed throughout the section, so I think using the equation is quite useful. The ${\displaystyle d\theta ^{2}+\sin ^{2}\theta d\phi ^{2}}$ could be rewritten as ${\displaystyle d\Omega ^{2}}$, as it is in Friedmann–Lemaître–Robertson–Walker metric, to simplify a bit and only include the notation details that are relevant here, though. Readers who aren't interested will presumably skip the section, I figure, but I'm not sure the detail hurts on reading it. —Alex (Ashill | talk | contribs) 00:57, 13 August 2015 (UTC)
There's no requirement that sources be accessible online, and there hasn't (as far as I know) been any significant change in this since the 70s (at least) except the observational realization that ${\displaystyle \Lambda }$ (the cosmological constant) is real. (But that doesn't change the descriptions in this section except for changing ${\displaystyle \Lambda }$ from a mathematical curiosity to a physical reality.) Therefore, I don't think old references are a problem. Of course, secondary sources or textbooks would be better than the primary used in solutions of the Einstein field equations. —Alex (Ashill | talk | contribs) 01:03, 13 August 2015 (UTC)
Yes, but please try to add online references as well, you seem to be the right person to pick these links. This helps people who do not have access to text books. Also the section just states that the cosmological constant is a parameter - this is nice but doesn't explains a lot, or the importance to the problem. Please sum up what is the problem with the equations, for a lay person - and elaborate the importance of the cosmological constant. prokaryotes (talk) 01:36, 13 August 2015 (UTC)
Update, i see you edited the intro of the section, much better now. Though it would be nice if there would be online sources, i will check archive later for the 1922 publication. Also i noticed the general Relativity section mentions the problem with quantum physics. Section might be a little more trimmed not sure. prokaryotes (talk) 02:16, 13 August 2015 (UTC)
Can we add this (after ref 109) from the CC article, quote "Cosmological constant is the simplest possible form of dark energy since it is constant in both space and time, and this leads to the current standard model of cosmology known as the Lambda-CDM model, which provides a good fit to many cosmological observations as of 2014." - Just stating it's a small parameter is to arbitrary, we need more context. prokaryotes (talk) 03:14, 13 August 2015 (UTC)
See also this blog http://scienceblogs.com/startswithabang/2013/05/23/what-is-dark-energy-2/ prokaryotes (talk) 03:24, 13 August 2015 (UTC)
And per Equation of state (cosmology), "Thus, cosmic inflation and the accelerated expansion of the universe can be characterized by the equation of state of dark energy." prokaryotes (talk) 04:26, 13 August 2015 (UTC)
But it is unclear if the part at the Dark Energy section about Scalar field theory, fits within the general Relativity section. prokaryotes (talk) 04:33, 13 August 2015 (UTC)
I added a different bit modified from cosmological constant: "given k and the value of the cosmological constant Λ, which represents the energy density of the vacuum of space and is likely related to dark energy." —Alex (Ashill | talk | contribs) 13:18, 13 August 2015 (UTC)

Can the sections on Shape, Geometry, and Model_of_the_Universe_based_on_general_relativity be combined into one (maybe shorter) section without equations? Isambard Kingdom (talk) 14:44, 18 August 2015 (UTC)

Perhaps. But there's only one equation, a very important equation that describes the evolution of the Universe in one place, so I actually think keeping it is preferable. It is certainly true that there's considerable overlap between the first two sections and the last one, with the last one approaching the description in a more mathematical way, but I'm not convinced that's a bad thing. —Alex (Ashill | talk | contribs) 15:18, 18 August 2015 (UTC)
I would keep both sections, the first is good entry level info, the second dives into much more. prokaryotes (talk) 16:59, 18 August 2015 (UTC)

## Failed GA on 12/3/06

I'm sorry, but this article has a few issues (and one glaring problem) that need to be corrected before it can become a Good Article. As per WP:WIAGA:

• 1(a)- well-written/prose: A lot of individual phrases needed to be changed. To wit:
• From "Expansion": "...the farther away from us galaxies are, the faster they move away from us." Writing should never be done in the first person; in this case, "us" should be "Earth."
• From "Expansion": "As with most things in physics, that certainly wasn't the end of the story, as attested by the update and reissue of The First Three Minutes in 1993." This is an incredibly unencyclopedic sentence. I certainly do not want to sound condescending, as a lot of hard work has obviously been put into this article, but "that certainly wasn't the end of the story" is simply unacceptable.
• From "Pre-matter soup": "..the first hundredth of a second was a bit of a mystery." Again, "a bit" should be changed. Ditto to "Fast forwarding to after the existence of matter..." from "First galaxies," "...there is no reason to believe that this bound is anywhere near right" from "Size," and a handful of other phrases that need to be improved in tone.
• 1(c)- WP:MOS adherence: There are no real style problems, except for there being far too many external links. Please see WP:EL; external links should be kept to a minimum and only added when necessary, which many of these are not. In addition, it would be a good idea to list what source each link comes from, as opposed to simply including the article's title. This is not a big deal (one could simply scroll over the link to see the address), but it's a little touch that can go a long way.
• 2- factually accurate and verifiable: The big one. The article currently has two {{citation needed}} tags, but there could be many more. For a topic this expansive, having only four references equals not having nearly enough references. I doubt there are any Good Articles within all of Wikipedia that contain so few references.

I know that this article could easily be a GA if a little more work is put into it. There are a lot of things to like about this article- it's very comprehensive, it's got an excellent image, and it's NPOV, touching on many different theories. Best of luck, and feel free to resubmit to WP:GAC when the above issues are addressed. -- Kicking222 16:25, 3 December 2006 (UTC)

## The big question

Is the universe finite or infinite? Timo3 13:09, 20 August 2015 (UTC)

The article already said, at the bottom of the very paragraph you edited, that it was unknown whether the universe was finite or infinite. However it is probably reasonable to put that fact in the more prominent place at the beginning of the section. --ChetvornoTALK 14:24, 20 August 2015 (UTC)
And the article also says it in the 4th sentence of the lede, as well as from a more mathematical point of view in the Model of the Universe based on general relativity section. But the paragraph in question dives into detail with no context and should be cleaned up anyway. —Alex (Ashill | talk | contribs) 14:35, 20 August 2015 (UTC)

## Good article review implementation

There are a number of very helpful points that have been brought up in the good article review. In case any editors aren't watching the review itself, I'd appreciate any help in using the comments to improve the article! —Alex (Ashill | talk | contribs) 14:05, 23 August 2015 (UTC)

## Subsections under Particles

I propose to reduce the content in each of the subsections for Hadrons, Leptons, Bosons, Photons down to about one paragraph each (for a total of 4 paragraphs). More detailed information can be found, of course, on the main page for each of these particle types. Isambard Kingdom (talk) 14:31, 24 August 2015 (UTC)

Actually i would keep it as it is. Look, who is reading this? People who are interested in the Universe. Thus, reducing a good overview introduction to a paragraph doesn't cut it. prokaryotes (talk) 15:27, 24 August 2015 (UTC)
I concur with Isambard Kingdom that there is too much detail. I don't think this level of detail is appropriate in a summary-style article. Best to focus efforts and maintenance on the relevant articles. Things like describing the hadron epoch etc are relevant here with just enough detail for that explanation to make sense in context should stay. However, that's already covered in the chronology section, so I'm not sure that even a paragraph on each type of particle is necessary. Things like the half-life of neutrons (which isn't connected to the timescale over which an epoch lasts, for example) and how the properties of leptons are studied in the lab are definitely too much detail for such a broad article. (Note that the particles section was added in a series of edits in June 2015 that increased the size of the article from ~100K to ~130 K. Here is the article before those edits began.) —Alex (Ashill | talk | contribs) 15:43, 24 August 2015 (UTC)
Where can i see the current file size? Well if you insist we could trim it, but i think the sections are a big improvement, give a good overview. It's not like people start reading at the top and then progress linear to the end. Hence readers skip parts which are to much detail, but others wont.prokaryotes (talk) 15:49, 24 August 2015 (UTC)
If you want to cut additional file size, move the historic part to a new article? prokaryotes (talk) 15:52, 24 August 2015 (UTC)
I think the history part is important, and it deserves to stay in a survey article of this type. I'm not so much proposing to reduce the length of the over-all article, but, rather, concentrate the content at a level appropriate for the article. Maybe not worry about things that haven't happened yet? And, in any case, I tend to prefer long paragraphs! Isambard Kingdom (talk) 15:58, 24 August 2015 (UTC)
Some stuff might be indeed trimmed, and i see you both are busy with that. It doesn't mean we have to reduce it to one strict paragraph. A bit of content is ok. For me it is important to have those main U content section names there, this immediately identifies to the reader what is integral. Most will skip it but at least they read the section topic. prokaryotes (talk) 16:26, 24 August 2015 (UTC)
Prokaryotes, there are several editors busy on this article. We've been kind of alternating (though not strictly) in working, revising, adding content, removing redundancy, making things succinct, adding citations, fixing sentences, etc. etc. and etc.You've contributed to that as well. My suggestion that a certain set of subsections could be condensed (down to a paragraph each) is just a rough estimate of what I think might be obtained, it is a projection of something I haven't tackled yet. If, upon working on the content, two or more paragraphs are needed, then, that would be fine as well. It is a dynamic process, and I just wanted to signal to everybody involved that there is some "opportunity" in the particle physics section needing to be worked on a bit. I hope you see that we are generally headed in a good direction with all of this, and, of course, you are welcome to weigh in as things continue to move forward. I share you concern that the content be approachable for the typical reader. Isambard Kingdom (talk) 16:36, 24 August 2015 (UTC)
I've taken a hack at the section. I left the subsection on bosons untouched because I'm not sure what to keep; perhaps cut the entire subsection?
The file size after each edit is shown in the history. See the very rough size guidelines at WP:SIZERULE. —Alex (Ashill | talk | contribs) 18:02, 24 August 2015 (UTC)