Talk:Chronology of the universe/Archive 1

Comments not showing up?

I saw some relevant diff's on the talk page that "disappeared" into the áether. One of the more interesting comments is the following. Can we incorporate this into the main article? I'd prefer it not to be word-for-word as it is a bit of dry factual information (from what I can tell). -- Zalasur 01:21, Apr 27, 2005 (UTC)

Comment on the web page

The hypothesis relies crucially on the type of dark energy in the universe. The key value is the equation of state w, the ratio between the dark energy pressure and its energy density. At w < -1, the universe will eventually be pulled apart. First the galaxies would be separated from each other, then gravity would be too weak to hold individual galaxies together. Approximately three months before the end, solar systems will be gravitationally unbound. In the last minutes, stars and planets will come apart, and atoms will be destroyed a fraction of a second before the end of time.

The authors of this hypothesis calculate that the end of time would be approximately 3.5×10¹⁰ years after the Big Bang, or 2.0×10¹⁰ years from now.

-- http://en.wikipedia.org/wiki/User:Kzzl

Let's get 'er done

I wanna merge the articles. Let's get 'er done. -- Zalasur 07:24, Mar 23, 2005 (UTC)

Okay that does it

Let's merge Timeline of the Big Bang to Timeline of the Universe. I took a re-review. Let's get 'er done. -- Zalasur 00:07, Mar 16, 2005 (UTC)

Hmmm

I'm beginning do have doubts about the layout I chose for the page. Too many entries in the TOC perhaps? Too many bullet points definitely.

-- Zalasur 09:31, Mar 10, 2005 (UTC)

References References References

Hm I gotta beef up the References section... soon it will be done...

Otherwise, I think I'm almost done with this one :)

Mostly done with the major edits

I don't see any reason why there needs to be any further major edits to the page. The Black Hole, Dark, and Photon Ages all need some padding out, and the References section is practically non-existant (I would like to find viable external references) but that can be done with minor edits. I think I would like to add a picture of a black hole to this article (after the picture of the asteroid but before the picture of the photons), but the only reason I haven't is because I can't find a good picture on Wikimedia's list of files, so I have to find a public domain one somewhere else or draw one myself.

I'm kind of curious about what to do with the "Timeline of cosmological eras" article... the information is highly redundant and I'm pulling most my data from there as far as when everything occurred. I think the two can be merged.

-- Zalasur 23:19, Mar 1, 2005 (UTC)

I need help

I could use references, corrections, and such. As of now I will focus on Wiki's formatting features to make this "look" better. This is my first Wikipedia article (although I may say it's a rewrite of an older article, it's really just a complete 98% rewrite).

Things I think I will fix (and play around with)...

1) formatting.. I need to learn Wiki's formatting guidelines and make this article "Feature Article" material. I need something to play around with and this is better than the Sandbox.

2) references... yeah let's make this a serious article. got any good sources? I could use 'em

3) pictures... picutres are pretty... mmmmmm donuts too

So who's with me on this one?

--Zalasur 20:45, Feb 27, 2005 (UTC)

I updated the page

I ran across this one one and kinda scratched my head... "it needs work" I thought. I pretty much updated everything and removed anything human-centric. I'm thinking that at the end of this I can write up a snap-shot (as of this day, the Universe is X old, the Milky Way is Y old, etc etc etc) or put that in another article.

Also needed (this will help me remind myself):

• more references (and more relevent ones too)
• more specific timelines... I need to look up some numbers to tack onto the events in terms of billions of years or something
• The "ultimate fate of the universe" section
• clean-up of grammar, spelling (oops), terms, and a little structural overhaul

Probably more too... whee

--Zalasur 05:14, Feb 27, 2005 (UTC)

Exponential format

I noticed the article uses "base ^ exp" format because neither "base^exp" nor "<math>base^{exp}</math>" display correctly in the TOC. :( Can we make a suggestion to the MediaWiki people to allow it? It looks really bad the way it is now. :| —Mar·ka·ci:2005-03-12 11:18 Z

Bright side

At least it let me use the caret in the TOC. I don't think I would have liked to type out 10^150 by hand.  :) -- Zalasur 18:05, Mar 12, 2005 (UTC)

New Thinking

I think the "Timeline of the Big Bang" article and the "Timeline of the Universe" article shouldn't merge because they are two seperate timelines. The Big Bang is part of the "Timeline of the Universe" article but the "Timeline of the Big Bang" article is a better explanation of its events -- Anonymous 18:50, Jun 29, 2005 (UTC)

Older comments below

Anonymous

I just changed info about formation of earth from 3.8 to 4.5 billion years ago and origin of life from 2.5 to 3.5 billion years ago.

While it is true that science currently predicts the uiverse to expand forever and not collapse back into itself, is the prediction of a googol years just someone fooling around with this article? -- Modemac 23:46 Mar 2, 2003 (UTC)

Anonymous

From the article:

2 billion years from now: life ceases to exist on Earth

What is the mechanism for this? Increased/decreased solar output? Cite, please.

Anonymous

• 2 billion years from now: life ceases to exist on Earth

Removed unless someone presents a justification. Also rephrased bit about future of the sun.

Comment

Moved here

Since human observations cover a very short time interval and relatively short distance, making detailed predictions about the distant future or distant past is difficult. Humans can only observe a fraction of the total universe, and the observations cover a very short time interval. It is possible that our current understanding of physics contains errors that are only noticeable on a very large time scale or very large astronomical scale.

We can see back 13 billion years and 13 billion light years across. Yes, it's possible that our physics is wrong, but you could add that disclaimer to all science articles.

User:Roadrunner

Anonymous

I don't know how this will hold up, but it seems that very recent work indicates that the universe is about 14.7 billion years old. Maybe add this as an external link for the time being? [1] --65.146.234.124 09:22, 27 May 2004 (UTC)

Humans

Shouldn't the stuff on Humans and Earth be on Timeline of Earth? It's not relevant to the evolution of the Universe itself. --Tothebarricades.tk 16:43, 20 Sep 2004 (UTC)

Wikipedia

Not that I'm doubting the significance of the Wikipedia or anything, but to have it listed here on the Timeline of the Universe? Oberiko 22:11, 26 Sep 2004 (UTC)

a bit messy

I think this article is a bit messy and needs some work. It should concentrate less on humans and even the earth; after all, earth only forms 10^-30 (or something) part of the universe. Some of the more interresting events are on the Longer times page.

contradiction in wikpedia

the timeline here doesn't suit the one in the article "timeline of evolution" in some cases, like that of the appearance of molecular life is dated here for 600 BP whereas in "timeline of evolution" it is in 1,000 BP.

I really don't know a lot about it, but somebody should check it out and fix it.

Ido Hartogsohn

further contradiction

The section as follows appears to conflict with other articles, notable the Timeline of the Big Bang.

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The Reionization Epoch: 300,000 years

Light energy from the initial expansion of the Universe stretches out and weakens to the point where matter finally dominates in influence (this is the generally agreed-to end of the Big Bang era). Telescopes are not able to see this far back into the history of the Universe because the deionization of hydrogen caused "empty space" to be opaque to light in most wavelengths. Instead scientists must use particle accelerators and theoretical physics to infer what occurred indirectly. The most direct evidence scientists can measure from the Big Bang is the cosmic microwave background radiation that is uniformly pervasive throughout the Universe. It is thought this background radiation is actually a snapshot of the early Universe and provides the best evidence of the creation of matter during the early epochs.

---

The other page lists 300,000 years as the DE-ionization period, which caused empty space to be transparent to light, not opaque. Can someone a bit more knowledgable clarify this?

Anonymous

At around 300,000 years, the universe became transparent to light because atoms formed from the electrons and light nuclei. Before this, the universe was opaque because the particles could abosrb and reemit any wavelength of light with a random change in direction between the absorbed and emitted photons.

At 300,000 years the universe became cool enough for atoms to form. The electrons in the atoms can only absorb specific wavelengths. This allows most of the light to pass by, making the universe transparent in most wavelengths.

So, it went from ions to atoms. This section also should not be named Reionization Epoch. The reionization happened later as the first stars converted atoms back to ions. Maybe reionization was confused with recombination, a word used for deionization.

I'll fix the section and add another one for the later reionization by stars.--BrendanRyan 01:29, 8 May 2005 (UTC)

I did the changes about deionization. I found that there was already a section that mentioned reionization by the first stars and galaxies.

No superscripts in TOC

Apparently the superscripts (exponential notation) in the headings don't show up in the Table of Contents, so you get: "The Planck Epoch: 10-43 seconds" "The Degenerate Age - 1040 years"

This is confusing. Of course nobody will be fooled for long, but it would still look better if there were something to distinguish it. Unfortunately, I can't think of any except "10^-43 seconds", which to most people would probably be even more confusing.

Any ideas?

Nickptar 01:37, 9 May 2005 (UTC)

The Big Bang and matter formation

The subsection, The Planck Epoch: 10-43 seconds, first sentence should be reworded to say: "..., and everything in it, could have possibly begun with the Big Bang...". I suggest this because it is not proven absolutely that the Big Bang is really the cause of the formation of the Universe. Note the fact that it is usually called the Big Bang Theory. Hoekenheef 21:51, 15 May 2005 (UTC)

This whole timeline is based on the Big Bang theory. If some other theory (divine creation, Steady State, some exotic stuff I don't know about) is true, then at least the entire early part and possibly the entire latter part are invalidated. Nickptar 22:38, 15 May 2005 (UTC)

So you're basically saying that since this is what the article is about it should be stated like that? (just clarifying) Hoekenheef 23:09, 15 May 2005 (UTC)

Pretty much. It already says "according to prevailing scientific theory", and I've clarified that this means the Big Bang. Nickptar 23:49, 15 May 2005 (UTC)

Okay, well then in that sense the phrase is fine so I will make no further inquiry about this. Hoekenheef 10:22, 16 May 2005 (UTC)

related question: what was in existence during the Planck Epoch? In a theory such as string theory, is it proposed that strings existed at the earliest times? --Memenen 03:18, 8 Jun 2005 (UTC)

Are epochs moments or periods?

The Epoch of Nucleosynthesis: 3 minutes

The universe is too cool for nuclear activity to occur

The above is a contradiction, unless we assume that an epoch of 3 minutes means that it lasts 3 minutes or ends at 3 minutes. The sentence continues: "and at this point...", and a "point" is a moment. The Planck epoch alternates several times between being a moment or a (very short) period. I think someone who understands this better than I do, should decide if the epochs are moments or periods, and rewrite the epoch titles accordingly - for instance, "The Epoch of Nucleosynthesis: 1 second to 3 minutes". Art LaPella 23:01, 29 September 2005 (UTC)

Merger

All the Big Bang information should be qualified and / or reduced. A neutral timeline of the various theory of the univers (BB, quasi-steady state, plasma cosmology, etc.) should be placed at this article. JDR 19:34, 17 November 2005 (UTC)

No. (cf. Talk:Big Bang, Talk:Plasma cosmology, etc...) Feel free to make a Timeline of Plasma Cosmology page, or Timeline of the quasi-steady state universe page. Why are you on such a rampage? –Joke137 19:36, 17 November 2005 (UTC)

Why is the NPOV policy bieing ignored?!?!? "Timeline of the Universe" is not a BB timeline ... you and other BB apologists are on a "rampage" to marginalized viable and competing theories along with POVing articles, sadly. JDR 16:10, 19 November 2005 (UTC)

Just a minute now. I have to agree with JDR on this one. That or rename this article Timeline of Big Bang Cosmology DV8 2XL 16:09, 19 November 2005 (UTC)

They already have Timeline of the Big Bang. JDR 16:12, 19 November 2005 (UTC)

Then this one should go as violating NPOV, and the other timeline articles started. -- DV8 2XL

Moved

All the information that was here (and was about the Big Bang) was moved to the Timeline of the Big Bang. JDR

I don't think this article is going to work as a non-Big Bang timeline, because there are too many incompatible stories to tell (see, e.g. cosmology). I think it should be a kind of gussied disambiguation page, with links to pages like Timeline of the Big Bang, Timeline of plasma cosmology, Timeline of Christian creationism, Hindu Timeline etc... –Joke137 01:41, 22 November 2005 (UTC)

Definitely that's what should happen. It's going to turn into a confusing mess no mater how hard someone tries to keep it under control. DV8 2XL 16:55, 22 November 2005 (UTC)

Article content moved to the Dating Creation/Timeline of Big Bang

This article as it stood was an article about creation dates according to different ideas. I can accept the fact that some may not like it being the Timeline of the Big Bang article, but we have to realize that the universe in common parlance is refered to as the Big Bang. We need to make an editorial decision at some point as to what qualifies as the universe and how it should be described. Do we pander to every so-called "skeptic" who thinks that the Timeline of geology is only 6000 years or so? --Joshuaschroeder 20:33, 22 November 2005 (UTC)

Yes, as a mater of fact, an encyclopedia does 'pander' to various ideas. If it is notable it deserves a non-judgemental entry. No editor may arrogate him/herself the position of arbiter of what deserves mention and what does not. "the universe in common parlance is refered to as the Big Bang" - say what? 20:52, 22 November 2005 (UTC)

Common parlance of some scientists. This is not NPOV to redirect it to the BB timeline. JDR 21:52, 22 November 2005 (UTC)

In the article on the universe where does it indicate that we should be dealing with points other than those dealt with at the Timeline of the Big Bang and dating creation? I have no objection to making a disambig page here, but the "beginnings" point was best left for a different place. --Joshuaschroeder 21:10, 22 November 2005 (UTC)

I support the current redirect. As recently as three days ago, this article (Timeline of the Universe) consisted almost exclusively of the content now found at Timeline of the Big Bang. Now that its content has been merged there, the only logical choice is to redirect to the content's new home. To do otherwise would be to deceive the dozens of articles that have linked here. (In time, those links should be changed to explicitly point to Timeline of the Big Bang, but we should wait for the issue to cool down first.) In the last couple of days, some content has been added here that now lives at Dating Creation, but presumably few if any links to here were created during that period, so it makes sense to move that content without a redirect.Melchoir 21:22, 22 November 2005 (UTC)

Just because there has been a bias history in dozens of articles that have linked here, that does not mean that this should be allowed. AND, the linked articles can and will be changed to the timeline of the BB if that is what they were trying to point to.

Also, if joshua would stop redirecting .... mabey a real timeline can be made. .... big articles are not made in one day nor one week ... and at time not in a month. BUT, many have grown over time. JDR 22:07, 22 November 2005 (UTC)

Sigh... it seems change has passed me by. What is it that you want, Reddi? Is this page going to become a conglomeration of all timelines ever proposed? Melchoir 21:36, 22 November 2005 (UTC)

To say that the "timeline of the universe" is the "timeline of the BB" is 'not NPOV. There are various timelines, religious and scientific. Joshuaschroeder is editing to make a point, clearly in violation of wikipedia's policies. JDR 21:52, 22 November 2005 (UTC)

User:Reddi has decided to revert any edit I make, no matter whether it is justified or not. See his RfC and his RfArb. --Joshuaschroeder 21:41, 22 November 2005 (UTC)

"Timeline of the Universe" isn't the most popular search phrase anyway, so the battle is somewhat void. As Universe can also seen as a term of philosophy or religion, putting all these dates in one table is only silly, not self-evidently false. But as en.wikipedia is the proud home of listmania-gone-wrong items like List of U.S. Presidents by height order, how much sanity can be asked for?

OTOH Timeline of the Big Bang is somewhat a silly lemma too, as the Big Bang in itself is the starting point of this timeline. What about Timeline of physical cosmology? And B.T.W. as Cosmology has become the umbrella article, why not just move the list of important dates in the universe according to all accounts I was able to google to that article.

Pjacobi 21:57, 22 November 2005 (UTC)

Thanks for chipping in, Reddi and Pjacobi. Reddi, please calm down. Let me clarify my concerns. Our first, short-term responsibility is to protect the integrity of Wikipedia. There are some seventy articles that still link here, and when those links were made, they were intended to point to the content now found at Timeline of the Big Bang. I don't think anyone is arguing that we should move it back. Here is, I think, the best solution:

1. For now, redirect to Timeline of the Big Bang for the reasons I've stated above and in my last comment.
2. Wade through all the articles that link to this article and change them to point to Timeline of the Big Bang.
3. Re-make this article into a glorified disambiguation page pointing to all articles containing a timeline of the universe, including Timeline of the Big Bang.

By the end of this process, everyone gets the content they want, and no one can complain about POV issues. Who's with me? Melchoir 22:12, 22 November 2005 (UTC)

Sorry, one last thing: I strongly oppose the creation of a Master Timeline that include all dates from all timelines of the universe. Since the various cosmologies involved are logically incompatible, the result would be meaningless. In any case, Reddi: if you really want to make such a thing, please try it during step 3 and not step 1. Quite frankly, once step 2 is done, I'll take this article off my watchlist. And, Pjacobi: the existence of List of U.S. Presidents by height order doesn't make all silliness okay, does it? Melchoir 22:28, 22 November 2005 (UTC)

It's only one of the bad precedents that I like to give in discussions about the ultimate faith of the Wikipedia. Category:Amputees also qualifies. An encyclopedia is not only defined by what it includes, but also by what it doesn't include. But this argument is lost on those, waiving the Wikipedia is not paper flag.

Sory for rant mode. --Pjacobi 22:38, 22 November 2005 (UTC)

I agree with your points, Melchoir. The article links directly from the Cosmology template for example and to insist that it remains in this form seems strange to me. --Joshuaschroeder 22:44, 22 November 2005 (UTC)

Okay, step 2 is progress...

...and it's almost done. Special:Whatlinkshere/Timeline of the Universe hasn't quite recovered from the change to Template:Cosmology, so I'm not sure if there are more relevant links to hunt down. Melchoir 00:41, 23 November 2005 (UTC)

Update: yeah, it's done. Melchoir 08:04, 4 December 2005 (UTC)

Big Bang and entropy

As a non physicist, I would like to ask about the nature of entropy and the big bang. As entropy increases over time, one would assume that the Big Bang occurred in a condition of incredibly low entropy, and that the big bang itself is a situation of increasing entropy over time... My question is, how and when did this low entropy situation occur? The inflationary epoch? Before? Was it built into the vacuum fluctuation? How is it that the structures we have today have evolved in a situation of increasing entropy, whilst the lower entropy universe at the big bang was almost structureless, and, prior to inflation, almost completely chaotic? John D. Croft 00:25, 17 May 2007 (UTC)

Asking for a merge

Let's get 'er done

I wanna merge the articles. Let's get 'er done. -- Zalasur 07:23, Mar 23, 2005 (UTC)

I think it's worthwhile having one article covering the timeline of the universe from the Big bang up to now, and having a separate article that summarizes this material and also includes projections about the future of the universe. Personally, I oppose the proposed merger for this reason. --Eric Forste 04:25, 12 Jun 2005 (UTC)

bigbangisdeliciouscosito

I'm not sure who is more confused. The person asking the question or the person answering the question.

External Link

• Did the Big Bang create primordial black holes?

---

Should we rename this page: "timeline of the early universe"?

you have my vote. -- looxix 10:02 Apr 11, 2003 (UTC)

Me too -Lethe | Talk

Me three -John D. Croft 12:12, 28 August 2007 (UTC)

CP violation

I'm curious. In the periods where quarks/antiquarks and electrons/positrons were annhiliated, was the excess possibly caused by change-parity violation? And if this is so, doesn't this suggest that even these are made of even smaller particles, because for the cp effect to occur, the particles mustn't be assymetric?

Sorry man but Who Knows???? Skeletor 0 (talk) 17:14, 15 April 2008 (UTC)

I have seen it suggested that the CP Symmetry violation needs Time to be factored in to give it Symmetry. CPT Symmetry then would have been the situation before the plank era, and CP violation would have led to the creation of time itself, with a specific arrow from past to future! Anyone with more information there whocan help? John D. Croft (talk) 23:56, 15 May 2008 (UTC)

10^-48 seconds?

Hi, does anyone have an idea where the 10^-48 mentioned on this slide of a presentation titled "A Timeline of the Universe" come from? (http://astro.uchicago.edu/home/web/mohr/Compton/HTML_five/sld022.html) -- Schnee 14:40, 9 Jun 2004 (UTC)

A typo? Given that it is about 5 orders of magnitude smaller than the Planck time there's little else it could be! Dazza79 (talk) 00:20, 24 February 2008 (UTC)

This isn't true

Quote. Imagine a block of ice and an aluminium Coca-Cola can. If you increase the temperature to an extremely high value, then both objects will vaporize, producing a mixture of water and aluminium vapor which can be considered a single entity. If the temperature decreases, then below a certain value the aluminium will condense and freeze and stop interacting with the water vapor. Unquote.

---

Water and aluminum raised to a temperature that both vaporize becomes a mixture of aluminum, hydrogen, oxygen, and various ions and is part plasma (gas heated to the point that electrons break free creating ions), part gas. When the temperature is decreased, aluminum OXIDE, water, hydrogen peroxide, and hydrogen gas will condense and freeze out of the mixture.

---

Perhaps "Imaginine a block of a and b" where a and b are elements and don't chemically react at gas temperatures. argon and gold may do the job if they start as frozen, and then heated, and then frozen back again.202.156.2.36 12:17, 24 May 2005 (UTC)

Remember to be bold, dude: if you see something you know is wrong, change it. I fixed it. --Superiority 05:06, 7 November 2005 (UTC)

Should we merge this with Timeline of the Universe?

At first I was hesitant to merge the two articles together but now I belive the two should be merged. Any thoughts?

See my reply to Zalasur above. --Eric Forste 04:30, 12 Jun 2005 (UTC)

dont no if that is a good idea i mean i see were you are coming from but its hard to put it together .

Should we merge this with Timeline of the Universe?

We should merge them cause the Timeline of the Universe is very low on info on the early seconds of the big bang. Timeline of the Universe might have to be expanded even more.

I agree that information from Timeline of the Big Bang about the early seconds ought to be summarized in Timeline of the Universe, but I think that two articles ought to remain, after this process is done. I'll work on summarizing early data from Timeline of the Big Bang in Timeline of the Universe if you don't merge them. --Eric Forste 04:51, 12 Jun 2005 (UTC)

I do not think the articles should be merged. There should be a summary in ...Universe linking to ...Big Bang. Firstly, there is much to talk about in respect to the Big Bang (as can be seen with the size of the article) and I think merging would just clutter things up and diffuse the subject matter. Secondly, while I subscribe to the Big Bang theory it is still under development, and any subsequent changes would be better applied to the smaller article than the large one. Mr. Brownstone 15:16, 30 July 2005 (UTC)

Mixed up epochs

It says, "The Epoch of Nucleosynthesis covers the time from 3 minutes to 379,000 years after the Big Bang." But if you click Nucleosynthesis (piped to Big Bang nucleosynthesis) it says "It only lasted for about three minutes". This is a contradiction. I think it only lasted 3 minutes, but in that case your other epochs need to slide over to make room, or else some epoch has two names or something. Art LaPella 23:10, 29 September 2005 (UTC)

You're tight. BBN stopped at +3min. At 400.000 the universe became transparent and CMB decoupled from matter. I'll fix it tomorrow, if novody was faster. --Pjacobi

There's another paradox in this section, "At this point the universe consists of about 75% hydrogen, 25% helium and trace amounts of deuterium, lithium, beryllium, and boron", so 3 minutes after the big bang BBN is finished and we have all of the abundant light elements formed.... but then... "379,000 years after the Big Bang: The temperature of the Universe is approximately 3000 kelvins. At this temperature hydrogen nuclei capture electrons to form stable atoms."

How can the universe consist of atoms before atoms exist? Maybe it should be specified that the universe consists of isotopes or nuclei of 75% hydrogen, 25% helium, etc. --Akira-no-Baka

It says "hydrogen, ... helium ... deuterium" etc., but it doesn't say atoms, just as the Sun article mentions hydrogen, helium, oxygen etc. but not atoms. At that temperature the universe would be a plasma of independent nuclei and electrons. According to atom: "Atoms are canonically distinguished from ions by their balanced electrical charge.", that is, nuclei in a plasma aren't atoms. Perhaps the semantics is debatable, but that's what it means. Yes, it would be helpful to add the word "nuclei" or "plasma", as part of the bigger rewrite discussed above. Art LaPella 21:17, 21 October 2005 (UTC)

Mixed up epochs unscrambled

I couldn't get the professional scientists to fix this, so here I go without you. My version could easily be improved. However, I'm confident my version is better than what was there before, as described above.

The temperature estimates kept conflicting, so I removed many of them rather that guess. Similarly, I removed the estimate of the size of inflation, as I could find no consensus for that figure elsewhere. And I removed the sentence that claimed hydrogen nuclei formed after 1 second, because a hydrogen nucleus is a proton, and it says protons and other hadrons formed earlier. Other sources seem to agree with the earlier time.

I often relied on [2] to help unconfuse this page.

Timeline of the universe has similar problems. First let's see how this change turns out. Art LaPella 23:19, 29 October 2005 (UTC)

timeline???

Um...I was kinda hoping to see an actuall timeline here....do you think you could make one? -Dr. Cribbit (message made by editing the page.)

Does that mean me in particular? If you mean an actual graphical line, no I don't have much experience with graphics. If you don't, I'm not sure what else you would want. Art LaPella 04:39, 2 November 2005 (UTC)

Cribbit: I mean anyone. And by geographical, I'm assuming you the type of timeline that's a stright line and there are notches on it with times and events and stuff? That was kinda what I'm looking for...

Yes! I was expecting a timeline too. I was looking to compare with Timeline of Motorized bicycle history --CyclePat 20:14, 26 November 2005 (UTC)

I'm missing something. That bicycle timeline has neither a straight line with notches, nor graphics. It looks like this timeline, but without the pictures. Art LaPella 00:13, 27 November 2005 (UTC)

Opps! Maybe I should have read a little about the article first. I was just looking at overal format. How was I to know that somewhere in the text (13.7 ± 0.2) x 109 was the year or some sort of indication of time. This article seems to have much more text information. Sorry. --CyclePat 03:17, 27 November 2005 (UTC)

Maybe this kind of confusion could have been prevented by making the Big Bang itself part of the timeline that starts at "The Big Bang and matter formation". That is, the paragraph preceding "The Big Bang and matter formation" should be the first event, dated at 13.7 billion years ago, followed by the Planck epoch a split-second later. Art LaPella 17:17, 27 November 2005 (UTC)

cleanup

I've been trying to clean this article up. It was in pretty sorry shape before. Some information in the previous article was wrong, or at least poorly worded, but a lot of it I've omitted out of laziness/limited time. If some interested parties could compare the present version to this version and put pertinent, credible seeming information back in, it would be appreciated. Otherwise, I'm sure I'll get to it... sometime. –Joke 00:30, 30 January 2006 (UTC)

I couldn't fix this sentence: "It is not known how inflation During inflation..." Some words were apparently lost before the word "During", but I can't guess what the words were. Art LaPella 05:11, 31 January 2006 (UTC)

Recombination

I think the era of recombination could be explained better here if you make some mention of Hydrogen atoms and perhaps the Bohr model.

If my understanding is correct, before "recombination" the protons and electrons were separate, and after "recombination" the protons and electrons form Hydrogen atoms.

When light of any frequency passes through a gas of free protons and electrons, it is all absorbed; because the motion of the electrons and protons is not quantized, it can absorb light of any frequency.

Once the electron gets into the quantum shells of the proton and the electron/proton pairs form hydrogen atoms, the electrons can then only absorb light which has a frequency high enough to move the electron out of the 1s Bohr orbital.

If light has to pass through layer after layer of Hydrogen gas, eventually all of it will be absorbed except for the light that has a low enough frequency that it does not knock the electron out of the 1s orbital.

The light that is not absorbed has a maximum frequency the same as as blackbody radiation of a surface of about 3000 K. Whether the observed 3 Kelvin of the Cosmic Background is due to a doppler effect and recession velocity, or whether it is due to some expansion of space having some effect on the wavelength seems to still be some controversy.

Also, it should be pointed out that this phenomena may actually describe a "first" combination of electrons and protons into hydrogen atoms, unless you have a steady-state or cyclic model of the universe. I think the term "recombination" comes from studies of chemistry where experiments separate the particles, then let them recombine. In Big Bang theory, the "re" does not really apply.JDoolin 16:55, 27 August 2006 (UTC)

Just Pondering

Wouldn't it be horrible if a vacuum metastability disaster occured while you were in the restroom? What if the last thing you did was use the toilet? Think of that next time you're on the john. Cissel 22:10, 18 September 2006 (UTC)

Confusion about structure: baryogenesis

Baryogenesis is described to in the "very early universe" section. Later it is described in the Quark-Hadron phase of the "early universe" section. I think this article needs more consistent structure.

Ordinary Person 06:49, 21 November 2006 (UTC)

Mixed up epochs (redux)

I notice there are several inconsistencies between the early universe epoch times in this article, in Graphical timeline of the Big Bang and in the individual epoch articles. For example, this article says the hadron epoch was 10^-6s to 10^-2s; Graphical timeline of the Big Bang says 10^-12s to 10^-6s; and hadron epoch says 10^-6s to 1s. Does anyone mind if I try to tidy up these inconsistencies, and maybe add some references at the same time ? Gandalf61 17:24, 3 February 2007 (UTC)

Okay, this is what I propose as a consistent timeline for the early universe as far as the origin of the cosmic microwave background, and a nomenclature for the various phases:

• Planck epoch : earlier than 10^-43s

• 10^-43s : Gravity separates from other forces

• Grand unification epoch - 10^-43s to 10^-35s

• 10^-35s : Strong force separates from other forces; X and Y bosons no longer created

• Inflationary epoch - 10^-35s to 10^-32s

• 10^-32s : Inflation ends; quark-gluon plasma created by reheating

• Electroweak epoch : 10^-35s 10^-32s to 10^-12s

• 10^-12s : Weak force separates from other forces; W and Z bosons no longer created; weak force becomes short range force

• Quark epoch : 10^-12s to 10^-6s - universe is quark-gluon plasma

• 10^-6s : Quarks become confined in hadrons

• Hadron epoch : 10^-6s to 1s - as temperature falls, new hadron-antihadron pairs no longer created; general annihilation of hadron-antihadron pairs; remaining heavier hadrons decay leaving only protons and neutrons

• 1s : Neutrinos cease to interact with other particles due to falling density

• Lepton epoch : 1s to 3s

• 3s : Electron-position pairs no longer created; general annihilation of electron-positron pairs leaving one electron per proton; universe now dominated by photons

• Photon epoch : 3s to 300,000380,000 years - Big Bang nucleosynthesis occurs between 100s and 300s

• 300,000380,000 years : electrons and nuclei combine to form atoms in recombination; photons no longer react significantly with matter; universe is transparent to photons; origin of cosmic microwave background

There is a lot of consistency from different sources over the milestones and their times; much less consistency over the naming of the epochs/eras. For the milestone times I have generally followed Allday Quarks, Leptons and the Big Bang, except for the milestone where quarks become confined in hadrons, which I have taken from Gribbin The Universe: A Biography. Things I have left out are:

• Baryogenesis : there seems to be no clear consensus on whether the asymmetry between matter and anti-matter originated in the "grand unification epoch" or the "electroweak epoch".
• "Inflation epoch" : I haven't used this term because there does not seem to be a clear consensus on when exactly inflation ends, although it must be sometime in the electroweak epoch.
• "Nucleosynthesis epoch" : I haven't used this term because this epoch would have to be placed inside the "photon epoch", creating the problem of what to call the interval between the end of the "lepton epoch" at 3s and the start of nucleosynthesis at 100s.

Feedback is very welcome. If there are no big objections then I will start making this article, the Graphical timeline of the Big Bang, and the various epoch articles consistent with this timeline. Gandalf61 12:28, 4 February 2007 (UTC)

Had further thoughts. Reinstated inflationary epoch in my proposed timeline - see above. Gandalf61 17:37, 6 February 2007 (UTC)

Have updated individual epoch articles and Graphical timeline of the Big Bang. Will update this article next. Gandalf61 12:00, 18 February 2007 (UTC)

There really is no "hadron epoch". When hadrons form out of the quark-gluon plasma, their rest mass is already much larger than kT, so annihilations are not replenished by pair-creation events. Immediately after the end of the Q-G plasma the available particles are photons, neutrinos, electrons, muons and the light mesons (+ antiparticles). It is probably fair to "date" the lepton epoch from this point. I'd update myself, but don't know how to adjust the graphics! PaddyLeahy 22:22, 16 May 2007 (UTC)

Formation of the Universe (Intro)

The sentence before last of the introduction :"Finally, the epoch of structure formation began ,[...], superclusters formed." This presents the predictions made by the "bottom-up" theory. There is also, I am sure amongst yet others, the "top-down" theory that says the highest order organisation (super clusters and clusters) formed first, and THEN working downwards the rest formed (galaxies, then stars, etc...)

Presenting one view of things is good, please present others, or let the reader know this is ONE theory on which there is no scientific consensus. 132.149.107.65 13:10, 12 July 2007 (UTC)

There are many theories, as plasma cosmologists and creationists often remind us, but which ones should be mentioned without violating WP:Undue weight? I found many Internet articles on Hawking and Hartog's theory, but I couldn't find anything on Wikipedia except Cosmic variance and Flexiverse, neither of which says superclusters came before galaxies and stars. Just how popular is this theory if it doesn't even have its own article? Art LaPella 21:21, 12 July 2007 (UTC)

Grammar

Timeline of the Big Bang#String Theory epoch says: "According to Maldacena's conjecture, has a counterpart from the ten-dimensional interior on the fourth dimensional surface." I leave the scientific merit of this sentence to the scientists here, but grammatically the sentence is incomplete without a subject (grammar). What "has a counterpart..."? Art LaPella 20:48, 24 July 2007 (UTC)

Resolved

 – Art LaPella 02:26, 26 July 2007 (UTC)

Units of time

The usage of billions and trillions of years in this article is problematic given the long and short scales. I'd prefer replacement with the SI units (gigaannum or teraannum respectively, abbreviated Ga or Ta).LeadSongDog 22:07, 25 July 2007 (UTC)

Discussing the Discussion?

This discussion would become much more profitable if it were separated into Discussion About the Topic vs. Discussion About the Article.

Even without the discussed changes to the subject matter, the article needs fixing. As of 20070821, there is far too much switching back and forth of verb tenses, to the point of ambiguity and confusion.

rowley 18:05, 21 August 2007 (UTC)

Wikipedia:Talk page guidelines states: "Talk pages are for discussing the article, not for general conversation about the article's subject", although in practice Discussion About the Article can depend on some Discussion About the Topic as long as we remember what the goal is. Although I haven't changed the verb tenses, I agree it would be clearer to describe the Big Bang and its sub-events in the past tense. Art LaPella 20:43, 21 August 2007 (UTC)

Either most or all of your new heading capitalizations should be reverted, according to Wikipedia:Manual of Style (headings)#Capitalization. Art LaPella 20:51, 21 August 2007 (UTC)

Yes, I thought so too, so I've reverted the capitalisations. Gandalf61 10:53, 22 August 2007 (UTC)

Umm....

May I ask who came up iwth 1 trillion years for heat death of the universe? I knwo full well where the 100 trillion came from.(Doctor Who, for those who don't know) 82.12.86.64 21:19, 26 August 2007 (UTC)

Yes, 1 Ta seems very short. Red dwarf stars have lifetimes ~ 1 Ta, so it should take at least several times as long for the heat death, even if we didn't include brown dwarf stars, etc. Jmacwiki (talk) 21:55, 29 August 2009 (UTC)

RFC - Timings need careful expert checking

The timings as cited in this article, and Big Bang nucleosynthesis need careful checking by a physicist.

For example, we are told in this article that:

• "Nucleosynthesis: Between 100 seconds and 300 seconds after the Big Bang"

and also:

• "nucleosynthesis only lasts for about three minutes"

which are fairly consistent (but could be more accurate).

But in Big Bang nucleosynthesis we are told:

• "There are two important characteristics of Big Bang nucleosynthesis (BBN): 1/ It lasted for only about seventeen minutes (during the period from 3 to about 20 minutes from the beginning of space expansion) ..."

This suggests the timeline, and mentions of all timings in the related sub-articles, need checking. FT2 ^{(Talk | email)} 00:00, 6 September 2007 (UTC)

Big Bang nucleosynthesis was not a single event. It was a series of linked atomic reactions which took place at different rates over a period of time - a detailed list of these reactions is given here. Different authors locate the start and end of nucleosynthesis at different times. The start of nucloesynthesis is typically set at 100 seconds because this was when the universe was cool enough to allow deuterium nuclei to form. The end of nucleosynthesis is more difficult to fix because the process didn't just stop - reaction rates slowed down as the universe expanded and cooled. It's like trying to fix the exact time at which you fall asleep. 300 seconds is quoted here, but this source puts the end of nucleosynthesis as late as 35 minutes ! It would be inapproriate to explain all these complications in a summary timeline article, so "between 100 second and 300 seconds" is a simplied timescale. Gandalf61 13:25, 6 September 2007 (UTC)

True, but would it be inappropriate to summarize the above as something like "on the order of 100 to 300 seconds", thus relieving the contradiction? Art LaPella 20:14, 6 September 2007 (UTC)

Ultimate fate of the Universe

The latest edit was inadvertently saved. My latest version would have been:

There are several speculations, theories about the ultimate fate of the universe. The term is widely used, although in fact it does not mean ultimate fate which would imply an END. The speculation is primarily about the question of whether it will have an END, and then What will its end be IF it will have one. The corollary heretic question is whether the Big Bang was a real beginning of space-time, or something already existed before it? Where did matter/energy come from to accumulate into a singularity at the time of the big Bang? These are two questions that we find hard even to contemplate.

I shall leave any alteration to another editor. LouisBB (talk) 22:09, 30 January 2008 (UTC)

Grand unification epoch

Before I was sidetracked I came here to find out: Why do we call the above 'Grand Unification epoch, when the gravitational interaction was already separating, and why only ends when the strong nuclear force separates from the electroweek force? LouisBB (talk) 22:32, 30 January 2008 (UTC)

The name comes from grand unification theory, which is the standard name in physics for a theory that unifies the electromagnetic, weak nuclear and strong nuclear forces. A theory that also attempts to unify the gravitational force is known as a theory of everything or ToE. Gandalf61 (talk) 00:18, 1 February 2008 (UTC)

Thanks Gandalf61. It is clear enough, when it is explained. Unfortunately the name confuses the uninitiated as it gives the impression that forces unify in this epoch.

Having just been loking at the Graphical timeline of the Big Bang article and some of the earlier discussions here I was surprised to see, that your suggestions of last february have not materialised. I am referring to separation of the individual interactions/forces from the others, as I always understood thet the individual fundamental forces supposed to have separated from all others. The abbreviated reference to the forces, such as week force, strong force could also confuse. Would it take much space to use consistently full names? Sorry about the nitpicking, but I am translating the graph and I want to be right. LouisBB (talk) 22:30, 3 February 2008 (UTC)

Wikipedia's CNB article says neutrino decoupling occured 2 seconds after Big Bang

This article says one second in the hadron epoch section —Preceding unsigned comment added by 72.65.170.104 (talk) 21:41, 26 February 2008 (UTC)

Someone keeps changing my corrections

The grand unification epoch did not occur between 10^-43 seconds and 10^-35 seconds after the Big Bang It ended 10^-36. And the electroweak epoch did not occur between 10^-32 seconds and 10^-12 seconds after the Big Bang. It began at 10^-36 when the Grand unification epoch ended. My source is Introduction to Cosmology by Barbara Ryden, which is an upper level college textbook. What do people think I'm just making these changes for fun?

AGAIN someone deleted by corrections. The electroweak epoch didn't "merge electromagnetism and the weak interaction into a single electroweak interaction." They were already unified in the Grand Unified epoch and earlier in the Planck epoch. The strong force just separated from the electroweak force. It became stronger. (I have the same source as above to support this) It even says this earlier in the article! What is the point of correcting these articles if people just delete your corrections? i thought this was supposed to be an encyclopedia anyone correct! —Preceding unsigned comment added by 72.65.170.104 (talk) 04:06, 27 February 2008 (UTC)

I'm not a scientist, but if your source is Introduction to Cosmology by Barbara Ryden, you would have gotten a more serious answer if you had included your source in your WP:edit summary, and/or named the book in a WP:reference. If you WP:Cite your sources, you're more likely to at least get a debate on whether your sources are good enough. Art LaPella (talk) 05:13, 27 February 2008 (UTC)

I dont understand big bang theory myself but I do understand wikipedia theory. Please give us something we can verify, ideally through reliable sources. Thanks,

SqueakBox 05:17, 27 February 2008 (UTC)

Introduction to Cosmology by Barbara Ryden is a very reliable source published in 2003. Like I said it is an upper level college textbook used at Brown university where I attend, and sometimes teach. The corrections I made about the times of the epochs comes from the bottom of page 196.

And the other correction I made about the electroweak epoch is extremely obvious. This wikipedia article contradicts itself. In the Grand unification epoch section it says "Eventually, the grand unification is broken as the strong nuclear force separates from the electroweak force." It became stronger than the electroweak force. The electroweak force (electromagnetism and the weak force) were already unified in the Grand Unified epoch and earlier in the Planck epoch. But in the electroweak epoch section it says that electromagnetism and the weak force unified, which is ridiculous. Also the link to the "the dark ages" is for the period in mid-evil history, not a link for the time before recombination and decoupling, possibly because there is no such article, so I'm going to delete that link. Someone should make a Dark ages (cosmology) page though.

I suggest resubmitting your change, but citing your source this time, preferably as described at Wikipedia:Citing sources. If you have no citable source for the second change, you could at least use an WP:edit summary referring to this talk section Talk:Timeline of the Big Bang#Someone keeps changing my corrections. I wouldn't WP:revert (undo) such a change, and I'm pretty sure SqueakBox wouldn't either. I won't speak for the scientists here, but I'm pretty sure they would either accept the change, or at least give you a good explanation why not. We just need to distinguish you from adolescents playing with the article for the hell of it. Wikipedia:Registering would also be helpful, after which you could describe yourself on your Wikipedia:User page. Art LaPella (talk) 22:31, 27 February 2008 (UTC)

The problem now is that the epochs are no longer consecutive. The grand unification epoch is "Between 10^-43 seconds and 10-³⁶ seconds after the Big Bang", the inflationary epoch is "Between 10^-35 seconds and 10^-32 seconds after the Big Bang", and the electroweak epoch is "Between 10^-36 seconds and 10^-12 seconds after the Big Bang". Also, the supporting articles grand unification epoch and electroweak epoch no longer match this article. Art LaPella (talk) 21:47, 28 February 2008 (UTC)

Well I can easily put the electroweak epoch first, but it does overlap with the inflationary epoch.

I see that the times in the separate articles no longer match this article, but the sources aren't listed with page numbers in those articles, so it's not to easy to check. I can consult some other professors at Brown. Or you could find out who listed those sources and ask them if they can find a page number that supports the times they listed. —Preceding unsigned comment added by 72.65.160.182 (talk) 04:36, 29 February 2008 (UTC)

I found that the person who listed those sources was User:Gandalf61. I invited him to comment here; see User talk:Gandalf61#Timeline of the Big Bang. Here are links to Gandalf61's edits: [3] [4] Art LaPella (talk) 05:59, 29 February 2008 (UTC)

1. Inflation has to start when the grand unification epoch ends because it is the phase transition at the end of this epoch that triggers inflation. Whether we put this at 10^-35 or 10^-36 seconds does not greatly matter to me - there are no doubt reliable sources for both figures. Important thing is that we should be consistent, and not imply that there was some unexplained gap between the two events.
2. Whether you count the inflationary epoch as being part of the electroweak epoch or as a separate stage preceding the electroweak epoch is a trivial matter of terminology. Personally, I like the simplicity of a conceptual model in which the epochs are sequential, and do not overlap, but I wouldn't fight an edit war over it.
3. Important considerations for anyone making changes here is (a) give sources (as already said); (b) make sure that there is consistency between this article, the individual epoch articles and the Graphical timeline of the Big Bang - at present they are not consistent. Gandalf61 (talk) 08:18, 29 February 2008 (UTC)

As I suspected, sources differ on both the start and end times of the inflationary period. I have:

10^-36 seconds to 10^-34seconds (Liddle An Introduction to Modern Cosmology p107)

10^-36 seconds to 10^-32seconds [5]

10^-35 seconds to 10^-33seconds [6]

10^-35 seconds to 10^-32seconds (Allday Quarks, Leptons and the Big Bang p335; Gribbin The Universe: A Biography p49)

As I said, I don't feel strongly about which set of times we use, as long as we are consistent. To make things consistent for the time being I have changed the start of the inflationary period to 10^-36 seconds in this article, in the Inflationary epoch article and in the graphical timeline. Gandalf61 (talk) 17:08, 1 March 2008 (UTC)

I didn't actually edit the inflationary epoch. I just edited the the grand unification epoch and electroweak epoch. I see what you're saying about it being simpler to have the electroweak epoch and the inflationary epoch separate, but if they did overlap we can't change it just for simplicity's sake. I think we should move the electroweak epoch into the very early universe section. But if we do this should the electroweak epoch come first or the inflationary epoch? Or should we combine them into the inflationary/electroweak epoch and of course list the separate times of their duration? —Preceding unsigned comment added by CosmologyProfessor (talk • contribs) 05:18, March 2, 2008

Read my point (1) above. The start of the inflationary epoch has to coincide with the end of the grand unification epoch because the phase transition at this time is what triggers inflation. When you moved the end of the grand unification epoch, you should have moved the start of the inflationary epoch for consistency. But you didn't, so I sorted it out for you.

As for your second point, if you want to say that the electroweak epoch extends all the way from the separation of the strong force to the separation of the weak force, then inflation occurs during the first part of the electroweak epoch - neither one comes first, because they overlap. As you have created the overlap, I will leave you to decide how best to explain it.

The distinction between the Very early universe section and the Early universe section is that the physics of the Early universe section, after the end of inflation and baryogenesis, is well understood, whereas the physics of the Very early universe section is still, to some extent, speculative. Your enlarged electroweak epoch straddles the boundary - physics is well understood at the end of it, but not at the beginning. This was another reason for making a distinction between the inflationary epoch and the original, shorter electroweak epoch. Again, I leave to you to decide how best to handle your new longer electroweak epoch. Gandalf61 (talk) 09:53, 2 March 2008 (UTC)

Reason for problem

Hi guys, I just want to suggest that the reason why this article is giving you so much trouble is because you are trying to merge several different incompatble theories. Just a heads up.Skeletor 0 (talk) 16:43, 15 April 2008 (UTC)

That's a bit cryptic. Which theories would they be, and in what way do you think they are incompatible ? Gandalf61 (talk) 16:41, 15 April 2008 (UTC)

Hold on one sec I gotta change computers. Back in a min. Skeletor 0 (talk) 16:44, 15 April 2008 (UTC)

Ok I'm back and I thought that maybe it not a problem but it's certainly a source of confusion. You have string theory and super symmetry which are not anywhere near each other. String is almost the opposite of super symmetry. I see how you are trying to explain all the theories but it is very confusing. Skeletor 0 (talk) 17:08, 15 April 2008 (UTC)

The article is using string theory as shorthand for the more precise description superstring theory, which does indeed incorporate supersymmetry. However, I agree that the "string theory epoch" section is misplaced - the period it refers to, when the universe is filled with a quark-gluon plasma, occurs much later, after inflation and reheating. Also the term "string theory epoch" is not a standard term in cosmology and seems to be a Wikipedia neologism. Easiest way to fix this is to remove the whole "string theory epoch" section, which I will do now. Gandalf61 (talk) 08:23, 16 April 2008 (UTC)

Glad I could help and sorry if I was a bit rude. Skeletor 0 (talk) 16:56, 17 April 2008 (UTC)

General Dismissiveness

This article has a lot of excellent information. But here and there is included a statement of general dismissiveness that, while perhaps technically supportable, goes a bit overboard in my view.

Here is just an example:

"However, as of yet there have been no observed Population III stars which leaves star formation a mystery."

Partially correct -- no Pop III stars have been observed, but that doesn't mean star formation is some complete "mystery." Just read Extreme Stars, At the Edge of Creation [2001] by James Kaler to get some idea of much we do know about star formation and evolution. It's true Pop III stars aren't exactly "pinned down" in all their specifics, but surely they are constrained in their possibilities. I seriously doubt that the failure to observe any means their existence is in question. Obviously that failure is more due to the fact that this population of stars resides somewhere in a neighborhood that is 13 billion years away. It's hard enough seeing entire galaxies 11 and 12 billion years distant.

Actually, there is no requirement that Pop-III stars have very high mass, so far as I know. So there could be some LOW-mass Pop-III stars surviving even in our own galactic, and even stellar, neighborhood. Say, within 100 or 1000 l.y. Jmacwiki (talk) 21:48, 29 August 2009 (UTC)

Notice any other examples that I might be talking about?

DCCougar (talk) 00:29, 21 April 2008 (UTC)

Yes I see what you mean, (nice catch by the way!) I don't know why this statment is in the article. We actually know alot about star formation. In fact I just had to do a school project on it so I know we know alot. What I think the statment is trying to say is that we dpn't know a lot about population III star foemation but I don't get that either. Star formation back them would not have been much different. in fact it would have only been faster. The citation used is three years out of date and should no longer be counted. Never the less I have only changed it to "However, as of yet there have been no observed Population III stars which leaves their formation a mystery.[7]"

I could not find a citation to back me up but I know that more is known about pop III stars then the article lets on. Skeletor 0 (talk) 18:01, 23 April 2008 (UTC)

An Error

The article seems to suggest that the inflationary era was after the Planck Era, and after Supersymmetry. I was of the belief that it occurred before the Planck Era, and that it was the "energy dumping" that occurred at the end of the inflationary period that filled the universe with matter. This would imply that it came first. Should we shift the order and ammend the figures to reflect this? John D. Croft (talk) 23:56, 15 May 2008 (UTC)

The linked articles Planck epoch and inflationary epoch each contain several references which confirm the times and order of events in the timeline article. Do you have sources that support your alternative view that inflation occured before the Planck epoch ? If not, then I think the article should be left as it stands. Gandalf61 (talk) 00:07, 16 May 2008 (UTC)

Cosmological inflation and large-scale structure by Andrew R. Liddle, David Hilary Lyth. Inflation can occur at different energies and the details of the inflationary scenario are determined by the particle physics governing the universe at that time. A reference within wikipedia is not a published scientific reference. Indeed you cannot quote wikipedia in a scientific article. 194.215.120.196 (talk) 17:11, 22 November 2009 (UTC)

http://discovermagazine.com/2006/jan/physics

This source states that the Universe in 10^-6 seconds was a symmetrical non-causal liquid, should this fact be added? —Preceding unsigned comment added by 24.22.111.99 (talk) 22:38, 17 May 2008 (UTC)

Big Rip in 50 billion years or 200 billion years?

In this article it says the Big Rip will happen in 200 billion+ years, but in the Big Rip article it says in 50 billion years? What is true 50 billion or 200 billion years? Please let me know. Thank You.Maldek (talk) 03:48, 21 June 2008 (UTC)

Well, both may be false, so we won't have to answer this! ;-) Jmacwiki (talk) 21:41, 29 August 2009 (UTC)

To some extent?

The article says:

"All ideas concerning the very early universe (cosmogony) are speculative to some extent."

Would it be in error if the last 3 words were dropped? Just curious.

Wanderer57 (talk) 07:08, 12 September 2008 (UTC)

Some background:

• The original and long-standing version was "necessarily speculative".
• User:CrazyInSane changed this to "purely speculative".
• I changed it to "speculative to some extent".

I felt that "purely specualtive" implied that scientific theories of the early universe have no basis in fact whatsoever, whereas of course they must be consistent with the constraints imposed by present day observations and known particle physics, quantum physics, general relativity etc. A theory that said "the universe was created when the Great Green She-Dragon sneezed" would be purely speculative, but would not be scientific.

I would be happy with "speculative" or even with "necessarily speculative". Gandalf61 (talk) 11:07, 12 September 2008 (UTC)

Thanks. I changed it to "speculative".

From the same paragraph: "All proposed scenarios differ radically, some examples being: the Hartle-Hawking initial state, string landscape, brane inflation, string gas cosmology, and the ekpyrotic universe. Some of these are mutually compatible, while others are not."

I'm wrestling with the idea that two scenarios could differ radically, yet be mutually compatible. Does this wording work, given the actual scenarios? Wanderer57 (talk) 16:06, 12 September 2008 (UTC)

Timeline incorrect !

I first posted this in another Section but realized it needs immediate attention. The time-line is incorrect. Inflation is the "earliest Epoch", the Big Bang, and everything else than inflation, is AFTER inflation; the Hot Big Bang is what we observe as the inflaton decays and the scalar fields present during the GUT era (if such an era existed) could well have been driving inflation. Inflation itself goes on for a some time: counted in e-folds. This period, when the inflaton causes the universe to expand, meanwhile filling the universe with its almost constant potential energy (which is the energy density of the unverse during this expansion), is known as the time of slow-roll. When slow-roll stops inflation stops. The easiest argument for why nothing happened before inflation is that we do not know what took place before inflation. When it comes to Supersymmetry, String theory etc. Inflation is just a model applied to that scenario. For example, we can look at inflation assuming General Relativity is valid but applying a Lagrangian insipred by Supersymmetry (the non-canonical terms caused by the Kähler potential, for example). This is known as non-canonic infaltion. That the Plank Era, or anything else was before Inflation is incorrect by the idea of inflation itself and needs to be corrected. Moreover, if you look at inflationary models you see that these begin from some arbitrary past and some physical theory (be it string theory or supersymmetry or GUT inspired). This is definitely contradicting the popularisation made in this article and causes a lot of confusion. To correct this, the "tag" after Big Bang should be removed from the Epochs and a note added that the physical theory valid during inflation depends on the energy at when inflation occurs. The Big Bang should be referred to as the moment when the inflaton decays and the universe becomes hot, happening some time after inflation ends. AnvlL 84.20.156.241 (talk) 19:08, 23 December 2008 (UTC)

Do you have a reliable source that says that the inflationary epoch is the earliest epoch and that places the Big Bang after the inflationary epoch ? I agree the term "Big Bang" is sometimes used to decribe the general "hot, dense" phase of the early Universe, rather than a specific event, but I have never seen it placed after inflation. As regards the pre-inflation period, John Gribbin in The Universe: A Biography says "Gravity split off from the other forces at the Planck time, 10^-43 sec, and the strong nuclear force by about 10^-35 sec. Together, these phase transitions released a huge amount of energy that made the universe expand exponentially for a fraction of a second". So in the generally accepted timeline, there are phase transitions before inflation that gave rise to inflation, and these phase transitions are taken as the boundaries between the epochs of the early universe. Gandalf61 (talk) 19:44, 23 December 2008 (UTC)

The terminology is as follows: Reheating is the process whereby the period of inflationary expansion gives way to the standard Hot Big Bang Evolution. Reheating recovers the Hot Big Bang to give the exact quotation from Cosmological Inflation and Large-scale Structure by Andrew R. Liddle, David Hilary Lyth, section 3.8. Section 3.8.3. says that the details of the field theory will strongly determine the temperature at which this "thermal equilibrium" will ultimately occur, re-entering the standard Hot Big Bang. This happens at the minimum of the inflaton potential. Before reaching this minimum the current paradigm is slow-roll whereby the field rolls into this minimum. The time to do this is not bound from below a-priori. And slow-roll is nothing but inflation, see the reference. And indeed inflation ends before re-heating starts: page 32 of Sean M. Carrolls TASI notes, hep-th/0011110. The other reference is free for viewing at the address http://books.google.fi/books?id=XmWauPZSovMC&pg=PA53&lpg=PA53&dq=reheating+%2Bhot+big+bang&source=bl&ots=62eTF21hJx&sig=J1q07a9HfevhGGkFhHD7d9THx8A&hl=fi&sa=X&oi=book_result&resnum=1&ct=result#PPA43,M1

see also the beginning of the book concerning the Epochs, and more on the terminology. It is an unfortunate truth of popularisation that these concepts sometimes translate less correctly for the sake of clarity. For example on Big Bang posters. Here the reason is apparently a more free use of the term Big Bang, why Hot Big Bang is used by the science community. Regards 84.20.156.241 (talk) 06:01, 30 December 2008 (UTC) AnvlL

I don't have time to join this discussion right now, but I just wanted to mention that AnvlL is right, except that I don't think the end of inflation is ever called the "big bang". "Big bang" refers to the notional origin of cosmological time. Cosmological time is not valid all the way back to t=0, it's only valid back to the end of inflation, which depends on the model but is something like t = 10⁻³² seconds. That doesn't mean inflation lasted 10⁻³² seconds or less, it means that inflation left the universe in the state it would have been in after 10⁻³² seconds of expansion in the traditional (incorrect) big bang model. Inflation could have been going on for billions of years, or forever, and still end at t = 10⁻³² seconds. Most of Wikipedia's cosmology articles still need a lot of work. -- BenRG (talk) 19:06, 30 December 2008 (UTC)

I don't know that inflation could have been going on for billions of years. The timescale for inflation sets the Hubble Constant at the end of inflation. If inflation had been happening for billions of years, the Hubble Constant would be a lot smaller than it is today. What's more, there are ways to extrapolate before inflation. Quantum cosmology in particular requires that we do this.

We can only observe the last (about) 70 something e-folds of inflation. Inflation is a way to calculate the power spectrum from a theory, be it string theory, general relativity, or something else. This idea can be applied to any such field theory. What we usually do is assume that observable inflation is according to general relativity, and that matter behaves with "minimal kinetic" terms. However, what we have is a minimum time of inflation (minimum number of e-folds) that is required to produce the inhomogeneities that we see today. 84.20.156.241 (talk) 14:50, 7 January 2009 (UTC) AnvlL

However, the problem is that the "Big Bang" is a complete misnomer because it deals specifically with a singularity that may not exist. The most naive models posit a singularity, but the most naive models take cosmological models to be linear extrapolations and do not deal with the logarithmic details. That's why inflation is so interesting: it acts as a kind of event horizon between us and any nastiness that was before. However, just because inflation provides us with the ability to sidestep the question doesn't mean that the universe starts at inflation.

ScienceApologist (talk) 04:37, 31 December 2008 (UTC)

I don't understand why we are so taken up with the "Big Bang" as it is only part of the ongoing "cycle of Big Bangs/matter" enlargement, consolidation, Big Bang.

I think AnvIL has misunderstood the sources that he references. When they talk about "re-entering the standard Hot Big Bang", AnvIL seems to think this means a second Big Bang after the inflationary phase. What the sources actually mean is that the cosmological history of the early universe can "re-enter" the "standard" (i.e. non-inflationary) Hot Big Bang history after reheating. In other words, an inflationary phase followed by reheating can be seamlessly grafted onto the early phases of the previously orthodox Hot Big Bang history. This was an important point for the early proponents of inflation, because it meant that an inflationary scneario could preserve the successes of the non-inflationary Hot Big Bang theory in explaining relative abundances of H and He; Hubble flow; CMB etc. Gandalf61 (talk) 10:31, 31 December 2008 (UTC)

The Hot Big Bang is after inflation, at the end of re-heating, when the inflaton field decays. Before that we can only observe some time, that is some 70 e-folds of inflation. Is this article about the Hot Big Bang or something else? What readers think about is definitely the Hot Big Bang. 84.20.156.241 (talk) 14:52, 7 January 2009 (UTC) AnvlL

Augustinian Era

There does not seem to be any explanation of the Augustinian Era, which, according to the timeline given, is the time before the Big Bang. That seems one of the most important parts of all, to me, anyway. I would jsut like to know what scientists think of it, even if it is something like, "The 'Augustinian Era' is just a name scientists use for the time before the Big Bang. While many theories have been proposed, none of them really have any idea what the heck it actually was or how it worked." Certain uncertainty like that is much better than having uncertain uncertainty; i.e., not even knowing what it is that we don't know. —Preceding unsigned comment added by 199.8.26.10 (talk) 15:41, 8 January 2009 (UTC)

There was one when I created the template, but it was removed. -- Army1987 – Deeds, not words. 18:05, 9 January 2009 (UTC)

Measurement of time in this context

I'm having trouble with the measurement of time in this context. In the context of these events, what does "one second" mean? Is it even meaningful? cmadler (talk) 18:50, 20 October 2009 (UTC)

The time intervals between the different milestones in the early universe are meaningful, but the absolute "after the Big Bang" time values are less meaningful. In the early universe, there is a fairly simple relationship between time and temperature (where "temperature" is actually shorthand for energy density) - see here for the maths. We know that the early universe cooled as it expanded and that certain milestones and transitions occured at certain temperatures, so the "after the Big Bang" time given for each events is just a conversion of its threshold temperature into a time value. However, the simple relationship between "time" and "temperature" predicts an infinite temperature at time 0, which is not physically meaningful. There is a period in the very, very early universe, the Planck epoch, during which the energy density was so high that we don't really understand what was going on - to understand this period, we would need to have a consistent theory of quantum gravity, which hasn't been found yet (although there are some candidates). It is possible that "time" (or, more precisely, "space-time") is not even a useful concept during the Planck epoch. So, to cut a long story short, you can mentally translate "after the Big Bang" into "after the end of the Planck epoch", without much loss of accuracy. Gandalf61 (talk) 08:40, 21 October 2009 (UTC)

Thanks! The graph of the time-temperature relationship at [7] was particularly helpful. I have no skill at such things, but if someone could add a similar image to this article I think it would help. Thanks, cmadler (talk) 18:10, 21 October 2009 (UTC)

White Space

Why is there a big glaring paragraph of white space at the top. Fix.174.3.98.236 (talk) 08:17, 10 February 2010 (UTC)

Midi-chlorian creation

Can we put in a section on midi-chlorians and what are exactly they? it would clear up a lot of confusion about and would merge both star wars universe and our universe a la LOST sideways verse and post nuclear blast island verse. —Preceding unsigned comment added by Jewwankenobi (talk • contribs) 00:58, 23 April 2010 (UTC)

No. {{in-universe}} — Arthur Rubin (talk) 02:46, 23 April 2010 (UTC)

Terminology

Is it just me, or should terms like very early universe have redirect pages? 70.247.169.197 (talk) 03:45, 8 August 2010 (UTC)

Sure. Early universe is already linked, and I've created very early universe as well (per WP:PAPER, electrons are cheap). --Christopher Thomas (talk) 05:54, 8 August 2010 (UTC)

Thank you! 70.247.169.197 (talk) 00:46, 11 August 2010 (UTC)

Is there a timeline?

According to the theory of General Relativity, time and space are stretched to infinite as we are approaching a black hole. Let's consider that the universe is contracting the same way as it is currently expanding. Time and space would become infinite as we were approaching singularity. Our planet will be as big as it is today, in relation to the whole universe. In addition, time will be streached to infinite, so our living period would not differ too much from today's. According to this alternative, we cannot say that we are in the middle of an expanding universe (13.9 bilion years old), or in the beggining of a big bang (10^-39 seconds after the explosion). User:Axs203dd 09:56, 24 Aug 2010 (UTC)

Time and space do not become infinite as one approaches a gravitational singularity. A freely-falling object instead observes a finite (and rather short) proper time between passing the event horizon and striking the singularity. Similarly, the time-reversal of such a collapse involves a finite proper time, and so a finite age. In practice, the Big Bang's model of the universe isn't quite a time-reversal of a collapse to a black hole; it just shares several of the same qualities, and is predicted by the same proofs (Penrose's proofs regarding gravitational collapse). That said, the FLRW metric (the model of the universe's evolution from a primordial singularity) still results in a finite time between the initial singularity and now.

Short version: No, it doesn't work that way; there's a finite amount of time with a definite beginning. --Christopher Thomas (talk) 09:20, 24 August 2010 (UTC)

Dear Christopher,

thank you for your answer. According to gravitational time dilation, time should run "slower" near a large mass in relation to an external obsever. In addition, the light that is emmited inside the event horizon would never pass it, because the time needed for the photons to travel the "infinite" observed distance and reach the event horizon would be infinite as well. From the external's observer prespective though, this event would have been taken place within a small amount of time. --User:Axs203dd 08:10, 25 August 2010 (UTC)

It's actually the other way around: the external observer sees the mass slow down as it approaches the event horizon, but the mass itself experiences a finite, short amount of time if it's freely falling. If you try to keep the mass at rest with respect to an outside observer, the situation breaks down as you approach the horizon (it becomes impossible to keep them at rest with respect to each other when the test mass reaches the horizon). As a result, using a coordinate system where you assume the test object is at rest gives you an apparent (not real) "coordinate singularity" at the horizon, whereas the actual singularity is at the centre of the black hole. See Schwarzschild metric for further discussion of that. --Christopher Thomas (talk) 20:01, 25 August 2010 (UTC)

Grand Unification Epoch expansion factor?

Should the " cm" be removed from this sentence? It reads as if it was 10^10 cm and expanded by a factor of 10^20 to result in a size of 10^30, which is too large, surely.

:For the period of time between 10^-35 seconds and 10^-33 seconds, it is believed that the size of the universe expands by a factor of approximately 10²⁰ to 10³⁰ cm.

Also about the quark-annihilations, should this instead read "resulting in one quark remaining for every billion matter-antimatter interactions?"

:Birth of quarks, which appear in particle-antiparticle pairs. Quarks and anti-quarks annihilate each other to create photons, but quarks are created at a ratio of approximately 10⁹ (1 billion) anti-quarks to 10⁹+1 (1,000,000,001) quarks, resulting in one quark per billion matter-antimatter interactions. Free quarks multiply rapidly. -Wikibob | Talk 14:37, 25 Jun 2004 (UTC)

i'm pretty sure the currently observable universe is larger than the Planck length

This sentence: "The diameter of the currently observable universe is theorized as 10-33 cm which is known as the Planck length." seems to me to be at best very badly worded, and possibly even wrong. I was going to change it to something like "The diameter of the currently observable universe would have been only 10^-33 cm at the end of the Planck time. This distance is known as the Planck length". But is that even true? Might not current the size of a "Planck volume" from the Big Bang depend on the details of the inflationary period and the age of the universe? -Lethe | Talk 00:15, 7 Dec 2004 (UTC)

Logarithmic version

Over at Logarithmic timeline someone suggested a reverse log timeline could be applied to the Big Bang, so I genned up a first draft (improvements welcome).--robotwisdom 01:46, 2 July 2005 (UTC)

Not sure my timeline should be a primary reference in this article. Maybe a link at the end.

Hi, I just noticed that some text and timeline graphic I composed is used as a reference in this article (Citation #4). This is flattering, but I don't think what I did should be used as an authoritative reference. I'm a librarian, not a cosmologist, even though I was very well read about this stuff at the time I did it. My timelines are themselves based on secondary sources, not generally primary sources. They should be viewed as interpretations of more authoritative works.

Anyway, I would feel funny about changing anything myself, so I'll leave any changes up to the people who made this excellent article. I have made a whole series of timelines about the evolution of the universe, which are more detailed than the one shown here. They are at www.worldviewposters.com, if anyone thinks they would be useful to link articles to. Rbmays (talk) 14:36, 28 July 2011 (UTC) Ross Mays

Requested move

The following discussion is an archived discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. No further edits should be made to this section.

The result of the move request was: page moved by a participant. The discussion appears to have reached the non-controversial stage, and there's a backlog of RMs, so I'm closing it anyway. Any objection minor or not, and I will happily undo and reopen the discussion. -- JHunterJ (talk) 15:39, 29 April 2012 (UTC)

---

Timeline of the Big Bang → Chronology of the universe – there are a few reasons why the name should be changed to this. First of all, it is not a timeline. A timeline would be a table or chart, not a paragraph based summary split into sections. Second of all it doesn't accurately reflect the content of the article, which goes beyond the initial big bang which occurred 13.7 bya, even discussing the fate of the universe. We have to define big bang: are we to call the whole history of the universe just a continuous big bang or is it the initial inflation that occurred 13.7 bya? To me this is a more accurate name. Has this not been discussed before? relisted-needs more input from other editors --Mike Cline (talk) 14:27, 16 April 2012 (UTC) Cadiomals (talk) 13:24, 8 April 2012 (UTC)

• Oppose history does not include the future. This article includes the heat death of the universe, clearly a future predicted event. However, it is clearly inappropriate to call it Timeline of the Big Bang, with anything past the recommencent of expansion, and probably anything past the Cosmic Dark Ages. So I suggest Timeline of the Universe instead. Universe is capitalized to make it distinctly refer to our Universe, and not any other or generic universe conceptions. It is possible to call this Timeline of the Big Bang Universe, if we need to differentiate between the Big Bang based origins of the Universe, with other bases, such as Islamic-Judeo-Christian Creation, or IJC Intelligent Design, or deist intelligent design, etc. 70.24.248.211 (talk) 14:18, 8 April 2012 (UTC)

I agree with most of what you said, except I still don't like the use of the word timeline, because there isnt even a timeline in this article , which is prose based. So unless we can find a better word, I still think we should rename it "history of the universe" and simply rename the "ultimate fate of the universe" section to "future of the universe" to create a distinction without going off topic. Or we could get rid of that section entirely (or just shrink it) since it has its own separate article. I also looked up the word history on dictionary.com to see if there was any variation in meaning besides past events, and it had a second definition saying "pattern of events determining the future," which I think is relevant in this article. As for capitalization of "universe" I really don't think that's necessary since we have no idea if other universes even exist; the simple use of the word "the" before it should suffice. Cadiomals (talk) 19:06, 8 April 2012 (UTC)

I'd prefer a capitalized "U", since if you say "the earth", it could mean dirt or ground as well as Earth. As for being prose, prose and being a timeline are not incompatible, since timelines are just a schedule of events, and how the events are described can be prose, which is why we have chart articles called "graphical timelines". 70.24.248.211 (talk) 06:28, 9 April 2012 (UTC)

I'm fine with the capitalized U, but I still think using "big bang" in the title is inappropriate. "timeline of the universe" sounds weird to me. Like i said we could call it "History of the Universe" and get rid of or rebame the "ultimate fate of the universe" section to "future of the universe." By the way, have you considered making an account instead of being an IP? It would make things easier for you, but we have to wait around for an admin anyway. Cadiomals (talk)

Yes, "Big Bang" is inappropriate, considering it extends beyond the Dark Ages or at the very latest, the resumption of expansion. As for splitting the article, that could be done, then it would be a "history" article. Ultimate fate of the Universe would work, since it's the title of the section that is in (again, with capital "U", because there are many academic papers on theoretical universes and what happens to them.) As for signing up, since I've been an IP editor for a long time, I don't see any reason to get one. 70.24.248.211 (talk) 07:48, 10 April 2012 (UTC)

So, do you then support or oppose changing the title to "History of the Universe?" If you do support it please change your bolded vote above. Also, signing up is highly beneficial and it isn't hard at all. It will take less than a minute. Since you seem to be fairly interested in Wikipedia (or at least this article) I highly recommend you do it. There are many articles on here that IP's can't participate in. Cadiomals (talk) 15:35, 10 April 2012 (UTC)

conditional oppose/support If the fate section is removed, then the rename is reasonable. Though I would prefer a capital "U"niverse. 70.24.248.211 (talk) 03:45, 11 April 2012 (UTC)

the Universe is already capitalized. As for the ultimate fate section, I don't think we should totally get rid of it as it still has educational value. We can drastically reduce the section to a one paragraph summary of the various theories for the fate of he universe, so it doesn't go too off topic from the subject of the article. I think that's a reasonable compromise. Still waiting on an admins opinion though. Cadiomals (talk) 12:07, 11 April 2012 (UTC)

• Lowercase "u"—Universe should be lowercased in running text. It is in this article. It is in universe. It appears to be overwhelmingly in scholarly writing. etc. For better or worse, Wikipedia titles are cased as the title phrase would be cased in running text, so it should be lowercase in this title. ErikHaugen (talk | contribs) 22:36, 25 April 2012 (UTC)
• Propose move → Chronology of the universe. It's not a timeline (no graphic), it's not a history (includes the future), it's about more than just the Big bang, and WP lowercases universe. All pages with titles beginning with Chronology of -- JHunterJ (talk) 13:32, 26 April 2012 (UTC)

  support Chronology of the universe—this seems like it addresses the issues raised above. ErikHaugen (talk | contribs) 16:15, 26 April 2012 (UTC)

  Support Chronology of the universe. Yes, more precise terms. Rothorpe (talk) 17:35, 26 April 2012 (UTC)

  I also Support Cadiomals (talk) 16:33, 28 April 2012 (UTC)

• Yes, I too Support the original suggestion. There should be a page for Chronology of the universe. It would not be, and should not be a timeline. I am indifferent about "universes" caps, but either way, timeline of the big bang would and should become redundant.-Tesseract²(talk) 19:21, 28 April 2012 (UTC)

The above discussion is preserved as an archive of a requested move. Please do not modify it. Subsequent comments should be made in a new section on this talk page. No further edits should be made to this section.

Vacuum metastability disaster

An IP removed the section on Vacuum metastability disaster arguing theory no longer supported this possibility. It seems rather speculative to be in a 'chronology' to me, but do we want to mention the possibility or at least the suggestion? (Do we have a reference that the theory has been rejected?) RJFJR (talk) 16:25, 17 July 2012 (UTC)

I undid the IP's edit, as their rationale made no sense (inflation was a false vacuum event, but that doesn't mean the vacuum it decayed to (ours) wasn't also false). The idea of a metastability event has gotten popular press (it was the basis for at least one novel). That said, I can see it being moved to an "in popular culture" or similar section, as I don't think anyone in the scientific community expects it to happen. --Christopher Thomas (talk) 20:34, 17 July 2012 (UTC)

Ultimate fate of the universe

Big freeze and heat death, what's the difference? Isn't this a repetition? --SamInside (talk) 23:32, 19 April 2013 (UTC)

Move discussion in progress

There is a move discussion in progress on Talk:Age of the universe which affects this page. Please participate on that page and not in this talk page section. Thank you. —RMCD bot 03:59, 3 October 2013 (UTC)

Clarifications

I think this article should have some clarifications concerning inflationary vs. non inflationary models. It should be made clear from the article that there are no non-inflationary models that are consistent with the standard model. At the same time it should be made clear that in the inflationary model there is no concept of "Big Bang" beginning before inflation. To our current best knowledge, given that recent findings (BICEP2) are indeed correct, we can be quite certain only that there was a period of cold very rapid growth of space-time which we call inflation, after this the hot but slow (in comparison) expansion began. Any event prior to this is outside the reach of current findings and we don't know how long this event lasted either. The article, as it is currently structured can easily be interpreted as saying that a timeline where a hot big bang from a gravitational singularity was followed by inflation and then hot big bang reassumed, which is not what the inflationary model claims. — Preceding unsigned comment added by 46.59.74.229 (talk) 19:23, 26 March 2014 (UTC)

I think this is a mistake with this page

The page currently says: "For the period of time between 10^-35 seconds and 10^-33 seconds, it is believed that the size of the universe expands to a size of approximately 10^-32 m to 10^-22 m."

Shouldn't it be "10^-32 m 10⁺²² m"? I have two astronomy texts which say it increased by a factor of 10⁵⁰. I would fix it, but I'd like input to make sure I'm right first. — Preceding unsigned comment added by 24.6.111.201 (talk) on 08:26, 16 Aug 2005

Answer: No, the phrase "10^-32 m to 10^-22 m" is a range of the terminal size, not an expression of the change of expansion. — Preceding unsigned comment added by 98.164.203.111 (talk) 09:52, 1 June 2014 (UTC)

Consistent narrative tense needed

The tense of the narrative changes back and forth several times, from past to present to past to ... Digressions may properly depart from the main, but the overarching tense should remain constant, either a recapitulation of the history of the universe in past tense, or an ongoing evolutionary process in present tense. — Preceding unsigned comment added by 98.164.203.111 (talk) 10:39, 1 June 2014 (UTC)