Talk:Age of the universe

Sorry, but some of this stuff really is too hard to make sense of by making minor corrections, so i've cut it out (today Boud 13:38, 3 Dec 2004 (UTC)) and pasted it here in case anyone wants to make sense of it:

This allows us to describe how the universe has evolved over time using an equation like this: $t=t_{0}(1+z)^{3}(1+w)/2$. As you can see, things are starting to get a bit more tricky, but this equation simply relates the age of the universe to the redshift. This particular example has an additional term w, which comes from something called the equation of state, relating the pressure and density of the universe (p=wdc^2, where p is pressure, d is density and c^2 is the speed of light squared).

For a standard model (cosmological constant = constant or zero, no quintessence), we have w = -1, and this equation gives t = t_0 (1+z)^0 = t_0 so time is constant and the universe doesn't expand at all. Maybe this is one of the early historical models with some minor error, but i don't recognise it. Boud 13:38, 3 Dec 2004 (UTC)

Things do start to get technical here, but there is a nice confirmation of this model which actually validates it against recent observations. Coming back to the math, the change in the distance is related to time with the redshift relation $t=t_{(}1+z)^{2}$. However, there is an additional change in time related to redshift as $t=to(1+z)^{1/2}$, which (the product of both) brings us back to the original form for our "dust" w=0 universe. The idea of time-variable time probably sounds bizarre, but this is expected since there is no "absolute" concept of time in General Relativity.

The two formulae look weird, i can't make sense of the discussion, and saying that there is no absolute concept of time in GR is misleading, since GR applied to the universe in the standard FLRW model very definitely has a favoured time axis in the comoving coordinates system.

The Planck stuff needs some checking too - i'm not familiar with stuff that theoretical, so i'm not sure whether it's meaningful or not. Boud 13:38, 3 Dec 2004 (UTC)

I was the originator of the discussion on the Talk:Universe page where a large part of this content came from. It wasn't meant to be turned directly in to an article, so the quality isn't great and there are some typos in the formulas. However, I would be glad to tidy up what currently exists in the article and hopefully resolve any remaining confusion. Nodem 00:23, 23 Feb 2005 (UTC)

CNO studies

Does anyone have citations for the "some recent studies" mentioned in the CNO section? —Joe Jarvis 14:43, May 24, 2005 (UTC)

graviational

I do more basic proofreading than science, which led me to this apparent typo: "Obviously, the entropy increases (due to graviational in fall) and this has the effect that the universe has become cooler than this simple model predicts." I almost corrected it to "gravitational", but that makes the sentence look backwards. Gravitational in fall of a meteorite, for instance, would convert gravitational potential energy to heat energy, and get hotter, not cooler - although I agree that it would increase entropy. Did I discover a typo and/or a more serious mistake? Art LaPella 02:36, August 22, 2005 (UTC)

I do not know where you are looking. Please direct me to the page with "graviational" Pdn 16:28, 22 August 2005 (UTC)OOps I see the page and the item on it. I will ponder it and maybe consult someone if needed. Good call - it does look odd. Pdn 16:46, 22 August 2005 (UTC)

This whole section looks amateurish, but I am not sure I'm qualified to fix it. One example is that the author refers to the Planck temperature as "measurable" and tries to project forward from it. But that is trying to look way past where we can see - we can't see past the "surface of last scattering" of the CMB. The stuff about Planck temperature is all done by estimating backwards in time from then, and using particle physics, and so it cannot serve as a useful age marker. In fact, things ran so fast near the Planck temperature that the time interval to get way below it is inconsequential compared to the present age. I am not sure if I could get Ned Wright, for example, to fix this. (see [1]). There is a generic Wiki-problem here - there is a lot of good information out there already, and it is not clear that Wikipedia can attract authors who want to spend time on poorly supervised pages repeating what they have said elsewhere, or what is in books. Wikipedia may be turning into a forum for creationists, "General Semanticists" (General Semantics), and other cranks to vent their ideas. I mean, really, do you have to study the works of Korzybski to learn that dogs do not create handbooks or literature, or that words are to be distinguished from the objects they refer to? Pdn 16:58, 22 August 2005 (UTC)

I've experimented with Wikipedia:Template messages when dealing with something wrong that I can't fix - simple example, Baotou. Templates might embarrass this stuff away, or at least warn people not to believe it. Here are some templates that we might want to choose from for the "Age based on temperature" section here: (I removed templates afterwards - they made the talk page show up in categories. 8/27/05)

Beyond that, I think Wikipedia is too democratic. Nobody is really equal, even though some situations go smoother by pretending they are. In particular, I would establish a class of newbies, forbidden to edit except indirectly, on a new provisional edit page that has to be approved by others. A newbie could graduate if enough text or changes are substantially approved. A banned user returning as a Wikipedia:sock puppet would have to qualify all over again. Art LaPella 20:51, August 22, 2005 (UTC)

Temperatures

2943K the temperature of a dully-glowing poker? I think not: iron melts at a mere 1811K. I don't feel adequately qualified to edit the page, though.

I've done a bit of poking (heh) around other articles. Unless you're using a tungsten carbide poker (melting point 3143K), you don't really stand a chance of getting a poker anywhere near that hot. I thought for a bit that it might have been a mistake with someone mistaking fahrenheit for kelvin, but even if that were the case the poker would be far from dull (iron melts at 2800 degrees fahrenheit, and alloys like steel at less than that). Anyway, I'll edit it now. --Dom 01:10, 22 December 2005 (UTC)

Accuracy template

Some similar language was added long ago, as described above at #graviational. Now someone has deleted the warning language without fixing that problem, so I replaced it with an official Wikipedia template. Art LaPella 04:58, 15 December 2005 (UTC)

380, 000 Years

I would like to point out that the 380 000 year age seems to be here just to put a hole in the page. I did not edit the page because I do not fully understand the math he has used. The idea of using bad science to 'prove' a religous theory is not a new idea, it is little more than kicking over someone elses sand castle because you can not build one that stands on its own. [Richard Bailey]

I'm taking it out because it makes no sense. We have dinosaur fossils from over 65 million years ago. It's absurd to have something like that in this article.

er... read it again: current age of the universe approx 13.7 Gyr gives us around 380,000 years for the age of the universe when the CMB was emitted. Replaced the deleted para. Vsmith 20:56, 29 January 2006 (UTC)

Open Idiocy

380,000 years as the age of the Universe? This doesn't even deserve to be dignified with a proper response. It needs to be removed immediately - as it stands, it compromises the integrity and perception of empricism that Wikipedia holds dear. Justifications of ludicrous religious theories, regardless of how widespread they are, doesn't deserve a place in an encyclopaedia.

This trend in Wikipedia towards including right-wing political, religious and moral sensibilities as valid 'criticism,' no matter how outlandish or utterly falsified by modern science, is disturbing and an indication of intellectual laziness and misguided belief that simply because there are two opposing positions, the factual middle ground is somewhere evenly between the two. In reality, almost no respectably accreditted scientist supports Creationsim, yet it seems that we must always qualify an article on evolution with the 'opposing view' of Creationism. Really, these opposing opinions deserve no more place in Wikipedia than the 'stork theory' in human reproduction.

Idiocy is widespread and commonplace: this is no excuse, however, for it to be given equal footing with our current, rational understanding of the world.

(above post by 146.87.193.90 moved to bottom of page)

To repeat my comment from above in the section entitled 380,000 years:

er... read it again: current age of the universe approx 13.7 Gyr gives us around 380,000 years for the age of the universe when the CMB was emitted.

Perhaps we need to reword that bit as at least two users have mis-read it. Vsmith 03:05, 6 February 2006 (UTC)

OK, I reworded the offending sentence to, hopefully, avoid further confusion. The whole section needs a re-write as it is a bit much for the average user (me included :-) Vsmith 03:26, 6 February 2006 (UTC)

The first sentence needs to be changed

I am a physicist, I have studied astrophysics, astronomy, and cosmology for years, and this is my suggestion: the first sentence of this article has to go, and asap. Because it is simply not true. It states, "Nothing is certain as to the extent of either the age or size of the universe..." That is factually at odds with the very laws of physics used to calculate the age of the Universe. Not only is there a currently accepted age of the universe, which is calculated in several different ways arriving at the same order of magnitude but in fact, the age of the universe is currently accepted within about 1.4% error. Since this is fact, it needs to be presented in this article as such; just click here for a clear and concise explanation of actual measurments of the age of the universe that are not based upon cosmological models for those measurments, such as the big bang. To leave the first sentence as it currently stands would be an egregious offense to the policies of WP to promote NPOV for this subject. I plan on making a change soon and I would like suggestions from those of you who have researched this subject, and understand a way to present it to a general audience for their maximum benefit. I realize how this can be a confusing issue for many people. To be able to do something as complex as measure the age of the universe requires advanced mathematics well beyond what most people are comfortable with, so there needs to be some way to balance the presentation of these measurments from their actual foundations, with a readability for a casual observer. I'd like to work on a solution to this as soon as possible and all feedback would be welcome. Thank you for your time. C.Melton 00:12, 11 February 2006 (UTC)

I agree. I am also an astrophysicist who has studied cosmology. The statement is equivalent to saying nothing is certain about the number of legs dogs have, when in fact the majority of evidence suggests that four is the number. Soloist 14:11, 17 February 2006 (UTC)