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The article says: reionization is the process that reionized the matter in the universe after the epoch of galaxy formation. But Graphical timeline of the Stelliferous Era shows the reionization phase starting at 100 million years after the Big Bang and completing before the formation of the first galaxies at 600 million years after the Big Bang. Which is correct ? Gandalf61 16:41, 23 January 2007 (UTC)
References
I added the link back to the disambiguation page for the time being, as it give some explanation. I may write create a recombination stub in the next few days and redirect the link there. James McBride 09:14, 15 August 2007 (UTC)
I would like to see a few more images in the article. In particular, the graph of the CMB polarization angular anisotropy map and an example Gunn-Peterson trough. A non-copyrighted version of the first should be possible, as it was generated by WMAP, but I only was able to find the image at other sites. James McBride 09:14, 15 August 2007 (UTC)
I think editors should give serious consideration to deleting the image given at http://imagine.gsfc.nasa.gov/Images/sats_n_data/exhibit/reion.diagram.jpg 1) The universe does not become opaque at the surface of last scattering. It's called that for a reason, and it's not because the universe suddenly starts scattering - the universe becomes transparent then, not opaque (exception being specific neutral hydrogen absorption features as mentioned in the GP trough sections) 2) The universe does not become neutral either for that matter. It was neutral already, but ionized. It becomes unionized at that point, which is not the same as neutral 3) The universe does not become transparent again at reionization. It'd be opaque again, except that the free electron density is low enough that the Thomson scattering cross section remains low and the universe stays opaque. In other words, that diagram from NASA is pretty badly wrong in a number of fundamental points. I'd get rid of it myself, but I'd probably be accused of vandalism for getting rid of something from a reputable source, even when it's got fundamental errors in it —Preceding unsigned comment added by 91.84.172.216 ( talk) 00:29, 21 February 2008 (UTC)
I would agree. Having just approached the subject for the first time, I found the diagram misleading. Unless there are further comments to the contrary, I would suggest removing the image soon. 82.24.250.218 ( talk) 21:39, 16 October 2008 (UTC)
I asked the NASA people to replace their erroneous image with a correct one, and after a few weeks they did, courtesy of their WMAP staff. Unfortunately I cannot add images to Wikipedia, according to the rules, because I haven't added 10 edits yet (I'm not "autoconfirmed"). Could somebody who is autoconfirmed please put the current version of http://imagine.gsfc.nasa.gov/Images/sats_n_data/exhibit/reion.diagram.jpg in the Wikemedia Commons and point to it from the Reionization page? Thanks in advance! Mike Pelizzari ( talk) 22:22, 29 December 2009 (UTC)
I suggest that the name of this entry should be changed to "Reionization event," to more clearly indicate its specific subject matter. -- Steve, Sm8900 ( talk) 14:53, 26 February 2010 (UTC)
It seems that several citations are lacking from the first few paragraphs. Really, there aren't any until the end of the second paragraph in the 'Quasars and the Gunn-Peterson trough' section. Can anyone cite a reference to this: "which occurred at a redshift z = 1089 (379,000 years after the Big Bang)"? The article seems to assume that we already know a lot, whereas we probably don't. Richard Nowell ( talk) 17:08, 19 June 2014 (UTC)
As of Jul 10, 2014 the 2nd P of the Background has some strange (inappropriate) wordings and sentences.
First:"The second phase change occurred once objects started to condense in the early universe that were energetic enough to ionize neutral hydrogen. As these objects formed and radiated energy, the universe reverted from being neutral, to once again being an ionized plasma."
Why are the Population III stars called "objects"?!? AFAIK, there is no controversy that the first objects to radiate significant amounts of emr were mostly Pop. 3 stars (whether black holes also formed then and were significant source of emr (from their accretion disks) is something I don't have a handle on (but doubt)). (Whether Pop. 3 stars formed in galactic structures or whether galactic structures formed around those stars, has not (to my knowledge, but it may be out-dated) been conclusively answered. Regardless, it is irrelevant here.)
Second: Isn't "The second phase change" actually called the "Reionization"? Why is that being avoided??
Third:"the universe reverted from being neutral, to once again being an ionized plasma." Wow! Talk about awkward!
The Universe is space and time and everything in it. PART, and ONLY part, of it is baryonic matter. To confuse the plasma in the matter(?) dominated Universe with the Universe itself is so egregiously WRONG as to be, to me, incomprehensible. Have you not heard of Dark Matter??? How about Dark Energy?? Wow! This MUST be changed!!
Here is a hint: the plasma is roughly 25% of the matter in the Universe and only 4% of the total energy content. So, whether or not you ignore Dark Energy, equating the Universe to the plasma in it is a blunder of epic proportions.
Fourth:"At that time, however, matter had been diffused by the expansion of the universe, and the scattering interactions of photons and electrons were much less frequent than before electron-proton recombination. Thus a universe full of low density ionized hydrogen will remain transparent, as is the case today."
"matter had been diffused" is gobble-de-gook. Why not:"By that time the expansion of the Universe had diluted the concentration of matter so that it was too diffuse to obstruct light transmission. Today's Universe is and will remain transparent." — Preceding
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This
level-5 vital article is rated B-class on Wikipedia's
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The article says: reionization is the process that reionized the matter in the universe after the epoch of galaxy formation. But Graphical timeline of the Stelliferous Era shows the reionization phase starting at 100 million years after the Big Bang and completing before the formation of the first galaxies at 600 million years after the Big Bang. Which is correct ? Gandalf61 16:41, 23 January 2007 (UTC)
References
I added the link back to the disambiguation page for the time being, as it give some explanation. I may write create a recombination stub in the next few days and redirect the link there. James McBride 09:14, 15 August 2007 (UTC)
I would like to see a few more images in the article. In particular, the graph of the CMB polarization angular anisotropy map and an example Gunn-Peterson trough. A non-copyrighted version of the first should be possible, as it was generated by WMAP, but I only was able to find the image at other sites. James McBride 09:14, 15 August 2007 (UTC)
I think editors should give serious consideration to deleting the image given at http://imagine.gsfc.nasa.gov/Images/sats_n_data/exhibit/reion.diagram.jpg 1) The universe does not become opaque at the surface of last scattering. It's called that for a reason, and it's not because the universe suddenly starts scattering - the universe becomes transparent then, not opaque (exception being specific neutral hydrogen absorption features as mentioned in the GP trough sections) 2) The universe does not become neutral either for that matter. It was neutral already, but ionized. It becomes unionized at that point, which is not the same as neutral 3) The universe does not become transparent again at reionization. It'd be opaque again, except that the free electron density is low enough that the Thomson scattering cross section remains low and the universe stays opaque. In other words, that diagram from NASA is pretty badly wrong in a number of fundamental points. I'd get rid of it myself, but I'd probably be accused of vandalism for getting rid of something from a reputable source, even when it's got fundamental errors in it —Preceding unsigned comment added by 91.84.172.216 ( talk) 00:29, 21 February 2008 (UTC)
I would agree. Having just approached the subject for the first time, I found the diagram misleading. Unless there are further comments to the contrary, I would suggest removing the image soon. 82.24.250.218 ( talk) 21:39, 16 October 2008 (UTC)
I asked the NASA people to replace their erroneous image with a correct one, and after a few weeks they did, courtesy of their WMAP staff. Unfortunately I cannot add images to Wikipedia, according to the rules, because I haven't added 10 edits yet (I'm not "autoconfirmed"). Could somebody who is autoconfirmed please put the current version of http://imagine.gsfc.nasa.gov/Images/sats_n_data/exhibit/reion.diagram.jpg in the Wikemedia Commons and point to it from the Reionization page? Thanks in advance! Mike Pelizzari ( talk) 22:22, 29 December 2009 (UTC)
I suggest that the name of this entry should be changed to "Reionization event," to more clearly indicate its specific subject matter. -- Steve, Sm8900 ( talk) 14:53, 26 February 2010 (UTC)
It seems that several citations are lacking from the first few paragraphs. Really, there aren't any until the end of the second paragraph in the 'Quasars and the Gunn-Peterson trough' section. Can anyone cite a reference to this: "which occurred at a redshift z = 1089 (379,000 years after the Big Bang)"? The article seems to assume that we already know a lot, whereas we probably don't. Richard Nowell ( talk) 17:08, 19 June 2014 (UTC)
As of Jul 10, 2014 the 2nd P of the Background has some strange (inappropriate) wordings and sentences.
First:"The second phase change occurred once objects started to condense in the early universe that were energetic enough to ionize neutral hydrogen. As these objects formed and radiated energy, the universe reverted from being neutral, to once again being an ionized plasma."
Why are the Population III stars called "objects"?!? AFAIK, there is no controversy that the first objects to radiate significant amounts of emr were mostly Pop. 3 stars (whether black holes also formed then and were significant source of emr (from their accretion disks) is something I don't have a handle on (but doubt)). (Whether Pop. 3 stars formed in galactic structures or whether galactic structures formed around those stars, has not (to my knowledge, but it may be out-dated) been conclusively answered. Regardless, it is irrelevant here.)
Second: Isn't "The second phase change" actually called the "Reionization"? Why is that being avoided??
Third:"the universe reverted from being neutral, to once again being an ionized plasma." Wow! Talk about awkward!
The Universe is space and time and everything in it. PART, and ONLY part, of it is baryonic matter. To confuse the plasma in the matter(?) dominated Universe with the Universe itself is so egregiously WRONG as to be, to me, incomprehensible. Have you not heard of Dark Matter??? How about Dark Energy?? Wow! This MUST be changed!!
Here is a hint: the plasma is roughly 25% of the matter in the Universe and only 4% of the total energy content. So, whether or not you ignore Dark Energy, equating the Universe to the plasma in it is a blunder of epic proportions.
Fourth:"At that time, however, matter had been diffused by the expansion of the universe, and the scattering interactions of photons and electrons were much less frequent than before electron-proton recombination. Thus a universe full of low density ionized hydrogen will remain transparent, as is the case today."
"matter had been diffused" is gobble-de-gook. Why not:"By that time the expansion of the Universe had diluted the concentration of matter so that it was too diffuse to obstruct light transmission. Today's Universe is and will remain transparent." — Preceding
unsigned comment added by
Abitslow (
talk •
contribs) 15:57, 10 July 2014 (UTC)
Hello fellow Wikipedians,
I have just modified one external link on Reionization. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
When you have finished reviewing my changes, you may follow the instructions on the template below to fix any issues with the URLs.
This message was posted before February 2018.
After February 2018, "External links modified" talk page sections are no longer generated or monitored by InternetArchiveBot. No special action is required regarding these talk page notices, other than
regular verification using the archive tool instructions below. Editors
have permission to delete these "External links modified" talk page sections if they want to de-clutter talk pages, but see the
RfC before doing mass systematic removals. This message is updated dynamically through the template {{
source check}}
(last update: 5 June 2024).
Cheers.— InternetArchiveBot ( Report bug) 13:21, 22 January 2018 (UTC)