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- 1 1950?
- 2 explanation of revert
- 3 BP
- 4 This article is too limited
- 5 I've Never Run Into the Phrase "Before Physics"
- 6 Radiocarbon nonsense
- 7 Comments on Rewrite
- 8 References need improvement
- 9 Gee Whiz
- 10 B.P.
- 11 BP "years" are not the same as caledar "years"
- 12 "BP" and "bp"
- 13 Recommendations of the style guide of the Society for American Archaeology
- 14 b2k - relevant to this article?
- 15 AUC - Ab Urbe Condita
What is special about 1950?? Georgia guy 22:34, 14 Apr 2005 (UTC)
- I'm looking into this for an answer. --Viriditas | Talk 06:25, 18 May 2005 (UTC)
- Found it. Adding... --Jemiller226 18:10, 21 May 2005 (UTC)
The "Before Present or Before Physics" section is really sloppy and incoherent. -- Ted
- Yes, and its content was apparently also incorrect. Here's another reputable reference besides the one i already quoted in the article:
- "B.P. originally did mean "before present" but eventually was changed to mean "before physics" after A.D. 1950 was standardized as the fixed point from which age determinations are (and I hope always will be!) calculated."
- --Espoo 19:52, 24 March 2006 (UTC)
explanation of revert
Jclerman, it is not OK to comment in the article itself on changes in the article. If you feel that AD should be used instead of CE, you should explain that here on the talk page.
Wikipedia is an international encyclopedia and has to take into consideration that many people consider use of Christian terminology in dates inconsiderate and rude. Although Common_Era lists about as many arguments for as against use of CE/BCE instead of the provincial, egocentric, and inconsiderate use of AD/BC, the fact remains that attempts to keep the Christian terminology are doomed to failure. In all truly international contexts where participants are equal and come from different cultures and religions, use of CE/BCE has been the norm for a long time. The following quotes should be enough to make you realise that you're fighting a losing battle and doing nothing but provoking anti-European and anti-US and anti-Christian sentiments:
from Common_Era: More visible uses of common era notation have recently surfaced at major museums in the English-speaking world: The Smithsonian Institution also prefers Common Era usage, though individual museums are not required to use it. As well, many style guides now prefer or mandate its usage.  Some style guides for Christian churches even mandate its use; for example, that of the Episcopal Diocese of Maryland.(pdf) The usage of the BCE/CE notation is growing in textbooks. It is used by the College Board in its history tests, as well as by the National Geographic Society and the United States Naval Observatory. 
from http://www.religioustolerance.org/ce.htm : We use the terms CE and BCE throughout this web site because they are less hurtful to non-Christians. We feel that this outweighs any of the objections to their use of which we are aware. We want to communicate ideas while being civil and considerate to people of all religious traditions. This is compatible with the purpose of this web site, which is to promote religious tolerance. We want to reduce discrimination, oppression and unnecessary pain caused to people on the basis of their religion. Some people call this being "politically correct" because it is sensitive to the feelings of others. That is their right. But we feel that the use of CE and BCE is the decent and considerate thing to do.
I also question the reasoning behind your changes of the quotes:
1) There is no reason to remove the explanation [U.S. National Bureau of Standards]
2) Splitting the explanation of the meaning into two parts is unnecessary and complicates the issue, and your paraphrase of the second part is so much more complicated that it's incomprehensible to most:
"redefined the meaning of the P in BP from the actual year of the laboratory analysis to Physics" is nonsense compared to the original's clarity: " redefined the meaning of B.P. from 'Before Present' to 'Before Physics' "
In addition, this note was confusing and irrelevant because there were and are no claims to the contrary: "Definitions such as BP can not be changed ad libitum but only by consensus obtained at international commitees."
Finally, you used nine edits to change only three things. This makes it difficult for others to decide which of your edits are OK and which not. Please use the "Show preview" button to check your edits before pressing "Save page".
--Espoo 04:34, 31 March 2006 (UTC)
I couldn't agree more; I was distressed to find AD used without comment in a Wikipedia entry. There is no rationale or excuse for using a term that has the name of one religion's principal deity in a non-religious context, especially when the alternative is the standard in academia.. and basically everywhere except Christians writing for Christians. Sebum-n-soda (talk) 01:20, 12 January 2012 (UTC)
Currently BP in WP means British Petroleum. This means that at least some articles link to British Petroleum (as in ' 26,000 BP ' when 'before present' is meant. It also means editors have to code the cumbersome ' 26,000 BP ' to correctly link to this article. Any support for the idea of trying to get article BP to be a redirect to 'Before Present' and making a 'BP (oil)' article to handle the oil company. Hmains 19:43, 30 December 2006 (UTC)
- Hello, I'm going through and fixing bad links like the example you gave, and I ran across your comment. I'm afraid I must disagree. The three main uses of "BP" or "bp" are those meaning "Before Present", "Base Pair(s)" (biology), and "British Petroleum" (the company). There are approximately 170 links within Wikipedia that want the "Before Present" meaning, about 90 for "Base Pair(s)", but over 600 for British Petroleum. Judging by that, "British Petroleum" is by far the most common meaning. Yes, it's annoying; I don't like it, either, but it's reality. --Tugbug 21:02, 15 May 2007 (UTC)
This article is too limited
bp is not just used for radiocarbon dating, i.e. for times less than 60 ka, but very generally in geology, palaeology and others. For palaeolithic times, i.e. those where many other physical measures besides radiocarbon are in common use, bp is the generally accepted way to state time and radiocarbon datings tend to be given as calibrated years BP to fall in line. Axel Berger 00:42, 26 February 2007 (UTC)
I've Never Run Into the Phrase "Before Physics"
We used to joke about events dated "After Present" (historical dates, not radiocarbon ones). Jacob Haller 21:38, 17 March 2007 (UTC)
- but you just did! Jclerman 22:35, 17 March 2007 (UTC)
- OMG, AP -- that's hilarious! I'm going to use it and everyone will think I'm SO clever! BTW, I know the guy who invented the "before physics" meaning (Hans Sues, the brother-in-law of my friend). I'll ask him if he intended it to be used seriously, as it sounds to me like a joke (as physics existed before 1950). if so, I'll remove the section. —Preceding unsigned comment added by TechnoFaye (talk • contribs) 15:50, 7 April 2008 (UTC)
I am a geophysicist. To say that this is only about radiocarbon or only about estimated ages is radically wrong. For example, BP is routinely used for ice cores, which are never dated with radiocarbon (i.e.   ). BP means years before 1950 whether or not they are "estimated radiocarbon years" or "calendar years". Dragons flight 17:51, 16 May 2007 (UTC)
- Also note Axel Berger's comment above. Dragons flight 17:53, 16 May 2007 (UTC)
- Those BP years used for geologic time don't need to be anchored in AD 1950 as required for the BP radiocarbon years. The ice cores are anchored in AD 1950 because they are isotopically studied by geochemists in environmental isotopes labs (C14, and stable C, O, etc) and because the yrs are counted with an accuracy of 1 yr.Jclerman 18:53, 16 May 2007 (UTC)u
- They are expressed in years BP because counting backward is a useful convention for measuring the gelogic time, same as Ma, Ga, etc. for longer intervals. There is nothing that requires years BP to reference radiocarbon and normal usage in ice core work would be for "BP" to mean calendar years BP. Dragons flight 20:08, 16 May 2007 (UTC)
- "BP" is NOT "routinely used for ice cores". E.g., Danish researchers have long ago switched to the much more intelligent "b2k" (before the year 2000), since the misuse of a common word like "present" for 1950 becomes the more ridiculous, the more we part from that year. Moreover, it can too easily be confused with the correct, conventional use of "BP", and thus repeatedly leads to tremendous errors in many papers. HJJHolm (talk) 12:39, 28 August 2009 (UTC)
Comments on Rewrite
(This refers to the 00:08, 18 May 2007 edit by Tugbug.)
It's amazing that such a simple, ordinarily non-controversial topic should be the scene of so many reverts lately. Sadly, this is resulting in a messy article. In my experience, the best thing to do in such situations is a rewrite. I have done one. See what you think.
My guiding principles:
- BP years are used for all kinds of dating (ice cores have been mentioned, etc.), not just radiocarbon.
- However, BP years were standardized by people doing radiocarbon dating, with their particular application in mind. Thus, radiocarbon dating should be considered the primary and motivating application of the BP scale.
- BP always means years before 1950 when the uncertainty in dates is small, and years before some date relatively close to the present when the uncertainty is large. Thus, years before 1950 is always an acceptable definition.
- If anyone knows of any exceptions to this, speak up.
- The article does not need a separate section for every little topic that pops up.
- I've taken it from 6 sections to 3.
- Everything in the article should have particular relevance to the BP scale.
- Thus, I've removed the mention of cal BC, cal AD.
- References should be given in a form that allows them to be looked up.
- Thus, for now, I have removed references that were only a name and a year. I found and included a complete citation for the Arnold-Libby paper. I removed the Mook-van der Plicht reference, since I could not get at it due to a subscription requirement; I also can not tell what it was included for. References certainly can be replaced if they can be given in more detail and/or made accessible.
--Tugbug 00:09, 18 May 2007 (UTC)
References need improvement
Reference 1 is to a website that uses the term but doe not establish a solid reference, which then refers to a paper which is in itself also uses BC/SD and is not a secondary reference to the origin or establishment of the term. I have added Template:Fact tags. Fireproeng (talk) 22:47, 17 February 2008 (UTC)
- The whole concept is ridiculous. The first rule of communication is to be understandable. Everyone knows what year you mean when you say "1000 B.C." If you say "BP" and really mean "1950" as "present" then you've made it harder to communicate. "BP" as a concept fails basic communication tests. --220.127.116.11 (talk) 19:55, 26 August 2008 (UTC)
- That depends who you're talking to. If its someone who understands radiocarbon dating, it makes perfect sense. Until 1950 the proportion of C14:C12 in the air was relatively constant. Then atmospheric nuclear weapons testing messed it up. So we take a carbon sample, and measure its 14/12 ratio. Log base 2. Divide by the 1950 atmospheric equivalent to get the number of half lives. Multiply by the half-life of C14. Get the number of years BP (uncalibrated). It's so silly, it won a Nobel prize. LeadSongDog (talk) 00:40, 27 August 2008 (UTC)
I agree. This pretentious pseudointellectual bs has to stop. Don't let these twits take over Wikipedia. Who cares if its convienent for radiocarbon dating, convert it to AD/BC and stop being idiots. You're all worse than Americans with thier imperial system. 18.104.22.168 (talk) 13:39, 27 September 2009 (UTC)
- REDIRECT Before Present —Preceding unsigned comment added by 22.214.171.124 (talk) 00:17, 27 May 2008 (UTC)
BP "years" are not the same as caledar "years"
I think it should be pointed out that BP "years" do not correlate nicely to calendar "years". For example, you can not simply subtract 10,000 from 1950 to figure out what callendar date equates to the date 10,000 BP. As time passes the BP "year" covers a longer period of time than one calendar "year". Its something to do with how carbon isotopes decay. Blueboar (talk) 15:04, 1 June 2009 (UTC)
- This only applies to "uncalibrated C-14 years". Most other fields do apply a 1-1 correspondence. It's not really an issue with BP so much as it is an issue with how carbon dating is reported. Dragons flight (talk) 15:11, 1 June 2009 (UTC)
- This is not my area of expertise, so I will bow to your knowledge... but I was under the impresson that BP was not always calibrated (and as the date gets older can not really be calibrated with any certainty.) It isn't a one to one ratio. In other words: 10,000 BP does not equal 8050 BC (1950 - 10,000). Am I misinformed? Blueboar (talk) 23:22, 2 June 2009 (UTC)
- A date reported as "10000 C-14 years BP" behaves as you suggest, but the counterpoint is "10000 calendar years BP" (cal. BP) which is one-to-one. When BP is used away from C-14 it is basically always calendar years. So the uncertainty you describe is a property of carbon dating, not a property of using BP notation. In technical literature a carbon dating number should always be labeled calibrated or uncalibrated in addition to saying BP, etc. Dragons flight (talk) 00:27, 3 June 2009 (UTC)
- There are a great many basis systems in use in stratigraphic analysis, from tree rings to layers in ice cores to layers in seabottom sediments. Many atmospheric factors vary year to year on a global scale leaving patterns that can be seen, repeated, in cores from widely varying sites, so that the corresponding layer in different cores can be identified as the same year. Counting layers in the cores gives exact integer year counts. Occasional fortuitous carbonaceous inclusions in the layers provide C12/C14 ratios for those exactly known years. These become calibration reference data points for converting radiocarbon dating to calibrated dating. Use of these tables allows for corrections for annual perturbations in the atmospheric C12/C14 ratios caused by major volcanic activity (increases) versus sunspots or forest fires in drought years (decreases). LeadSongDog come howl 04:33, 3 June 2009 (UTC)
- While you are broadly correct, I don't think there has ever been a countable ice core of any significant age with a large enough carbon content to be reliably measurable using C-14. As discussed at radiocarbon, calibration curves generally use dendrochronology, cave deposits, and corals. The last two are generally cross-dated with U-Th or similar techniques. Dragons flight (talk) 04:49, 3 June 2009 (UTC)
- I think I understand better now... but all this needs to be better explained in the article. Thanks. Blueboar (talk) 14:45, 3 June 2009 (UTC)
- This is all correct, and therefore the misuse of "BP" outside the conventional radiocarbon dating should not be tolerated. Moreover, the chapters on radiocarbon dating here intersect the proper wikipedia articles and must be removed.HJJHolm (talk) 12:42, 28 August 2009 (UTC)
- It is not our job to decide what should and should not be tolerated. People working in paleoclimate, uranium-thorium and other methods frequently use BP to mean calendar years. Wikipedia needs to document things as they are not as we wish they would be. Dragons flight (talk) 18:35, 28 August 2009 (UTC)
"BP" and "bp"
- Do we have wp:Reliable sources showing this convention is still practiced? LeadSongDog come howl! 01:06, 28 June 2010 (UTC)
Recommendations of the style guide of the Society for American Archaeology
I suggest to regard the style guide of the Society for American Archaeology here: When reporting radiocarbon dates and ages, the following information should be included: In the first citation, the uncalibrated radiocarbon age must be given. The uncalibrated radiocarbon age must be
- Based on the 5,568-year 14C (radiocarbon ages based on the 5,730-year half-life must be divided by 1.03),
- Expressed as years BP (i.e., Before Present; do not convert to radiocarbon years AD/BC),
- Followed by the 1-sigma (σ) standard error, as provided by the laboratory,
- Accompanied by the sample identification number given by the laboratory (use conventions for laboratory code abbreviations as provided in the journal Radiocarbon)
- Accompanied by the type of material that was dated (e.g., wood charcoal, corn cob),
- And defined as to whether the date was corrected for isotropic fractionation (a 13C value indicates correction has been made; best way to indicate this is to include the 13C value if available).
An example of an uncalibrated radiocarbon age is 480 ± 70 BP (ISGS 5965; plant [Pragmites sp./Equisetum sp.]; δ13C, −25.1). When calibrated dates are included, they must be identified as such by using the conventions "cal AD" or "cal BC," and the calibration used must be identified. Indicate whether the calibration was made for 1σ or 2σ (the latter is preferred), and present the calibrated age as a range of calendar age. If there is more than one possible range of age, include any probabilities provided by the calibration program. (For the date 3680 ± 60, the two possible calibrated age ranges are 2279–2232 cal BC [p = .05] and 2209–1905 cal BC [p = .95].) An example of a calibrated radiocarbon age is ca. cal AD 1480–1532 (calibrated with CALIB 5.0 at 2σ). — Preceding unsigned comment added by HJJHolm (talk • contribs) 10:19, 21 March 2012 (UTC)
b2k - relevant to this article?
Whilst I accept that 'b2k' (before 2000) can be cited, I don't understand why it belongs in this article. Indeed I think its inclusion is confusing because 'present' in BP doesn't mean 'today', it means 'before the atomic isotope record was disrupted by nuclear weapons [testing]'. So adding stuff about Y2K undermines that point. In my view, 'b2k' needs its own article and no more than a mention in the 'see also' in this one. --John Maynard Friedman (talk) 16:30, 28 October 2014 (UTC)