text:
Talk:List of climate change controversies

Possible way forward
There is now another merger discussion to merge this article into climate change denial, see here: Talk:Climate change denial. An alternative option could be to rework this article to become one that just lists past and ongoing debates (calling it purposefully debates not controversies). It could then be renamed "climate change debates" and contain quite a few excerpts. It could be a bit like a landing page to point people to the right sub-pages. A bit similar to climate change action (but longer). Thoughts? EMsmile (talk) 16:30, 17 November 2023 (UTC)
 * I am still trying to reach consensus for the way forward. My move proposal below was closed and the result was "not moved". I copy below what RCraig09 wrote on the talk page at: Talk:Climate change denial. Is that the broad consensus? EMsmile (talk) 09:33, 4 December 2023 (UTC)
 * The above arguments that are on-point, favor dismantling the GWControversy article. The issue is that a "controversy" doesn't really exist, so the arguments that don't directly address this issue should not carry weight for consensus. The GWControversy article should be merged out of existence and replaced with a redirect to CCdenial. A fraction of what's still in the GWControversy article might be moved... somewhere, not necessarily here. — RCraig09 (talk) 23:52, 3 December 2023 (UTC)
 * I've now moved all content out and have begun to convert the article to a list type article. I think this might work. It's basically just a landing page to show people where they can look for more detail. Does that work for everyone? EMsmile (talk) 10:13, 6 December 2023 (UTC)

Requested move 22 November 2023

 * The following is a closed discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. Editors desiring to contest the closing decision should consider a move review after discussing it on the closer's talk page. No further edits should be made to this discussion.

The result of the move request was: not moved. (non-admin closure) Edward-Woodrow (talk) 21:49, 1 December 2023 (UTC)

Global warming controversy → Climate change debates – I have recently reworked this article to become one that just lists past and ongoing debates (calling it purposefully debates not controversies). I propose to rename it to "climate change debates". It could contain quite a few excerpts and be a bit like a landing page to point people to the right sub-pages. A bit similar to climate change action (but longer). - We also discussed merging it into climate change denial and a few editors have supported this but I think some of its content is not about denial per se but just about past discussions. One of the Wikipedians said "Global warming controversy should be eliminated as "controversy" is a fabrication of deniers.". At a later stage, some of its content could also be moved to history of climate change science. EMsmile (talk) 18:47, 22 November 2023 (UTC)

 * Oppose with every atom of my being: The concept of "Climate change debates" is not substantively different from "Climate change controversy". Both are a fabrication of denialists undeserving of a Wikipedia article, and should be redirected to Climate change denial. — RCraig09 (talk) 21:22, 22 November 2023 (UTC)
 * I too supported the proposal to merge to climate change denial, but as you know it has not acheived consensus. So if this proposal is also rejected I think you should make a formal proposal as it seems none of us are happy with the current situation. Chidgk1 (talk) 14:53, 23 November 2023 (UTC)

 * Strong oppose: as far as I can tell, all of the "X debate" sections on this page now are almost entirely fabricated debates that are just denialist smoke blowing. These aren't debates in the scientific literature, and calling them "debates" adds credence to them that they don't deserve. - Parejkoj (talk) 21:27, 22 November 2023 (UTC)
 * Perfectly stated. — RCraig09 (talk) 21:36, 22 November 2023 (UTC)
 * I think your view is too simplistic here: As far as I can see there were some valid discussions around various aspects of climate change science and policies. They were often hijacked very quickly by climate change deniers but they were originally valid discussions at the time. For example, the section "Discussions around locations of temperature measurement stations" and "Debates over most effective response to warming". Those debates about mitigation options are now mostly explained in Economic analysis of climate change but they were and are legitimate discussions and not just "climate change denial stuff". Also, the "Antarctica cooling controversy" started off by a discussion amongst scientists; yes, it got hijacked and distorted by denialists. But originally it was simply a scientific investigation which is worth remembering (OK, another approach would be to move that to history of climate change science). - In any case, it feels to me a bit like you are saying any "discussions" around climate change equate to denialism.
 * See also related discussion here: https://en.wikipedia.org/wiki/Talk:Climate_change_denial#Merge_global_warming_controversy_into_here? Let me ping in two more people, User:KimDabelsteinPetersen and User:Mary Mark Ockerbloom who had commented there. Kim D. Petersen had written there which I thought was interesting: "While denial and conspiracies is a subset of the whole, the controversy also encompasses the political and economic struggle to figure out how to translate the very real problem into action (or inaction). If anything denial and conspiracies stem/arise from the controversy not the other way around." (I had replied there but got no further replies from them) EMsmile (talk) 11:48, 23 November 2023 (UTC)

 * Support Although it is not a good title it is better than the one we have now. Supporting this move does not stop anyone editing the article further or proposing another move next year. Chidgk1 (talk) 14:45, 23 November 2023 (UTC)
 * I agree with you, to think of this as an incremental improvement but not necessary the "final" situation. I think my proposed title (and scope) would certainly be better than the existing status quo. Merging all of it into other articles may or may not work, time will tell (I don't think all of it would fit at climate change denial; also, that article is already way too big and needs to be condensed).
 * Looking at the edit history of this article you can see that it's been in existence since 2002 (21 years!). Most of its content was added in 2007. After that it was slowly growing in size until I came along and slashed it down a lot recently. So deleting this article completely might not be warranted. For now, I think it would be a good compromise to re-focus it (like I have done) and to give it a more neutral name. That is what I am proposing at this stage. EMsmile (talk) 08:47, 24 November 2023 (UTC)
 * Oppose I see no reason to doubt that an average reader, who infamously rarely even makes it past the lead, would approach any article with the proposed title exactly as we all fear - as the reason to debate the existence of climate change - rather than as a debate about the higher-level aspects which the supporters of the move want them to see. In that sense, the move would be massively unhelpful.
 * The main issue is that the current article is very loosely scoped, as a range of arguments about very different things, and of highly variable validity, are all crammed into a single article. In some ways, it reminds me of effects of climate change on terrestrial animals (now a redirect): that used to have anything and everything from impact on domestic cattle to wild bats and birds, to snails going extinct to the spread of pest insects and pathogens - all because "terrestrial animals" is an inherently loose formulation that covers far too many species which often have very little in common, and me and EMsmile had to spent weeks on moving the content to more appropriately focused articles.
 * This is what I currently make of the article's subsections:
 * "Debates around the...Authority of the IPCC" - massive issues with WP:UNDUE, and not in one, but in two ways. Firstly, it gives undue weight to the perspective of deniers and delayers, based on statements from 2000s, which overlooks that a larger and more recent "debate" has been from the other side of the spectrum - the various figures who have accused the IPCC of being too timid and optimistic about the impacts of climate change, with varying credibility. Secondly, even including "both sides" in even proportion would still be WP:UNDUE - if you take a look at scientific consensus on climate change, there have been surveys of hundreds of climate scientists which altogether represent a resounding endorsement of the IPCC. On balance, it seems like we should cover these matters on the IPCC article itself and on one of the "history of climate change" articles (themselves clearly far from ideal.)
 * "Emphasizing studies that are regarded as flawed" - the way this is written, I do not see why this does not belong in climate change denial. It clearly has no role in any article about good-faith debate on any aspect of the matter.
 * "Funding for scientists who are skeptics or deniers" - This also seems rather out of place for an article which is supposedly intended to examine higher-order aspects of the matter?
 * "Debates around details in the science" - for me, the most charitable reading is that this could be used as a basis for something like Uncertainty in climate change science. However, a lot more material would have to be combined (some more from the "delayer" side, like the iris hypothesis, but the majority from the "alarmist" side - i.e. the debates around climate sensitivity or the thresholds of various tipping points) to justify the existence of something like this than what is currently present in that section (Interestingly, it seems like this article did mention some of those things earlier, albeit not in the ideal way, before EMsmile culled all of that.) Everything that is left here now can be reworked to fit History of climate change science: right now, that article effectively tapers off after 1988, with mere two paragraphs describing "Increased consensus amongst scientists: 1988 to present". That article is still mid-sized (34 kB, ~5.5k words), and it can certainly fit a few more paragraphs describing how some figures tried to use these supposed discrepancies to oppose the consensus, and how the science had moved past that.
 * "Debates over most effective response to warming" - the article's defenders suggest that this should be the crux of the article, but right now, it's mostly just an excerpt and there's almost nothing relevant there. At the risk of excessive self-promotion: at the start of the year, I proposed to create an article titled "Secondary impacts of climate change responses", which would describe how climate change mitigation and adaptation can have additional benefits if done right (incorporating Start-class Co-benefits of climate change mitigation in the process) and how they can have negative impacts, and how to balance those issues. You can see a very rough draft of this proposal on my userpage here.
 * TLDR; I strongly oppose the new name of this article, and I believe that its remaining material doesn't belong under the same roof and should be moved to other articles, whether existing or newly formed. InformationToKnowledge (talk) 13:19, 25 November 2023 (UTC)
 * If you have time to rework it in that way, I wouldn't stand in your way. I just wanted to make sure that the current status quo does not persists any longer. I think a basic name change for now is better than nothing but I do agree that the article has many flaws in its current format (and that it's loosely scoped). Do you have time to move any content that is worth keeping to either climate change denial or History of climate change science in the near-ish future? If yes, go ahead would be my suggestion. EMsmile (talk) 15:47, 25 November 2023 (UTC)
 * Have done your good suggestion and moved subsection →Emphasizing studies that are regarded as flawed - thanks Chidgk1 (talk) 15:17, 26 November 2023 (UTC)

 * Oppose "Debates" can be seen as WP:FALSEBALANCE, since the general scientific consensus is that global warming/climate change itself is not a matter of debate. I think this article should be merged into climate change denial, as when you remove the FALSEBALANCE aspects of it, it's pretty much the same thing. ᴢxᴄᴠʙɴᴍ (ᴛ) 08:26, 26 November 2023 (UTC)
 * Yes if you can persuade the people opposing Talk:Climate change denial that would be wonderful Chidgk1 (talk) 14:33, 26 November 2023 (UTC)
 * I pretty much reiterated there what I also said here, although keep in mind you aren't allowed to directly ask someone to influence a discussion per WP:CANVASS. Bringing it up in a neutral manner is what should have been done. ᴢxᴄᴠʙɴᴍ (ᴛ) 06:49, 28 November 2023 (UTC)
 * Oppose I agree with those above who have pointed out that both "debates" and "controversy" can be interpreted as supporting the idea that there is a lack of scientific consensus on climate change. I think that some good suggestions have been made for reorganizing and moving materials to other pages, and if that can be done, I see it as preferable to renaming. Mary Mark Ockerbloom (talk) 19:51, 27 November 2023 (UTC)

 * Oppose - It should be kept as is. 120.28.224.32 (talk) 08:58, 28 November 2023 (UTC)
 * This is not a vote. You are supposed to give reasons. --Hob Gadling (talk) 10:14, 28 November 2023 (UTC)
 * Comment - I think it's good to move some of the content to other articles where it fits, like I have just done with a segment on climate change mitigation which I have moved to climate change denial. However, I still think there could be merit in having a form of "landing page" which then sends people to the relevant sub-articles on a range of topics. We could easily use excerpts for this. With "landing page" I mean a page (with an appropriate article title, to be decided) which basically says "this is not about disputing the existence of climate change. This is about past and present discussions about some specific aspects in relationship to how climate change pans out, how it happens, how fast, how we can deal with it, how the research is carried out and so forth".
 * We cannot claim that each of those past debates was the work of climate change deniers: Some of those debates were real and valid, e.g. about the siting of temperature measurement devices. They usually got hijacked in no time by the climate change deniers but that's a different problem. So a landing page that provides an overview of the difficult topics could still be useful in my opinion. Unless we say it's not the job of Wikipedia to provide such a landing page. But isn't climate action also a kind of landing page? Or call it a disambiguation page, or a list article.
 * Maybe the new title should be Topics of discussion around climate change or Climate change discussion topics or List of discussion topics on climate change. Or maybe this would make it too broad and it wouldn't work at all? EMsmile (talk) 10:56, 28 November 2023 (UTC)
 * Note we do have something a bit similar called Index of climate change articles. EMsmile (talk) 10:59, 28 November 2023 (UTC)
 * "Discussion topics..." (etc.) is definitely too broad. Index of climate change articles serves a valid purpose more succinctly and neutrally. — RCraig09 (talk) 16:45, 28 November 2023 (UTC)

The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

"Brownlash" listed at Redirects for discussion
The redirect [//en.wikipedia.org/w/index.php?title=Brownlash&redirect=no Brownlash] has been listed at redirects for discussion to determine whether its use and function meets the redirect guidelines. Readers of this page are welcome to comment on this redirect at  until a consensus is reached. Steel1943 (talk) 15:02, 30 November 2023 (UTC)

Requested move 8 December 2023

 * The following is a closed discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. Editors desiring to contest the closing decision should consider a move review after discussing it on the closer's talk page. No further edits should be made to this discussion.

The result of the move request was: Moved to List of climate change controversies. Per consensus on the alternative proposed title. (closed by non-admin page mover) – robertsky (talk) 01:20, 15 December 2023 (UTC)

Global warming controversy → List of global warming controversies – This article has now been reworked to be a list article. It's basically a landing page to show people where they can look for this kind of content. Most of the previous content has been moved to climate change denial. I think it is important to change it to plural (i.e. controversies, not controversy). My previous proposal to change it to "climate change debates" achieved no consensus. Setting this up as a basic list article is a good compromise solution, I think. EMsmile (talk) 11:16, 8 December 2023 (UTC)
 * Support - Thanks for all your cleanup work. I think this is in a much better state now, and that rename makes sense. - Parejkoj (talk) 18:08, 8 December 2023 (UTC)
 * Support. The proposed title is appropriate given that the article is now mainly a list of links to more specific subjects. ╠╣uw [ talk ] 18:12, 8 December 2023 (UTC)
 * Per VQuakr below, List of climate change controversies seems preferable, since it's the form used by all the listed articles. ╠╣uw [ talk ] 11:14, 9 December 2023 (UTC)

 * Support great work! VQuakr (talk) 18:36, 8 December 2023 (UTC)
 * But why not List of climate change controversies? All the listed items seem to be in the form of the latter. VQuakr (talk) 18:39, 8 December 2023 (UTC)

 * Comment: Yes, I agree, List of climate change controversies would actually be much better. My original thought was to stick closer to the current title but actually List of climate change controversies would work better. Glad to see the supportive responses. Thanks! EMsmile (talk) 16:40, 10 December 2023 (UTC)

 * Comment: I still retain concerns that an article with such a title may be misinterpreted, and that we could see attempts to add denialist talking points into such an article, but I cannot currently think of a better alternative, so I will not formally oppose this.
 * I should also note if the move happens, as it seems like it will, we would likely need to reintegrate the mention (in the form of links, I suppose) of some of the things which got cut out of this article earlier, such as the iris hypothesis or arguments that the IPCC/mainstream science is too conservative. InformationToKnowledge (talk) 19:28, 11 December 2023 (UTC)
 * Yes, we'd have to watch this new list article to ensure it stays as a list and no substantial new content, especially not denialism stuff, (other than links) get added. Regarding the two points that you mentioned they are already included with links in the article:

 * History of climate change science (in here you will find the info about the iris hypothesis, amongst others (to be built up in future)
 * Intergovernmental Panel on Climate Change (this contains the criticism about the IPCC processes) EMsmile (talk) 08:40, 12 December 2023 (UTC)

The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

Request for comment regarding related articles
I noticed that there are several users who have been quite active in discussions on this talk page, even though I do not usually see them participate in Wikipedia talk:WikiProject Climate change. According to WP:CAN, it is perfectly acceptable to request comments on talk pages of related articles, so I would like to do that right now for two articles.

 * Scientific consensus on climate change - a highly related article. I voiced several suggestions on the talk page there two weeks ago, yet nobody had commented on them yet in one way or another.

InformationToKnowledge (talk) 19:38, 11 December 2023 (UTC)
 * Climate apocalypse - a controversial topic, and there has been a long-running merge discussion there (in addition to some other proposals) which hasn't really gone anywhere. Perhaps input from editors active here could help to resolve the question.


text:
Floating-point unit

A floating-point unit (FPU, colloquially a math coprocessor) is a part of a computer system specially designed to carry out operations on floating-point numbers. Typical operations are addition, subtraction, multiplication, division, and square root. Some FPUs can also perform various transcendental functions such as exponential or trigonometric calculations, but the accuracy can be low, so some systems prefer to compute these functions in software.

In general-purpose computer architectures, one or more FPUs may be integrated as execution units within the central processing unit; however, many embedded processors do not have hardware support for floating-point operations (while they increasingly have them as standard).

When a CPU is executing a program that calls for a floating-point operation, there are three ways to carry it out:
 * A floating-point unit emulator (a floating-point library in software)
 * Add-on FPU hardware
 * Integrated FPU (in hardware)

History
In 1954, the IBM 704 had floating-point arithmetic as a standard feature, one of its major improvements over its predecessor the IBM 701. This was carried forward to its successors the 709, 7090, and 7094.

In 1963, Digital announced the PDP-6, which had floating point as a standard feature.

In 1963, the GE-235 featured an "Auxiliary Arithmetic Unit" for floating point and double-precision calculations.

Historically, some systems implemented floating point with a coprocessor rather than as an integrated unit (but now in addition to the CPU, e.g. GPUs – that are coprocessors not always built into the CPU – have FPUs as a rule, while first generations of GPUs did not). This could be a single integrated circuit, an entire circuit board or a cabinet. Where floating-point calculation hardware has not been provided, floating-point calculations are done in software, which takes more processor time, but avoids the cost of the extra hardware. For a particular computer architecture, the floating-point unit instructions may be emulated by a library of software functions; this may permit the same object code to run on systems with or without floating-point hardware. Emulation can be implemented on any of several levels: in the CPU as microcode, as an operating system function, or in user-space code. When only integer functionality is available, the CORDIC methods are most commonly used for transcendental function evaluation.

In most modern computer architectures, there is some division of floating-point operations from integer operations. This division varies significantly by architecture; some have dedicated floating-point registers, while some, like Intel x86, go as far as independent clocking schemes.

CORDIC routines have been implemented in Intel x87 coprocessors (8087,    80287, 80387  ) up to the 80486 microprocessor series, as well as in the Motorola 68881  and 68882 for some kinds of floating-point instructions, mainly as a way to reduce the gate counts (and complexity) of the FPU subsystem.

Floating-point operations are often pipelined. In earlier superscalar architectures without general out-of-order execution, floating-point operations were sometimes pipelined separately from integer operations.

The modular architecture of Bulldozer microarchitecture uses a special FPU named FlexFPU, which uses simultaneous multithreading. Each physical integer core, two per module, is single-threaded, in contrast with Intel's Hyperthreading, where two virtual simultaneous threads share the resources of a single physical core.

Floating-point library
Some floating-point hardware only supports the simplest operations: addition, subtraction, and multiplication. But even the most complex floating-point hardware has a finite number of operations it can support – for example, no FPUs directly support arbitrary-precision arithmetic.

When a CPU is executing a program that calls for a floating-point operation that is not directly supported by the hardware, the CPU uses a series of simpler floating-point operations. In systems without any floating-point hardware, the CPU emulates it using a series of simpler fixed-point arithmetic operations that run on the integer arithmetic logic unit.

The software that lists the necessary series of operations to emulate floating-point operations is often packaged in a floating-point library.

Integrated FPUs
In some cases, FPUs may be specialized, and divided between simpler floating-point operations (mainly addition and multiplication) and more complicated operations, like division. In some cases, only the simple operations may be implemented in hardware or microcode, while the more complex operations are implemented as software.

In some current architectures, the FPU functionality is combined with SIMD units to perform SIMD computation; an example of this is the augmentation of the x87 instructions set with SSE instruction set in the x86-64 architecture used in newer Intel and AMD processors.

Add-on FPUs
Several models of the PDP-11, such as the PDP-11/45, PDP-11/34a, PDP-11/44,  and PDP-11/70,  supported an add-on floating-point unit to support floating-point instructions. The PDP-11/60, MicroPDP-11/23 and several VAX models  could execute floating-point instructions without an add-on FPU (the MicroPDP-11/23 required an add-on microcode option), and offered add-on accelerators to further speed the execution of those instructions.

In the 1980s, it was common in IBM PC/compatible microcomputers for the FPU to be entirely separate from the CPU, and typically sold as an optional add-on. It would only be purchased if needed to speed up or enable math-intensive programs.

The IBM PC, XT, and most compatibles based on the 8088 or 8086 had a socket for the optional 8087 coprocessor. The AT and 80286-based systems were generally socketed for the 80287, and 80386/80386SX-based machines – for the 80387 and 80387SX respectively, although early ones were socketed for the 80287, since the 80387 did not exist yet. Other companies manufactured co-processors for the Intel x86 series. These included Cyrix and Weitek. Acorn Computers opted for the WE32206 to offer single, double and extended precision to its ARM powered Archimedes range, introducing a gate array to interface the ARM2 processor with the WE32206 to support the additional ARM floating-point instructions. Acorn later offered the FPA10 coprocessor, developed by ARM, for various machines fitted with the ARM3 processor.

Coprocessors were available for the Motorola 68000 family, the 68881 and 68882. These were common in Motorola 68020/68030-based workstations, like the Sun-3 series. They were also commonly added to higher-end models of Apple Macintosh and Commodore Amiga series, but unlike IBM PC-compatible systems, sockets for adding the coprocessor were not as common in lower-end systems.

There are also add-on FPU coprocessor units for microcontroller units (MCUs/μCs)/single-board computer (SBCs), which serve to provide floating-point arithmetic capability. These add-on FPUs are host-processor-independent, possess their own programming requirements (operations, instruction sets, etc.) and are often provided with their own integrated development environments (IDEs).

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Floating-point unit


text:
User:Larry Sanger

Dear Wikipedians,

I'm no longer associated with Wikipedia, which I co-founded. (I named it, crafted much of the policy that now guides the project, and led the project for its first year. As Jimmy Wales declared on March 25, 2002, a week before I resigned, I was "the final arbiter of what the consensus is" on Wikipedia.)  You can read my own account of my involvement with Wikipedia and Nupedia, "The Early History of Nupedia and Wikipedia: A Memoir," here:
 * Part I
 * Part II

Links to some of my other writings about the project, and other topics, can be found at http://www.larrysanger.org.

Here are some links about my role in Wikipedia. To the best of my knowledge, I was first described as co-founder of Wikipedia back in September 2001 by The New York Times. That was also my description in Wikipedia's own press releases from 2002 until 2004. With my increasing distance from the project, and as it grew in the public eye, however, some of those associated with the project have found it convenient to downplay and even deny my crucial, formative involvement. In fact, in the early years of the project, my role was not in dispute at all. The preceding links should dispel much of the confusion.

I am now working on various educational projects. Among other things, I recently web-published a 140-page essay titled How and Why I Taught My Toddler to Read.

I can be reached at sanger (a t) watchknow (d o t) org.

--Larry Sanger

P.S. Here's what I posted when I left in 2002. Still good advice:

All the best to Wikipedia and Wikipedians. May you continue
 * to be open and warmly welcoming, not insular,
 * to be focused singlemindedly on writing an encyclopedia, not on Usenet-style debate,
 * to recognize and praise the best work, work that is detailed, factual, well-informed, and well-referenced,
 * to work to understand what neutrality requires and why it is so essential to and good for this project,
 * to treat your fellow productive, well-meaning members of Wikipedia with respect and good will,
 * to attract and honor good people who know a lot and can write about it well, and
 * to show the door to trolls, vandals, and wiki-anarchists, who if permitted would waste your time and create a poisonous atmosphere here.

P.P.S. From September 2006 through 2009 or so, I worked on another wiki encyclopedia project, called the Citizendium. It requires that contributors use their real names (but articles are still unsigned), and the project is guided by expert editors (but the general public is still the mainstay and strongly urged to join). I also have a blog with lots of my old essays and speeches.

P.P.P.S. I have recently made a couple of short videos about how I helped get Wikipedia started here: Part 1 and Part 2.

P.P.P.P.S. My more recent projects include WatchKnowLearn and, just launched last week, Reading Bear. (11/3/2011)

P.P.P.P.P.S. I’m now strategizing and organizing putting Everipedia (which is a fork of the English language Wikipedia, plus 1,000,000 new articles) on the blockchain. This will decentralize encyclopedia article production and make it possible for people, finally, to be compensated for their previously volunteer-only work on encyclopedias. (1/2018)

Archive

title: User:Larry Sanger


text:
User:BF

BF is a closet scientist and website designer who needs to trance out with New Age to balance  Known  ½ Unknown the spirit with the machines and those unrelenting visions of truth. Hello everyone. Enjoy editing. I will write.
 * New_Age Dakini  my first  M-theory  Aludra  Think_tank  Delerium

 * M-theory_simplified Tesseract  The_Sophia_of_Jesus_Christ   Paradigm_shift  Edgar_Cayce

 * Purple Graffiti
 * Pink Graffiti

title: User:BF


text:
Talk:Ole Rømer

Untitled
In Denmark his name is written "Ole Rømer". Seindal, Wednesday, April 3, 2002

My book explicitly says that he never calculated the speed of light and that the orbit of Earth and Jupiter was not known in his time. The article said differently. Lir 02:23 Nov 19, 2002 (UTC)

 * Hello. You would need to state the title of "your" book. 86.52.114.223 (talk) 16:16, 20 January 2014 (UTC)

Dubious
"Notable is also his definition of the new Danish mile. It was 24,000 Danish feet, which corresponds to 4 minutes of arc latitude, thus making navigation easier."

This is a conflation of the definitions of two different units of measure, the Danish land mile of 24,000 feet, and the geographical mile of four minutes of arc.

I'm pretty sure it hasn't always been mixed up this way in the article, so the first thing I'll do is check the history. Gene Nygaard (talk) 01:19, 3 March 2008 (UTC)

 * My recollections were faulty, and this has been incorrect since User:Egil added it over 3 years 1 month ago in this edit. So there isn't any better version to revert to, it just needs fixing.  Gene Nygaard (talk) 01:25, 3 March 2008 (UTC)

 * I agree that this looks wrong and I've removed the mention of the "four minutes of arc"-mile. Rømer defined the Danish mile as 24,000 Danish feet which corresponded to about 7,532m, while the geographical mile of four minutes of arc is about 7,422m, so there are clearly two different miles here. For all I know, Rømer may have chosen the value of 24,000 to correspond roughly with 4 seconds of arc, but I can't find a source supporting that idea, so unless someone else can, this certainly does look like someone conflated the two miles by mistake. Hemmingsen 19:22, 25 October 2008 (UTC)

Section on determination of speed of light
I think those other materials re basing on Romer's strategy should be placed somewhere... This article is a biography on the person. --Bentong Isles (talk) 05:21, 11 November 2008 (UTC)

The paragraph below:

"Assume the Earth is in L, at the second quadrature with Jupiter (i.e. ALB is 90°), and Io emerges from D. After one orbit of Io, 42.5 hours, the Earth is in K. Rømer reasoned that if light is not propagated instantaneously, the additional time it takes to reach K, that he reckoned about 3½ minutes, would explain the observed delay."

contains a mistake. For the Earth to be 3.5 light-minutes more distant from Jupiter than it was at position L, it must move around the Sun for approximately 25 days; during this time, Io would make about 14.2 orbits of Jupiter. Not a single orbit, as the paragraph above states.

Sincerely, A Ph.D. Physicist —Preceding unsigned comment added by Tenorio40 (talk • contribs) 01:43, 20 June 2009 (UTC)

I was hoping that someone would rewrite the entire light speed calculations part, since it is not very good, but I suppose correcting small errors is better than nothing. I shall make an attempt.DanielDemaret (talk) 08:31, 20 June 2009 (UTC)

I made that small change. However, I think that the explanation right now still contains several irrelevant notions that should be left out, and that some more relevant details should be put in. An example of a better explanation is here: http://www.is.wayne.edu/mnissani/a&s/light.htm. If n-oone protests, no-one changes this and I feel like it sometime I shall then rewrite that small paragraph. If I feel like it. DanielDemaret (talk) 08:47, 20 June 2009 (UTC) Since there are many different kinds of "minutes" and the articele does not specify nor make it clear which kind, it is confusing.DanielDemaret (talk) 08:54, 20 June 2009 (UTC)

Daniel - Since your improvement of June 20, 2009 it is much better. But I agree with you, the entire light-speed calculation section could be improved further. If you don't mind doing it, please do, since the Romer measurement was very interesting and important in the history of science. This does not matter now, but in the original mistaken paragraph (with only one orbit of IO around Jupiter), the Earth would have only moved away from L by 15 light-seconds after 42.5 hours, which is 14 times less than 3.5 light-minutes. But, as I mentioned, this is now irrelevant. I encourage you to rewrite the paragraph. Thanks in advance. Richard. —Preceding unsigned comment added by Tenorio40 (talk • contribs) 18:30, 22 June 2009 (UTC)
 * I agree that there's probably enough material to create a separate article on Rømer's determination of the speed of light, especially as I want to add some more! But, in the meantime, a couple of comments here:
 * I'm not sure the note about the date of the opposition of Jupiter is really relevant, at least not if it is referenced to Dieter Egger's applet. If we want to find a date for the opposition in 1676, we should look to a professional ephemeris: someone at WikiProject Astronomy must have access to one, or there might be the relevant data in
 * Where does "Rømer's data" come from? There's no reference for it, and one recurring modern comment about Rømer's determination is precisely the lack of available experimental data to support it.
 * Physchim62 (talk) 12:02, 20 October 2009 (UTC)

 * I don't know what reference has been used for the eclipse data currently in the article or why the 1676 observations are picked out but they clearly originate in Rømer's own manuscript. While Rømer never published his experimental data and they were thought to be lost, Kirstine Meyer discovered Rømer's manuscript with all original data (and parts of his calculations) in 1913 and published them in 1915. I uploaded it to commons a couple of months ago, so next time you hear someone complaining about the lack of experimental data to support Rømer's determination, just point them the way to commons :) Hemmingsen 18:21, 20 October 2009 (UTC)
 * Wow! That's great! I can easily explain the concentration on 1676 values.
 * On 22 August 1676, Cassini made an announcement to the Royal Academy of Sciences that he would be updating his ephemeris of Io to take account of a new effect (or "irregularity" as he called it). He seems to have given the figure of "ten or eleven minutes" as the time it takes light to travel the distance detween the Earth and the Sun, and he certainly predicted that the emersion of Io from Jupiter's shadow on 16 November 1676 would occur ten minutes later than would otherwise be calculated.
 * For some reason, the eclipse of 16 November was never used – maybe it was just cloudy in Paris that night – but there was another eclipse on 9 November 1676 which also fitted with the new model. Rømer then presented the new calculations to the Royal Academy of Sciences on 21 November.
 * Hence, it is fairly clear that these are not Rømer's original results, the one's he used to make his 1676 predictions, as they have observations from 1677 and 1678. Nor is it clear that all of the observations are Rømer's – Rømer arrived in Paris in 1672, while the table has observatons from 1669 and 1671: in fact, it is widely accepted that Rømer also took advantage of obervations by his friend Picard. Rømer might have used some of his own results from Uranienborg, but he must have known that doing so would introduce a new factor – the difference in longitude – and so make his calculations less precise. Anyway, he was working in what was then the world centre for observations of Jupiter, so why not take advantage of the long set of observations that were available to him.
 * The document seems to be more of a convenient table of eclipse observations that he could use to try to refine his calculations. Still, it allows anyone (who can be bothered) to reconstruct what he should have seen on the given dates, and so rework the calculation. Physchim62 (talk) 11:32, 21 October 2009 (UTC)

 * In 1677 Huygens wrote to Rømer with some questions on how Rømer had determined his value of 22 minutes. Quoting from Rømer's reply from September 1677 (I am using a Danish translation in Friedrichsen, Per & Tortzen, Chr. (eds.) (2001) Ole Rømer of the Latin original, so the translation may be slightly rough)
 * I have collected and examined all observations of the eclipses of the first moon made by either Mr. Picard or myself since 1668. It is actually more than 70.
 * Of these I have selected and compared the following intervals.
 * As the Earth was moving away from Jupiter between March 1671 and May 1671.
 * Immersions as the Earth was approaching Jupiter between October 1671 and February 72.
 * Emersions as the Earth was moving away from Jupiter March 72 to June 72.
 * Immersions as the Earth was approaching Jupiter between November 72 to March 73.
 * Emersions as the Earth was approaching Jupiter April 73 to August 73.
 * Emersions as the Earth was moving away between July 1675 and October 1675.
 * Immersions as the Earth was approaching May 76 to June 76.
 * Emersions as the Earth was moving away August 76 to November 76.
 * Immersions as the Earth was approaching June 77 to July 77.
 * [...]
 * With regards to the determination of the famous 22 minutes I primarily chose observations from the years 71, 72 and 73, partially because we had more from that period, [...]
 * It is partially on the basis of that letter that Meyer concluded that the observations in the document are Rømer's original data, and it is also why I find picking only the 1676 observations is a bit arbitrary, since Rømer's focus apparently was on 71-73.
 * You are of entirely right that it probably isn't be the original document (the later observations could have been added later, though, I suppose).
 * Rømer apparently used observations made in both Paris, Uranienborg and Copenhagen (Rundetårn) and attempted to correct for the difference in longitude using the values on the top of page 2.
 * If anyone's interested, Meyer's 1915 article does reconstruct Rømer's calculations to significant detail so it shouldn't be necessary to rework them. Hemmingsen 12:59, 25 October 2009 (UTC)

One might add, near the end of the section, that the speed of light is nowadays defined as precisely 299,792,458 metres per second, which (the second being already well-defined) defines the length of the metre. Wikipedia will have the details. Date around 1975, I think. 94.30.84.71 (talk) 22:28, 18 June 2022 (UTC)

Confusing
In the section on the speed of light the articles says:

 * When the angle α is 180° the delay becomes 22 minutes, which may be interpreted as the time necessary for the light to cross a distance equal to the diameter of the Earth's orbit...

Then in the next paragraph it says:

 * ...Huygens deduced that light travelled 16+2⁄3 Earth diameters per second, misinterpreting Rømer's value of 22 minutes as the time in which light traverses the diameter of the Earth's orbit.

What did Huygens misinterpret, the value of 22 minutes or what it means?

Anachronism?
The article mentions that "Rømer joined the observatory of Uraniborg on the island of Hven, near Copenhagen, in 1671"; however, the article on Uraniborg mentions that "The institution was destroyed in 1601 after Tycho's death" and later "both Uraniborg and Stjerneborg were destroyed shortly after Tycho's death," without any mention of the observatory being rebuilt at any point until recently ("Uraniborg's grounds are currently being restored," which doesn't specify the date, but obviously in the 20th or 21st century).

Does anyone have any explanation for this apparent anachronism?

Thanks in advance.

CielProfond (talk) 03:10, 19 February 2017 (UTC)

Den Store Danske Encyklopædi tells the story of Ole Rømer as follows: He worked on Tycho Brahe’s manuscript at Copenhagen University when Jean Picard came to Denmark to measure the precise location of “Uraniborg Plads” (Uraniborg square), so probably where Uraniborg used to stand. Also the Encyclopædie Britannica states similarly that Picard was interested in Uraniborg’s precise location to compare Tycho Brahe’s measurements with those made elsewhere. Donik (talk) 07:56, 26 September 2018 (UTC)

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title: Talk:Ole Rømer