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—
Yamara
✉
08:45, 18 February 2008 (UTC)
It took me months to figure out that the Recent Changes page bases its clock on UTC. Several times I've been tempted to send an email to Jimbo asking him to reset the Wikipedia internal clock. If others have been confused and considered this a minor annoyance, then I'd like to suggest that the term (UTC) be added to the timestamp on the Recent Changes page. -- Modemac 20:10 Feb 8, 2003 (UTC)
The following sentance in the article makes little sense to me, since no reference date is given:
"As of 1 January 1999, TAI is ahead of UTC by 32 seconds."
Over what period of time was 32 seconds lost? < /br>
wamquark< /br>
Sunday, November 27, 2005, 12:36:42 PM EST
I've removed the above links, as they don't describe UTC in any useful way. They seem to be about an obscure date/time formatting specification which, as it happens, may use UTC as the timezone. -- Brion 12:12 Feb 9, 2003 (UTC)
From http://www.ietf.org/internet-drafts/draft-ietf-impp-datetime-05.txt
This document defines a date and time format for use in Internet protocols that is a profile of the ISO 8601 standard for representation of dates and times using the Gregorian calendar
So, ISO 8601 it´s a standard. And the rest are proposed profiles of the standard in the Internet. Very important for people that uses UTC, specially in the Internet.
Because of this I propose include a link to UTC(Internet). If interesting for the user, the user will deciede clicking in the link ;)
Regards
I have translated the UTC article into Spanish ;)
Why "UTC"?
Putting stronger language into the article abt this is low among my prioriies. --
Jerzy 23:03, 2003 Dec 15 (UTC)
Article should say whether UTC implies 24-hour format. And in any case, whether format is specific as to range:
(or their 12-hour equivalents) -- Jerzy 23:14, 2003 Dec 15 (UTC)
This is correct. A whole moment of time begins at zero, and ends on the fullest point before 1. This is 0.9999999. The statement below was in the link above. This is wrong. For by the logic here, if the beginning of the 2nd millenium was 2001, the beginning of the 3rd millenium will be 3002. Just thought Id point this out. Zero hour is a mysterious point in time, yet is is definitely on the AM, rather than the PM. Our midday begins the night and midnight begins the day. Interesting.
When did the current millennium begin?
Since a millennium is 1000 years, and the first millennium began at the start of the year 1, it ended at the end of the year 1000. The second millennium then began with the year 1001 and concluded at the end of the year 2000. Therefore, the current millennium technically began with the year 2001. For historical information, see an exhibit on Calendars.
This statement was found here.
Why "UTC"? We truly cannot always use the internet to source articles on the Wiki. Time is a difficult concept to grasp though.
WikieWikieWikie ( talk) 23:21, 7 August 2008 (UTC)
The table of conversion from UTC appears so far to the left that the Special Pages links cover part of it. I'm in Cologne Blue, 1024x768 with a fixed left sidebar - anything we can do about this unsightliness? -- Rissa 19:48, 4 Jun 2004 (UTC)
It should be noted that in DST there is a different UTC -/+ time (E.g in winter, CST is UTC-6 while in Summer it is UTC-5...slightly annoying for me actually [considering WP is UTC]). Ilyanep 02:12, 21 Jun 2004 (UTC)
Quaint mention "also referred to as Zulu time". A bit of explanation might raise the human interest of the page...I'd never even heard of UTC (AFAIK everyone still uses GMT in the UK)-- BozMo |talk 15:37, 19 Aug 2004 (UTC)
http://www.grc.nasa.gov/WWW/MAEL/ag/zulu.htm
(The standard is coordinated universal time, abbreviated UTC. This was formerly known as Greenwich mean time (GMT). UK uses GMT/BST/IST) "Zulu" is just one of 25 designations that NATO and US Military uses.)
I've added a short sentence to try to clarify the meaning of Zulu time, and a link that has a good summary of the Alpha-Zulu time zones, listing some key locations worldwide. Of course, the time zone can change when a country uses a daylight-saving time. For example, in winter the UK uses GMT/UCT, i.e Zulu time; in summer it moves to British Summer Time (BST), which is one hour ahead, i.e Alpha time.-- RDT2 13:19, 18 June 2006 (UTC)
The US Navy uses "Zulu" for UTC. Do other services? Other nation's militaries? Gerardw ( talk) 19:32, 21 September 2008 (UTC)
There should be a disambiguation section added, since the letters UTC form the initials of the University of Tennessee at Chattanooga. -- ZekeMacNeil 23:13, 10 Jan 2005 (UTC)
An extensive discussion regarding the Time Cube edit war has been taking place at Talk:Greenwich Mean Time#Time Cube discussion. I hope the issues have been resolved for now and am unprotecting this page. — Knowledge Seeker দ 20:40, 2 May 2005 (UTC)
The merge on this and UT seems a bit silly. They are different and warrant different articles. Whoever put the notices on hasn't said why they think they should be merged either. If nobody gives any reasons then I'll just take the notices off. KayEss | talk 09:05, 28 December 2005 (UTC)
Although the scientific discussions concerning Universal time etc are no doubt important and valid it should be made clear that the people of the world generally and all broadcasters etc use Greenwich Mean Time and not Universal Time. The simple fact is that these are of course identical, each starting from Greenwich London England. The only real reason Universal Time and its variants Zulu Time etc is used is because of irritation at Britain still being the place from which the world takes its time. If people are honest they will admit this..
The problem with non scientific people using "Universal Time and its variants is obvious... If the time is UNIVERSAL then it must be the same EVERYWHERE!! So.. if its 0900 in Paris it must be 0900 in New York! As this is impossible you have to do a calculation..and for other places? Well of course UTC is really the time at a place called Greenwich in England! so we have returned to GMT.!!. GMT will never vanish because it is much easier for people to visualise time zones when they have a real place in the world from which to start... It may give some people a thrill at stamping on those pesky British but it wont work you know.. You could help the world just a little bit by promoting GMT and making life easier for everybody!!! —the preceding unsigned comment is by 80.98.112.51 ( talk • contribs) 19:14, 2 January 2006 (UTC1)
I believe GMT changes with daylight savings time and UTC does not. Am I wrong about this? mike 18:06, 28 September 2006 (UTC)
I think there's a point to the above comment which asks how does UTC relate to local time and to GMT. I think it is true that UTC and GMT will never differ by more than a second, and that the differences are really important for, say, astronomic observations, and as a legal standard. -- Ozga 05:36, 26 May 2007 (UTC)
In general common usage UTC is identical to GMT and this article should clearly state that right at the top! On my PC I have GMT listed as a time zone but no UTC, and then I receive an email with a UTC time and I wonder if UTC is the same as GMT? Then I come to Wikipedia to find out. Many will go through this process and you should tell us what the answer is. Of course they are effectively the same but your article doesn't clearly state that at the top, for petty technical reasons. I tried to add it in but some pillock removed it. When are you wikipedia editors going start thinking about your readers and use some common sense? GMT has various meanings but the commonest is UTC (atomic clock based), and the main other GMT meaning, based on astronomy, differs at most by 0.9 of a second from UTC. Very few people use the latter meaning anymore. There is an article here that explains it in detail
"http://www.apparent-wind.com/gmt-explained.html". Retrieved 2007-08-19. {{
cite web}}
: External link in
(
help). --
190.76.7.166
02:22, 20 August 2007 (UTC)
|title=
Given that UTC is a French inception the original editors remarks that it was utilised as an anti-English reliance having to cite Grenwich as the center of the chronological earth is correct. The only countries I have found use UTC in any open forum are France and America. That being said, 99% of publications of time are in GMT even IN those countries. I see UTC only on Wikipedia, throughout my travels around the world it's popped up once or twice, but mostly as an oddity. I find it very problematic that we at Wikipedia utilise UTC because it doesn't allow me to understand the time frame reference they're talking about exactly. GMT everyone understands. Fair enough they're 'near identical', but they're not and UTC is unreliably different and requires an understanding of the mathematical principals to deduce from a given time, I know that when it's midday here it's 2am at Grenwich and from that I can deduce (exactly) all other time lines around the world.
I turned to Wiki to find out what Pacific Standard Time is and it has, for the first time ever, truly failed me as a resource to be able to work out the time difference. I'd say perhaps we should move to GMT like the rest of the world, but given the different target audience that Wikipedia has, I doubt that would go down well for the most part. 210.49.15.52 13:05, 13 November 2007 (UTC)
Following the ISO standard one have to include T to separate date and time in UTC format. The Z to indicate zulu time (zero time) is not necessary. -- 82.159.136.238 05:54, 20 April 2006 (UTC)
Leap seconds are solely a feature of UTC, and UTC cannot be defined without discussion of leap seconds. They form a single topic, so it is silly for them to have separate articles. 81.168.80.170 12:15, 29 April 2006 (UTC)
Sandford Fleming was the inventor of Universal Standard Time. He proposed linking of Time Zones to the 180º Meridian in the 1884 International Meridian Conference. Why this fact is not registered here?. -- Fev 22:10, 14 May 2006 (UTC)
Why is it abreviated that? It's Coordinated Universal Time, not Universal Time Coordinated. Why UTC, it should be C.U.T. -- 71.224.19.29 16:16, 25 May 2006 (UTC)
Could someone define the meaning of UT1 before using it in the article? It would help in understanding the concepts.
Thanks —Preceding unsigned comment added by 206.173.170.67 ( talk • contribs)
For heaven's sake, they are completely different things. Why propose this merger in the first place is what I'm wondering.-- Saoshyant 11:01, 9 October 2006 (UTC)
Okeh, I know it's a technical term, but instead of burying the key sentence (for the average user) at the bottom of the first or second paragraph, couldn't we some-how make it easier to see that UTC is (for many purposes - e.g., use on Wik) GMT? Kdammers 00:39, 11 March 2007 (UTC)
In the following paragraph: Most UTC days contain exactly 86,400 seconds, with exactly 60 seconds in each minute. However, since the mean solar day is slightly longer than 86,400 seconds, occasionally the last minute of a day will have 61 seconds. (If a UTC day were to have 86,399 or 86,401 seconds, the last minute of the day would have 59 or 61 seconds, respectively, but this has never happened). The irregular day lengths mean that fractional Julian days do not work properly with UTC. The intercalary seconds are known as "leap seconds".
Logically, the statement If a UTC day were to have 86,399 or 86,401 seconds, the last minute of the day would have 59 or 61 seconds makes sense, however with the explanation that a solar day is slightly longer than 86,400 seconds statement above, the time reference there leads me to believe that the bolded statement is wrong, technically, because it doesn't reference that occasional adjustment in the same paragraph. I inevitably am wrong, but I suggest making the two points more clear.
Proposed Revision: Most UTC days contain exactly 86,400 seconds, with exactly 60 seconds in each minute. However, since the mean solar day is slightly longer than 86,400 seconds, occasionally the last minute of a solar day will have 61 seconds. If a UTC day were to have 86,399 or 86,401 seconds, the last minute of the solar day would have an adjustment of one, in each respective direction, however this has not happened to date. The irregular day lengths mean that fractional Julian days do not work properly with UTC. The intercalary seconds are known as "leap seconds".
I'm not sure if my change is better, but it clears up my confusion. Musikgoat 08:37, 6 September 2007 (UTC)
what i´m wondering is how "Universal Time Coordinated" is errounous. as far as i can udnerstand it, the article first sais that UTC is Universal time with Coordinated added and then it sais it´s been errounously expanded into "Universal Time Coordinated" Psilorder 21:44, 11 September 2007 (UTC)
that they didnt settle on naming it something that abbreviates to UTC, but simply to move around the letter in the abbreviation.
Psilorder 21:51, 11 September 2007 (UTC)
[[ hopiakuta Please do sign your signature on your message. ~~ Thank You. -]] 07:00, 1 January 2008 (UTC)
Phrases starting with cut:
"...procedure for change data emplacement,..." seems poorly worded; I cannot translate it.
How did that get there?
Why did it get there?
Who did it?
What sort of code would do that?
Does it provide any perspective? How?
Does it relate to Greenwich, Greenwich_Mean_Time, Universal_Time, somehow?
[[ hopiakuta Please do sign your signature on your message. ~~ Thank You. -]] 07:00, 1 January 2008 (UTC)
I just had a look at the article, and it stated close to the top:
Example: Thursday, 2008-01-31 14:05 UTC This was the actual time in UTC when you loaded this page
While the date is correct, the time is off by more than 7 hours, as it was actually more like 21:35 UTC. I'm in central Europe, and the time was 22:35 CET. Maybe there is some sort of caching going on on the Wikipedia server? If so, either that should be disabled for this page if possible, or the "current time" gimmick should be removed.
As I understand it, UTC is determined with hindsight. An institute in France determines the exact UTC time some time afterwards. The time is determined using about 300 atomic clocks spread over the world, this information is accumulated from these clocks the actual UTC is determined. Each of the locations get then a report how much that clock was off from the determined UTC time. As I understood this process takes weeks. So owning an atomic clock you get reports afterwards so the correct time is known but only for clock times a few weeks in the past. So UTC actual can only be used for events which are allready in the past by some weeks.
Offcourse for most practical uses, even when using atomic clocks this 'small' correction is not needed. Crazy Software Productions ( talk) 14:15, 1 March 2008 (UTC)
The reference given for the above statement only had one line evoking any correlation between UTC and Zulu, that being:
The conjunction of 'or' lacks a comma before it, meaning it is used to indicate an alternative, usually only before the last term of a series, if there were a comma before it can be used to indicate a synonymous or equivalent expression. As illustration, 'this or that' is different to 'acrophobia, or fear of great heights.' Noticably so. The fact this entire thing was sourced based on a missing comma is disgusting.
UTC and GMT are identical with minor differences in seconds. Thus only in instances where extreme accuracy is required do we find it implemented. The above error in logic led me to scroll down to the Uses section, which was even more abhorrent. I shall address each section specifically as I excised them due to flawed logic.
By commenting on FCC regulations in relation to LOGGING CONVERSATIONS that statement attempts to draw legitimacy to an unsourced claim that UTC is used. In twenty years of amateur radio operation I've never heard anything but GMT used.
Yeah? Irregular leap seconds sent out as updates. High tech watch, or psychic powers. I think not.
Bzzt, debunked above.
NTP uses Marzullo's algorithm with the UTC time scale, including support for features such as leap seconds. NTPv4 can usually maintain time to within 10 milliseconds (1/100 s) over the public Internet, and can achieve accuracies of 200 microseconds (1/5000 s) or better in local area networks under ideal conditions.
NTP does NOT use UTC as a standard, it uses UTC and Marzullo's algorithm to compute a standard far more precise than GMT or UTC as a whole.
The above paragraph has been changed to:
There's two more paragraphs left which could be merged into the bloody body. So so far, this UTC article has been nothing but puff and bollocks. Come on people, get it together. 122.107.42.146 ( talk) 05:09, 27 March 2008 (UTC)
A plea to regular editors of this page: make sure it's always crystal clear that for non-technical purposes, UTC is the same as GMT.
I like detailed scientific discussions. I spend much of my life writing them. But that's not the only purpose of this page. Many people come here because they read a wikipedia page saying "such-and-such occurred at 11:23 UTC", think "what on earth is UTC?", and type "UTC" into the search box. All they want to know is that UTC is — for these purposes — what they know as GMT. That's all. And that information should leap out at them. It shouldn't take more than five seconds for a casual reader to find that information and move on.
In mid-March there was a nice clear paragraph stating that in one line. Since then that paragraph has got progressively more technical. I repeat: I have nothing against technicalities. But please, set aside one tiny part of the introduction for readers who wish to avoid them. 86.0.204.154 ( talk) 01:44, 5 April 2008 (UTC)
Isn't UTC anti-british pro-americanisation racism. Isn't this yet another prime example of the forced americanisation the world is going through at the moment. I say that GMT is more useful and UTC is a waste of some americanising idiots time and effort in thinking up this crap.-- 134.225.179.54 ( talk) 11:49, 27 April 2008 (UTC)
This article is quite long and of a technical/scientific nature. 18 references seems a low number to me. Dose anyone else agree?-- Talkshowbob ( talk) 02:12, 19 May 2008 (UTC)
It is important that a short introduction is added summarising the basis of UTC. UTC has evolved from GMT and it is imperative that unaware users from the UK and around the world understand this. After a small research study in the UK, I have learned that only a small proportion know what UTC is, whereas almost all understand GMT and still use it today. Therefore, a short sentence briefly summing up the comparison between GMT and UTC will suffice before going into the technical explanation which some users at first may not understand. Please feel free to discuss this. -- AlexTheComposer ( talk) 08:04, 31 July 2008 (UTC)
In what way is this statement from the article lead insufficient:
In casual use, Greenwich Mean Time (GMT) is the same as UTC and UT1. Owing to the ambiguity of whether UTC or UT1 is meant, and because timekeeping laws usually refer to UTC, GMT is avoided in careful writing.
Coordinated Universal Time is the time scale which is the basis of civil time around the world. It ticks along at the same rate as the ultra-consistent International Atomic Time (TAI) but is adjusted by leap seconds, when necessary, to keep it within 0.9 seconds of UT1, which is synonymous with the slightly inconsistent mean solar time along the Prime Meridian.
Whenever any expression of time occurs in any Acts of Parliament, deed, or other legal instrument, the time referred shall, unless it is otherwise specifically stated, be held in the case of Great Britain to be Greenwich mean time, and in the case of Ireland, Dublin mean time. Act 43 & 44 Vict. c.9
- Coordinated Universal Time is the standard time scale which is the basis of civil time across the world. UTC is used internationally so that it is the same everywhere regardless of local time zones. UTC developed initially from Greenwich Mean Time (GMT) and with increasing demand for accurate timekeeping, this new time scale was created by adding leap seconds to International Atomic Time (TAI) to compensate for the Earth's slowing rotation. This is now known as UTC and closely follows GMT, which is recognised as UT1 internationally
I've been thinking that GMT and the various Universal Times are really different animals. Let me try to put them into categories:
Conceptual time scale: GMT
Measured time scale, available retrospectively: UT0(xxx), UT1, UTC
Measured time scale, available near-real-time: UTC(NIST), UTC(NPL), UTC(USNO), etc.
Obviously the time scales available near-real-time are the easiest to use in day-to-day affairs. -- Gerry Ashton ( talk) 21:25, 1 August 2008 (UTC)
In the previous section, Blake the Bookbinder asked for responses to a number of points or questions. The previous section had too may levels of indention, and was getting to long, so I'm answering here. Except this paragraph, unindented text is from Blake.
Gerry, now we're getting somewhere! We're in agreement that the legal time scale (the one recognised by law in the UK) is GMT, and that no national time dissemination service, in the UK or elsewhere (so far as I know), disseminates GMT. Breaking things down to basic assumptions might be the way to go; let me run a few by you and you can reply agree, disagree or don't know (with explanation if you want). I believe all of these to be true.
"Civil time" is the time scale used by the general public in daily life.
In the UK, civil time is the time disseminated by the National Physical Laboratory.
The time disseminated by the National Physical Laboratory is UTC.
In the UK, civil time is UTC.
In the UK, legal time ought to be UTC.
The definition of UTC is not the same as the definition of GMT and when UTC and GMT are the same, it's coincidental.
About the two questions you've posed; I haven't got a clue! I don't know what exactly you want to elicit from me so I don't really know how to approach them. If I wanted to determine what time an event happened on the GMT time scale I'd hire a team of competent blokes and have them figure it out and staple the answer to their invoice for the job. I believe that the GMT time scale is too elastic and/or irregular to be of use in a world built for precision. I doubt GMT is appropriate for events that need to be measured to the tenth of a second, or better. I don't know what the second question is fishing for, unless it's to point out that a GMT day, two months after the event, will likely be of a different length than the day of the event. If there's some other bit of the whole scenario you want me to opine about, I'll try, but you'll have to ask me in a different way, that is, point blank.
If we can tackle more than one thing at a time, how about steering this discussion back to the subject of your sandbox draft of the opening paragraphs of the UTC article.? I'll just throw out a few questions, that are not necessarily things I'd change – just some points around which to start a conversation about something that may pay dividends.
I know it's been there for a long time, but why does this article give the French translation of Coordinated Universal Time? The header for the GMT article is not followed by (Fr. Temps moyen de Greenwich). I'm sure every article title has a French translation, but we don't usually include it.
In the sentence fragment, “…is one of several replacements for Greenwich Mean Time, which was mean solar time at the Royal Observatory, Greenwich, England” why do you define Greenwich mean time when a simple click on the link would take the reader to a complete definition; the beauty of Wikipedia is that terms and definitions are linked like that.
The article mentions UTC replacing GMT then another replacement called UT1 and then follows with a sentence that starts, “This replacement became necessary…” To which replacement is “[t]his replacement” referring?
And just one more to chew on tonight: Should the opening paragraph try to give the history of UTC, or define it? Your draft mentions GMT and the Royal Observatory and UT1 and the 1930s and unsteady rotation and 1956 and 1961 and gets through all that without ever telling me what UTC is. Wouldn't a definition be appropriate here? I know there are many who want GMT in the opening paragraph (I think they'd be happy if it said “Don't worry, UTC is just French for GMT!”) but can we not define UTC at the top of the article and save GMT for the third paragraph, or wherever history is covered? I don't want to obscure UTC's relationship to GMT, but UTC is not GMT and the definition of UTC is not "the replacement for GMT”. Gordon Brown's Wikipedia article doesn't start with “Gordon Brown (Fr. Gordón Marron) is the replacement for Tony Blair."
-- Gerry Ashton ( talk) 03:40, 4 August 2008 (UTC)
Gerry, what's your definition of Civil Time?-- Blake the bookbinder ( talk) 17:41, 4 August 2008 (UTC)
User:WikieWikieWikie changed the introduction to read as follows:
I don't think this change is helpful for several reasons, and have reverted the change. For one thing, it is confusing to say what is or is not "universal"; our current phrase "universal time" ignores locations other than earth in the universe. It is confusing to say that observations at Greenwich were not accurate measurements; without a source to the contrary, I would expect that the measurements were considered accurate for their time. Also, the sentence "it is on the basis of the UT1 computations, and the calculation of the Earth's slowing rotation, UTC serves as our international standard time" is long, confusing, and emphasizes only calculation with no mention of measurement, and adds to the confusion with the phrase "standard time", which is usually used to mean zone time with no daylight savings adjustment. -- Gerry Ashton ( talk) 02:37, 8 August 2008 (UTC)
On 10 August
User:Abberley2
changed a sentence in the intro to read "In casual informal use,
Greenwich Mean Time (GMT) is the same as UTC and UT1. Owing to the ambiguity of whether UTC or UT1 is meant, and because timekeeping laws usually refer to UTC, GMT is avoided in careful technical writing."
I don't think there is a problem with the change of "casual" to "informal", but I'm concerned about changing "careful" to "technical". I don't think it's right to imply that informal and non-technical go together, and that formal and technical go together. The changed wording would suggest that UTC should be avoided unless sub-second precision is necessary, or the in scientific and high-technology use. -- Gerry Ashton ( talk) 00:51, 11 August 2008 (UTC)
The editor using IP address 81.98.162.220 added a {{ fact}} tag and used this edit summary:
(PLZ READ DONT JUST ADD REF! If it has been changed to track UT1 it can not now be approximating UT1 with the correction!!! ONE OF THESE THINGS IS WRONG.)
I don't quite understand the edit summary. I'll explain how I understand it, and perhaps the editor will follow up with questions.
Before 1972 the length of the UTC second was changed slightly to make UTC be an approximation of UT2. Beginning 1972, two changes were made. First, the goal was to approximate UT1, not UT2. Second, the second was always the SI second provided by atomic clocks, and leap seconds were used to keep UTC within 0.5 s of UT1 (later this was relaxed to 0.9 s). So UTC used to be an approximation to UT2, and now it is an approximation to UT1. -- Gerry Ashton ( talk) 15:17, 19 October 2008 (UTC)
Should the article state that UTC is a coordinate time, as opposed to proper time? Clock are now becoming more and more accurate that this distinction is becoming more important. Martin Hogbin ( talk) 17:45, 26 October 2008 (UTC)
![]() | This page is an archive of past discussions. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page. |
![]() | This is an archive of past discussions. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page. |
Archive 1 | Archive 2 | Archive 3 |
Want to help write or improve articles about Time? Join
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Time Portal for a list of articles that need improving.
—
Yamara
✉
08:45, 18 February 2008 (UTC)
It took me months to figure out that the Recent Changes page bases its clock on UTC. Several times I've been tempted to send an email to Jimbo asking him to reset the Wikipedia internal clock. If others have been confused and considered this a minor annoyance, then I'd like to suggest that the term (UTC) be added to the timestamp on the Recent Changes page. -- Modemac 20:10 Feb 8, 2003 (UTC)
The following sentance in the article makes little sense to me, since no reference date is given:
"As of 1 January 1999, TAI is ahead of UTC by 32 seconds."
Over what period of time was 32 seconds lost? < /br>
wamquark< /br>
Sunday, November 27, 2005, 12:36:42 PM EST
I've removed the above links, as they don't describe UTC in any useful way. They seem to be about an obscure date/time formatting specification which, as it happens, may use UTC as the timezone. -- Brion 12:12 Feb 9, 2003 (UTC)
From http://www.ietf.org/internet-drafts/draft-ietf-impp-datetime-05.txt
This document defines a date and time format for use in Internet protocols that is a profile of the ISO 8601 standard for representation of dates and times using the Gregorian calendar
So, ISO 8601 it´s a standard. And the rest are proposed profiles of the standard in the Internet. Very important for people that uses UTC, specially in the Internet.
Because of this I propose include a link to UTC(Internet). If interesting for the user, the user will deciede clicking in the link ;)
Regards
I have translated the UTC article into Spanish ;)
Why "UTC"?
Putting stronger language into the article abt this is low among my prioriies. --
Jerzy 23:03, 2003 Dec 15 (UTC)
Article should say whether UTC implies 24-hour format. And in any case, whether format is specific as to range:
(or their 12-hour equivalents) -- Jerzy 23:14, 2003 Dec 15 (UTC)
This is correct. A whole moment of time begins at zero, and ends on the fullest point before 1. This is 0.9999999. The statement below was in the link above. This is wrong. For by the logic here, if the beginning of the 2nd millenium was 2001, the beginning of the 3rd millenium will be 3002. Just thought Id point this out. Zero hour is a mysterious point in time, yet is is definitely on the AM, rather than the PM. Our midday begins the night and midnight begins the day. Interesting.
When did the current millennium begin?
Since a millennium is 1000 years, and the first millennium began at the start of the year 1, it ended at the end of the year 1000. The second millennium then began with the year 1001 and concluded at the end of the year 2000. Therefore, the current millennium technically began with the year 2001. For historical information, see an exhibit on Calendars.
This statement was found here.
Why "UTC"? We truly cannot always use the internet to source articles on the Wiki. Time is a difficult concept to grasp though.
WikieWikieWikie ( talk) 23:21, 7 August 2008 (UTC)
The table of conversion from UTC appears so far to the left that the Special Pages links cover part of it. I'm in Cologne Blue, 1024x768 with a fixed left sidebar - anything we can do about this unsightliness? -- Rissa 19:48, 4 Jun 2004 (UTC)
It should be noted that in DST there is a different UTC -/+ time (E.g in winter, CST is UTC-6 while in Summer it is UTC-5...slightly annoying for me actually [considering WP is UTC]). Ilyanep 02:12, 21 Jun 2004 (UTC)
Quaint mention "also referred to as Zulu time". A bit of explanation might raise the human interest of the page...I'd never even heard of UTC (AFAIK everyone still uses GMT in the UK)-- BozMo |talk 15:37, 19 Aug 2004 (UTC)
http://www.grc.nasa.gov/WWW/MAEL/ag/zulu.htm
(The standard is coordinated universal time, abbreviated UTC. This was formerly known as Greenwich mean time (GMT). UK uses GMT/BST/IST) "Zulu" is just one of 25 designations that NATO and US Military uses.)
I've added a short sentence to try to clarify the meaning of Zulu time, and a link that has a good summary of the Alpha-Zulu time zones, listing some key locations worldwide. Of course, the time zone can change when a country uses a daylight-saving time. For example, in winter the UK uses GMT/UCT, i.e Zulu time; in summer it moves to British Summer Time (BST), which is one hour ahead, i.e Alpha time.-- RDT2 13:19, 18 June 2006 (UTC)
The US Navy uses "Zulu" for UTC. Do other services? Other nation's militaries? Gerardw ( talk) 19:32, 21 September 2008 (UTC)
There should be a disambiguation section added, since the letters UTC form the initials of the University of Tennessee at Chattanooga. -- ZekeMacNeil 23:13, 10 Jan 2005 (UTC)
An extensive discussion regarding the Time Cube edit war has been taking place at Talk:Greenwich Mean Time#Time Cube discussion. I hope the issues have been resolved for now and am unprotecting this page. — Knowledge Seeker দ 20:40, 2 May 2005 (UTC)
The merge on this and UT seems a bit silly. They are different and warrant different articles. Whoever put the notices on hasn't said why they think they should be merged either. If nobody gives any reasons then I'll just take the notices off. KayEss | talk 09:05, 28 December 2005 (UTC)
Although the scientific discussions concerning Universal time etc are no doubt important and valid it should be made clear that the people of the world generally and all broadcasters etc use Greenwich Mean Time and not Universal Time. The simple fact is that these are of course identical, each starting from Greenwich London England. The only real reason Universal Time and its variants Zulu Time etc is used is because of irritation at Britain still being the place from which the world takes its time. If people are honest they will admit this..
The problem with non scientific people using "Universal Time and its variants is obvious... If the time is UNIVERSAL then it must be the same EVERYWHERE!! So.. if its 0900 in Paris it must be 0900 in New York! As this is impossible you have to do a calculation..and for other places? Well of course UTC is really the time at a place called Greenwich in England! so we have returned to GMT.!!. GMT will never vanish because it is much easier for people to visualise time zones when they have a real place in the world from which to start... It may give some people a thrill at stamping on those pesky British but it wont work you know.. You could help the world just a little bit by promoting GMT and making life easier for everybody!!! —the preceding unsigned comment is by 80.98.112.51 ( talk • contribs) 19:14, 2 January 2006 (UTC1)
I believe GMT changes with daylight savings time and UTC does not. Am I wrong about this? mike 18:06, 28 September 2006 (UTC)
I think there's a point to the above comment which asks how does UTC relate to local time and to GMT. I think it is true that UTC and GMT will never differ by more than a second, and that the differences are really important for, say, astronomic observations, and as a legal standard. -- Ozga 05:36, 26 May 2007 (UTC)
In general common usage UTC is identical to GMT and this article should clearly state that right at the top! On my PC I have GMT listed as a time zone but no UTC, and then I receive an email with a UTC time and I wonder if UTC is the same as GMT? Then I come to Wikipedia to find out. Many will go through this process and you should tell us what the answer is. Of course they are effectively the same but your article doesn't clearly state that at the top, for petty technical reasons. I tried to add it in but some pillock removed it. When are you wikipedia editors going start thinking about your readers and use some common sense? GMT has various meanings but the commonest is UTC (atomic clock based), and the main other GMT meaning, based on astronomy, differs at most by 0.9 of a second from UTC. Very few people use the latter meaning anymore. There is an article here that explains it in detail
"http://www.apparent-wind.com/gmt-explained.html". Retrieved 2007-08-19. {{
cite web}}
: External link in
(
help). --
190.76.7.166
02:22, 20 August 2007 (UTC)
|title=
Given that UTC is a French inception the original editors remarks that it was utilised as an anti-English reliance having to cite Grenwich as the center of the chronological earth is correct. The only countries I have found use UTC in any open forum are France and America. That being said, 99% of publications of time are in GMT even IN those countries. I see UTC only on Wikipedia, throughout my travels around the world it's popped up once or twice, but mostly as an oddity. I find it very problematic that we at Wikipedia utilise UTC because it doesn't allow me to understand the time frame reference they're talking about exactly. GMT everyone understands. Fair enough they're 'near identical', but they're not and UTC is unreliably different and requires an understanding of the mathematical principals to deduce from a given time, I know that when it's midday here it's 2am at Grenwich and from that I can deduce (exactly) all other time lines around the world.
I turned to Wiki to find out what Pacific Standard Time is and it has, for the first time ever, truly failed me as a resource to be able to work out the time difference. I'd say perhaps we should move to GMT like the rest of the world, but given the different target audience that Wikipedia has, I doubt that would go down well for the most part. 210.49.15.52 13:05, 13 November 2007 (UTC)
Following the ISO standard one have to include T to separate date and time in UTC format. The Z to indicate zulu time (zero time) is not necessary. -- 82.159.136.238 05:54, 20 April 2006 (UTC)
Leap seconds are solely a feature of UTC, and UTC cannot be defined without discussion of leap seconds. They form a single topic, so it is silly for them to have separate articles. 81.168.80.170 12:15, 29 April 2006 (UTC)
Sandford Fleming was the inventor of Universal Standard Time. He proposed linking of Time Zones to the 180º Meridian in the 1884 International Meridian Conference. Why this fact is not registered here?. -- Fev 22:10, 14 May 2006 (UTC)
Why is it abreviated that? It's Coordinated Universal Time, not Universal Time Coordinated. Why UTC, it should be C.U.T. -- 71.224.19.29 16:16, 25 May 2006 (UTC)
Could someone define the meaning of UT1 before using it in the article? It would help in understanding the concepts.
Thanks —Preceding unsigned comment added by 206.173.170.67 ( talk • contribs)
For heaven's sake, they are completely different things. Why propose this merger in the first place is what I'm wondering.-- Saoshyant 11:01, 9 October 2006 (UTC)
Okeh, I know it's a technical term, but instead of burying the key sentence (for the average user) at the bottom of the first or second paragraph, couldn't we some-how make it easier to see that UTC is (for many purposes - e.g., use on Wik) GMT? Kdammers 00:39, 11 March 2007 (UTC)
In the following paragraph: Most UTC days contain exactly 86,400 seconds, with exactly 60 seconds in each minute. However, since the mean solar day is slightly longer than 86,400 seconds, occasionally the last minute of a day will have 61 seconds. (If a UTC day were to have 86,399 or 86,401 seconds, the last minute of the day would have 59 or 61 seconds, respectively, but this has never happened). The irregular day lengths mean that fractional Julian days do not work properly with UTC. The intercalary seconds are known as "leap seconds".
Logically, the statement If a UTC day were to have 86,399 or 86,401 seconds, the last minute of the day would have 59 or 61 seconds makes sense, however with the explanation that a solar day is slightly longer than 86,400 seconds statement above, the time reference there leads me to believe that the bolded statement is wrong, technically, because it doesn't reference that occasional adjustment in the same paragraph. I inevitably am wrong, but I suggest making the two points more clear.
Proposed Revision: Most UTC days contain exactly 86,400 seconds, with exactly 60 seconds in each minute. However, since the mean solar day is slightly longer than 86,400 seconds, occasionally the last minute of a solar day will have 61 seconds. If a UTC day were to have 86,399 or 86,401 seconds, the last minute of the solar day would have an adjustment of one, in each respective direction, however this has not happened to date. The irregular day lengths mean that fractional Julian days do not work properly with UTC. The intercalary seconds are known as "leap seconds".
I'm not sure if my change is better, but it clears up my confusion. Musikgoat 08:37, 6 September 2007 (UTC)
what i´m wondering is how "Universal Time Coordinated" is errounous. as far as i can udnerstand it, the article first sais that UTC is Universal time with Coordinated added and then it sais it´s been errounously expanded into "Universal Time Coordinated" Psilorder 21:44, 11 September 2007 (UTC)
that they didnt settle on naming it something that abbreviates to UTC, but simply to move around the letter in the abbreviation.
Psilorder 21:51, 11 September 2007 (UTC)
[[ hopiakuta Please do sign your signature on your message. ~~ Thank You. -]] 07:00, 1 January 2008 (UTC)
Phrases starting with cut:
"...procedure for change data emplacement,..." seems poorly worded; I cannot translate it.
How did that get there?
Why did it get there?
Who did it?
What sort of code would do that?
Does it provide any perspective? How?
Does it relate to Greenwich, Greenwich_Mean_Time, Universal_Time, somehow?
[[ hopiakuta Please do sign your signature on your message. ~~ Thank You. -]] 07:00, 1 January 2008 (UTC)
I just had a look at the article, and it stated close to the top:
Example: Thursday, 2008-01-31 14:05 UTC This was the actual time in UTC when you loaded this page
While the date is correct, the time is off by more than 7 hours, as it was actually more like 21:35 UTC. I'm in central Europe, and the time was 22:35 CET. Maybe there is some sort of caching going on on the Wikipedia server? If so, either that should be disabled for this page if possible, or the "current time" gimmick should be removed.
As I understand it, UTC is determined with hindsight. An institute in France determines the exact UTC time some time afterwards. The time is determined using about 300 atomic clocks spread over the world, this information is accumulated from these clocks the actual UTC is determined. Each of the locations get then a report how much that clock was off from the determined UTC time. As I understood this process takes weeks. So owning an atomic clock you get reports afterwards so the correct time is known but only for clock times a few weeks in the past. So UTC actual can only be used for events which are allready in the past by some weeks.
Offcourse for most practical uses, even when using atomic clocks this 'small' correction is not needed. Crazy Software Productions ( talk) 14:15, 1 March 2008 (UTC)
The reference given for the above statement only had one line evoking any correlation between UTC and Zulu, that being:
The conjunction of 'or' lacks a comma before it, meaning it is used to indicate an alternative, usually only before the last term of a series, if there were a comma before it can be used to indicate a synonymous or equivalent expression. As illustration, 'this or that' is different to 'acrophobia, or fear of great heights.' Noticably so. The fact this entire thing was sourced based on a missing comma is disgusting.
UTC and GMT are identical with minor differences in seconds. Thus only in instances where extreme accuracy is required do we find it implemented. The above error in logic led me to scroll down to the Uses section, which was even more abhorrent. I shall address each section specifically as I excised them due to flawed logic.
By commenting on FCC regulations in relation to LOGGING CONVERSATIONS that statement attempts to draw legitimacy to an unsourced claim that UTC is used. In twenty years of amateur radio operation I've never heard anything but GMT used.
Yeah? Irregular leap seconds sent out as updates. High tech watch, or psychic powers. I think not.
Bzzt, debunked above.
NTP uses Marzullo's algorithm with the UTC time scale, including support for features such as leap seconds. NTPv4 can usually maintain time to within 10 milliseconds (1/100 s) over the public Internet, and can achieve accuracies of 200 microseconds (1/5000 s) or better in local area networks under ideal conditions.
NTP does NOT use UTC as a standard, it uses UTC and Marzullo's algorithm to compute a standard far more precise than GMT or UTC as a whole.
The above paragraph has been changed to:
There's two more paragraphs left which could be merged into the bloody body. So so far, this UTC article has been nothing but puff and bollocks. Come on people, get it together. 122.107.42.146 ( talk) 05:09, 27 March 2008 (UTC)
A plea to regular editors of this page: make sure it's always crystal clear that for non-technical purposes, UTC is the same as GMT.
I like detailed scientific discussions. I spend much of my life writing them. But that's not the only purpose of this page. Many people come here because they read a wikipedia page saying "such-and-such occurred at 11:23 UTC", think "what on earth is UTC?", and type "UTC" into the search box. All they want to know is that UTC is — for these purposes — what they know as GMT. That's all. And that information should leap out at them. It shouldn't take more than five seconds for a casual reader to find that information and move on.
In mid-March there was a nice clear paragraph stating that in one line. Since then that paragraph has got progressively more technical. I repeat: I have nothing against technicalities. But please, set aside one tiny part of the introduction for readers who wish to avoid them. 86.0.204.154 ( talk) 01:44, 5 April 2008 (UTC)
Isn't UTC anti-british pro-americanisation racism. Isn't this yet another prime example of the forced americanisation the world is going through at the moment. I say that GMT is more useful and UTC is a waste of some americanising idiots time and effort in thinking up this crap.-- 134.225.179.54 ( talk) 11:49, 27 April 2008 (UTC)
This article is quite long and of a technical/scientific nature. 18 references seems a low number to me. Dose anyone else agree?-- Talkshowbob ( talk) 02:12, 19 May 2008 (UTC)
It is important that a short introduction is added summarising the basis of UTC. UTC has evolved from GMT and it is imperative that unaware users from the UK and around the world understand this. After a small research study in the UK, I have learned that only a small proportion know what UTC is, whereas almost all understand GMT and still use it today. Therefore, a short sentence briefly summing up the comparison between GMT and UTC will suffice before going into the technical explanation which some users at first may not understand. Please feel free to discuss this. -- AlexTheComposer ( talk) 08:04, 31 July 2008 (UTC)
In what way is this statement from the article lead insufficient:
In casual use, Greenwich Mean Time (GMT) is the same as UTC and UT1. Owing to the ambiguity of whether UTC or UT1 is meant, and because timekeeping laws usually refer to UTC, GMT is avoided in careful writing.
Coordinated Universal Time is the time scale which is the basis of civil time around the world. It ticks along at the same rate as the ultra-consistent International Atomic Time (TAI) but is adjusted by leap seconds, when necessary, to keep it within 0.9 seconds of UT1, which is synonymous with the slightly inconsistent mean solar time along the Prime Meridian.
Whenever any expression of time occurs in any Acts of Parliament, deed, or other legal instrument, the time referred shall, unless it is otherwise specifically stated, be held in the case of Great Britain to be Greenwich mean time, and in the case of Ireland, Dublin mean time. Act 43 & 44 Vict. c.9
- Coordinated Universal Time is the standard time scale which is the basis of civil time across the world. UTC is used internationally so that it is the same everywhere regardless of local time zones. UTC developed initially from Greenwich Mean Time (GMT) and with increasing demand for accurate timekeeping, this new time scale was created by adding leap seconds to International Atomic Time (TAI) to compensate for the Earth's slowing rotation. This is now known as UTC and closely follows GMT, which is recognised as UT1 internationally
I've been thinking that GMT and the various Universal Times are really different animals. Let me try to put them into categories:
Conceptual time scale: GMT
Measured time scale, available retrospectively: UT0(xxx), UT1, UTC
Measured time scale, available near-real-time: UTC(NIST), UTC(NPL), UTC(USNO), etc.
Obviously the time scales available near-real-time are the easiest to use in day-to-day affairs. -- Gerry Ashton ( talk) 21:25, 1 August 2008 (UTC)
In the previous section, Blake the Bookbinder asked for responses to a number of points or questions. The previous section had too may levels of indention, and was getting to long, so I'm answering here. Except this paragraph, unindented text is from Blake.
Gerry, now we're getting somewhere! We're in agreement that the legal time scale (the one recognised by law in the UK) is GMT, and that no national time dissemination service, in the UK or elsewhere (so far as I know), disseminates GMT. Breaking things down to basic assumptions might be the way to go; let me run a few by you and you can reply agree, disagree or don't know (with explanation if you want). I believe all of these to be true.
"Civil time" is the time scale used by the general public in daily life.
In the UK, civil time is the time disseminated by the National Physical Laboratory.
The time disseminated by the National Physical Laboratory is UTC.
In the UK, civil time is UTC.
In the UK, legal time ought to be UTC.
The definition of UTC is not the same as the definition of GMT and when UTC and GMT are the same, it's coincidental.
About the two questions you've posed; I haven't got a clue! I don't know what exactly you want to elicit from me so I don't really know how to approach them. If I wanted to determine what time an event happened on the GMT time scale I'd hire a team of competent blokes and have them figure it out and staple the answer to their invoice for the job. I believe that the GMT time scale is too elastic and/or irregular to be of use in a world built for precision. I doubt GMT is appropriate for events that need to be measured to the tenth of a second, or better. I don't know what the second question is fishing for, unless it's to point out that a GMT day, two months after the event, will likely be of a different length than the day of the event. If there's some other bit of the whole scenario you want me to opine about, I'll try, but you'll have to ask me in a different way, that is, point blank.
If we can tackle more than one thing at a time, how about steering this discussion back to the subject of your sandbox draft of the opening paragraphs of the UTC article.? I'll just throw out a few questions, that are not necessarily things I'd change – just some points around which to start a conversation about something that may pay dividends.
I know it's been there for a long time, but why does this article give the French translation of Coordinated Universal Time? The header for the GMT article is not followed by (Fr. Temps moyen de Greenwich). I'm sure every article title has a French translation, but we don't usually include it.
In the sentence fragment, “…is one of several replacements for Greenwich Mean Time, which was mean solar time at the Royal Observatory, Greenwich, England” why do you define Greenwich mean time when a simple click on the link would take the reader to a complete definition; the beauty of Wikipedia is that terms and definitions are linked like that.
The article mentions UTC replacing GMT then another replacement called UT1 and then follows with a sentence that starts, “This replacement became necessary…” To which replacement is “[t]his replacement” referring?
And just one more to chew on tonight: Should the opening paragraph try to give the history of UTC, or define it? Your draft mentions GMT and the Royal Observatory and UT1 and the 1930s and unsteady rotation and 1956 and 1961 and gets through all that without ever telling me what UTC is. Wouldn't a definition be appropriate here? I know there are many who want GMT in the opening paragraph (I think they'd be happy if it said “Don't worry, UTC is just French for GMT!”) but can we not define UTC at the top of the article and save GMT for the third paragraph, or wherever history is covered? I don't want to obscure UTC's relationship to GMT, but UTC is not GMT and the definition of UTC is not "the replacement for GMT”. Gordon Brown's Wikipedia article doesn't start with “Gordon Brown (Fr. Gordón Marron) is the replacement for Tony Blair."
-- Gerry Ashton ( talk) 03:40, 4 August 2008 (UTC)
Gerry, what's your definition of Civil Time?-- Blake the bookbinder ( talk) 17:41, 4 August 2008 (UTC)
User:WikieWikieWikie changed the introduction to read as follows:
I don't think this change is helpful for several reasons, and have reverted the change. For one thing, it is confusing to say what is or is not "universal"; our current phrase "universal time" ignores locations other than earth in the universe. It is confusing to say that observations at Greenwich were not accurate measurements; without a source to the contrary, I would expect that the measurements were considered accurate for their time. Also, the sentence "it is on the basis of the UT1 computations, and the calculation of the Earth's slowing rotation, UTC serves as our international standard time" is long, confusing, and emphasizes only calculation with no mention of measurement, and adds to the confusion with the phrase "standard time", which is usually used to mean zone time with no daylight savings adjustment. -- Gerry Ashton ( talk) 02:37, 8 August 2008 (UTC)
On 10 August
User:Abberley2
changed a sentence in the intro to read "In casual informal use,
Greenwich Mean Time (GMT) is the same as UTC and UT1. Owing to the ambiguity of whether UTC or UT1 is meant, and because timekeeping laws usually refer to UTC, GMT is avoided in careful technical writing."
I don't think there is a problem with the change of "casual" to "informal", but I'm concerned about changing "careful" to "technical". I don't think it's right to imply that informal and non-technical go together, and that formal and technical go together. The changed wording would suggest that UTC should be avoided unless sub-second precision is necessary, or the in scientific and high-technology use. -- Gerry Ashton ( talk) 00:51, 11 August 2008 (UTC)
The editor using IP address 81.98.162.220 added a {{ fact}} tag and used this edit summary:
(PLZ READ DONT JUST ADD REF! If it has been changed to track UT1 it can not now be approximating UT1 with the correction!!! ONE OF THESE THINGS IS WRONG.)
I don't quite understand the edit summary. I'll explain how I understand it, and perhaps the editor will follow up with questions.
Before 1972 the length of the UTC second was changed slightly to make UTC be an approximation of UT2. Beginning 1972, two changes were made. First, the goal was to approximate UT1, not UT2. Second, the second was always the SI second provided by atomic clocks, and leap seconds were used to keep UTC within 0.5 s of UT1 (later this was relaxed to 0.9 s). So UTC used to be an approximation to UT2, and now it is an approximation to UT1. -- Gerry Ashton ( talk) 15:17, 19 October 2008 (UTC)
Should the article state that UTC is a coordinate time, as opposed to proper time? Clock are now becoming more and more accurate that this distinction is becoming more important. Martin Hogbin ( talk) 17:45, 26 October 2008 (UTC)
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