Talk:Coordinated Universal Time

Future

The Future section reeks of non-objective content. For instance, it is claimed that the proposed 2001 change is "drastic". I'm sure someone will argue that a yotto-second difference is "huge", but no reasonable person would find 6-7 hrs over 2600 years to be "drastic", imho. Worse yet, the 2022 *agreement* to eliminate the leap-second "by 2035" is completely missing!! Is this the "same" as the non-conference of 2023 that was cited? (several times.) Who ever is editing this either needs to do their due duty or step aside. By the way, I understand some of the issues involved in the loosening the coupling of atomic to orbital times (is there enough discussion here about the difference between the (fictitious) point through which the Earth passes to start another year and the (fictitious) point at which (supposedly) all points on the Earth (tectonics aside) "match" their cosmological orientation of previous year? Just a digression.) but it would be useful to understand or at least see a discussion about WHY people don't want the change AND why people DO want the change - both politically and technically. That's sorely lacking -it's called being objective.71.30.94.234 (talk) 22:00, 25 October 2023 (UTC)

'234:"Worse yet, the 2022 *agreement* to eliminate the leap-second "by 2035" is completely missing!!"

The CGPM resolution is mentioned, but the date was only in the citation, not the body of the article. I corrected that.

'234: "Is this the "same" as the non-conference of 2023 that was cited?"

That's a different organization, the ITU. The World Radiocommunication Conference of 2023 is scheduled for 20 November to 15 December 2023 in Dubai, UAE. Jc3s5h (talk) 23:03, 25 October 2023 (UTC)

Etymology

The article states that English speakers originally proposed CUT, while French speakers proposed TUC. The compromise that emerged was UTC
But what about German and Danish people? Why were they not asked? Why only English and French? Konijnewolf (talk) 13:50, 17 December 2023 (UTC)

The cited source from NIST says

The ITU felt it was best to designate a single abbreviation for use in all languages in order to minimize confusion. For example, in English the abbreviation for coordinated universal time would be CUT, while in French the abbreviation for "temps universel coordonné" would be TUC. To avoid appearing to favor any particular language, the abbreviation UTC was selected.

So according to the source, English and French are just examples of possible language issues. One would have to dig through the literature of the International Telecommunications Union in the 1960s to find what proposals were actually made. Jc3s5h (talk) 14:44, 17 December 2023 (UTC)

I see that phrasing similar to the present phrasing was introduced by Looie496 (talk · contribs) in October 2011. Jc3s5h (talk) 14:52, 17 December 2023 (UTC)

I edited the article and added a quote by Dennis McCarthy about the origin of UTC. I eliminated unsourced claims that unnamed, unsourced English and French speakers made proposals. Jc3s5h (talk) 15:54, 17 December 2023 (UTC)

Thanks Jc. It looks better now. Konijnewolf (talk) 12:11, 25 December 2023 (UTC)

Successor to what?

On 7 February 2024 @Daniel Quinlan: modified a sentence in the lead to read

It is the effective successor to Greenwich Mean Time (GMT), although GMT remains in use in some contexts, alongside other regional and industry-specific time standards.

I request a word-by-word justification for this change, and that any passages that support it in the main body of the article be identified.

My issues with the sentence are (some emphasis added):

• the effective successor to Greenwich Mean Time. Clearly UTC is the most widely used successor to GMT. But other successors serve critical roles in science, navigation, and timekeeping, especially UT1.
• other regional. The claim that there are regional successors is not supported by a reliable source that I can see, and I don't know what time scales are being referred to.
• industry-specific. It's unclear what this refers to. Maybe Amazon's time-smearing? At least some of the referents should be clear and supported by reliable sources (which would be in the body of the article). Jc3s5h (talk) 17:28, 7 February 2024 (UTC)

That sentence suffered from over-editing. The "regional" was more about GMT still being used as a term in the UK and several other contexts, but that got tangled up with the more important part about other successors. The "industry-specific" was referring broadly to other standards such as UT1, TAI, GPS time, various leap second smearing time services, etc. I don't think the introduction needs to be exhaustive, but a few examples might help with clarity. (There are other articles like time standards for an exhaustive list.)

Putting the effective aside for the moment, I suggest something like:

It is the effective successor to Greenwich Mean Time (GMT), complemented by specialized time standards such as UT1 and TAI that are vital in science, navigation, and timekeeping.

I'll be back later with more on UTC being the effective successor to GMT. A bit more detail on the replacement of GMT with UTC would also be good for the history section. Daniel Quinlan (talk) 19:47, 7 February 2024 (UTC)

TAI and UT1 are mentioned here in a context that suggests they are "effective successors" to GMT. But the language is weak, and lends itself to misinterpretation. "effective successor" is ill-defined, and "complemented by" suggests that UT1 and TAI are also "effective successors", which is misleading (TAI in particular isn't even a civil timescale).

It's perfectly reasonable to note that GMT was retired (except by the **** Brits) when UTC was introduced; but that sentence is all over the place. I'm afraid I don't have a better sentence to propose, so for now I think it's best to scrap it.

As a Brit, I'm embarrassed by the BBC's insistence on declaring the time using GMT, and idiosyncratically at that: e.g. "Four Gee Emm Tee" (with the letters pronounced emphatically and smugly). It's imperialistic jingoism; and stupid, because GMT has never been well-defined, and is now not defined at all. We simply don't say "4 GMT"; we say "4 O'clock GMT", or "4AM GMT" (because GMT was used before 24-hour times-of-day were in wide usage in the UK). MrDemeanour (talk) 21:50, 7 February 2024 (UTC)

Breaking it into two sentences for better clarity is always an option:

It is the effective successor to Greenwich Mean Time (GMT) in everyday usage and common applications. However, in specialized domains such as scientific research, navigation, and timekeeping, other standards like UT1 and TAI play a vital role.

I don't know whether this rephrasing helps alleviate the original concern so I will still come back with more on the "the effective" assertion later today. Daniel Quinlan (talk) 22:55, 7 February 2024 (UTC)

It is clearer as two sentences.

Re. the first proposed sentence: "effective successor" is weasely; either it is the successor, or it isn't. Just say "the successor".

Re. the second proposed sentence: UT1 and TAI do "play a vital role", but not as "effective successors" to GMT. The "however" suggests that the vital role they play is related to UTCs role as the successor to GMT, which isn't true. So just drop the second sentence. MrDemeanour (talk) 15:18, 8 February 2024 (UTC)

I think leaving in "effective" is appropriate because it highlights the practical transition from GMT to UTC without necessarily implying a formal or official succession. I'm open to removing it if there's broader support for that, though. It's certainly easily sourced. Daniel Quinlan (talk) 20:15, 8 February 2024 (UTC)

As promised, here are some sources that say "the successor":

• Evers, L. (2013). It's About Time: From Calendars and Clocks to Moon Cycles and Light Years - A History. Michael O'Mara. ISBN 978-1-78243-087-2. Retrieved 2024-02-08. The pips are no longer broadcast from Greenwich, but from the National Physical Laboratory in Teddington, Surrey, which uses Coordinated Universal Time (UTC) - the successor of GMT - for its reading.
• Chowdhury, D.D. (2021). NextGen Network Synchronization. Springer International Publishing. ISBN 978-3-030-71179-5. Retrieved 2024-02-08. The primary time standard by which the world regulates clocks and time is UTC. It is a 24-h time standard that uses highly precise atomic clocks combined with the Earth's rotation. Timing centers around the globe agreed to keep their time scales synchronized or coordinate and hence, the name coordinated universal time. It is the successor of Greenwich Mean Time (GMT). The UTC was defined by the International Radio Consultative Committee (CCIR), a predecessor organization of the ITU-TS, and is maintained by the Bureau International des Poids et Measures (BIPM).
• Kelly, A. (2005). Challenging Modern Physics: Questioning Einstein's Relativity Theories. Universal Publishers. ISBN 978-1-58112-437-8. Retrieved 2024-02-08. UTC is the successor of Greenwich Mean Time (GMT) and is sometimes still called GMT.
• New Scientist. IPC Magazines. 1997. Retrieved 2024-02-08. ...(UTC). This global standard, the successor to Greenwich Mean Time, steers the world's clocks and silently regulates our lives.
• Vaughan, L. (2023). Python Tools for Scientists: An Introduction to Using Anaconda, JupyterLab, and Python's Scientific Libraries. No Starch Press. ISBN 978-1-7185-0267-3. Retrieved 2024-02-08. UTC is the successor to Greenwich Mean Time (GMT) and represents the primary time standard by which the world regulates clocks and time.
• Usborne, Simon (13 March 2015). "About time". The Independent. p. 41. There, the International Bureau of Weights and Measures (BIPM) collects and averages time to produce International Atomic Time, which gives us Coordinated Universal Time. UTC, as its known, is the time; the global standard and successor to Greenwich Mean Time. If you want to know the real time in real time go to BIPM.org, and check the UTC master clock.
• "Time and Frequency Standards". Popular Electronics. No. v. 17. Ziff-Davis Publishing Company. 1979. Retrieved 2024-02-08. ...heard all over Europe broadcasting Coordinated Universal Time (UTC, the successor to Greenwich Mean Time or GMT) in Morse Code.
• Joy, M. (2015). Upon a Trailing Edge: Risk, the Heart and the Air Pilot. Matador. ISBN 978-1-78462-472-9. Retrieved 2024-02-08. ...UTC (Coordinated Universal Time after a French fudge; it is the successor to Greenwich Mean Time (GMT) or 'Zulu').

Other words, but same idea:

• Stacey, Michelle (December 2006). "Clash of the Time Lords". Harper's Magazine. 313 (1879): 46–56. The U.S. victory would in turn officially and finally spell the end of the last vestige of empire for the United Kingdom, which still retains its beloved GMT as the official time standard even as most of the world has anointed UTC. Until now the distinction between the two has been merely semantic, because the two standards have remained linked by the leap second. But GMT is by definition based on earth time. If the leap second disappears and official time diverges from earth time, GMT will be a relic, an historical curiosity--like the Greenwich Observatory itself, which is now a privately owned museum rather than a working national scientific center.
• David Adam,Science c. (26 June 2003). "What time is it? Well, no one knows for sure: As the Earth spins slower, methods of telling time diverge. Experts warn this could end in disaster". The Guardian. pp. 9-1.9. A time standard established for British navigation in the mid-19th century. GMT has now been officially replaced by coordinated universal time, so Big Ben, the BT speaking clock and the BBC radio pips all mark UTC, not GMT as some people think -although the two are usually very close. British law still refers to GMT because a 1997 bill that tried to update it to UTC was never passed. It ran out of time.{{cite news}}: CS1 maint: year (link)
• Falk, Dan (27 December 1998). "Science: Ahead of the times So accurate are atomic clocks, they keep better time than the planets. Dan Falk reports on the leap second that will align the two this New Year: [FINAL Edition]". The Independent. The result is Coordinated Universal Time, the modern version of GMT.
• "Why time is a companion, not an enemy of reward". The Transcontinental. 10 January 2021. In 1972, UTC replaced GMT because of the earth's changing rotational speed that results in our planet slowing down each year.
• Leake, Jonathan (2011-10-02). "Loss of GMT gives Britain the pip". The Times & The Sunday Times. Archived from the original on 2022-11-04. Retrieved 2024-02-08. In the early 1960s, Greenwich Mean Time was replaced with UTC, which is set not on the Earth's rotation, but on atomic measurements.

Daniel Quinlan (talk) 04:19, 8 February 2024 (UTC)

I'd like to slightly rephrase my previous proposal for a replacement because "However" is too contradictory:

It is the effective successor to Greenwich Mean Time (GMT) in everyday usage and common applications. Nonetheless, in specialized domains such as scientific research, navigation, and timekeeping, other standards like UT1 and TAI play a vital role.

It might also be worth mentioning astronomy parenthetically like "scientific research (especially astronomy)". Daniel Quinlan (talk) 04:46, 8 February 2024 (UTC)

None of those quotes mention TAI or UT1. I'm fine with UTC being "the" successor to GMT; but you seem to be going through gyrations to keep your reference to UT1 and TAI somehow involved in the GMT succession. "However" and "Nonetheless" are more-or-less synonyms; but "however" isn't the problem. The problem is that TAI and UT1 are in no way successors to GMT. You seem to want to say that they are, without directly saying that they are (because they are not).

Wouldn't it solve your problem to just skip the mention of TAI and UT1? MrDemeanour (talk) 15:28, 8 February 2024 (UTC)

UT1 is a successor to GMT because before the variability of the rotation of the Earth was understood well enough to measure it, GMT was the only timescale available, so it was used in applications where the actual orientation of the Earth was needed, such as navigation and pointing telescopes. Now, in those applications, UT1 is used as a replacement for GMT. GMT was also used in applications where the durations needed to be found by subtracting a start time from an end time. TAI is more suitable for that purpose than UTC or UT1. Jc3s5h (talk) 15:50, 8 February 2024 (UTC)

All that the second sentence is conveying that while UTC has become the standard replacing GMT in most contexts, there are still applications where other time standards are crucial. The two sentences allow readers unfamiliar with this topic to better understand the role of UTC. I don't think we need to say whether TAI or UT1 are successors. It's enough to say they play a vital role in several areas and we can source it.

It would also be good for the body of the article to briefly discuss applications where UTC isn't used and why. Daniel Quinlan (talk) 20:05, 8 February 2024 (UTC)

OK, so it's arguably fine to mention in the article that TAI and UT1 have subsumed some of the functionality previously served by GMT. I'm objecting to that mention being part of a specific claim about the successor to GMT, whether as a single sentence, or two sentences joined by a conjunction such as "however" or "nonetheless". That is, I would like to make a clear separation between the claim that UTC is the successor of GMT, and statements about TAI and UT1 filling part of the gap left by GMT. Note that TAI and UT1 both predate the introduction of UTC, so they cannot be its successor in any normal sense. MrDemeanour (talk) 12:43, 9 February 2024 (UTC)

I respectfully disagree. There is a clear separation indicated by a full stop. "Nonetheless" is an adverb, not a conjunction; it introduces a statement that qualifies the preceding one. The proposed phrasing clearly distinguishes the roles of other standards such as UT1 and TAI without implying they are successors to UTC. I can find another way to phrase it, but I don't understand how you can be reading it that way. Daniel Quinlan (talk) 18:39, 9 February 2024 (UTC)

I revised the article. It seems like everyone agrees the phrasing in the article was not ideal. I'm going to add a source as well, but I want to review the above citations to see if I can cover both sentences with a single citation rather than requiring multiple citations. Daniel Quinlan (talk) 19:05, 9 February 2024 (UTC)

I'm satisfied with the edit by Danisl Quinlan. Normally, citations are not needed in the lead if the body of the article supports the statement. But it might be hard to find which part of the body supports this, so maybe it would be best to add a citation. Jc3s5h (talk) 19:53, 9 February 2024 (UTC)

Thanks for the review. I think more definitely needs to be added to the history section regarding the transition to and adoption of UTC, but one thing at a time. Daniel Quinlan (talk) 20:14, 9 February 2024 (UTC)

I went ahead and removed the discuss tag and cleaned up the introduction a bit more, but I am happy to continue the discussion here, regardless. I'm working on adding that source now. Daniel Quinlan (talk) 05:06, 10 February 2024 (UTC)

MrDemeanor wrote "note that TAI and UT1 both predate the introduction of UTC, so they cannot be its successor in any normal sense." But we're not saying TAI and UT1 are successors of UTC, we're saying they're successors of GMT which satisfy the traditional roles of GMT. Originally, UTC was the functional replacement of GMT because it tracked UT2, which was similar to UT1 and gave the Earth's orientation as accurately as most users could take advantage of. TAI served the duration role and was used in comparisons between time laboratories. Since 1972 UTC has leap seconds, which makes it more of a compromise: it's good enough for civil time keeping, and can be used for Earth orientation or durations after the appropriate adjustments are made. Jc3s5h (talk) 19:42, 9 February 2024 (UTC)

Yeah, sorry; "cannot be its successor" should have been "cannot be GMT's successor".

I'm OK with @Daniel's latest edit; I think it's now pretty clear. I still think the attempt to wedge UT1 and TAI into a paragraph about the successor to GMT is strained and unnecessary; but it's no longer susceptible to misinterpretation. MrDemeanour (talk) 11:34, 10 February 2024 (UTC)