2266: Leap Smearing - Revision history

Wilh3lm: /* Explanation */ Decimal point for consistency

2023-04-18T12:05:42Z

‎Explanation: Decimal point for consistency

Jacky720: rv

2022-05-04T20:57:11Z

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Ex Kay Cee Dee at 20:44, 4 May 2022

2022-05-04T20:44:01Z

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172.70.238.137: Undo revision 243994 by Ex Kay Cee Dee (talk)

2022-05-04T20:43:25Z

Undo revision 243994 by Ex Kay Cee Dee (talk)

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Ex Kay Cee Dee at 20:41, 4 May 2022

2022-05-04T20:41:06Z

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Davidy22: Reverted edits by X. K. C. D. (talk) to last revision by 172.70.162.155

2022-05-04T02:01:11Z

Reverted edits by X. K. C. D. (talk) to last revision by 172.70.162.155

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X. K. C. D. at 00:25, 4 May 2022

2022-05-04T00:25:37Z

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172.70.162.155: Undo revision 232527 by X. K. C. D. (talk)

2022-05-03T21:50:39Z

Undo revision 232527 by X. K. C. D. (talk)

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X. K. C. D. at 21:33, 3 May 2022

2022-05-03T21:33:08Z

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162.158.129.149: /* Explanation */ Corrected 'integral' to 'integer' in the context of the number of days in a year.

2021-12-07T10:33:47Z

‎Explanation: Corrected 'integral' to 'integer' in the context of the number of days in a year.

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 Clocks {{w|Japanese clock|usually}} measure time by regularly-sized intervals, but the natural world is not always so accommodating.  Since the solar year is not an integer number of days long, we add {{w|leap days}} every four years (except for years divisible by 100 but not 400) to prevent our calendars from drifting with respect to the seasons.  We also add {{w|leap seconds}} to the clock every now and then, to prevent noon on our clocks from drifting away from solar noon.  Unfortunately, Earth's day is not as regular as Earth's year, so leap seconds cannot be predicted with a formula but are added as needed, most recently in 2016.  Officially, the leap second is added at midnight UTC (so a clock will tick 23:59:59...'''23:59:60'''...00:00:00), but this is an extremely inconvenient edge case, to the point that there are many proposals to do away with leap seconds entirely (as of this comic strip's publication, the matter will be discussed in the World Radiocommunication Conference in 2023).
-Rather than inserting an extra tick into timestamps and dealing with the resulting hiccups (e.g. programs hard-coded to expect that [https://infiniteundo.com/post/25509354022/more-falsehoods-programmers-believe-about-time#_=_ every minute will contain exactly sixty seconds]), {{w|Google}}'s services 'smear' the leap second over the course of a 24-hour period, officially called [https://developers.google.com/time/smear Leap Smear] by Google. The smear is centered on the leap second (at midnight) so from noon the day before to noon the day after each second is 11.6 μs longer (1s/(24*60*60) = 11,574 μs). This difference is too small for most of Google's services to be bothered with, and by centering on midnight, the difference in time will never be more than half a second at midnight; just before midnight it will be half a second behind, after midnight it'll be half a second ahead.  This comic's joke arises from the idea of extending this practice to smearing leap days over the month of February.  This comic strip was published February 10th, 2020, almost three weeks before the leap day on February 29th, 2020.
+Rather than inserting an extra tick into timestamps and dealing with the resulting hiccups (e.g. programs hard-coded to expect that [https://infiniteundo.com/post/25509354022/more-falsehoods-programmers-believe-about-time#_=_ every minute will contain exactly sixty seconds]), {{w|Google}}'s services 'smear' the leap second over the course of a 24-hour period, officially called [https://developers.google.com/time/smear Leap Smear] by Google. The smear is centered on the leap second (at midnight) so from noon the day before to noon the day after each second is 11.6 μs longer (1s/(24*60*60) = 11.574 μs). This difference is too small for most of Google's services to be bothered with, and by centering on midnight, the difference in time will never be more than half a second at midnight; just before midnight it will be half a second behind, after midnight it'll be half a second ahead.  This comic's joke arises from the idea of extending this practice to smearing leap days over the month of February.  This comic strip was published February 10th, 2020, almost three weeks before the leap day on February 29th, 2020.
 In the comic, [[Cueball]] is visiting one of Google's facilities, presumably during office hours on the 10th day of February, when the comic was released. But when he looks at their clocks he sees they are all around 3:00 AM (which is in the middle of the night). He thus asks [[Ponytail]] and [[Hairy]] why their clocks are wrong. Ponytail tells him it is because of leap day smearing.

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 ==Explanation==
-Clocks {{w|Japanese clock|usually}} measure time by regularly-sized intervals, but the natural world is not always so accommodating.  Since the solar year is not an integral number of days long, we add {{w|leap days}} every four years (except for years divisible by 100 but not 400) to prevent our calendars from drifting with respect to the seasons.  We also add {{w|leap seconds}} to the clock every now and then, to prevent noon on our clocks from drifting away from solar noon.  Unfortunately, Earth's day is not as regular as Earth's year, so leap seconds cannot be predicted with a formula but are added as needed, most recently in 2016.  Officially, the leap second is added at midnight UTC (so a clock will tick 23:59:59...'''23:59:60'''...00:00:00), but this is an extremely inconvenient edge case, to the point that there are many proposals to do away with leap seconds entirely (as of this comic strip's publication, the matter will be discussed in the World Radiocommunication Conference in 2023).
+Clocks {{w|Japanese clock|usually}} measure time by regularly-sized intervals, but the natural world is not always so accommodating.  Since the solar year is not an integer number of days long, we add {{w|leap days}} every four years (except for years divisible by 100 but not 400) to prevent our calendars from drifting with respect to the seasons.  We also add {{w|leap seconds}} to the clock every now and then, to prevent noon on our clocks from drifting away from solar noon.  Unfortunately, Earth's day is not as regular as Earth's year, so leap seconds cannot be predicted with a formula but are added as needed, most recently in 2016.  Officially, the leap second is added at midnight UTC (so a clock will tick 23:59:59...'''23:59:60'''...00:00:00), but this is an extremely inconvenient edge case, to the point that there are many proposals to do away with leap seconds entirely (as of this comic strip's publication, the matter will be discussed in the World Radiocommunication Conference in 2023).
 Rather than inserting an extra tick into timestamps and dealing with the resulting hiccups (e.g. programs hard-coded to expect that [https://infiniteundo.com/post/25509354022/more-falsehoods-programmers-believe-about-time#_=_ every minute will contain exactly sixty seconds]), {{w|Google}}'s services 'smear' the leap second over the course of a 24-hour period, officially called [https://developers.google.com/time/smear Leap Smear] by Google. The smear is centered on the leap second (at midnight) so from noon the day before to noon the day after each second is 11.6 μs longer (1s/(24*60*60) = 11,574 μs). This difference is too small for most of Google's services to be bothered with, and by centering on midnight, the difference in time will never be more than half a second at midnight; just before midnight it will be half a second behind, after midnight it'll be half a second ahead.  This comic's joke arises from the idea of extending this practice to smearing leap days over the month of February.  This comic strip was published February 10th, 2020, almost three weeks before the leap day on February 29th, 2020.