There is a growing movement in the timekeeping community that agrees that keeping UTC close to UT1 is no longer important and that leap seconds should be abandoned.
Oh by the way, unless you live smack in the middle of a timezone, solar noon isn't clock noon anyway. Plus it gets all jacked up with daylight savings (which should also be abandoned), so the whole notion of leap seconds is farcical on its face.
Its obvious the only solution is to slow Earth rotation down so we have no need for leap seconds while maintaining high noon precision for millenia
" ... one day I would like to do the math on the “great leap second gyroscopes” that we could mount near the poles to steady the Earth’s rotation, so we can stop talking about this. We may occasionally have to desaturate these gyroscopes with huge rockets also."
I have an alternative solution, which is that we stop earths rotation and get it tidally locked to the sun, so it's always 00:00:00.000 midnight at Greenwich UK. This'll screw up the ski resorts in New Zealand, but anyone who's spent a winter in Invercargill on the South Island there will agree that it'd be much much nicer as a tropical paradise.
Even if you are at the exact center of the time zone, clock noon is only rarely at solar noon. See https://en.m.wikipedia.org/wiki/Equation_of_time
Even if you ignore this issue and assume you could somehow measure local noon exactly, you still would need almanac data in order to do the correction. Once you are involving almanac data, it stops mattering if local noon has any connection at all to 12:00 on your clock.
Or when we exist as a society on the moon and Mars and in the asteroid belt - and the relevance of the rotational angle of earth will be no more interesting to almost everybody the same way local time in Greenwich UK doesn't matter to 23/24ths of the planet.
(Hopefully that's well before the "few millennia" it'll take for TAI to be radically different to what we use UTC for these days, and "soon enough" that it's worth taking into account already.)
And the Julian calendar was 'good enough' for a long time… until it wasn't and Pope Gregory XIII had to announce the skipping over of 10 days so that (e.g.) the Spring Equinox actually lined up with the season of spring more accurately.
I understand the sentiment of wanting to simplify things, but kicking the can down the road so it's someone else's problem is wrong in my eyes.
If human civilisation still exists by the time we've reached just 1 hour of difference we'll be occupying multiple bodies throughout the solar system, if not further afield, and have to have come up with a new time system anyway. Even the length of a second varies because of relativity.
You could skip leap years and still have the sun up at noon, while your solstice date drifts away. Or, you could skip leak seconds and still have the solstice on 21 Dec, but have your noon drift away from mid day.
The sun is overhead from Greenwich at 12:06 GMT today, it varies by about half an hour from 1143 to 1214 through the year (ignoring daylight saving)
I'm not sure if varying from 1150 to 1221 would be any better. Even after a minute of leap seconds (say 100 years) the point where the "sun is overhead at 12:00:00" point for points at UK/Ireland latitude would have moved about 10 miles from its current position. in a few millenia the timezone would be wrong, but easilly corrected by either skipping a "spring forward" or "fall back" time.
Except it's not every four years.
It's every four years, but it is skipped if the year is divisible by 100… but not skipped if it is also divisible by 400—which ended up biting people in 2000 which was a leap year:
* https://slate.com/technology/2016/02/the-math-behind-leap-ye...
> Except it's not every four years.
> It's every four years, but it is skipped if the year is divisible by 100… but not skipped if it is also divisible by 400—which ended up biting people in 2000 which was a leap year ….
Unless they edited, that's exactly what your parent said, after you cut off the quote:
> Yeah, we already do the Feb 29 thing every 4 years. We make exceptions to that rule every 100 years, and an exception to the exception every 400 years.
Yes, and how many things break every time this common thing occurs? Or every four years when February 29 rears its ugly head.
And these are code paths that should be well tested because of their frequency.
A drift of a minute over a lifetime makes no difference.
We should just use TAI (with timezone offsets) for general time and be done with it.
Even today UT1 is widely different to UTC (183ms), so it's not like using UTC is accurate. Why is 183ms an acceptable difference (no leap milliseconds), a couple of hours (timezone sizes), one hour (DST), but we have to correct for 40 seconds each century?
That's because it doesn't make any sense to describe the middle of the day by '12 PM', since 'PM' should mean "after midday". To be sure we have conventions about this, but not knowing those arbitrary conventions is no reason to think that people don't understand the concept. I think better usage is 12 noon and 12 midnight (https://en.wikipedia.org/wiki/12-hour_clock#Confusion_at_noo... )—though that still requires further disambiguation at midnight (is "midnight on August 3" between August 2 and 3, or between August 3 and 4? I don't know whether there's a common disambiguation here, as with 12 n versus 12 m).
Sure, although, if we're re-defining how people tell time anyway, we might as well use a 24-hour clock and so avoid the need for AM/PM at all; and, even if we do that, there is still, inevitably, the confusion about on what day 00:00 AM falls. My point was just that not knowing that "12 PM" means noon is a matter of not being aware of an arbitrary convention, rather than of not understanding the concept of AM vs. PM. (Indeed, arguably it is a matter of understanding their meaning all too well!)
Not so much actually: 00:00 is on the day that is starting, 24:00 is on the day that is ending.
That makes a lot of sense!
Except when leapseconds come along and make it 23:59:60
And daylight saving skips an hour, or repeats it.
AM and PM are really anachronisms though, I don't remember the last time I've ever seen "4pm" written down in normal life.
True in the US (and IIRC the Anglophone world more generally), but AFAIK 24-hour is more commonly used outside of military/technical domains in many other countries.
UK TV schedule: https://www.bbc.co.uk/schedules/p00fzl6p
France opening hours: https://www.malathronas.com/wp-content/uploads/DSC_6720.jpg
Thai train timetable: https://teakdoor.com/images/north.gif
I just checked my OS X machine, it has it. My Linux machine has it, though I grant that among the many DEs for Linux, some might not use it. (I use MATE, a fork of GNOME 2, for reference.) And I've Googled a screenshot of Windows, which seems to still use it.
My phone, microwave, and stove, I guess, seem to presume I know whether it is morning or not.
Or maybe 12:00 vs 00:00
12 PM = noon is something I remember learning in kindergarden, and should be common knowledge for most adults in the US.
Well, maybe, although assuming a commonality between others' education and mine is always dangerous; but I've got way more respect for someone who understands a concept but doesn't know about an arbitrary exception to it, than for someone who understands a pile of arbitrary rules and doesn't know how to fit them to any conceptual framework.
I think that explanation fails because, IME, people who know that “PM” means “post meridiem” which means “after midday” are more, not less, likely to also know that 12:00 PM is noon than those to whom PM is just an arbitrary marker.
TAI is very smooth. TAI gives the sort of predictable monotonic clock you might appreciate if you care about milliseconds. One second after another, with a perfect 1000 milliseconds between them, forever.
UT is based on a large rock (the planet Earth) spinning. It varies a bunch 'cos the rock is a weird shape and is seismically active so it spins differently over time. If you care about "millisecond accuracy" then you do not want to base that on the spinning of a big rock when you can get a perfectly nice atomic clock and use TAI.
If your thought is "But I need millisecond accuracy for my astronomical observations" what you've got there is a big misunderstanding of your context. While UT might seem convenient for figuring out where and when to point telescopes at thing, it's useless for actual time. You need TAI.
I'm all for a universal world-wide time. then we'd just have to learn what time is middle of the night for what location, but we have digital aids for that. It solves all timezone bs.
My guess is is that we whine for about a month and then it becomes normal for ie. 14:00 to be middle of the night depending on you location.
The date line? Yeah lets put that in the center of the Pacific.
Adding/subtracting the local time offsets when necessary is easier for me than trying to think in local times and DST.
Moreover, I have not lost the context for the earth's rotation, but I am better aware of it, by remembering which is the GMT time of the noon where I live.
During summers (i.e. with DST), the noon is delayed here by about 75 minutes from 12:00, so keeping in mind the correct UTC time of the noon makes me more aware of the Sun position. There are many places where the time difference between noon and 12:00 local time is much larger, making the official local time pretty useless for determining the Sun direction.
The time of the noon varies from place to place depending on the longitude.
In the beginning, every major town had its own local time, with noon at 12:00. After the time zones were introduced, noon should have been everywhere some time between 11:30 and 12:30.
With DST, you can have a difference of up to 90 minutes between noon and the official 12:00, but there are countries which occupy more than one time zone, but do not bother to have so many time zones as necessary to minimize the differences between noon and 12:00, so there are places where there can be more than 2 hours between the true noon and 12:00.
It does not matter how far east/west you are but only how the time zones are set in your country, together with the DST.
If you would want to use the traditional boy scout technique of finding the south using a watch and either the Sun or the Moon, you would need to know the hour of the true noon in that place, otherwise the angular errors would be excessive.
Like a clock that you can adjust so that 0:00 is the middle of the night?
So when does Monday start? 14:00 UTC in your location?
Basically you are replacing Time Zones with Day-of-Week Zones.
There is one thing that is highly inconvenient and to have day border during working hours.
Now sure people who work night shifts have that, but it's a small number of people and a small number of services that are open 24/7.
So the question really becomes, "Who is the 'we' who wants to have a more theoretically pure timekeeping system that gets worse and worse at its primary purpose?" Turns out that's a pretty small audience.
Nor that of your children, grandchildren etc etc, as the change is gradual enough that nobody would notice. The only way to get a significant difference is by somehow sleeping for thousands of years (1k would be 6 minutes, which would still be impossible to tell with human senses).
It really is a pretty pointless solution to a non-existing problem.
If these were the only bugs that ever got written, I might buy it. But we all know that's not the case. Adopting a less correct timekeeping system will reduce the total number of bugs written by 0.000000001%. That is putting the cart firmly before the horse. Computers are here to serve people, not the other way around. Whenever we find ourselves making systems worse due to engineer convenience, we should think real hard about why we get paid the big bucks.
Precisely the opposite, and that's the root of the problem. We started with astronomical clock ticks and have gradually transitioned to progressively more accurate measurements. The attempt to maintain synchronization with astronomical units is for backward compatibility, not because they're more correct.
I agree that for a narrow set of science/technology use cases, a more abstract notion of time is useful. In those narrow realms, it makes sense to stick with the more abstract system. E.g., the way "these three navigation systems broadcast a continuous monotonic clock signal that is not influenced by leap seconds" is reasonable in context. But once we leave those narrow contexts, we need to translate back to the actual human purpose that kicked all of that off. Which again, is what happens: "navigation satellites do transmit when leap seconds happen".
Insisting that we make the actual system worse from the perspective of most humans for the convenience of technologists is a mistake. Even more so when we do it in the name of abstract ideas.
There is nobody who can tell the difference, so I call bullshit on the thesis that the average person profits from this.
I haven't had to implement anything like this, but as an observer it just feels like a pointless effort.
But it's already decided, so we will have to live with it no matter how pointless it is.
The military is a big one. ICBMs still use celestial navigation to determine their position and adjust their trajectory in flight.
The increase is quadratic. Without leap seconds, the difference will be an hour in 1000 years, but already a full day in 5000 years.
https://www.ucolick.org/~sla/leapsecs/dutc.html -> Effects of disconnecting time from the sun
It's not totally clear to me why they think "Given that the first leap hour would not happen for centuries, it is not clear that any systems (legal or technological) would build in the necessary complexity for handling it." It seems like that infrastructure is already in place— the IANA time zone database, and associated technology. UTC would become disconnected from sun-time, but all the other zones could shift relative to it, and it seems like most things would continue to handle it as expected.
But, I also trust that other folks have thought about it in more depth than I have. I'm not seriously trying to solve the problem (If I were, I'd get involved in standards committees or similar), and I'm happy to concede that my solution misses key details :)
In that case UTC has the same problem (steadily increasing numbers of leap seconds till we run out of places^Wtimes to put them), so we may as well have a less defective timekeeping system in the mean time.