Where I live, high noon today occurs at 1:03 PM. No one is complaining that it is 3 minutes (or 63 minutes) off. It's a non-issue for 99.9% of the population.
But I do think there is a valid argument that the infrequency of these events cause more issues than maybe one large adjustment 500 years from now would cause. Not sure where I land on this one.
Thanks for making me a decade younger :)
Is that true? Per Wikipedia:
> Since [1972], 27 leap seconds have been added to UTC, with the most recent occurring on December 31, 2016. All have so far been positive leap seconds, adding a second to a UTC day; while a negative leap second is theoretically possible, it has not yet occurred.
Either way, it's due in part to Earth's rotation slowing down, so the average drift would still be non-zero.
The time period of the Earth fluctuates a lot [0] and actually in 2020 it was less than 24 hours, but not a large enough change to warrant a negative leap second. If you go back to the 1940s, we would had needed negative leap seconds if we had leap seconds at all then, and going back 150 years we would have needed multiple negative leap seconds every year for several consecutive years.
What we can say is that on average, it is close enough to 24 hours and the average over hundreds of years is even closer to 24 hours that it's not worth adding these extra seconds as you'd then need to remove them again later on.
[0] https://c.tadst.com/gfx/900x506/graphlength-of-day.png from https://www.timeanddate.com/time/negative-leap-second.html
For 99% of the world today, high noon =/= 12:00:00. Nothing breaks because of this. The world continues to run.
I was told the sun would show up on the calendar in the floor at noon. As noon approached, I saw nothing. Then I figured it probably needed to be solar noon, so had to look that up and wait around until that time. Today, that will be 12:20pm.
Nothing would have broken had I missed this, and nothing of critical importance is running on a solar clock (I don’t think), but it still led to a discrepancy in what was expected and where I needed to be when, based on drift from solar noon.
Astronomers need either true time, which is TAI, to be used in computing the positions of celestial bodies, and they need for observations the so-called Sidereal Time, which is not a time but the angle between a coordinate system attached to the Earth and an inertial system of coordinates attached to distant celestial objects that have negligible angular movement (in the past those were distant stars, now they are distant galaxies or quasars).
The Sidereal Time can be computed in a complex way from TAI, because it is determined by the periodic rotation and precession of the Earth and by various superposed periodic or random movements.
The UTC is not adjusted to match the current true rotation angle of the Earth, which you can measure by looking up to the stars, but it is adjusted to match within 1 second a fictitious angle that would be the rotation angle of the Earth-Sun direction corresponding to an Earth that would rotate uniformly both around itself and around the Sun, so that the duration of a day would have been constant.
In reality, the duration of a Solar day, i.e. the time between 2 consecutive noons, varies a lot during the year, by a large fraction of an hour (by about a half of hour peak-to-peak), so using UTC directly for estimating the position of the Sun gives a very big error, of many minutes of hour.
So what you need for astronomy is to know the current TAI and you need a Sidereal Time calculator, which you need for knowing in what direction to point your telescope, to find a given celestial object.
UTC cannot be used directly in astronomy, but only after passing either explicitly or implicitly through TAI. The fact that astronomical almanacs are published using UTC in their tables is obfuscating this, because the values in the tables have not been computed using UTC, but everything has been converted to UTC to match the time that is presumably shown by the watch or clock that the almanac user may have.
Compare that to removing the leap day, where the start of seasons would be noticeably affected within just a few decades. Hundreds of years ago, a pretty insignificant headache was invented which is providing constant payoffs.
https://rin.org.uk/news/624222/Leap-Seconds-To-Be-Phased-Out...
Before modern standardization, maintaining calendars and clocks was typically the responsibility of states or similar authorities, often guided by astronomers. Now it seems that international organizations are effectively following the early UNIX/POSIX model, and astronomers no longer have the same authority over timekeeping.
And anyone that cares about the relationship of the time of day and the position of the Sun.
Granted, it's not a lot, only a minute per century.
How can people manage with noon off by minutes, yet want leap-second accuracy every 6 months?
But yes, point taken.
The counterpoint is that it costs little.
Radical changes to time-related software cost little ? Stop press !
I haven't once done a single software upgrade related to leap seconds.
Statistically, nobody on Earth knows what UTC is. People know about their local time zone and how it related to time zones in other countries. Where the position of the sun is relative to UTC, almost nobody knows.