[Vvector]

Leap Seconds need to be abolished. The only people who need it are Astronomers. They could just use an offset. Implementing leap seconds correctly is a huge burden, for no gain.

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.

[coldpie]

Hmm. I understand that perspective, but I'm not sure I agree. It does seem to matter over a relatively short & realistic time scale. According to the Wikipedia page, there have been 27 seconds added since 1972, which is only 44 years ago. At that rate, that's about 1 minute per 100 years. We have many systems that have existed for several centuries and I think it's not unreasonable to start making plans for systems that may exist for millennia, where you're starting to talk about a 10+ minute offset at the current rate.

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.

[8fingerlouie]

> since 1972, which is only 44 years ago

Thanks for making me a decade younger :)

[Vvector]

Can you explain how a 10 minute offset would affect you in any way?

For 99% of the world today, high noon =/= 12:00:00. Nothing breaks because of this. The world continues to run.

[al_borland]

I ran into this trying to view the meridian line at the Basilica of Saint Mary of the Angels in Rome.

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.

[ralferoo]

The problem is that Earth's rotation isn't consistently faster. Some years leap seconds need to be added, some years they need to be removed. Would be far better to leave them alone, let them average out, and as the GP said let the people who care about this add the offset they need.

[coldpie]

> Some years leap seconds need to be added, some years they need to be removed.

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.

[ralferoo]

We've not had to apply negative leap seconds yet since leap seconds were introduced in 1972, but that wasn't the point.

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

[philwelch]

You make a good argument for the opposite of your conclusion. If you’re planning a system that’s supposed to last for millennia, that system shouldn’t depend on the fiat of the International Earth Rotation and Reference Systems Service.

[zarzavat]

Let's just do leap minutes. If humanity survives long enough to witness a leap minute without destroying ourselves then that's ample compensation for the minor inconvenience.

[adrian_b]

Astronomers do not need leap seconds, because even with this adjustment UTC cannot be used to determine anything in astronomy.

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.

[xorcist]

Unless you want to abolish timezones entirely, which would simplify clocks but complicate a whole lot else in society, you're going to need leap-something. Would leap minutes or hours really be much better? The idea that doing things less often causes more problems is a reasonable one.

[delecti]

In the 56 years since UTC was established, there have only been 37 leap seconds. At that rate it would take more than 5400 years before it would affect solar noon more than DST does. I'm more than okay kicking the can that far down the road in the name of avoiding all the ridiculous solutions that are needed to accommodate leap seconds. We've endured these headaches to potentially solve a problem for people who might not even still be using UTC.

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.

[vilhelm_s]

We need to do "leap hours" anyway--just today they changed to daylight saving time in the U.S.! And time zones are also adjusted every now and then, which also amounts to a one-hour change in the affected regions. Even if we didn't have continous practice with leap seconds, I think we could definitely include an extra one-hour shift for earth rotation reasons along with all the other ones.

[edgsousa]

They already got to that conclusion, but because of computers.

https://rin.org.uk/news/624222/Leap-Seconds-To-Be-Phased-Out...

[r2vcap]

That’s super interesting—I didn’t know that.

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.

[paulddraper]

> The only people who need it are Astronomers.

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.

[phicoh]

Which means that time changes slowly enough that we don't notice. At some point everybody goes work half an hour earlier because it makes sense. Schools start earlier, shops open earlier. It doesn't have to be coordinated worldwide. Every region or even town can have its own customs. Then people notice they are in the wrong time zone and a country moves to a different time zone.

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.

[Vvector]

Yet high noon at my current location comes at 12:03 (1:03 with DST). It's three minutes off. If I lived further west in my timezone, noon would come much later.

How can people manage with noon off by minutes, yet want leap-second accuracy every 6 months?

[paulddraper]

More like every 2 years.

But yes, point taken.

The counterpoint is that it costs little.

[euroderf]

> The counterpoint is that it costs little.

Radical changes to time-related software cost little ? Stop press !

[paulddraper]

What radical software changes are you doing?

I haven't once done a single software upgrade related to leap seconds.

[bloak]

I think the best solution for minimising overall _long-term_ hassle is to switch to using TAI internally and UTC for display.

[8fingerlouie]

I mean, in 53 years we have added 27 leap seconds, so in 119 years you'll have to set your alarm a minute earlier if you still want to arrive on time.