alt Hacker News"But over time, if we didn't have leap seconds, the difference would accumulate. The accumulated difference now between UTC and TAI is 37 seconds--which is almost twice the maximum variation in actual solar noon from mean solar noon that you refer to."
No, the 10-15 seconds I mentioned is the daily variation in solar noon.
From the link I posted, in NYC, solar noon on 2026-01-01 is at 11:59am. On 2026-01-31, solar noon is at 12:09pm. In one month, it has drifted 10 minutes. That's much greater than the 37 leap seconds we have added in 60 years.
"We humans have collectively decided that we don't want that, and that it's better to do the adjustments a little at a time rather than in bigger lumps."
Yet we just reversed that decision. No more leap seconds after 2035. After trying it, we decided it was terrible.
> the 10-15 seconds I mentioned is the daily variation in solar noon.
Yes, but averaged over an entire year, it still comes out to zero. The difference between mean solar and atomic time does not. It accumulates over the years.
> we just reversed that decision
We paused it for 100 years after 2035. That doesn't change the physical fact that the Earth's rotation will continue to slow over the long term. We might eventually decide to just not care about that when it comes to civil timekeeping, but that's not what the decision you're referring to did. It just said we can afford to let the difference between UTC and TAI accumulate from 2035 to 2135 (by which time it is predicted to be about a minute) while we figure out what we want to do over the longer term.