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Comment by mikeash | Hacker News Reader

The problem is that the effect being compensated for is so tiny that it's really noisy. It's not like leap years, where all you have to do is measure the actual period of the Earth's orbit very precisely and come up with a nice way to fit the appropriate correction factor into the calendar.

The Earth's rotation is slowing, but it's not a steady process. For example, the Boxing Day earthquake in 2004 permanently decreased the length of the day by about 3 microseconds. Here is a graph of the changes over the past few decades:

https://upload.wikimedia.org/wikipedia/commons/5/5b/Deviatio...

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As long as we have a standardized way of determining when leap seconds are going to happen, some authority determining and announcing, there shouldn't be problem. Leap years are predictable, but leap seconds can be accounted for a decade after an event disrupts the pattern.

Also, given all that variance and the fact that we only seem to be shifting around 1 minute per century at the current rate, we probably could get by having a leap minute every few decades when necessary.

This works fine for any system trying to interact with other computers and humans while keeping consensus on the time. Any system that is trying to determine earths yaw would no longer be able to rely on F(time), but that is only a minor inconvenience.

How is that different from what's being done now? There is a standardized way of determining when leap seconds are going to happen (they always happen on June 30th or December 31st when the deviation reaches about 0.6s), there is an authority that determines and announces it (the International Earth Rotation and Reference Systems Service) and it is, in fact, done by causing the last minute on the day in question to have 61 seconds instead of the usual 60.

The complication is just that there are a whole lot of systems out there that assume that every minute has exactly 60 seconds with no exceptions, so you end up with crazy workarounds like smearing to hide that 61st second from such systems.

>How is that different from what's being done now? There is a standardized way of determining when leap seconds are going to happen (they always happen on June 30th or December 31st when the deviation reaches about 0.6s)

It's different because you don't have to keep track of what an authority is saying or deal with the actual time adjustment except once in a century. Once in a century is acceptable since we will only deviate by around a minute at our current rate.

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