3 ms·

Because we are still correlating time with the rotation of the earth. Time is an absolute measure, a second is defined as a precise amount of time, and you can

Because we are still correlating time with the rotation of the earth. Time is an absolute measure, a second is defined as a precise amount of time, and you can count the time that one event with that measure. Only historically the second was defined as a fraction of the day, and was correlated to the speed of the rotation of the earth, to this days we have better ways to define it. Who said that time needs to be in sync with rotation of the earth? Nobody, who cares? It's a so small variation happening in a so long period of time to not be noticeable to any practice use: it's not that we take the sun as a reference of time anymore! We can keep counting time as we want and not be bothered with something not precise as the rotation of the earth. And for the applications that require that sort of precision, and only them, adjust the time accordingly. I mean, a meter was once defined as the one ten-millionth of the distance from the equator to the North Pole along a great circle. It's not that for this reason if the distance between the North Pole and the equator changes we are all throwing away our meters... it's just that we found a more precise definition of one meter. Same happened with the second (and all the time measures, such as a day): we express them in a new format where it no longer matters what the earth and the sun do.

ok_dad 4y ago
> Who said that time needs to be in sync with rotation of the earth? Nobody, who cares? Humans sleep, usually at night time, and the rotation of the Earth defines night in any location, so regardless of the continual tick of some sort of "universal clock" we need a way to measure daily events that humans can use that rely on the sun going up and down at certain times and thus we need to adjust our local Earth times based on it's rotation. Maybe we can decouple UTC (or whatever) from local times completely, so then a leap second is just a second we add to or remove from the offset for any given location, but we still need to deal with adjusting local clocks to the rotation of the Earth and it's orbit around our star, the "Sun".
- nullc 4y ago
  > Humans sleep, usually at night time This seems like a kind of navel gazing point, however-- without leapseconds it would take on the order of 4000 years to slip an hour, quite a big longer so that nights hours aren't aren't at night. We already have a good mechenism for matching local sun time-- timezones. I don't see anyting in your post to justify one second level offsets. (aside, UT1 is technically defined in terms of earth's orientation with respect to distant quasars, not the sun :) )
  - ok_dad 4y ago
    Well at least engineers in 6022 will have job security dealing with the leap hour!
    - nullc 4y ago
      That could be just a timezone switch, which our geopolitics seems to like to subject us to frequently in any case.
- alerighi 4y ago
  Sleep is not influenced by a second before or more. And I never understood this, it's far simpler to adjust the time you wake up/go to work/go to bed/whatever than to adjust the clocks. These solutions (including daylight saving time, timezone, etc) were probably a good solution where the clock were local and it didn't exist the problem of synchronizing clocks all around the world. But to these day, it doesn't really make a lot of sense sense. Even timezone, it would be far easier knowing that there is only a world clock (UTC) and we adapt our time to the clock and not change the clock. Timezone, daylight saving, and leap seconds generate a ton of problems only for a minor convenience...

ok_dad 4y ago

> Who said that time needs to be in sync with rotation of the earth? Nobody, who cares? Humans sleep, usually at night time, and the rotation of the Earth defines night in any location, so regardless of the continual tick of some sort of "universal clock" we need a way to measure daily events that humans can use that rely on the sun going up and down at certain times and thus we need to adjust our local Earth times based on it's rotation. Maybe we can decouple UTC (or whatever) from local times completely, so then a leap second is just a second we add to or remove from the offset for any given location, but we still need to deal with adjusting local clocks to the rotation of the Earth and it's orbit around our star, the "Sun".

nullc 4y ago
> Humans sleep, usually at night time This seems like a kind of navel gazing point, however-- without leapseconds it would take on the order of 4000 years to slip an hour, quite a big longer so that nights hours aren't aren't at night. We already have a good mechenism for matching local sun time-- timezones. I don't see anyting in your post to justify one second level offsets. (aside, UT1 is technically defined in terms of earth's orientation with respect to distant quasars, not the sun :) )
- ok_dad 4y ago
  Well at least engineers in 6022 will have job security dealing with the leap hour!
  - nullc 4y ago
    That could be just a timezone switch, which our geopolitics seems to like to subject us to frequently in any case.
alerighi 4y ago
Sleep is not influenced by a second before or more. And I never understood this, it's far simpler to adjust the time you wake up/go to work/go to bed/whatever than to adjust the clocks. These solutions (including daylight saving time, timezone, etc) were probably a good solution where the clock were local and it didn't exist the problem of synchronizing clocks all around the world. But to these day, it doesn't really make a lot of sense sense. Even timezone, it would be far easier knowing that there is only a world clock (UTC) and we adapt our time to the clock and not change the clock. Timezone, daylight saving, and leap seconds generate a ton of problems only for a minor convenience...