3 ms·

> The Earth's wobbling and halting deceleration should not impact, let alone underly, our definition of time If you define time in terms of days and years, I.

> The Earth's wobbling and halting deceleration should not impact, let alone underly, our definition of time If you define time in terms of days and years, I.e in term of revolutions of the earth around the sun and itself, of course it’s wobbling and deceleration has an impact. If you think it shouldn’t then measure time differently, for example as seconds since a certain instant

mattnewton 4y ago
> If you think it shouldn’t then measure time differently, for example as seconds since a certain instant Isn’t that what the article is arguing we do? What practical benefit does keeping this historical definition of time give us? Outside of people trying to account for the rotation of the earth precisely who could even notice?
- Gigachad 4y ago
  Sounds like it would be massively simpler for the users who need to use time like this to deal with leap seconds rather than require that all software deal with it all the time
nullc 4y ago
It would take thousands of years for UTC-without-leaps to shift an just an hour. Our timezones are often wider than an hour. If you really need a 'solar-ish' time, you could also define a fixed function correction for UTC->'solar' and then extend that thousands of years by an order of magnitude. (Sadly the SI second is somewhat far off from the 1/86400th of a solar day, so a big portion of the correction caused by leapseconds is just this predictable portion of the difference). > If you think it shouldn’t then measure time differently, for example as seconds since a certain instant Plenty of stuff would love to do that, but we distribute UTC. To get back to "time from an instant" given UTC you have to know about and correctly and consistently handle leapseconds. It's quite tricky, because when an interface hands you UTC you don't know if the latest leapsecond has been processed in it. It's getting even harder recently because the widespready distributed systems failures caused by leapseconds are causing some people to deploy varrious kinds of "leap smear" which smears out leapseconds over some number of hours. Interfaces that are supposed to return UTC now sometimes return leapsmeared UTC with some unknowable choice of smearing scheme. Arguably the root issue is that we've based out computer timekeeping hierarchy on UTC instead of TAI (or GPS time or whatever non-leaping thing). Had we based everything on atomic time and handled 'UTC' as a presentation layer thing like timezones are normally handled things would work much better. Unfortunately that ship has really sailed. Fortunately, if leap seconds are just not issued essentially everything keeps working without issue for hundreds if not thousands of years.
- denton-scratch 4y ago
  > Our timezones are often wider than an hour. The handling of timezones and of leap-seconds are orthogonal problems, arising from distinct causes. Leap-seconds are a response to the desire to synchronise an atomic timescale with the uneven rotation of the Earth; timezones (and DST) are strictly a political problem. Politicians often don't understand the consequences of timezone changes; they often introduce them without giving enough time for people to update their timezone database - sometimes just a few days. The result is that the new timezone is nothing more than a political gesture, because hardly anyone is using it.

mattnewton 4y ago

> If you think it shouldn’t then measure time differently, for example as seconds since a certain instant Isn’t that what the article is arguing we do? What practical benefit does keeping this historical definition of time give us? Outside of people trying to account for the rotation of the earth precisely who could even notice?

Gigachad 4y ago
Sounds like it would be massively simpler for the users who need to use time like this to deal with leap seconds rather than require that all software deal with it all the time

nullc 4y ago

It would take thousands of years for UTC-without-leaps to shift an just an hour. Our timezones are often wider than an hour. If you really need a 'solar-ish' time, you could also define a fixed function correction for UTC->'solar' and then extend that thousands of years by an order of magnitude. (Sadly the SI second is somewhat far off from the 1/86400th of a solar day, so a big portion of the correction caused by leapseconds is just this predictable portion of the difference). > If you think it shouldn’t then measure time differently, for example as seconds since a certain instant Plenty of stuff would love to do that, but we distribute UTC. To get back to "time from an instant" given UTC you have to know about and correctly and consistently handle leapseconds. It's quite tricky, because when an interface hands you UTC you don't know if the latest leapsecond has been processed in it. It's getting even harder recently because the widespready distributed systems failures caused by leapseconds are causing some people to deploy varrious kinds of "leap smear" which smears out leapseconds over some number of hours. Interfaces that are supposed to return UTC now sometimes return leapsmeared UTC with some unknowable choice of smearing scheme. Arguably the root issue is that we've based out computer timekeeping hierarchy on UTC instead of TAI (or GPS time or whatever non-leaping thing). Had we based everything on atomic time and handled 'UTC' as a presentation layer thing like timezones are normally handled things would work much better. Unfortunately that ship has really sailed. Fortunately, if leap seconds are just not issued essentially everything keeps working without issue for hundreds if not thousands of years.

denton-scratch 4y ago
> Our timezones are often wider than an hour. The handling of timezones and of leap-seconds are orthogonal problems, arising from distinct causes. Leap-seconds are a response to the desire to synchronise an atomic timescale with the uneven rotation of the Earth; timezones (and DST) are strictly a political problem. Politicians often don't understand the consequences of timezone changes; they often introduce them without giving enough time for people to update their timezone database - sometimes just a few days. The result is that the new timezone is nothing more than a political gesture, because hardly anyone is using it.