4 ms·

Astronomers and navigators. These also were the first people that needed accurate time and first people capable of measuring time accurately, so much of the exp

by sjburt 5y ago

Astronomers and navigators. These also were the first people that needed accurate time and first people capable of measuring time accurately, so much of the expertise is in astronomical or naval institutions. This was still very relevant in the 1950s when the modern time systems were being developed. There is a growing movement in the timekeeping community that agrees that keeping UTC close to UT1 is no longer important and that leap seconds should be abandoned.

myself248 5y ago
I tend to agree. Let astronomers use a rotation-synchronized time. (Aren't they bothered by jumps anyway? They probably need a more gradual skew, which is to say, not SI seconds.) Let everyone else use TAI, and in a few millennia when high noon isn't noon anymore, we'll worry about it then. Oh by the way, unless you live smack in the middle of a timezone, solar noon isn't clock noon anyway. Plus it gets all jacked up with daylight savings (which should also be abandoned), so the whole notion of leap seconds is farcical on its face.
- MaxikCZ 5y ago
  This is the kind of half assed solution that could be called procrastination. Its obvious the only solution is to slow Earth rotation down so we have no need for leap seconds while maintaining high noon precision for millenia
  - dylan604 5y ago
    Or just change the orbit of the earth and moon. You'd solve the leap seconds problem && climate change!!!
  - bigiain 5y ago
    The article addresses that nicely in it's 4th sentence: " ... one day I would like to do the math on the “great leap second gyroscopes” that we could mount near the poles to steady the Earth’s rotation, so we can stop talking about this. We may occasionally have to desaturate these gyroscopes with huge rockets also." I have an alternative solution, which is that we stop earths rotation and get it tidally locked to the sun, so it's always 00:00:00.000 midnight at Greenwich UK. This'll screw up the ski resorts in New Zealand, but anyone who's spent a winter in Invercargill on the South Island there will agree that it'd be much much nicer as a tropical paradise.
- sjburt 5y ago
  Yeah, I think the real mistake was when everyone decided to use UTC instead of TAI. I can't actually hold the astronomers to blame for this. More likely it was telephone network engineers or someone at a stock exchange.
- benchaney 5y ago
  I don’t think this actually benefits navigators and astronomers. You just can’t predict local area noon based on clock time without additional data. Even when you have that data, it won’t be accurate to the second anyway. Even if you are at the exact center of the time zone, clock noon is only rarely at solar noon. See https://en.m.wikipedia.org/wiki/Equation_of_time https://en.m.wikipedia.org/wiki/Equation_of_time
  - sjburt 5y ago
    If you’re on a ship and want to get longitude, you don’t predict local noon. you measure local noon and compare it to a clock that was set to noon at a known longitude (such as Greenwich), and correct the offset using the equation of time.
    - benchaney 5y ago
      That doesn't actually work. You can't measure local noon accurately enough for it to give a useful longitude. My celestial navigation textbook estimates the accuracy of this method as 15' under the best possible circumstances, and 40' under more realistic circumstances. Even if you ignore this issue and assume you could somehow measure local noon exactly, you still would need almanac data in order to do the correction. Once you are involving almanac data, it stops mattering if local noon has any connection at all to 12:00 on your clock.
- bigiain 5y ago
  > Let everyone else use TAI, and in a few millennia when high noon isn't noon anymore, we'll worry about it then. Or when we exist as a society on the moon and Mars and in the asteroid belt - and the relevance of the rotational angle of earth will be no more interesting to almost everybody the same way local time in Greenwich UK doesn't matter to 23/24ths of the planet. (Hopefully that's well before the "few millennia" it'll take for TAI to be radically different to what we use UTC for these days, and "soon enough" that it's worth taking into account already.)

by sjburt 5y ago

myself248 5y ago

I tend to agree. Let astronomers use a rotation-synchronized time. (Aren't they bothered by jumps anyway? They probably need a more gradual skew, which is to say, not SI seconds.) Let everyone else use TAI, and in a few millennia when high noon isn't noon anymore, we'll worry about it then. Oh by the way, unless you live smack in the middle of a timezone, solar noon isn't clock noon anyway. Plus it gets all jacked up with daylight savings (which should also be abandoned), so the whole notion of leap seconds is farcical on its face.

MaxikCZ 5y ago
This is the kind of half assed solution that could be called procrastination. Its obvious the only solution is to slow Earth rotation down so we have no need for leap seconds while maintaining high noon precision for millenia
- dylan604 5y ago
  Or just change the orbit of the earth and moon. You'd solve the leap seconds problem && climate change!!!
- bigiain 5y ago
  The article addresses that nicely in it's 4th sentence: " ... one day I would like to do the math on the “great leap second gyroscopes” that we could mount near the poles to steady the Earth’s rotation, so we can stop talking about this. We may occasionally have to desaturate these gyroscopes with huge rockets also." I have an alternative solution, which is that we stop earths rotation and get it tidally locked to the sun, so it's always 00:00:00.000 midnight at Greenwich UK. This'll screw up the ski resorts in New Zealand, but anyone who's spent a winter in Invercargill on the South Island there will agree that it'd be much much nicer as a tropical paradise.
sjburt 5y ago
Yeah, I think the real mistake was when everyone decided to use UTC instead of TAI. I can't actually hold the astronomers to blame for this. More likely it was telephone network engineers or someone at a stock exchange.
benchaney 5y ago
I don’t think this actually benefits navigators and astronomers. You just can’t predict local area noon based on clock time without additional data. Even when you have that data, it won’t be accurate to the second anyway. Even if you are at the exact center of the time zone, clock noon is only rarely at solar noon. See https://en.m.wikipedia.org/wiki/Equation_of_time https://en.m.wikipedia.org/wiki/Equation_of_time
- sjburt 5y ago
  If you’re on a ship and want to get longitude, you don’t predict local noon. you measure local noon and compare it to a clock that was set to noon at a known longitude (such as Greenwich), and correct the offset using the equation of time.
  - benchaney 5y ago
    That doesn't actually work. You can't measure local noon accurately enough for it to give a useful longitude. My celestial navigation textbook estimates the accuracy of this method as 15' under the best possible circumstances, and 40' under more realistic circumstances. Even if you ignore this issue and assume you could somehow measure local noon exactly, you still would need almanac data in order to do the correction. Once you are involving almanac data, it stops mattering if local noon has any connection at all to 12:00 on your clock.
bigiain 5y ago
> Let everyone else use TAI, and in a few millennia when high noon isn't noon anymore, we'll worry about it then. Or when we exist as a society on the moon and Mars and in the asteroid belt - and the relevance of the rotational angle of earth will be no more interesting to almost everybody the same way local time in Greenwich UK doesn't matter to 23/24ths of the planet. (Hopefully that's well before the "few millennia" it'll take for TAI to be radically different to what we use UTC for these days, and "soon enough" that it's worth taking into account already.)