
Leap-second decision delayed by eight years - skreuzer
http://www.nature.com/news/leap-second-decision-delayed-by-eight-years-1.18855
======
akira2501
"Once the drift is appreciable, the argument goes, a correction could be added
much further down the line, perhaps by adding a leap minute or hour."

Well.. if the leap second is any lesson, that should go smoothly and be really
easy to implement.

~~~
blahedo
True, although for the same reasons that "fail fast" is sometimes better than
the alternatives, a "leap hour"\---being _much_ easier to perceive than a leap
second---may be easier to work with. At least then you'll know if someone's
off because they didn't leap, vs some sort of clock drift or other error.

~~~
greglindahl
Wait - for "fail fast" reasons, we're going to do something important every
few thousand years, instead of about once a year?!

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andrew-lucker
Why are these options mutually exclusive? Is there some technical limitation
here preventing us from having one monotonic clock and a separate orbital
clock?

~~~
Jach
From
[https://github.com/urbit/urbit/blob/master/include/vere/vere...](https://github.com/urbit/urbit/blob/master/include/vere/vere.h#L582)

    
    
        /*  Urbit time: 128 bits, leap-free.
        **
        **  High 64 bits: 0x8000.000c.cea3.5380 + Unix time at leap 25 (Jul 2012)
        **  Low 64 bits: 1/2^64 of a second.
        **
        **  Seconds per Gregorian 400-block: 12.622.780.800
        **  400-blocks from 0 to 0AD: 730.692.561
        **  Years from 0 to 0AD: 292.277.024.400
        **  Seconds from 0 to 0AD: 9.223.372.029.693.628.800
        **  Seconds between 0A and Unix epoch: 62.167.219.200
        **  Seconds before Unix epoch: 9.223.372.091.860.848.000
        **  The same, in C hex notation: 0x8000000cce9e0d80ULL
        **
        **  New leap seconds after July 2012 (leap second 25) are ignored.  The
        **  platform OS will not ignore them, of course, so they must be detected
        **  and counteracted.  Perhaps this phenomenon will soon find an endpoint.
        */

~~~
jepler
There is no "0AD", and if you don't have leap seconds then the number of
seconds per repeat of the Gregorian calendar is not fixed—just have a look at
the graph at
[http://www.ucolick.org/~sla/leapsecs/deltat.html](http://www.ucolick.org/~sla/leapsecs/deltat.html)

There may be at least 8 different answers to "how many seconds have elapsed
since 1972-01-01 until now" depending on legal jurisdictions:
[http://www.ucolick.org/~sla/leapsecs/epochtime.html](http://www.ucolick.org/~sla/leapsecs/epochtime.html)

[ed: added second link]

~~~
urbit
TLDR: if you define a bunch of complexity into your definition of time, you'll
have a very complex model of time.

Eg, if you define the Gregorian calendar as a function of the position of the
planets, rather than a function from atomic-clock seconds to a string, then
the Gregorian calendar is not fixed. I suppose Pope Gregory designed it as a
function of astronomy, so who are we to roll our own?

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brudgers
UTC does not bear an appreciably worse relationship to my local solar time
than GMT. For that matter, at the granularity of seconds my time zone is
pretty far off from solar time and 20 miles down the road is about as bad but
an hour earlier.

Clocks are useful for coordinating human events. The idea that they have some
deep relationship to the cosmos is a conceit as useless as the geocentric
solar system model.

~~~
c22
Except historically some humans have found it useful to coordinate certain
events to, say, recur at the same time of winter every year so suddenly a
deeper relationship to the cosmos becomes necessary.

~~~
brudgers
By "deep of winter" can I assume you were referring to July?

~~~
c22
No, winter was an arbitrary example. Humans need to track yearly events during
all seasons.

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zaroth
Complexity in this case can only be added, not subtracted. However I think
there is huge demand for the simplest yet most accurate shared monotonic
counter, and you want it to act as unsurprising as possible, and to be as
widely adopted as possible. UTC has pretty wide adoption as far as things go,
so they have that going for them.

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Veedrac
If we were to require but not have one leap second a year into perpetuity, it
would take 1000 years to drift 1/4h off from true time.

That's 1000 years of more regular, workable time. And I'd hope in 1000 years
people would have adjusted to the small offset.

Plus, one hour-big adjustment every 4000 years is certainly easier than 4000
second-long adjustments every year, if they really haven't gotten used to it
by then. Note that 4000 years ago we hadn't an alphabet - no doubt we'll be
thought of on equal footings.

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sova
as long as it is still monotonically increasing i don't really mind the
labeling... =D

