
Why time may be running out for the leap second - edward
http://www.economist.com/blogs/economist-explains/2015/11/economist-explains-4?fsrc=scn/fb/wl/ee/st/whytimemayberunningoutfortheleapsecond
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kozak
So they want to switch to what would be to de facto a non-fixed prime meridian
(from time counting point of view) just because developers of time-critical
systems are too lazy to use TAI or GPS time for internal time calculations...

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phicoh
At least for me the problem is that leap seconds are unpredictable. How many
seconds are there until January 1st 2020? We don't know, nobody knows. You can
only know for sure in 2019. That's bad, that's really bad. Performing internal
calculations in TAI doesn't help if conversion between UTC and TAI is
undefined for dates more than a year in the future.

Another way to fix the issue would be to define predictable leap seconds, just
like leap years are predictable.

But I'd like to see them go. Nobody looks up to the sky and says "the sun is
getting later and later". Half of the year most countries are far from solar
time anyhow.

Do I care where the sun is relative to some arbitrary line in England? No.

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ars
I do like knowing when sunset is though. A second or two won't matter, but
after some decades all the formulas for calculating sunset time will be wrong.

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phicoh
During one lifetime, you will see (at the current rate) about 60 leap seconds.
Do you really notice if the sunset time is off by one minute?

Note that moving 30 km (or 20 miles) east or west also changes the sunset by
one minute.

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manicdee
To a photographer, a few seconds of error in sunset time is the difference
between an awesome sunset with oranges, reds and purples, versus an
uninspiring mass of grey clouds.

Of course a photographer would start well before sunset and continue well
after, but if you want to program a machine to photograph su sets you will end
up having to use techniques other than checking the time.

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wodenokoto
I don't really get what the proposed alternative is here. To just let the time
of day drift away from the time on the clock?

Then way not abolish leap years as well?

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hugh4
Just let it drift, yes, I assume.

Then maybe in a few thousand years when we're a full hour out we can think
about having a leap hour.

Abolishing leap years, on the other hand, would cause the calendar to shift
relative to the seasons by a notable amount during your lifetime.

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kqr
> Then maybe in a few thousand years when we're a full hour out we can think
> about having a leap hour.

If we even care, at that point. We might well have switched time keeping
systems several times by then, seen massive improvements in artificial
lighting and heating and such.

I think that's the general idea of "what's the point of leap seconds". By the
time they actually matter, we're not sure they matter anymore.

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HappyTypist
Perhaps we could adjust leap seconds once every 10 or 15 years. A 5 second
change is unlikely to be disruptive if there is a common, semirare schedule.

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ars
That would be worse since most likely every single machine will fail - if it's
not common no one will think to test or implement it.

And a many-second jump is harder for the computer to handle smoothly,
especially if it's a backward jump.

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kqr
It's not a backward jump – you just let the clock run a bit slower for a
minute, or an hour, or whatever. Smearing the second out works for 99% of
people/computers, and when it doesn't you probably have much bigger problems
keeping your clocks in sync anyway, so you should be able to handle a few leap
seconds too.

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upofadown
This seems like a natural progression to me. When the rotation of the earth
was the most accurate period available then it made sense to use that as a
reference. Now it is not and it doesn't.

I think that in the future people will just use UT for anything where people
have to coordinate activities. We can have a separate time scale for things we
want to coordinate relative to sunrise and sunset. This scale will be able to
be completely accurate based on location so we would abolish stupid stuff line
time zones and DST. The result will be much simpler.

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drallison
The very concept of a leap second is flawed. Given two times (say T1 and T2)
we need to be able to compute, accurately, the elapsed time. Time series data
becomes difficult to interpret accurately.

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nuxi7
We should abolish DST while we are at it.

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vacri
I like having more sun-filled evening time.

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throwaway7767
I think the idea is that we'd achieve the same effect by changing working
hours. There's nothing sacred about 9-5. If you're dealing with people in
different timezones, you need to know the offset of your timezones, and take
DST into account. If this were changed, you'd need to know the offset of your
timezones, and take local working hours into account.

The benefit is not having to upgrade all the numerous specialised systems that
may or may not be supported anymore every time a politician decides to change
the clock. Having to throw out or hack around timekeeping problems with
outdated-but-working embedded equipment carries costs.

(This discussion is of course completely tangential to the article)

