All right - I guess we can go another round or two while waiting - perhaps indefinitely - for reports of leap second related catastrophes to filter in.
First, an apology for posting my previous reply publicly. It escaped my notice that I was replying to a private message. On Jan 3, 2006, at 12:32 PM, Poul-Henning Kamp wrote:
If you already have to cope with DUT1 anyway, how much difference can it possibly make if the definition says |DUT1| < .9 or |DUT1| < 10sec or |DUT1| < 1 hour
The amplitude of the effect is 3600 times as great. The interval between each event much longer (though quadratic, not proportionate, of course). The larger amplitude implies a larger impact on human activities. The longer interval implies that future instrumentalities will be less prepared to deal with the impact.
If we can increase the tolerance to 10sec, IERS can give us the leapseconds with 20 years notice and only the minority of computers that survive longer than that would need to update the factory installed table of leapseconds.
No. Rather all computers that exist during such an event are obligated to deal with it. The number of deployed systems follows some increasing trend similar to Moore's law. By delaying the adjustments, you guarantee that more systems will be affected when they do occur. And, unless you can guarantee that a particular deployed system (and systems derived through various upgrade pathways) will be retired prior to the adopted horizon, prudent policy would require remediation in any event. Would like to see a proposed architecture a little more detailed than a "factory installed table".
As far as I know, less than 1% of people on this planet actually have the sun straight south at 12:00 local time today and a quite sizeable minority (a lot of China) lives perfectly happy with the sun being further than 15 degrees from south at local 12:00.
Once again confusing secular and periodic effects. Leap seconds are the result of a monotonic trend. Time zones and daylight saving repeat seasonally or represent geographic constants.
It follows from this, that a proposal for a 1hour tolerance on DUT1 is perfectly feasible without odd things happening to the cows milk etc.
Got me. Might it not be prudent to ask a farmer? We interviewed a guy last year who networks dairy cattle via instrumented capsules that monitor pH and communicate wirelessly from cow to cow back to the barn. Farmers are likely among the more technologically literate community for temporal data products. Why not benefit from their expertise?
I think the leap hours is a political tool to make the proposal go through without commiting anybody to anything for the next couple of hundred of years.
Of course. We differ on whether it is: A) ethical, or B) viable.
There are three orders of magnitude difference between a leap second and a leap hour, and consequently the need for leap hours will grow less rapidly than the need for leapseconds.
Bzzz! Nice try, but an incorrect answer. Thanks for playing our home game. I've appended Steve Allen's excellent plot of the long term behavior of length of day. LOD grows linearly over scales pertinent to this discussion (discounting wiggles due to interesting geophysics). This is due, of course, to angular momentum transfer from the Earth's rotation to the Moon's orbit. Mitigating factors include the rebound of the continents since the last ice age. Leap seconds accumulate as the integral under this curve (thus quadratically). The last hour's worth took 1200 years. (Hence the 600 year estimate for issuing the first leap hour to limit excursions to +/- 0.5 hours.) The hour before that, only four centuries. It does not matter whether these are binned as leap seconds or leap hours, they will arrive when they arrive. That being the case, one argues that bleeding off the accumulation in smaller, more frequent doses is a better choice. Rob Seaman National Optical Astronomy Observatory ---
ancient.pdf
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