[LEAPSECS] h2g2

[Nero Imhard]

Warner,

On 2010-09-03, at 20:04, M. Warner Losh wrote:


> : The difference doesn't matter, the fact that the difference is constant does.

> 

> I'm asking these question: Why does it matter so much?


Because UTC was defined this way. Staying close to UT was its very design goal and is its main defining property. That's the only point, in fact.

If people, countries, scientists, etc. choose between time scales, we have to assume the choice is deliberate, and, by necessity, based on the properties of these time scales. 


> What does

> keeping things in sync buy you that merely measuring the difference

> and knowing that number doesn't?


I don't know. I don't have to. It's irrelevant to the debate. It all depends on your requirements. These dictate your choice of time scale.

If governments (through whatever agencies) decide that civil time is better off referring to another time scale (one that's uniform and lacks leap seconds) I guess that would be entirely reasonable. Personally I think it would be a pity *but that is irrelevant*. If civil time is based on another time scale, and radio time signals stop disseminating UTC, I'll have to get it from elsewhere if I really need it. Bummer. I'll cope.

But the one thing I vehemently oppose is having to accommodate a change in an existing definition, and having to cope with the semantic confusion that will arise from it. I'll feel insulted and become frustrated, maybe even enraged, by such irresponsible behaviour from (what I had assumed was) some kind of standards body.


> Why must UTC be used as the method

> to synchronize "noon and the sun is approx overhead" when we have wide

> timezones that already do that function?  Does the cost of

> synchronizing to UTC exceed the benefits from synchronizing there and

> not at a different, easier to change level?


Maybe not. Again, it all depends on your requirements. In the "UTC debate" I guess it's up to the legislators, who need a notion of official time.


> Given the changes in how

> time is used, propagated, etc, in the last 20, 50 or 100 years, does

> it make sense to reevaluate things?


Yes. Of course. By all means, reevaluate and decide if UTC still meets your needs.


> Those are the questions I'm asking...


Now the one you're not asking, which is at the core of the ITU/UTC-issue as I see it (and I'm quoting myself here):

[is it] appropriate/ethical/allowed to change the definition of a widely used existing time scale in mid-flight rather than construct new or use existing time scales according to whatever requirements you may have (and others may not have)?

THAT is the question I keep asking.


> Oh, and with Daylight Savings Time, the difference isn't even constant

> anymore.


Well, DST has more to do with civil time than UTC. But indeed DST has its own costly problems. The burden of moving all clocks twice a year, made worse because every microwave and refrigerator comes with its own clock these days (none of which are self-setting of course), falls on the shoulders of the entire population, a significant part of which is becoming quite fed up with the practice. If the ITU wants to do something useful, they start lobbying against DST. And I'm quite serious here.


> And why does MEAN solar time matter more than ACTUAL solar

> time?  And what flavor of MEAN solar time is best?  What does solar

> time mean on mars, the moon, etc?


Irrelevant questions. The one central to the debate stays: why on earth redefine an existing time scale? (and I always feel like adding "are you out of your mind??")

I have the feeling that I'm repeating myself (like so many of the people here) and that we're going in circles. This is what I wrote to you almost exactly a year ago:

    Valid points are being raised about leap seconds being royal PITAs for the
    purposes of the ITU, and it is only reasonable that they want to get rid
    of them.

    But I'm quite disappointed that the question on the table continues to be
    "should UTC abandon leap seconds?", while the relevant question is "should
    the ITU stop using/broadcasting a time scale that is causing trouble?".

    I'm worried that this hasn't even been considered by WP7A.

    Decoupling UTC and UT isn't [even] wrong in a way related to ITU's actual problem
    (which makes the whole thing so disturbing); it's wrong in itself.

I honestly don't believe that over the last year, anyone has addressed this, let alone has begun to convince me that ITU's proposal isn't too silly to even discuss (were it not for the fact that they are actually pushing it).

shaking my head in disbelief and dismay...

Nero