[LEAPSECS] Vive la différence! (was Re: financial markets)

Rob Seaman seaman at noao.edu
Mon Apr 27 09:04:12 EDT 2015

On Apr 26, 2015, at 11:34 PM, Poul-Henning Kamp <phk at phk.freebsd.dk> wrote:

> In message <20150426160837.GA11909 at ucolick.org>, Steve Allen writes:
>> Both messages show the conceptual failure that results from
>> Recommendation 460, that is a complete lack of concern for the
>> distinction between UTC and GMT.

> What's going on here is that the biggest financial hub in the USA doesn't
> know the difference between UTC and GMT.

For many practical purposes there currently is no difference.

An ITU redefinition of UTC would create situation in which it is neither fish nor fowl.  For a period covering the last several decades, UTC would be closely interchangeable with GMT.  In the future there would be a significant and growing difference.

> That just shows that timekeeping is already far to complex for normal
> people and that simplification and fewer timescales is the way to go.

This may be the desire.  It will not be the reality.  The point of engineering requirements is that they describe the problem-space as it actually exists.  Solar time and Atomic Time are different things.  That difference will continue to emerge under all scenarios, but if UTC is redefined in the future there would be too few international standards to model the behavior.

The way to go is to have international standards that adequately describe reality.

Rob Seaman
National Optical Astronomy Observatory

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