[time-nuts] 15 Seconds error...??

Tom Van Baak tvb at LeapSecond.com
Wed Jan 18 19:22:14 EST 2012

> But there's the rub. Many people/organizations use "UTC," and it's enshrined in many legal systems. But, just like TAI, is 
> really only on paper as it isn't known until after the fact, when all the contributing clocks are compared and the data 
> massaged.

Typically when "UTC" is used in legal systems they are referring
to it as a timescale, an abstract system. They are not specifying
which cesium clock in which lab must be used for the timestamp
or how many nanoseconds it's off from some mean.

> Put another way, can someone say they know UTC any better
> than they know TAI?

No, in that context they just differ by 34 seconds (until July).

> US Code says "Coordinated Universal Time defined
> In this section, the term “Coordinated Universal Time” means the time scale maintained through the General Conference of Weights 
> and Measures and interpreted or modified for the United States by the Secretary of Commerce in coordination with the Secretary 
> of the Navy."
> You tell me, is that UTC, or UTC(USNO) or UTC(NIST), or something completely different?

That's a good one for the other list (LEAPSECS). A couple of
the posters delight in these questions. Or better yet read its
archives. There are literally hundreds of postings about these
sorts of legal issues.


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