[LEAPSECS] the big artillery

[Zefram]

Warner Losh wrote:
>                                       The conflicting definitions I've seen
>have been from one of the time scientists that helped to setup TAI when he was
>at NBS(later NIST) who strenuously instructed me that they weren't equivalent and
>was quite patient with my stupid questions about "why not".

Intriguing.  I'd really like to learn more about this.

>> Anyway, this isn't about the notation, it's about the concept.
>
>The concept I'd agree with you. But without a realization of the time scale, it
>doesn't actually exist.

My claim is that UTC(k)+DTAI (which I've been referring to as "TAI(k)")
*is* a realisation of TAI.  It's available in real time: as available
as UTC(k) is, in contexts where DTAI is readily available.  Its accuracy
and other qualities are traceable to k, and are by construction identical
to those qualities of UTC(k).

>                        I know that I'm being picky here about the difference
>between realizing TAI directly and deriving it from some realization of UTC.

I don't see what difference you're basing this distinction on.
The realisations of UTC and TAI seem equally direct.

>                  But if you zoom in far enough, you'll see there's a lot more
>chaos than that going on, and that TAI and UTC(k) aren't quite the same thing
>when you get to the nanosecond level or beyond.

Red herring.  Once again, you're bringing in the nanosecond-level
UTC(k)-UTC difference as if it's a difference between TAI and UTC.
I never claimed that canonical TAI was available in real time; I never
claimed an equivalence between UTC(k) and TAI.  The nanosecond-level
tracking error UTC(k)-UTC needs to be considered, if nanosecond precision
matters, regardless of whether you're using TAI or UTC at the seconds
level.

-zefram