[LEAPSECS] Letters Blogatory

[Rob Seaman]

On Mar 11, 2015, at 11:04 AM, Tom Van Baak <tvb at LeapSecond.com> wrote:

> The entire purpose of UTC is to provide a single timescale for all human-related activity.

Well…  ;-)

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Intending to provide a single timescale is different from this being possible either across timezones, between mean time, local time, apparent time, sidereal time, for activities on Earth versus other planets, relativistically corrected, chrono-biologically calibrated, etc and so forth.

In particular, atomic timescales and solar timescales are simply two different things.

However, if you wish to eliminate leap seconds from some broad subset of timekeeping use cases, then call the resulting timescale something other than Coordinated Universal Time.  Universal Time, coordinated or not, has always denoted a solar time scale.  Debasing the meaning of Universal Time is unwarranted and unwise.

> I would not worry or argue what happens beyond 1,000 years or 10,000 years. Knowing what little I do about earth dynamics, and how science, technology, culture, and politics [d]evolves, it would be irresponsible for anyone in the year 2000 to dictate the details of atomic or civil time in the year 2500 or 3000.

Current usage is applied to both past and future timestamps.  It would be irresponsible NOT to plan these details.  Future lawyers might later arrange to change future standards, but current standards must be applicable for enduring purposes.  (Angering the lawyers who do show up here in the mean time is a poor strategy ;-)

If the goal of redefining UTC is to render TAI (and presumably GPS) obsolete (“one timescale to rule them all”), one might suggest there are other ways to go about it without intruding on the solar concept of Universal Time in the first place.

Rob

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