[LEAPSECS] LEAPSECS Digest, Vol 51, Issue 7

[Stephen Colebourne]

On 2 February 2011 15:33, Finkleman, Dave <dfinkleman at agi.com> wrote:

> I suggest that the terms second, minute, hour, day, and month stated

> without qualification have "normative" status:  the SI second, 60 SI

> seconds, 3600 SI seconds, 86,400 SI seconds, and Gregorian calendar

> numbers of days expressed as 86,400 seconds.


Funilly enough, I'll start by disagreeing with those definitions. The
meaning of the things named "second" and "day" being key, the best
that consensus will agree to is precise definitions, rather than any
"land grab" of key terms.

The terms SI-based-minute, SI-based-hour and SI-based-day will, I
suspect be acceptable to all. At the end of the process, the
defniition of the simple terms can then be considered.

Statements:
- an SI-based-minute is formed from exactly 60 SI-seconds
- an SI-based-hour is formed from exactly 60 SI-based-minutes and thus
exactly 3600 SI-seconds
- an SI-based-day is formed from exactly 24 SI-based-hours and thus
exactly 86400 SI-seconds


> Anything else requires qualification such as: mean solar seconds.

> Actually I can't think of other forms of hour, day, etc. that require

> qualification, since those are neither fundamental time intervals nor

> time scales.


Defining things that are *not*  fundamental time intervals nor time
scales is key to the problem.

I'll resend in the main thread an updated list so far.

Stephen