[LEAPSECS] Consensus building?

[Stephen Colebourne]

Statements so far - disgree or add please (in particular something on
UT1/UT/etc as I will only get it wrong...):

General:
- the terms seconds, minutes, hours and days are overloaded, thus
pedantic and explicit terms are used here

SI
- the SI-second is a standardised unit of measurement
- the SI-second is currently defined as a fixed number of transitions
of a caesium atom
- the current definition of the SI-second was ratified in 1967
- 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

Solar
- a solar-day is a measured period of time
- the length of a solar day in in SI-seconds varies over time
- the length of a solar day in in SI-seconds is on average increasing with time
- a solar day is not a fixed number of SI-seconds
- a solar-hour is the period of 1/24th of a single measured solar-day
- a solar-minute is the period of 1/60th of a solar-hour and thus
1/1440th of a single measured solar-day
- a solar-second is the period of 1/60th of a solar-minute and thus
1/86400th of a single measured solar-day

Humanity
- a humanity-day is a non-scientific, commonly used term understood by
6bn humans
- a humanity-day is interpreted in line with the rising and setting of the Sun

TAI-2011
- the TAI-2011 time-scale is known as TAI in the year 2011
- the TAI-2011 time-scale is defined as a uniformly increasing count
of SI-seconds from a fixed epoch

UT-2011
???

UT1-2011
???

UTC-2011
- the UTC-2011 time-scale is known as UTC in the year 2011
- the UTC-2011 time-scale is a continuous count of SI-seconds
- the UTC-2011 time-scale defines UTC-2011-days
- a UTC-2011-day is either 86400 SI-seconds or 86401 SI-seconds long
- the additional SI-second in a UTC-2011-day is a leap-second
- the presence or absence of a leap-second is determined up to 6
months in advance


Lets see, how we go on these...

Stephen