[LEAPSECS] Consensus building?

[michael.deckers]

    On 2011-02-02 16:47, Stephen Colebourne wrote in part:


>   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 in "SI seconds" of a time interval during which
    UT1 increases by 1 d ("solar-day") is not a well-defined notion
    unless you state how you measure that interval. "SI second" is
    just the unit -- but a length in SI seconds depends on how you
    measure it (and this is not prescribed by the unit).

    You probably mean a comparison with TAI (a kind of average proper
    time on the geoid) or with TT.  Thus, a concise way to define this
    "length of a solar-day" uses the rate of the two time scales that
    are involved: d(TAI)/d(UT1) d (invoking the mean value theorem).

    Of course, your statement is totally correct as stated. I just
    think it might be misunderstood by non-astronomers like me.

    Michael Deckers.