On 2014-11-05 15:30, Warner Losh wrote on the determination of TAI - UT1:
Now, back to the SI second vs the UT1 second. The UT1 second is 1E-8 or 1E-9 different from the SI second. Unless they are computing the results to 7 or more digits, the answers will be identical, no matter which definition of second you use.
I don't understand. Measuring (mean solar day)/(1 d) is equivalent to measuring d(TAI - UT1)/d(UT1); if you assume the first quantity is 1, then the second becomes 0. Looking at a recent Bulletin B, the uncertainty for measurements of the rate d(UT1)/d(TAI) is of the order 1₁₀-9 (the IERS give 13 digits!), and typical uncertainty for LOD is around 10 µs/d. The IERS certainly won't fudge on their units. Michael Deckers. _______________________________________________ LEAPSECS mailing list [email protected] https://pairlist6.pair.net/mailman/listinfo/leapsecs
