On Wednesday, May 17, 2017 at 3:03:19 PM UTC+1, Chris L Peterson wrote:

.. Certainly we have instruments which measure the rotation of
the Earth via inertial properties to very high precision... and
clearly demonstrate that its rotation rate is less than one rotation
every 24 hours.

Such a strange illness you have insofar as it is the easiest thing imaginable to ask what you think the Equatorial speed of the Earth is for a 24901 mile circumference. The 24 hour system and Lat/Long system determine a rotational rate of 15 degrees per hour or a speed of 1037.5 miles per hour at the Equator and diminishing towards either poles yet you unfortunates can force yourselves to ignore not only the answer but the question.

The Equation of Time creates the average 24 hour day out of the variations in the natural noon cycle, this average is quite similar in nature to the word constant hence the conversion of an average rate of rotation at 15 degrees per hour to a constant rate of rotation at 15 degrees per hour. There is no external reference for this wonderful feature yet what keeps it all together is the day/night cycle correlating cause and effect.