Sheesh! Next they’ll be telling me the speed of light is not constant to due to entropy.
The secular slowing of the earth and recession of the moon is a well established fact. Ancient eclipses documented in cuneiform tablets show that the ratio of the time of day and the lunar cycle have changed over the centuries. Edmund Halley attributed the change to an acceleration of the moon in its orbit. Today, we know from a century of observations that the moon is receding, and it’s orbital period therefore increasing, but the Earth’s rotation period is increasing even faster.
This “secular” deceleration is what caused the moon to become tidally locked to the earth: It always keeps the same face pointing towards earth. If the solar system lasts long enough (it won’t) eventually, the earth would be tidally locked to the moon, with a period of about 48 days: The lunar month, currently about 29.53 days would be about 48 of our current days long, and the day would be about 48 times its current length.
Today, the average length of a solar day is about 86400.002 seconds, because the adopted length of the second (defined by the cesium atom) can be traced to the mean length of day in 1825. (The length of second is traceable to Simon Newcombe’s theory of the sun, which was based on observations during the period 1700-1900.)
*In orbital mechanics “secular” terms are long term trends, as opposed to cyclical terms, like the period of an orbit. Secular meaning, particular to a certain time and place. In theology secular authority, as opposed to ecclesiastic authority, which is permanent and applies to all places and ages.