User:PeterBarnett30/sandbox

Wikipedia "Coordinated Universal Time" explains the need for a leap second by assuming the earth is slowing down 1 second every 19 months due to tidal friction. If we accepted the earth is slowing down 1 second every 19 months, can you imagine how fast it must have been rotating when it first formed 4 billion years ago? The maths is beyond me but I suspect it would spin so fast it would have flown apart.

A second is 1/(24*60*60) part of a solar day. The rotation of the earth is effected by every other body in the solar system. A measurement of the length of a solar day (using our atomic clocks) for 4000 years, would give a better average. (I am guessing that all planetary alignments repeat every 4000 years.) The second was redefined in 1967, primarily to enable very accurate time interval measurements. An unfortunate side effect has been to redefine the rotational period of the earth.

See "Earth's rotation" (Wikipedia) for a better estimate of rotational variation.