The Earth is generally expected to spin more slowly over time, due to tidal friction. But it has been spinning faster and faster since the 1960s. As shown in the figure in the wikipedia article [0].
I have read numerous explanations, but haven't found a really authoritative discussion.
I have read numerous explanations, but haven't found a really authoritative discussion.
[0] https://en.wikipedia.org/wiki/Leap_second#Rationale