I just read a popular book on chemical elements, The Disappearing Spoon by Sam Kean. It was very entertaining, and seemed quite credible and clear, even if slightly fuzzy on the quantum mechanics. There was one claim that I took exception to, though:
The length of a day is slowly increasing because of the sloshing of ocean tides, which drag and slow earth’s rotation. To correct for this, metrologists slip in a “leap second” about every third year, usually when no one’s paying attention, at midnight on December 31.
Is there any time in the year when people are paying more attention to the time exact to a second than precisely at midnight on December 31? Does he think people would notice an extra second if it were interpolated at noon on July 7? I always assumed they did it at the one time of year when people would notice an extra second precisely because they want to be noticed. “Never fear, humble citizens. While you sleep, we are looking after your time.”