NavList:

Starting in 1972 almost every year on December 31 just before midnight a leap second would be inserted into the calendar to keep UTC reasonably aligned with the position of the mean Sun (defined by UT1) --to keep it clock noon at mean noon, despite the small vagaries of the Earth's slightly weather-modified rotation. Leap seconds used to be fun. You could sit around and watch the entire sexagesimal system of counting come crashing down! That last minute of the year would have 61 seconds in it instead of 60. The Babylonians would have been appalled.

Thanks to some lucky convergences of the numbers in the past two decades, no leap seconds have been required for quite a long time, and all told there have been very few in the 21st century: one each in 2005, 2008, and 2012. After that the last two were on 30 June 2015 followed by the last "New Year's" leap second on 31 December 2016. That's seven long years ago. No leap seconds!

Read more and reminisce about the before time, those decades of leap seconds, in the Wikipedia article: https://en.wikipedia.org/wiki/Leap_second.

As I write this, it is only 45 minutes to the New Year by Univeral Time, that standard not so very different from the celestial navigator's obsolete old friend, GMT. Soon it will be 00:00:00 UT as the date rolls over to 1 January 2024. Happy New Year to you all! Best wishes in the year ahead!!!

Frank Reed
Clockwork Mapping / ReedNavigation.com
Conanicut Island USA