No, this is not a Dr. Who fanfiction, but I couldn’t resist the allure of what I like to think passes for a clever title for a post about a new change to international standard timekeeping. That’s right: instead of worrying about minor controversies over things like religion, politics, or the Great Pumpkin, what should really be getting your blood pressure up is the CGPM’s vote to abolish the leap second.
The General Conference on Weights and Measures, which, among other things, is responsible for managing the international system of units (read: the metric system) had a busy week, voting to add new prefixes to describe even larger and smaller numbers, and to abolish the leap second that keeps coordinated universal time (UTC) synchronized with the Earth’s rotation. While Nature’s piece on the subject, “The leap second’s time is up: world votes to stop pausing clocks,” lauds the decision, I have reservations.
First, some background, in case you don’t happen to work with leap seconds on a regular basis. Like our calendar adds leap days every four years to account for the fact that the Earth does not take precisely three hundred sixty five days to revolve around the sun, leap seconds have been implemented since 1972 to keep universal UTC aligned with the Earth’s rotation (UT1, a timing standard used by astronomers). Unlike leap days, leap seconds are implemented based on evidence – they do not come at a set time, but rather are added (or subtracted – there should have been a subtraction in 2020) when the difference between UTC and UT1 exceeded 0.9 seconds.
I do understand the temptation and the attraction of doing away with such an arbitrary adjustment. It makes calculations more complicated, adds complexity to programming, and can throw off data collection and analysis if not properly accounted for in pre or post processing. In some ways, I even agree with the decision – if we have a separate standard that synchronizes with the Earth’s rotation that we can use for purposes where that is relevant, why not also have an unadjusted standard that is entirely consistent and does not concern itself with anything but the steady, irrevocable progression of the official, standard definition of the second based on atomic decay?
My concern, though, is that divorcing the world’s standard time from physical reality risks making that time irrelevant. It might be easier in some respects, but what is the point of keeping time if it does not remain linked to practical methods of timekeeping? As long as we maintain a measure of the year, the day, the week, and other cyclical demarcations, we would be better served by ensuring that our standards of time are aligned, even if it does mean more work for us. Perhaps, eventually, we will just have a continuous count up from some arbitrary starting point, and that will be our standard time, but for now, that is not the case (besides, by then we’ll hopefully have relativistic travel capabilities, and that adds a whole new layer of complexity to timekeeping).
This was just supposed to be a quick, Saturday article post, but it got a little long. Hopefully, you found this interesting. Measurement standards might seem a long way from affecting your everyday life, but they are all around you, from navigation systems to credit card transactions. Knowing a little about who’s deciding them and why is more relevant than you might think.