⌚ Redefining Time

This has to be the wildest set of meeting minutes I’ve read lately:


They’re the minutes from the “27th meeting of the General Conference on Weights and Measures”, published by the International Bureau of Weights and Measures. Skip to page 19 for English.

Resolution 1 is a slow start. It notes “the increasingly multidisciplinary nature of measurement in new or disruptive technologies, and the new requirements for metrology in digital technologies, sensor networks, and big data,” and sets up some working groups. That’s metrology – the scientific study of measurement – not meteorology.

Resolution 2 considers that while everybody is chasing digital transformation, our existing SI unit system (basically the metric system) isn’t going to cut it for much longer. Specifically, “maintaining and building confidence in the accuracy and global comparability of measurements will require the creation of a full digital representation of the SI, including robust, unambiguous, and machine-actionable representations of measurement units, values and uncertainties”.

Resolution 3 says the data scientists have been busy generating bigger and smaller numbers, using orders of magnitude in excess of 1024. The ol’ kilo/mega/giga prefixes are comparatively tiny these dates. Unofficial new prefix names have taken hold, so we should probably make them official. Introducing: ronna/R (1027), ronto/r (10-27), quetta/Q (1030), and quecto/q (10-30).

Resolution 4 just casually starts to redefine time. Most countries run time based off UTC and a time zone offset. Every four years we throw in a bonus day to keep the calendar lined up with Earth’s orbit: a leap day. There’s a smaller effect that most people don’t know about though, and that’s the leap second. This exists because we currently have a rule that UTC must stay in agreement with another time system, known as UT1, which is based on the angular rotation of Earth. Whenever the Earth is approaching 0.9 seconds ahead, the UTC clock gets shoved forward by 1 second to catch up. This is enacted using a process defined by the International Telecommunication Union (what‽). It doesn’t happen on a regular schedule like every 4 years; it happens whenever the International Earth Rotation and Reference Systems Service says it needs to happen, which makes it a nightmare to plan for. It’s also really hard to do without crashing everything; few software packages expect to see 61 seconds in a minute. Google and Amazon achieve it in their cloud environments by “smearing” the extra second in over the course of a whole day. If that didn’t all sound hard enough already, here’s the real kicker: the Earth’s rotation is slowing down, and we might soon need to do our first ever negative leap second. What could possibly go wrong? The resolution is to buy ourselves time (boom-tish) by increasing the allowable variance, and to come up with a new model that will work for at least the next century. Whilst pragmatic, it’s a bit sad that computers are forcing us to disconnect our concepts of time and space.

Resolution 5 keeps up the pace on redefining time, by saying that our definition for a second isn’t good enough anymore either. In 1967, the second was defined as “the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom”. In 2018, they rearranged the math, but stuck with the underlying physics. Our measurement tools now far surpass the definition. The solution is: a competition! Competitors (countries) must bring their proposals to the next meeting (in 2026), so that a new definition can be adopted at the following meeting (in 2030). How many stakeholder alignment meetings do you think occur in the run-up to those‽

Resolution 6 is basically a recruitment drive for world domination, so that the metric system may provide global sanity. There were 48 member countries in 1999, and there are 64 now. The last time the US had a functioning government, their view was to provide no useful opinion, and leave metric adoption entirely to individual consumer choice.

Resolution 7 lays out the fees for countries to stay involved: €13m/yr.

What a fascinating document.

Header photo taken while we were camping somewhere along the Birdsville Track, in July 2021. The trees in the foreground are lit by our campfire.