Everything is Relative
Earlier this evening, a friend mentioned in passing that the international reference kilogram — known officially as the International Prototype of the Kilogram, or IPK — wasn’t stable. It has been reported to gain or lose mass, thus upsetting in small but notable ways the rather extensive house of cards for which it is the unremarkable but absolutely essential foundation.
I tucked that fact away to read up about later, because I was curious, and I hadn’t even known the IPK was a thing. Turns out it’s quite the rabbit hole once you start investigating.
The somewhat pedantic but important bottom line is that the IPK isn’t getting heavier or lighter in relation to itself (that we know of, anyway), but in relation to its copies. Since these are the objects which literally define what a kilogram is, the water gets murky fast: which one is actually changing, and why, and by how much? How do you continue to rely on it as an incontrovertible standard when it changes like that? How do you limit or streamline the ongoing comparisons and calculations necessary to ensure a relatively fixed value over time?
This brings us around to the decades-long struggle to determine a fixed value for the kilogram that doesn’t rely on a physical object (which is, as are all such objects, prone to being altered by its environment), and the push to instead have it be defined by a stable, calculable, universal constant that would — at least theoretically — allow anyone in the world to determine the precise value of the kilogram at any given moment.
The whole tangle is very interesting, and very convoluted; the Wikipedia article goes into a mind-numbing level of detail not only about the history and maintenance requirements of the IPK itself, but also about various alternatives for long-term, reliable definition that might free us from the need for a physical, fallible reference. It’s worth reading if you have the time (and attention span).
What I took away from it was twofold:
- It’s blatantly obvious that whichever individuals wrote or have updated the wiki entry for the kilogram really love their jobs. This is their passion and life’s work, and that laser-focused enthusiasm, attention to detail, and willingness to explain their field with admirably simple language fairly leaps off the screen, even if a lot of it goes straight over your head. That’s pretty cool. It made me smile.
- Everything is relative.
That second point made me think about how we rely in so many ways on things that we have no objective, 100% reliable method of calculating — let alone reproducing.
The kilogram is a great physical example: as explained in the section I linked above, any changes in its value affect a seemingly never-ending laundry list of dependent units (in order of appearance: the newton, pascal, joule, watt, ampere, coulomb, volt, tesla, weber, candela, lumen, lux … there are likely plenty more). The fact that there is uncertainty in this unit — by which so much of our physical understanding of the universe is measured — isn’t something I’d ever even thought about before.
I’m probably not alone in that, either. For many of us, the world is a space bounded and detailed by numbers and facts that we learn in school, and that’s about where it ends: we take it for granted that most of those fundamental nuggets of information are infallible, and we live our lives in the blithe assurance that we can rely on them forever.
But while it’s only come to my attention tonight that the humble kg’s constancy is something of a illusion, there are plenty of other concepts that I’ve always known were unstable and prone to being redefined on the fly — at least in part because they were never globally agreed upon by a bunch of people who cared as much about precision as the aforementioned, very impassioned metrologists (hey Ma, look at me, learning new words!).
Things like love. Or family. Or friendship. Essential components of a non-solitary (some might say ‘healthy’) life, and relative to a degree so radical that it makes the IPK quandary almost laughable. We operate on a strange and very broad continuum of certainty, where things like SI units are somewhere at the lower, more stable end, and abstractions involving interpersonal activity are way out in the fog of war.
Somehow, we manage to reconcile those extremes and get on with our lives, whether with rock-solid assurance, or the frank and painful knowledge that we are merely dreaming those ideas into life.
There’s no profound conclusion here, as is so often the case with my musings. Or at least none that comes to mind right now.
It’s just something to think about, to mull over in quiet moments, to take out from its double-nested bell jars and turn over in my hands. Curious. Realising anew, with a sense of shaky wonder, that I am part of a large and mysterious universe that I don’t fully comprehend and never will, no matter how much knowledge I accrue in my lifetime — and that I can continue to exist and to make progress despite the haze that will always, to some degree, cloud my understanding.
It’s a reminder that in many ways, we are what we are seen (or assumed, or calculated, erroneously or otherwise) to be. Yet we also simply are, in some obscurely objective sense, whether we can put numbers or words to it at all.
We are all striving, in various ways, to become. To become clear, to become more, to become known. And it is a messy and imprecise endeavour, regardless of whether we’re 90% platinum and 10% iridium, or flesh and bone — and whether or not everyone else agrees with what we’ve observed from within our own fragile, malleable minds.
Perspective. It’s a good thing.
