72. The Compass I Wear Which Works Only At Night (And Why the Moon Matters When All Else is Lost)

(Epistemic status: earnest thoughts about a piece of functional jewelry I wear daily; contains both practical utility and more symbolism than is strictly warranted; heavy towards the end.)

 

Every morning I put on my necklace. On it are four Favors, my class ring, a tritium safety light (ice blue), and a small metal pendant that tells me where the moon is. That's not meant metaphorically. At any given time of night, I can look down at it to turn a rough sense of the phase of the moon and its position in the sky into a pretty accurate compass heading.

It's made by Wndsn, a company specializing in precision analog instruments - tools that work without batteries, without satellites, without any infrastructure at all past your eyes and brain. The pendant is a simple lookup table based on a trick you might already know: line up the points of the moon's crescent or draw a line tangent to its changing edge, and draw the great circle on the dome of the sky. Wherever it hits the ground, that's southwards - at least in the northern hemisphere where you probably live. I find it beautiful in the same elegant way that mathematical instrments are beautiful - form follows function, the design is purposeful and reasonably rugged, but where there is room for artistry and decoration, tasteful decoration there is. I didn't buy it because I needed to know where the moon is on any given night; I bought it - and had it passed to me in arguable contravention of whatever the tariff decrees are on any given day - because I wanted to be the kind of person who could pull compass directions seemingly out of thin air.

So what does it actually do? It's in keeping with elegant mathematical techniques and the rest of Wndsn's catalog: given any pair of three vital but often easily found pieces of information - phase of the moon, time of night (or more accurately the position of the moon in its arc across the sky), and the compass heading of the moon - you can look up the third one. But none of those pieces of information are things you really need in the modern world. You likely have a watch and a phone, and the phone has in itself GPS, accurate timekeeping, moon phase apps, maps, and the entire internet. The pendant is thus redundant - redundant in the way that a mechanical watch is redundant, or knowledge of how to start a fire without matches is redundant, or local data storage is redundant in the age of the cloud.

Until, of course, it abruptly isn't.

I'm certainly not a prepper in any traditional sense. I don't stockpile MREs, the idea of a bunker confuses and disgusts me, and if I have water storage and purification, it's for some thing out in the desert. But I think a lot about resilience and more mundane preparation - about how easy it is for complex systems to fail and what happens when they do; what happens when infrastructure breaks down and the things you always took for granted are suddenly no longer there.

And in this frame, I find digital systems supremely unimpressive. They are immensely powerful, sure, but they're extremely fragile, too. Your phone is a miracle of technology and delicate interlocking supply chains and it's also a very nice paperweight the moment the battery dies, or the network fails, or an ill-thought-out software update bricks it. GPS is the kind of thing that changes society - people have now come of age in a world where getting lost takes effort! - but what happens when the satellites go down or someone starts jamming the signals? The internet is the sum total of human knowledge, right up until the power grid fails or AWS is having a bad day.

The nice thing about analog tools is, they don't have this problem. A mechanical tool needs no batteries; a mathematical principle will never fall prey to a badly-written software update. If you know how fast sound travels, then you can tell how far away a thunderstorm is, and whether it's coming or going. And if you know how to read the stars, then you can still navigate even if a Kessler catastrophe comes for us; people certainly did so before the first satellite was ever dreamt of.

In some scenarios, this is even practical. Power outages, getting lost while hiking, infrastructural collapse, losing your phone, whatever. But there's a philosophical, almost mystical power to it, too. There's something hard to describe that fills me with deep satisfaction and security, knowing that I have knowledge and tools that no server downtime or electromagnetic pulse or corporate policy could ever take from me.

Analog tools don't have this problem. A mechanical tool doesn't need batteries. A mathematical principle doesn't need a satellite network. If you know how to read the stars, you can navigate even if every GPS satellite falls out of orbit. If you know where the moon should be, you have a clock that works as long as the moon still circles the Earth. In fact, the moon symbolizes this whole dynamic for me in so many different ways:

• It moves predictably across the sky. Just as you can tell how long it is until sunset by angular measure by way of fingers at arm's length - every finger is 15 minutes, and a fist is an hour - you can tell how long until sunrise from the phase and height of the moon. Full and right above you? It's about midnight and sunrise is maybe 6 hours away. Waning crescent and just rising? Sunrise is about to come.
• It changes predictably over the course of the year. A lunar month is almost exactly 29.5 days; new to full is thus a touch over two weeks. Tracking the phases of the moon gives finer-grained rhythm to my life than the slow inexorable changing of the seasons.
• You can skip the cool lookup table and use the trick I alluded to earlier - draw a line between the points of the moon's crescent, or tangent to its changing edge if gibbous. Draw the great circle that connects them - a straight line, locally - and follow it to the horizon. That's south, if you're in the northern hemisphere like me. (If it's new, you're on your own, and if it's full, then it rose due east.)
• If you're by the sea, the phase of the moon tells you how extreme the variation between low and high tide will be. Full or new means a spring tide, with high variation and surging changes. First or third quarter means a neap tide, with relatively less in the way of depth change.
• Knowing what time the moon sets and what phase it's in tells you when the sky will be truly dark - good for stargazing. Or sneaking around.

So what I love best about wearing this pendant is the fact that it's a constant reminder that I can know and infer things for myself. I don't need to ask my phone where the moon is; I don't need to blindly trust an app, a database, or a satellite network. I can just work it out for myself from first principles, observation, and a little bit of lore. "You don't need a weatherman", it has been sung, "to know which way the wind blows.". It's a trinket, a small thing, almost trivial, I know. But it's a tiny piece of a broader pattern I've tried to cultivate all my life - the development of capabilities that aren't dependent on vast fragile systems outside my control and beyond my sight. Learning to navigate without GPS; understanding basic astronomy; knowing how to cook well; knowing how to estimate distances and heights and directions from observation and measurements of my shockingly regular stride length (32 inches) rather than sophisticated measurement tools; learning to cast metal and shape wood; learning the basics of self-defense and fitness, especially how to fall well.

I don't, to be clear, think that civilization is about to collapse - though given the shape these days of the world and of the future and of the plague-ridden recent past these days, I'm not quite as sure about that as I once was. But I think there's a particular flavor of agency that comes from having skills and tools that work no matter what else is happening around you. When you know how to work things out from first principles and know how the vast systems around you work, you're less dependent on infrastructure, less vulnerable to those systems' failures, and more able to adapt on the fly to circumstances you didn't anticipate.

The moon pendant, then, is a tiny practical symbol of that - both in the abstract, and as a tool for practicing it. I no longer need to shrug and give up when I'm curious as to what direction I'm walking on any given quiet evening. I can just spend a few thoughtful moments working my way through the lookup table and end up with a strong sense - though I generally check my work by phone anyway. But it's important, I think, that I worked it all the way through myself first. Every time I look down and work out what direction the moon is in, I'm exercising a kind of thinking - observational, mathematical, independent - that will atrophy like any other muscle if unused. Call it cognitive participation, if you like. It's the kind of thing that's become all the more vital in a world of LLM magic on one hand and constant propaganda and lies on the other.

The subtitle of this post is maybe a little melodramatic: "when all else is lost", like I'm planning for some post-apocalyptic survival scenario, or a panicked flight after a lost battle. But the thing is, you don't need a full-on apocalypse for redundancy and preparedness and robustness to matter. All you need is to be out in the woods overnight with a dead phone. Or for power to be out for a week. Or for GPS to be unreliable or unavailable wherever you find yourself. More abstractly, there is a need to preserve knowledge and skills that may not seem all that useful in the modern day, alienated from the ground truths of existence, but that represent millennia of hard-won human understanding about the world. Everything came from somewhere and all knowledge and technology came from someone. We figured out the path of the moon and the schedules of the planets, even if those latter are hard to spot amidst the light pollution. We figured out how to make plants and animals more useful to us, even if these days we have grocery stores and catered offices. We pieced together timeless truths about arithmetic and geometry, even if these days it's easiest to pull out a calculator app or a speed square. And that knowledge is valuable and useful, even if you don't personally need it right now. In wearing this pendant, I wear a small piece of that knowledge, interwoven carefully and cleverly and put to use. Silently, it says: "The universe has patterns to it, those patterns can be understood and predicted, and you can work things out for yourself if you know where to look and how to think about it.".

I am well aware that in a real crisis it won't save me. If civilization hits its proverbial two missed meals, I'll generally have much more exciting problems than needing to know which direction the moon is. But it means I'm still practicing the mindset that might matter when smaller things go wrong, or might just barely make the difference when larger problems loom. And it means that I'm helping preserve, in my own small way, a type of knowledge that we shouldn't lose hold of just because we invented smartphones.

But frankly that's virtuous and all but it's not the heart of why I do it. I just find it deeply satisfying to be able to look up at the moon, down at the pendant, trace through some simple estimation, and amaze and confound whoever I'm with by pointing due north (within some reasonable bounds of error). That feeling of understanding, of being able to predict, navigate, and orient yourself, and effortlessly impressing and confusing others in the process - that's got value past mere utility. The moon is still there; the patterns are still there; the knowledge is still there; and I carry that all with me around my neck, right next to a tiny lantern. Just in case I need it, or even if I just want it. There's a magic to knowing that nothing is magical.

As a postscript, it's April 4th today, 3 days into the waning gibbous phase. The last full moon was April 1st, and the next one will be May 1st, with a blue moon on the 31st. Maybe you can keep that rhythm for yourself, and tonight as the moon rises, you'll have a better guess on where you're pointed.