The following was written by Foone, posted to Twitter on 2022-09-21.
Someday aliens are going to land their saucers in a field somewhere in New Jersey and everything is going to go just fine right up until we try to explain our calendar to them "yeah we divide our year into a number of sub units called 'months' made up a number of days, and they're not all the same length" "I guess that's unavoidable, if your rotations-count per orbit is a prime number" "yeah, our's isn't prime" "but surely you have most of these 'months' the same length and just make the last one shorter or longer?"
"No... They're different lengths following no logical pattern"
"what" "and we further subdivide the months into 'weeks', which is 7 days." "ahh, so each month is an integer multiple of weeks?" "that would make sense, but no. Only one is, sometimes" "SOMETIMES?!" "yeah our orbit around the sun isn't an integer number of days, so we have to change the number of days to in a year from time to time" "oh yes, a similar thing happens on Epsilon Indi 7, where they have to add an extra day every 39 years to keep holidays on track" "yeah that's how ours work! Although the ratio doesn't work out cleanly, so we just do every 4 years, except every 100 years, except except every 400 years" "oh, you number your years? What's the epoch?" "uh, it's supposed to be the birth of a religious leader, but they got the math wrong so it's off by 4 years, if he existed at all." "if? You based your calendar off the birth date of someone you're not sure exists?" "yeah. He's written about in a famous book but historical records are spotty." "interesting. I didn't realize your planet was one of the ones with a single universal religion, that usually only happens in partial or complete hive minds." "uhh, we're not." "You're not?!" "yeah we have multiple religions." "oh but they all have a common ancestor, which agrees on the existence of that leader, right?" "uh, no. Two of the big ones do, but most of the others don't believe in him" "YOUR CALENDAR IS BASED ON A RELIGIOUS LEADER THAT NOT EVERYONE BELIEVES IN?" "well, on his birth. And yeah, we got it wrong by a couple years." "OK, fine. So, you have somewhat complicated rules about when you change the length of your years, and I'm scared to ask this, but... You definitely just add or subtract that extra day at the end, right?" ".... Nope." "At the start of the year? " "nah. The end of the second month"
"WHY WOULD IT BE THE SECOND MONTH?" "I'm not sure, really." "huh. So at this point I'm dreading asking this, but how do you measure time within each day?" "oh that's much simpler. Each day is divided into hours, each hour has minutes, and each minute has seconds." "ok. And 10 of each?" "10 hours? No. There's 24 hours, 60 minutes, 60 seconds" ".... I thought you said you used a base-10 counting system" "we do! Mostly. But our time system came from some long gone civilization that liked base-60 like 5000 years ago" "and you haven't changed it since?" "No." "huh. Okay, so why 24? That's not a divisor of 60" "oh because it's actually 12!" "what" "yeah each day is 24 hours but they are divided into two sets of 12." "and that's 5 12s, right, I see the logic here, almost. So like, after hour 12, it becomes the second half, which is 1?" "No, after 11." "oh, you zero-index them! So it's hours 0-11 in the first half, then 12-23 in the second half?" "No. 12 to 11 in the first half, and again in the second half" "please explain that before my brain melts out my mouth" "the first hour is 12. Then the next one is 1, then it goes back up to 11, then 12 again" "that is not how numbers work. And how do you tell first 12 apart from second 12?" "oh we don't use numbers for that!" "you don't number the two halves of your day?" "nah, we call them AM and PM" "WHAT DOES THAT MEAN" "I think it's ante-meridian and post-meridian? But I'm not sure, I dont know much Latin" "Latin?" "yeah it's an ancient language from an old empire which controlled a lot of the world and we still use some of their terms" "oh, and that was the civilization that liked base-60 and set up your time system?" "that would make sense, but... No, completely different one." "okay, and what do you do to if you want to measure very short times, shorter than a second?" "oh we use milliseconds and microseconds" "ahh, those are a 60th of a second and then 60th of the other?" "No. Thousandths." "so you switch to base-10 at last, but only for subdivisions of the second?" "yeah." "but at thousands, ie, ten tens tens" "yeah. Technically we have deciseconds and centiseconds, which are 1/10 of a second, and 1/100 of a second, but no one really uses them. We just use milli." "that seems more like a base-1000 system than a base-10 system." "it kinda is? We do a similar thing with measures of volume and distance and mass." "but you still call it base-10?" "yeah" "so let me see if I get this right: Your years are divided in 10 months, each of which is some variable number of days, the SECOND of which varies based on a complex formula... and each day is divided into two halves of 12 hours, of 60 minutes, 60 seconds, 1000 milliseconds?" "12 months, actually." "right, because of the ancient civilization that liked base-60, and 12 is a divisor of 60." "No, actually, that came from the civilization that used latin. Previously there were 10." "what" "yeah the Latin guys added two months part of the way through their rule, adding two more months. That's why some are named after the wrong numbers" "you just said two things I am having trouble understanding. 1. Your months are named, not numbered? 2. THE NAMES ARE WRONG?" "yep! Our 9th month is named after the number 7, and so on for 10, 11, and 12." "your 12th month is named... 10?" "yeah." "what are the other ones named after?!" "various things. Mainly Gods or rulers" "oh, from that same religion that your epoch is from?" "uh... No. Different one." "so you have an epoch based on one religion, but name your months based on a different one?" "yeah! Just wait until you hear about days of the week." "WHAT" "so yeah we group days into 7-day periods-" "which aren't an even divisor of your months lengths or year lengths?" "right. Don't interrupt" "sorry" "but we name the days of the week, rather than numbering them. Funny story with that, actually: there's disagreement about which day starts the week." "you have a period that repeats every 7 days and you don't agree when it starts?" "yeah, it's Monday or Sunday." "and those names come from..." "celestial bodies and gods! The sun and moon are Sunday and Monday, for example" "but... I looked at your planet's orbit parameters. Doesn't the sun come up every day?" "yeah." "oh, do you have one of those odd orbits where your natural satellite is closer or eclipsed every 7 days, like Quagnar 4?" "no, the sun and moon are the same then as every other day, we just had to name them something." "and the other days, those are named after gods?" "yep!" "from your largest religion, I imagine?" "nah. That one (and the second largest, actually) only has one god, and he doesn't really have a name." "huh. So what religion are they from? The Latin one again?" "nah, they only named one of the God-days" "only on... SO THE OTHER DAYS ARE FROM A DIFFERENT RELIGON ENTIRELY?" "Yep!" "the third or forth biggest, I assume?" "nah, it's one that... Kinda doesn't exist anymore? It mostly died out like 800 years ago, though there are some modern small revivals, of course" "so, let me get confirm I am understanding this correctly. Your days and hours and seconds and smaller are numbered, in a repeating pattern. But your years are numbered based on a religious epoch, despite it being only one religion amongst several." "correct so far" "and your months and days of the week are instead named, although some are named after numbers, and it's the wrong numbers" "exactly" "and the ones that aren't numbers or rulers or celestial objects are named after gods, right?" "yup!" "but the months and the days of the week are named after gods from different religons from the epoch religion, and indeed, each other?" "yeah! Except Saturday. That's the same religion as the month religion" "and the month/Saturday religion is also from the same culture who gave you the 12 months system, and the names for the two halves of the day, which are also named?" "right! Well, kinda." "please explain, slowly and carefully" "yeah so cultures before then had a 12 month system, because of the moon. But they had been using a 10 month system, before switching to 12 and giving them the modern names" "the... Moon? Your celestial body?" "yeah, it completes an orbit about every 27 days, so which is about 12 times a year, so it is only natural to divide the year into 12 periods, which eventually got called months" "ok, that makes sense. Wait, no. Your orbital period is approximately 365.25 days, right?" "yeah. That's why we do 365 or 366 based on the formula" "but that doesn't work. 365 divided by 27 is ~13.5, not 12" "yeah I'm not sure why 12 was so common then. Maybe it goes back to the base 60 people?" "okay so one final check before I file this report: Years are numbered based on a religious leader. Years always have 12 months, but the lengths of those months is not consistent between each other or between years." "don't forget the epoch we number our years from is wrong!" "right, yes. And your months are named, some after a different religion, and some after numbers, but not the number the month is in the year." "right. And when we change the month lengths, it's the second one we change" "how could I forget? After months you have a repeating 'week' of 7 days, which is named after gods from two religons, one of which is the month-naming one, and a nearly extinct one. And you don't agree when the week starts." "nope! My money is on Monday." "that's the Monday that's named after your moon, which supposedly influenced the commonality of the 12 months in a year cycle, despite it orbiting 13 times in a year?" "correct!" "and as for your days, they split into two halves, named after a phrase you don't really understand in the long dead language of the same culture that named the months and Saturday." "Yep. I took some in college but all I remember is like, 'boy', 'girl', 'stinky', 'cocksucker'" "charming. And then each half is divided into 12 hours, but you start at 12, then go to 1, and up to 11" "all I can say is that it makes more sense on analog clocks." "i don't know what that is and at this point I would prefer you not elaborate. So each of those hours is divided into 60 minutes and then 60 seconds, and this comes from an ancient civilization, but not the one that gave you the month names" "yep. Different guys. Different part of the world." "ok. And then after seconds, you switch to a 'base-10' system, but you only really use multiples of a thousand? Milliseconds and microseconds?" "right. And there's smaller ones beyond that, but they all use thousands" "right. Got it. All written down here. Now if you'll excuse me, I just gotta go make sure I didn't leave my interociter on, I'll be right back."
The tall alien walks back into their saucer without a wave. The landing ramp closes. The ship gently lifts off as gangly landing legs retract. There's a beat, then a sudden whooshing sound as air rushes back into the space that previously held the craft, now suddenly vacuum. NORAD alarms go off briefly as an object is detected leaving the earth's atmosphere at a significant fraction of the speed of light. In the years to come, many technological advances are made from what was left behind, a small tablet shaped object made of some kind of artifical stone/neutrino composite material. The alien message left on screen is eventually translated to read "Untitled Document 1 has not been saved, are you sure you wish to quit? (yes) (no) (cancel)" Many years have passed, and we await the day the aliens return.
They have not. With our new advancements, we build space-radar systems and can see the many species flying around the galaxy. It's not long before we realize they're intentionally giving earth a wide berth. Drone ships criss-cross the galaxy, but when they get within a lightyear of earth they detour around it. We finally get a subspace radio working, and start working to decode the noisy traffic of a thousand civilizations talking to each other. We broadcast a message of greetings and peace Less than a week later, the subspace net goes quiet. Our space radar reports the solar system is now surrounded by small vessels, suspected to be some kind of automated probe, and they're blocking all radio traffic in or out.
Even the pulsars go quiet, all radio waves are gone. We focus on cracking the secret of FTL travel. The first prototype never makes it off the ground, as before the rocket can even ignite, it's crushed by a small meteor Forensic reconstruction suggests it was a sundial, carved from rock dug out of the far side of the moon.