Unix Time and a Modest Proposal(johndcook.com)
johndcook.com
Unix Time and a Modest Proposal
https://www.johndcook.com/blog/2024/12/27/unix-time/
42 comments
I agree, moving the earth's axis with respect to the sun seems actually feasible compared to getting a standards body to agree on coordinated change.
They should just solve the problem in the traditional way that international disputes have been settled, and have the most heavily armed member of the committee kill everyone that disagrees with them.
The title refers to a 1729 Jonathan Swift essay, "A Modest Proposal for Preventing the Children of Poor People from Being a Burthen to Their Parents or Country, and for Making Them Beneficial to the Publick"[1].
As with the subject article, Swift's work begins reasonably enough, and contains much great discussion before veering off wildly at the end.
[1] https://en.wikipedia.org/wiki/A_Modest_Proposal
As with the subject article, Swift's work begins reasonably enough, and contains much great discussion before veering off wildly at the end.
[1] https://en.wikipedia.org/wiki/A_Modest_Proposal
The ratio is around 365.2422. Calling it 365 is too crude. Julius Caesar said we should call it 365 1/4, and that was good enough for a while.
This was known, to greater precision, a century before Julius Caesar:
https://csuitemind.com/quotes/i-have-composed-a-book-on-the-...
Not a big deal, if you have some time and real estate.
Assume that you know about noons and solstices, and can catch either by watching a shadow of a post.
During a summer solstice, position two posts along the line of the rays / shadow; the longer the better. Watch the sun hit the same line during a winter solstice. Along the way, notice when, relative to the exact solstice moment, is the noon. Sometimes you'll miss the exact solstice moment because the sun will be below horizon.
A dozen or two years of watching and recording should show you that the positions of the sun during solstices, and the time oof the exact solstice positions relative to the noon, roughly repeat every 4 years.
For bonus points, mark the positions of bright stars, like Sirius, Vega, Arcturus, etc, and notice how they repeat their patterns on solstice days / nights. They will repeat every 365 days approximately (like solstices, yearly), and every 1641 days exactly (4 years).
This all takes a large, flat, undisturbed surface to put posts on, to mark angles.
Not a lot of work, and could fit in one lifetime pretty well, given some prior ideas of watching the sky and measuring angles.
Of course, as you improve your instruments, you will notice how your neat approximations actually are imprecise, etc, and you'll have to invent a Gregorian calendar to spread the error more uniformly :)
Assume that you know about noons and solstices, and can catch either by watching a shadow of a post.
During a summer solstice, position two posts along the line of the rays / shadow; the longer the better. Watch the sun hit the same line during a winter solstice. Along the way, notice when, relative to the exact solstice moment, is the noon. Sometimes you'll miss the exact solstice moment because the sun will be below horizon.
A dozen or two years of watching and recording should show you that the positions of the sun during solstices, and the time oof the exact solstice positions relative to the noon, roughly repeat every 4 years.
For bonus points, mark the positions of bright stars, like Sirius, Vega, Arcturus, etc, and notice how they repeat their patterns on solstice days / nights. They will repeat every 365 days approximately (like solstices, yearly), and every 1641 days exactly (4 years).
This all takes a large, flat, undisturbed surface to put posts on, to mark angles.
Not a lot of work, and could fit in one lifetime pretty well, given some prior ideas of watching the sky and measuring angles.
Of course, as you improve your instruments, you will notice how your neat approximations actually are imprecise, etc, and you'll have to invent a Gregorian calendar to spread the error more uniformly :)
Averaging the observations over several years was the insight I was missing. Was trying to understand how to use contemporary timekeeping devices to that kind of resolution in a single cycle.
That's blowing your mind because the currently implicitly or mindlessly acknowledged understanding by the majority of people is that today is the peak of human's evolution. Majority thinks that they inherently and collectively know everything better in relation to what our ancestors knew, especially compared to those thousands of years ago. But how do you really know. Because they had no iPhones and cars? Development of technical tools, yeah there we _might_ well be on the peak, but that doesn't really cover all aspects of actually _understanding_ our earth and the universe.
Kids these days.
Keeping a calendar is fairly simple (requires knowing writing). Observing which day the solstice is on is also fairly simple (requires a sundial: the shortest/longest shadow at noon are the solstices. If you're in the tropics just observe when the sun passes directly overhead instead). Observing that the solstice moves by a day every 4 years isn't too hard by analyzing those observations.
The tricky part seems like it would be that one needs precision quite a bit better than one day. So either the measurement can be done over the course of many years or the time of the solstice needs to be determined to excellent precision.
It requires someone to at some point remember that "Hey when I was a kid 20 years ago the solstice was on December 22 but now it's on December 17, what happened?" and then go looking at historical records to generate a trend line with a slope of 0.25 days / year. The measurement doesn't have to be at one point.
Not to tut-tut too much, because it is interesting the extent to which a lot of science is older than any of us tend to think[1], but this isn't so hard. You need two measurements:
1. A count of days. Have your acyolytes put a rock in a jar every morning, whatever. Tedious, but easy.
2. A measurement of the sun's highest[2] angle each day. Harder, but not that hard. Put a stick in the ground and have the acolytes spend their lunch carefully moving a pebble to see how close the shadow gets to the base of the stick, then carefully paint the ground to show where the pebbles have been. Change the color each year. If it's cloudy, paint a line between the dots to interpolate.
Do this for four years. You'll note that the highest point of the fourth year is 4x365+1 days, give or take. Do it for a decade or two and you'll see that 365.25 isn't quite right either because you're still a little off.
It requires patience and rigor, but those aren't modern inventions.
[1] While a lot of it, including most of medicine, is much younger than we'd expect.
[2] Or lowest. But acolytes prefer to do their tedious stuff in the summer, lest they start engaging in idolatry and moon worship or whatever.
1. A count of days. Have your acyolytes put a rock in a jar every morning, whatever. Tedious, but easy.
2. A measurement of the sun's highest[2] angle each day. Harder, but not that hard. Put a stick in the ground and have the acolytes spend their lunch carefully moving a pebble to see how close the shadow gets to the base of the stick, then carefully paint the ground to show where the pebbles have been. Change the color each year. If it's cloudy, paint a line between the dots to interpolate.
Do this for four years. You'll note that the highest point of the fourth year is 4x365+1 days, give or take. Do it for a decade or two and you'll see that 365.25 isn't quite right either because you're still a little off.
It requires patience and rigor, but those aren't modern inventions.
[1] While a lot of it, including most of medicine, is much younger than we'd expect.
[2] Or lowest. But acolytes prefer to do their tedious stuff in the summer, lest they start engaging in idolatry and moon worship or whatever.
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They probably could measure summer solstices, and count the days between 4 of them, and they got 1461. They could've measured 1461 days -43 minutes, and be more precise, if they had wanted. Julius Caesar was as short-sighted as most software developers today, and he was only planning for like 40 years (that's already more than 7 hours off) but not much more.
Internet "influencers" really have us convinced that humans were barbaric apes until a century or two ago and then suddenly invented the modern world. What about all the achievements before then? Could we not have used math and science a few thousand years ago? Nope, it was all aliens of course.
It's only internet influencers if you grew up in the last few years and get most of your world information from them. I'm sure that's more than a roomful of people. Anthropologists have been doing it for well over a hundred years.
> were barbaric apes
(Looks at the news) Sadly, still pretty much are.
There’s a huge contrast between how much human intelligence had achieved scientifically and culturally, and how humanity (at large, on a global scale) behaves itself.
(Looks at the news) Sadly, still pretty much are.
There’s a huge contrast between how much human intelligence had achieved scientifically and culturally, and how humanity (at large, on a global scale) behaves itself.
This is an excellent idea! It would probably make the most sense to perform these adjustments on April 1.
Wish I'd known about Swift's 'A Modest Proposal' first - I came expecting practical Unix time insights, but found an attempt at satire in need of both editing and purpose.
We're putting together a class action suit. Register here, you may be entitled to compensation:
Leap seconds are about keeping 12pm synchronized with solar noon, not the length of the year?
This makes no sense:
> … or not add leap seconds and allow the year to drift with respect to the day.
This makes no sense:
> … or not add leap seconds and allow the year to drift with respect to the day.
if we mobilized a whole-of-society effort to build millions of rocket engines and fired them year round, it'd only take a few hundred years to get this done
There lies the rub. All it takes is a rumor that these rocket engines are secretly being used for <insert collective fear du jour> to kill support for the project.
If we’re changing unix time we should probably do something about the year 2038 problem. It’ll not be nearly as fun as new years in 2000.
Debian developers, glibc developers and many others have been working on this for the past few years. It's more or less solved for most free software applications.
https://lwn.net/Articles/938149/
https://lwn.net/Articles/938149/
Doesn't also count plenty of legacy servers out there that are on the MBA style of IT: Don't fix what's not broken and deny, delay, defend but for the IT department.
DOS, Win9x, and NT broadly speaking should be relatively fine though depending on how Y2K was fixed.
DOS, Win9x, and NT broadly speaking should be relatively fine though depending on how Y2K was fixed.
That’s been solved. Most modern implementations of Unix Time are 64 bit.
we could fix timezones too, by rearranging the continents (and the civilizations within them) into a narrow longitudinal strip
Solar sails? Dyson sphere? Do we need to run in the same direction in a coordinated fashion?
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If you have problem with Unix time you are probably using it wrong. It is monotonically rising timer that increments every second. That's it. It doesn't care about leap second, leap years or any of the orbits.
wrong. unix time is discontinuous around leap seconds.
If you think you have no problems with unix time, it's because you never noticed them.
TAI is what you want.
If you think you have no problems with unix time, it's because you never noticed them.
TAI is what you want.
> unix time is discontinuous around leap seconds.
Wrong. It's continuous, it's just not monotonically increasing.
Wrong. It's continuous, it's just not monotonically increasing.
Feel free to update the wikipedia article in line with your opinion https://en.wikipedia.org/wiki/Unix_time
Unfortunately, that isn't true.
https://www.wired.com/2012/07/leap-second-glitch-explained/ https://developers.google.com/time/smear
https://www.wired.com/2012/07/leap-second-glitch-explained/ https://developers.google.com/time/smear
This is like an xkcd comic as a blog post
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Unix time should never have been a number of seconds.
It should be a structured of the iso datetime fields, like in "struct tm", see https://cplusplus.com/reference/ctime/tm/
It should be a structured of the iso datetime fields, like in "struct tm", see https://cplusplus.com/reference/ctime/tm/
And for the other challenge, to stabilize the variation of the the sidereal year (i.e. the gravities of Jupiter &c. pulling the orbit slightly faster or slower), we simply schedule the launches at either the fore- (morning) or aft- (evening) ends.
To anyone sympathetic to my ideology, please consider using "fore", "aft", "port", and "starboard" to refer to the morning, evening, day, and night quadrants of the clock.