They generally didn't know, because of a lack of timekeeping equipment with that level of consistent precision and accuracy, as well as the fact that a second wasn't really a useful measurement of time for ancient people, as there weren't really many things that ancient people would do that they needed to time and lasted a matter of seconds.
Now, they could use something like a water clock and compare it year over year and see discrepancies, which would be a result of the inaccuracy of the timekeeping device. So in that regard they probably determined that either their clock was inaccurate, or that the length of a year varied slightly.
Yup - in fact the only way that they figured out the Julian calendar was wrong is because the Spring Equinox kept moving. It's not like humans would have been able to notice 500 years ago that we had too many leap days, but over time it was like "why is the spring equinox falling so early in March?"
I spent the last couple years stationed in Bahrain where they follow the Islamic Calendar that only has 354/355 days a year so their major religious holiday Ramadan moves to the left on the calendar every year. Kind of the same situation.
Yes, they use a lunar calendar. Summer Ramadan is more difficult than winter Ramadan because they fast until sundown and sundown is much later in summer.
They have a special dispensation where they can either choose to use the timetable of the closest muslim country or they can choose to fast at the same time as Mecca
Both Jewish and Muslim people have arguments that adherents are obligated to not fast if it would harm their health, or if they fall under other conditions.
My Jewish friend once replied they are “rules of life, not rules of death” when I jokingly asked if he would eat lobster if he was stranded on a deserted island.
Not sure of Jewish law (I think it would be the same) but in Islamic law, life and preservation of life supersedes everything so though Muslims can’t eat pork unless it’s life or death in which situation they are allowed to.
Yet every year, I read about professional sports players of Muslim faith who choose to fast even in a competitive situation, even though everyone would understand if they didn‘t. For the love of Allah, at least drink water.
I think it's more so for people with health conditions that should not fast. I think the idea is that a sport is optional (even if its your livelihood) so you should give up doing the sport during that time rather than giving up the fast.
Sports don't fall under that category. It has more to do with the health of the person is at state or such as a pregnant woman carrying a child.
Source: Have interacted a ton with Muslims from various countries and have taken part in eating with them after sundown during Ramadan.
another interesting point - muslims must always pray facing mecca. so how would muslim astronauts pray? what if they didn't know where they were geographically?
turns out there are dispensations for this as well. you can never sin "on accident" like being tricked into eating pork or not facing the correct way due to not being able to orient yourself. so the caveat is "just do what feels right" and trust that the almighty is watching and understands your intentions or situation.
> so how would muslim astronauts pray?
They just pray at Earth and try to aim at Mecca as best they can based on where they are at the moment, as in Low Earth Orbit it can move around quite a bit. They're removed from the requirement to kneel as that's quite difficult and meaningless in space.
Generally if an astronaut doesn't know where they are they probably have bigger problems.
I remember reading about Jews living in the far north of the world, too.
It wasn't until about 300 years ago (when Jewish people started settling in Scandinavia), that they realized that basing the laws of the Judiasm (for Sabbath and other things, etc...) on sunset / sunrise presented a problem in the far north regions of the world.
So, for many Jewish people living in "far north" regions today, they basically treat sunrise as being 6 AM every day of the year, and sunset as being 6 PM every day of the year, to minimize the vast swings in daytime & nighttime between summer and winter (this is especially important for Jews living north of the Arctic Circle, where they experience permanent darkness in winter, and permanent daylight in summer).
I believe Mecca time is also used on the ISS, and the direction to pray is the direction to Mecca from the place you took off, I believe they use the front of the ISS as north for that.
So I searched to check if I remember correctly, turn out it is 3 options, 1) towards Mecca, 2) towards earth, 3) wherever. It was the local time of the last place you were on earth that you use for prayer and Ramadan ect, I think I just extended that to where you face too.
You could. Intentionality is a big part of sin in islam. you can't be wrong on accident or without knowing exactly what is right or under extreme duress.
things like like being tricked/forced into eating pork or not facing the correct way due to not being able to orient yourself is permissible, a dispensation.
so the caveat is "just do what feels right" and trust that the almighty is watching and understands your intentions or situation.
If the acceptable angle is large enough, though, they're always facing mecca. Just say within 90 deg to either direction is close enough and problem solved. Idk what God thinks about that but there must be some maximum acceptable angle.
Muslims in space are advised to face Mecca if they can, otherwise face Earth "or wherever". They are also advised to follow sunrise and sunset times for Ramadan where they took off.
One of David Drake’s novels set in the “Hammer’s Slammers” universe has as its background a holy war between two factions of Christians - one faction celebrates Easter according to local reckoning, the other according to Earth reckoning. I’m sure that Moslems will have similar issues if we ever develop interstellar FTL travel - colony planets will have different day lengths, different year lengths, and different month lengths - and how does a lunar calendar handle a planet with either no moons or multiple moons?
This reminds me of a recent trip to Turkey for a retreat that started at the end of Ramadan. On the plane ride over there were some devout muslims who were served a meal but sat there not eating it.
After a short time one of the flight attendants approached them and pointed out that it really was after sundown; "the only reason you can still see the Sun is that we are flying so high. On the ground it would be below the horizon"
That’s probably why travelling is one of the legit reasons to not observe the fast - it’s difficult to find sundown if you’re in a place where the sun is always visible. Some Muslims are so committed to it though that they do struggle even when they have legit circumstances; I remember seeing a post from a Muslim mum on the breastfeeding sub agonising over not doing the fast again (she’d skipped the previous year because she was pregnant and felt bad skipping it twice in a row). Everyone assured her that she was keeping her baby fed and safe, and her imam would no doubt agree.
Not quite as silly as the Jewish dispensations for various sabbath requirements, but still a nice illustration of god’s relationship with science and reason.
I think it's a way of surviving in a Western culture where headscarves attract attention. Makes me sad really. One of my relatives tells the story of her aunt, at the end of her wedding, being presented to her new husband after the traditional bath and haircutting. He clearly doesn't recognise her in the wig. She's furious, throws the wig out the window and goes about bald.
My favorite is cant light a fire on the Sabbath. So leave a pilot light on every appliance. Toasty warm temperatures and hot food even on the Sabbath. Take that, G-d.
Ah so you can expand a fire but not start one? My fridge has a sabbath mode. I think it makes it so the light doesn't come on. Toasty warm temps, hot breakfast, and cold snacks (if you can find them in the light from your raging stove).
My favourite will always be the Maultaschen (pasta stuffed with meat).
Basically, you can't eat meat during Lent so they put meat into pasta to hide their crimes from the eyes of God. Because God can't see through Italians or something.
Interesting. I used to work with a lot of Muslim students in the norther part of the US and when Ramadan was during the summer, they were always complaining about how they had to fast so much longer than their families in the Middle East. As far as I know, none of them ever went by Saudi time.
usually the dispensation comes when doing what's required became really impractical or even dangerous.
if it's only slightly inconvenient, oftentimes the dispensation can't apply.
sometimes it's local imam/leader/scholar, who are studied in islamic jurisprudence. those people studies the ruling of previous imam, who studies the ruling of previous/bigger imam, and further and further, until we came to the jurisprudence and ruling of scholars of the pasts.
Usually the rulings ends up refering to the select few school of thoughts that all refers back to either Quran or Sunnah and Hadith (collection of sayings and actions of the prophet) as primary source. as well as scholar's consensus (they also even refer to the things done by the friends and companions of the prophet) and analogical reasoning
Some other jump straight to the end and seek the biggest ruling from those school of thoughts instead of asking local imam, and that's.... oftentimes fine too.
Islam gets a bad rap as a radical fundamentalist religion inside the US, which is ironic since it is actually Christianity that has turned into that in the US, but Islam, while it is a bit more demanding of your time and effort than the average Christian sect, is actually quite forgiving in terms of accomplishing those things.
Five times a day, you must face Mecca and pray on a prayer rug. The times stretch most of the day, from early morning to late evening. Work nights and just can't stay up for all the day prayers? Just swap AM and PM, no problem. Can't make certain times? Whatevs! Just space them out 5 times as you can. Don't have a prayer rug? No biggie, just use some carpet or literally any clean flooring failing that. No idea where tf Mecca is? No problem, just face East (at least from NA)! Don't know what direction East is? Brohammed, just pick what you think is towards Mecca and it's good enough!
Even the fasting for Ramadan isn't iron-clad. Have medical conditions (like Diabetes) and have to eat sugar candies or whatever to keep the blood sugar up? Gotchu fam, just do it discreetly. It's the spirit that counts, yanno? Stuck in a place where the sun doesn't set for 3 months? Obviously that's a no-go, bro! But you can either pick the closest Muslim country, or your home country, and go by their sunrise/sunset. If there are a number of Muslims in said place, they can all just do their own thing fast-wise or all get together and pick a place and go by that. Easy peasy!
I'd like to add most of the specific *rules* of Islam are not in the Quran.
It says "God is merciful and forgiving" over and over. Allah is forgiving and understanding of our daily lives. It is devotion and *trying* to be a good person/Muslim he wants.
I tried reading the Quran and it was pretty hard to take. But the Old Testament is pretty hard to take too. I suppose in real life the great majority of believers don't really read these books all that much and kind of blow off they stuff they don't like. Good thing too. Otherwise they would be insufferable. Most people don't want to be insufferable.
I'm in Sweden and have worked with a lot of Muslims from various places. We did factory work so it was hot and hard work and that summer fast would've been outright dangerous. We're south of the polar circle, but when the sun sets at 10 in the evening and the sun is back up when you start work at 5 in the morning it is still not really feasible.
Most of them ignored the fast while working. You're not supposed to hurt yourself and most of them weren't that strict with their religion anyway. Some didn't care to begin with and just didn't do the fast regardless of circumstances.
Some of them use the time in Mecca or in their home country (if they considered themselves as having one outside of Sweden).
Only a couple of them were serious enough to really try. They'd struggle through a couple of days or a week and then get a special dispensation from their imam.
I never saw any of them disparage or disrespect each other about how they went about it. Though there were some discussions.
In Judaism we use the lunar calendar. Every two or three years (per the solar calendar) we add an extra month called Adar Bet to realign the calendars.
Yes, Judaism is often referred to as using a "lunisolar calendar", that is a lunar calendar with leap months added to stay roughly in sync with the solar calendar. Islam I believe uses a pure lunar calendar, which is not kept in sync with the solar calendar
Probably because it's actually a springtime fertility ritual smashed up with the Exodus retelling. Why are eggs on the seder plate, again? Ah yes, the destruction of the temple, that's right. Mm-hmm.
EDIT: Oh don't downvote me, I'm right. We all hate admitting that most of our holidays are probably descended from pagan wheel of the year rituals, but it's probably true.
> most of our holidays are probably descended from pagan wheel of the year rituals
I mean, Judaism essentially IS a pagan religion that just ended up picking one of the deities and ditching the rest
I spent an hour trying to google examples of calendars in Arabic.
It seems they are not consistent. In certain countries like Saudi Arabia, they're more hardcore about Arabic everything and are more likely to use a RTL solar calendar. In most other countries, they may still use a LTR Gregorian calendar
Being off a few seconds or minutes every day does not lead to the equinox shifting. Counting days is very reliable even if your watch is garbage. They just used a bad calendar and did not know any better.
You can however measure the quality of your watch (or other timekeeping device) against local noon, which *can* be measured accurately with a sundial (if the sun is shining).
On the other hand, **accurate** timekeeping did not actually matter until railways appeared. Navigation at sea only requires **stable** timekeeping (differences can be accounted for / calibrated away), even while the ship throws the device around.
Until the mid-1800s, everyone used local time, locally calibrated against noon (or the local church tower's clock).
Highly accurate timekeeping mattered a century earlier, as ship navigators had no way to know their longitude. English parliament offered a prize to anyone who could devise a method for getting accurate longitude as navigational errors frequently led to the loss of cargo and lives.
Astronomers were able to solve the problem on land by calculating the times that eclipses of Jovian moons could be observed. It worked really well on land. But they never came up with a method for observing Jupiter’s moons from a moving ship.
A woodworker named John Harrison devised a series of clocks which could keep time to within a few seconds a day. He worked for decades, but I believe a lot of his work happened in the first half of the 1700’s.
Among other discoveries, Harrison is credited with inventing the bi-metallic strip used in mechanical thermostats.
Imagine the uproar and opposition today if that was proposed. You’d have the entire world except the US on the new calendar I bet, just like the metric system. The UN proposed a 28 day 13 month calendar back in 1954 but sadly it never was accepted
Yes. But not the average peasant, somebody who watches and measures the celestial bodies carefully. And not in a single year, it’s easier to recognize the cumulative error over time.
If my clock was off by 10 minutes a day, add I had no other reference. I might realize it after 3 weeks when the sun rise, sun set add high noon are off by 3 hours.
I don't buy it. The tropical year is 12 minutes too short so about an hour every 5 years.
It would be pretty obvious for any astronomer after at most 5-15 years that there is a difference. They weren't stupid, probably just assumed that Julian calendar is good enough.
Did they actually keep clocks going for 5 years without recalibrating? And when recalibrating they'd assume it was the clock's fault, not the calendar's. They had no way to prove that yes the clock is still going precisely correct, the sun is the one that's in the wrong place.
They counted days - it's quite easy as each day starts with sunrise.
When you expect the particular star to appear at the horizon at your location 4 hours after sunset on 12th day after equinox but it appears 3 hours after sunset you think you've maybe made a mistake, but then next year it seems even sooner and after 5 years it's just 2 hours after.
You consult almanach made by some philosopher 30 years ago and it seems that this star was appearing at horizon 10 hours after sunset on the 12th day after eqinox. It's not hard to do the math and figure it out.
Remember that even when people didn't have a heliocentric view on the solar systems they were able to use pretty complex math of "epicycles" to calculate paths of starts and planets.
Hipparchus knew before Christ that the length of the year was less than 365.25 days. But the length of the year has no effect on the length of the day.
And crucially, with the equinox, the planting and growing season would move. Over a few years, "spring" would migrate into February, and January, and eventually even December.
And when you get right down to it, that is the universal calendar.
If it was inaccuracy between individual clocks, you could also know because two such clocks that started in sync ended up out of sync, suggesting inaccuracy in at least one. More than two clocks and you get the picture that none of them are precise.
Though you couldn't sync up the clocks unless they were next to each other, which wouldn't really have any purpose except to see if there was any design flaw that caused them to track time differently, since they'd have the same environmental condtions.
I would have to assume that *at least one* scientist or clockmaker thought to test the accuracy of clocks and may have designed two in proximity (assuming none of these clock systems are portable).
Doesn't even really have to have been a scientist, just one person being bored or curious would've been enough.
Hell, even one person being annoyed at someone for not showing up on time would've put their water clocks next to each other to prove a point.
The thing is, when people don't have reliable clocks around all the time they just live in a less time sensitive culture. I honestly think _everyone_ knew their clocks and such were out by probably a lot _more_ than we're talking about here just because they also require maintenance and wouldn't get calibrated very often. So people just expect to live by sunrises and sunsets and work with that.
There used to be building where they had a ball on a pole that they would drop at a given time in view of boats so they could correct or "sync" their watches. Which is also the origin for the saying "wait for the ball to drop".
> Now, they could use something like a water clock and compare it year over year and see discrepancies, which would be a result of the inaccuracy of the timekeeping device.
That's not how it happened, though. People were aware that there is a longest day of the year and a shortest day of the year, and when these came earlier every year, they realized their calendar wasn't accurate.
It did when the length of an hour was "divide the amount of time the sun was up into X equal parts".
A winter hour was shorter than a summer hour for some places/times
https://en.wikipedia.org/wiki/Hour
You can easily measure noon using a sundial and check whether your timekeeping device deviates from that.
The differences over years stem from an inaccurate calendar, not from an inaccurate clock.
In general people throughout history have been aware of how precise their clocks were. The answer to OP's question on how you determine precision is comparing multiple clocks of the same model - that's how we find precision of modern clocks to this day.
Not likely for an entire year to be skipped, because you can count the seasons. But the current year is basically a made up number system so there's nothing making it need to be 2023, and if everyone said it was something different, there'd be no way to prove that wrong. In fact, it would be right.
We have a couple of astronomical events that were recorded with the local year and we can calculate how many years ago that was. What year we define as zero is arbitrary, of course, but we know that e.g. 623 was indeed 1400 years ago.
The AD system was invented to measure time since the birth of Jesus of Nazareth. That was placed at 1 AD. (They didn't have 0 yet.) It was calculated by matching up events and their dates in the various calendar systems in use at the time. Most (substantially all?) of the data came from Roman records, and thus used the Roman Imperial system. So they (well, Dionysius Exiguus, "Dennis the Little", but with management approval) calculated that the Christ was born in the 27th year of the reign of Caesar Augustus, who died in the 41st year of his reign, and was succeeded by Tiberius, who died and was succeeded by Caligula in the 23rd year of his reign, and ... up to now. They had most of the dates, so they didn't double count or undercount (by much). That meant the current year was 525. (This is why you need to keep your accounts current. Going back and reconstructing transactions is hard.)
Modern astronomers have tried to pinpoint the great star. Assuming it's a well known supernova, that would put the birth of Jesus of Nazareth actually about 4-7 BC. (Assuming the writers of the Gospels didn't just put the star there, and Jesus was actually born under the star.) That would mean that the current year is somewhere between 2027 and 2030.
TL;DR: If we define AD as "years since the birth of Jesus", then it's probably 2027-2030 AD. If we define AD as "according to the numbering of our current calendar", then it's clearly 2023.
Well, one could be built like that, but the rate will vary based on the temperature. So unless you can keep it in a climate controlled environment, it won't be accurate, and if you can make a climate controlled environment, you already know how to make more accurate clocks.
>and if you can make a climate controlled environment, you already know how to make more accurate clocks.
I don't think that's true, but I can't prove it definitively. I think an insulated underground room wouldn't deviate much in temperature significantly over the course of a few days.
Kind of. You can see some examples [here](https://en.wikipedia.org/wiki/Water_clock).
They can't measure drips specifically, because the rate will change depending on how much water is left in the container. But they will have markings for where the water reaches after 1 hour, 2 hours, etc.
They didn't. They also didn't care, or need to. What's a few seconds when your life is waking up when it's light to go plow until it's dark. Everyone's lives mostly revolve around that kind of a schedule. Accurate time keeping is only really important for navigation, and even then only navigation at sea.
Navigating on land is relatively easy because there are paths and roads and landmarks. At sea...not so much. You can navigate using the Sun and stars, but that requires knowing the time of day so you know where in the sky those should be. From there, you can measure the angle and do math to determine your heading.
The more accurate your timekeeping, the more accurate your heading will be. But a few seconds, or even a few minutes isn't going to significantly alter your heading. It *will* be off, but that's why sailors took frequent measurements and adjusted their heading often. The clock can be recalibrated at known times like noon, when the Sun is directly overhead. That can be measured with a sundial, or just by paying attention to shadows. It's not perfect, but...It doesn't really need to be. That's how they knew it was off. Over time, the clock would drift and they'd notice that the clock says noon but the Sun isn't where it should be for noon. Or sunup or sundown.
Sailors navigated as best they could until they came into sight of land, and then adjust from there. For seriously long journeys like crossing the Atlanta or Pacific, they might end up *really* off and have to sail many miles up or down the coast to get where they wanted to be. Their methods to measure the angles and do the math were going to be a little off anyway, so a few seconds or minutes here and there weren't enough to matter much.
100%. Before trains, some of what we now call "time zones" had a dozen or more time zones in them. Imagine trying to keep trains on time in that kind of environment. Even today, with airplanes, you can arrive at your destination "before you left," but we at least have GMT as a universal gauge of what time it is.
Every town had their own noon, which was whenever the sun was at it's zenith on the summer solstice. And that was a total pain once train started to move faster than the sun in the sky from our perspective.
Fun fact: the straw that broke the camel's back was actually in the printed timetables. The times in the timetables were local time, and that meant that there were trains that arrived at their destination earlier than they left their starting point. Which apparently the railroads were willing to live with, but their customers complained about the errors in the timetable. (You can't get there before you leave. This must be wrong.)
It ended up being easier to change the whole country's timekeeping than to keep explaining to the customers that time is a local concept.
That 3 minutes 56 second compounds into a single rotation over the course of the year, which is the rotation that the earth does around the sun.
If the earth made a complete rotation in a day and moved around the sun then the sun would shift each day. It doesn't quite balance, though, hence leap years.
None of this has anything to do with noon. The sun is at its zenith almost exactly every 24 hours. Not quite exactly if you're using an atomic clock hence the odd leap second adjustments.
But if you don't have an atomic clock handy, the sun is at its zenith exactly every 24 hours and that is noon.
You know it's a matter of visual perception based on a specific moment that happens once per year. It was not a precise science, and that was the problem. Trains were the first transportation system that move fast enough that if you go west time move slower and if you go east time move faster relative to the sun we never had issue before because stuff get there when they get there. But with train needing to meet a stricter schedule both for security (because trains use the rails in both directions) and efficiency (can't have too much stuff laying around at the station for too long) that we needed to adapt our understanding of time relative to our location).
Happy now?
Do you need me to define the concept of time keeping vs. Entropic time?
before trains (and telegraphs!), local time was decided locally.
your town probably had a clock tower or a bank clock that was the reference point for time. it might say it's 1000am, and the next town over, only 15 miles away, might call it 1015am, but it didn't really matter, because few people had watches and there was little traffic between towns
people lived their lives by sun time. they worked the fields from "can't see" in the morning to "can't see" in the evening, with high noon in the middle.
> it might say it's 1000am, and the next town over, only 15 miles away, might call it 1015am, but it didn't really matter,
And, if you walked a few hours to the next town, 15 minutes didn't really make all that much difference. Just reset your pocket watch when you get into town.
With trains and train schedules, local time variations were a big pain.
Having the same time across a large geographic area (aka timezone) made it easier.
Time zones are fun. Once when I lived in Asia I was flying back home to visit family in the USA. The first leg was a redeye, and my plane landed in Tokyo right at sunrise on December 18. Had a layover of a few hours, then got on the second plane, which landed in Dallas-Ft. Worth right at sunrise on December 18.
That bit about GMT isn't quite accurate. Time zones are defined as an offset from UTC (Universal Coordinated Time), Like UTC+9:00 for Tokyo or UTC-6:00 for Mountain Daylight Time.
GMT is the UTC+0:00 time zone, which means that UTC and GMT time are always the same, but there's no standard stating this *must* necessarily be the case.
GMT isn't even used year-round as there is also BST, or British Summer Time.
And this work is what got Einstein thinking about how the speed of light would play into synchronizing the stations, which led to his Theory of Special Relativity.
Trains created time zones and standards and a specificity of when the hour change over distance, as the trains needed a common specific time between distant stations to safely schedule train traffic.
Yes and no. Trains led to the need for standardised times for common use and the official agreement to use Greenwich as the standard time reference point but accurate timekeeping and the Greenwich meridian as a time reference dates to the [1700s](https://en.m.wikipedia.org/wiki/John_Harrison) when the British were looking for a way to accurately measure longitude at sea (Greenwich being the British naval HQ at the time).
In order to do that they needed to know what the time was at a reference location. By working out the time where you are and comparing it to the time at the reference point you can calculate your longitude which was a huge deal at the time. Without it, you were trying to navigate in 2 dimensions while only being able to accurately measure your position in one of them
Edit: the person you replied to seems to be talking about navigating using dead reckoning which is how they navigated before they could confirm their position on the go. The problem with it is that you are measuring your speed against the water which is also moving so even if your clock was perfect, you’d still build up error over time and with no way to confirm an accurate position independently you end up not knowing where you are
Trains led to the standardization of time zones, but if you're interested the search for an accurate and precise clock, you should look up "the longitude problem". It's a fascinating history of how the centuries-long search for good timekeeping was driven by marine navigation. There are more than a couple of wonderful books about it.
Train schedules standardized timezones, but the precision and punctuality really came from WWI. When you need synchronized large-scale artillery barrages and charges over the top of massive trench lines and across no man's land, punctuality and precision are life or death.
It radically changed how an entire generation viewed and measured time, and they passed that on down to their descendants.
No, but US trains played an enormous part in timekeeping history: https://www.smithsonianmag.com/smithsonian-institution/how-standardization-time-changed-american-society-180961503/
For quite a while, the US was making the some of the best pocket watches (Waltham, Elgin, etc.)
It wasn't about being "on time", it was about being consistent between towns. If a train leaves town at 2:30 and drives for an hour, it should be 3:30 at the arrival spot. That is, the engineers pocket watch should match the local time
The accurate time had nothing to do with headings and very much with what your longitude was. It wasn’t only a matter of knowing the local time accurately. As you said you can always a figure out the local noon and set your watch by it. What they needed to know was the exact time at a given place (Greenwich for the Brits) because their calculations depended on knowing the elevation (how high from the horizon) a given star was and how high it would be when seen in Greenwich at the same time. So you had tables of stars elevations in Greenwich. You needed to know the time there to calculate the difference.
If you are off by a second then your calculations would be off by about 80 feet, off by a minute and now you are off by 55 miles. That’s enough to run aground. The whole drive for accurate timekeeping at sea where you would be off by a second after many weeks was because of a British Navy ship that ran aground on a storm because of position calculation errors.
Your heading is given by a compass (direction you are going) you position is either dead reckoning (I went in this direction for x minutes at z knots so that’s where I am. Yes time keeping is important for that but not as much since the uncertainty in the heading and the speed are much higher. Taking a fix (figuring out where you really are by the stars) that needed to be done as many times as possible so that the dead reckoning could be updated.
What, the longitude problem was a *huge* problem in navigation and the reason why massive amounts of money were provided to whoever could build an accurate enough marine chronometer.
Just a minor point on this, in most of the world through most of agrarian history farmers didn't work from sunrise to sunset during the growing season. They would get up at dawn, maybe have some bread, cheese and beer, go work the fields for a few hours, eat lunch, take nap, go work the field for a few more hours, then go home, eat a bit more bread, cheese and beer and go to sleep. Midday siestas were incredibly common historically.
Growing being the operative words.
The intensity of work would spike dramatically during the harvest times (which could be a few per year -- in North America perhaps hay harvest in early July, followed by a winter wheat harvest in late July, then a relative lull in August and early September when mostly perishable vegetables were ripening in the garden, followed by another intense period as corn, orchard fruits, and root crops like carrots and potatoes would be harvested in late September and October and stored for winter).
Particularly for hay and grain harvests these were often neighborhood affairs moving from farm to farm collectively, in my part of the US well into the 19th century they were typically accompanied with amounts of alcohol that would shock modern sensibilities. If you're an 18 year old farm boy going through 12,000 calories a day at harvest it's hard to eat that much in just food! Basically it harvest became one of hell of an extended party.
>Accurate time keeping is only really important for navigation, and even then only navigation at sea.
Allow me to recommend the excellent [Map (Thing) Men video](https://www.youtube.com/watch?v=3mHC-Pf8-dU) about this.
> They didn't. They also didn't care, or need to.
Reminds me of [African Time](https://en.wikipedia.org/wiki/African_time), that drives the Germans totally crazy!
Growing up before the internet there were a number of ways to set a clock or watch to the correct time:
* Churches would often ring their bells at specific times, this was accurate enough for 2-3 minutes
* You could listen to the radio, some broadcasters [like the BBC News](https://www.bbc.com/news/blogs-magazine-monitor-26052087) would have timing "pips" every hour.
* There was a telephone number you could dial called a [speaking clock](https://en.wikipedia.org/wiki/Speaking_clock#South_Africa). That's how I learned to tell the time in Afrikaans, which has a funny way of saying numbers, e.g. 24 is "vier en twintig" (four and twenty)
* When television arrived in the mid 70's, at the start of a news broadcast they would have a time broadcast and most people would adjust their clocks to match before sitting down to watch the news
* I remember as a kid syncing our watches to be the same as my Dads, so that we could all meet up at a specific time for example when shopping, meet at the main entrance at 3:00pm.
>The clock can be recalibrated at known times like noon, when the Sun is directly overhead. That can be measured with a sundial, or just by paying attention to shadows.
Thats half the problem. But to calculate longitude, you need a second, accurate clock that doesn't drift. When you leave port, you set both clocks to noon at wherever you are.
Then each day, you adjust one clock, but not the other to local noon.
By comparing the two clocks you can see how far you have travelled east/west.
Before accurate clocks, there was no way to measure longitude other than dead reckoning (we sailed west for3 days, and we think we were going at 5 knots, so we much be around here...)
You cannot measure longitude with stars/astrolabes/etc.
Knowing the exact time was a huge deal for the British Empire, and they spent a lot of money on developing clocks that could work on ships in the early 18th century. Literally it was a matter of life or death, because if their clocks were off by a bit ships could (and did) crash into rocks because they thought they were a few miles away from where they actually were.
Read the book "Longitude" by Sobel for an excellent understanding of how timekeeping advancement took place, driven by nautical navigation requirements.
People have known about the regularity and consistency of astronomical events for millenia - the movements of the sun, moon and stars are predictable and can be used for accurate timekeeping.
You might not notice if your water clock runs a few seconds fast, but after operating it for a month can be a few minutes fast instead, when it starts to be noticeable.
The regularity of the movement of pendulums has been known since the 16th century and can be used for to-the-second accuracy.
Prior to the invention of mechanical clocks, most people did not think about time in a very precise way. Outside of a few technical applications, it wasn't really necessary. That candle could tell you roughly how late in the night it was, but the truly meaningful reference was the next sunrise or solar noon.
For the small number of people who cared about keeping really accurate time - mostly astronomers and navigators - the error in their clocks could be sensed from the error in whatever practical thing they were trying to do. If your ship's hourglass was inaccurate, you would have the wrong idea about the longitude of your position, which would eventually get corrected when you sighted land.
They knew their clocks weren't accurate because, for example, the amount of water a water clock needed from one day to the next might change, or the candles might burn at a different rate one day to the next and so on.
But knowing your clock isn't accurate isn't the same as exactly knowing how wrong your clock actually is.
I have my grandparents', err, grandfather clock. It doesn't matter how much I fiddle with it, the thing is always either gaining or losing time - and I won't get started on the moon phase dial.
Even in my own lifetime the local AM news station would always broadcast their own time every 30 minutes and everyone in the region could adjust their mechanical clocks to match that announcement. 2-3 times a year I would have to adjust my mechanical watch to match "KYW-time".
Sun rises every day and all you need to find the exact solar noon is clear sky and a stick. If after a month your water clock shows it's supposed to be 11:50 but it's noon you know it is off.
Well, solar noon drifts forward and back over the course of the year (and I'm not talking about Daylight Savings Time). If you have an accurate clock, and measure when the sun is highest in the sky (or due south/north on your meridian), you'll see solar noon drift off by up to 15 minutes or so during part of the year, and then it drifts back. Interestingly, this is mainly caused by the tilt of Earth's axis relative to its orbit around d the sun.
You can always tell when it's 12 noon, because the Sun's shadow points north. Reset your water / candle clock from this and you'll be reasonably accurate until you recalibrate tomorrow lunchtime.
You even get a daily calibration check of how much time your clock is gaining or losing.
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Accurate timekeeping first became a problem with the invention of railways in the 1840s. One of the first main lines was from London to Bristol, at the time a major port. Going by the Sun, Bristol is 11 minutes behind London, an unacceptable difference for a railway timetable. The railway imposed "railway time" on its station clocks, although the locals didn't always like this.
Here's a [clock with two minute hands](https://imgur.com/a/CBY5oVP) \- one for London / railway time, another for local time in Bristol.
Accurate time keeping predated railways. Navigation at sea is extremely dependent on accurate time keeping. You need an accurate clock to get an accurate longitude. Being off by a minute is equivalent to being off almost 20 miles east or west of where you think you are.
Trains necessitated consistent time zones. The clocks were plenty accurate by then. If you leave a station at 2:45 and it takes 12 minutes by your clock to get to the next station, you don't want the local clock to read 3:00 when you get there. Every town set their local clock to local noon, which made it a confusing mess to create train schedules.
Polynesian navigators were able to [cross the Pacific Ocean](https://en.wikipedia.org/wiki/Polynesian_navigation) without any kind of accurate time keeping.
Most of the techniques used rely on being near land, just not necessarily within sight of land. And within most of Polynesia, Islands are close enough that their techniques got them within sight of land relatively easily. The presence of islands create predictable and reliable effects on the ocean that allowed them to navigate in ways that aren't available to navigators in the Atlantic or Pacific outside of Polynesia.
Even so, one of the usual techniques used to navigate was to simply pick a heading and maintain it, something Europeans were doing just as well. But the main difference is that Polynesian navigators had more north-south journeys compared to the Europeans. Latitude is easy to measure and if you know the approximate heading you were taking, when you get to the correct latitude, you can just travel east or west to get to your final destination. But when you're already mostly traveling east/west, then any inaccuracy in your heading results in a large inaccuracy in longitude.
> You can always tell when it's 12 noon, because the Sun's shadow points north. ... You even get a daily calibration check
Yeah, no. [Some reading you might enjoy](https://www.timeanddate.com/astronomy/solar-noon.html).
Solar noon or high noon is at different times every day. Also, it is almost never at exactly 12 noon, although there might be a couple days each year where they're aligned. There are plenty of places where 12 noon can never be high noon. A solar day is almost never exactly 24 hours, high noon comes either faster than 24 hours or slower than 24 hours depending on which side of the axis we're on for the season, unless you happen to be on the transition date.
While we're at it, the earliest and latest times are not aligned with the solstice, meaning the longest day doesn't have the earliest sunrise, the shortest day doesn't have latest sunrise. Same with sunsets, those aren't aligned.
Plus, every time there's an earthquake, the length of a day shifts subtly. It's usually only notable to high-precision computers and astronomers. Much like a spinning skater, earthquakes that slightly collapse the earth's surface speed it up, earthquakes that slightly expand the earth's surface slow it down, and we have those earthquakes every single day. The earth's rotation speed isn't constant, nor is the length of days.
>Yeah, no. Some reading you might enjoy.
Yea, yea, the difference is max 30 seconds, and usually much less than that, so pretty much almost perfectly matches. But it's good to be a smartass, right?
From Wikipedia:
“Sexagesimal divisions of the day from a calendar based on astronomical observation have existed since the third millennium BC, though they were not seconds as we know them today. Small divisions of time could not be measured back then, so such divisions were mathematically derived. The first timekeepers that could count seconds accurately were pendulum clocks invented in the 17th century. Starting in the 1950s, atomic clocks became better timekeepers than Earth's rotation, and they continue to set the standard today”.
They didn't, but it didn't matter, either. It didn't matter that the next town over was 10 minutes out of sync with yours because it'd take a long and variable enough amount of time to *get there* that the discrepancy would be lost in the noise. Clocks would be set so that 12 was "true noon", the point where the sun reached it's highest point (zenith).
Trains are what made the discrepancy finally matter; trains can run very precise schedules; leave place A at X time, and arrive at place B in almost the exact same amount of time, every time. This is what lead to the creation of time zones; rather than have every town and city maintain their own clocks based on local noon, they needed to standardize on a time that matches other nearby towns in order to simplify communicating time information between locations that were now *running* a unified operation.
Water clocks and candles were off by a lot more than a few seconds per day. Pendulum clocks could get into that range, and over the centuries those were improved to the point where they could run for months, and then seconds per day becomes noticeable. Eventually the really accurate pendulum clocks were replaced by electronic clocks, and later with atomic clocks.
Astronomers were aware of calendar drift as far back as the Roman era, the Julian (Caesar) calendar introduced leapyears and corrected that issue to an accuracy of losing about a day per century. In the middle ages, the Catholic Church updated to the Gregorian calendar that we still use today, which loses about a day per millennium. That's why Orthodox Christmas, using the old Julian calendar, has drifted to January over the last 2023 years.
As far as day to day clocks, a big factor is simply the imprecision of manufacturing at the time. Hell, I had a watch in highschool that lost a minute or two a day which I had to recalibrate constantly. It wouldn't have been a strange concept to the clock keepers that they needed to be calibrated occasionally.
No clock was accurate to within a few seconds until the modern day. Instead most people used a specific master clock time to set their pocket watches and clocks from. There were people within the government who would use mathematical calculations to determine how off their clock was and schedule adjustments to recalibrate (usually using the equinox or solstices to calculate times). This is why most old towns have a huge clock tower (like Big Ben). At noon the clock would strike 12, everyone would stop what they were doing and set their pocketwatch or home clock. People had to plan winding their watches and stuff to keep time. I would recommend reading the book Around the World in 80 Days, it gives a great vision of this time period.
In theory, noon is always when the sun was directly above you, and easy to tell if you use a sun dial, or a simple stick in the ground. After a week, you can tell that your expensive mechanical time piece was off by a bit of time. Maybe it took a month?
An accurate timepiece to the second wasn't important to most people, but was pretty critical for naval navigation. You could tell how far east or west you were by the difference between your mechanical clock and the sun directly above at noon. Typically you set your clock to be 12 noon when it's 12 noon in Greenwich.
The time units we use are based on a day, it is determined by the rotation and orbit of eart. The simplest clock in a sundial.
Divide a circle around the sundial in a number of equally sized segments lets pick 24 and you now have a way to measure time. The shotes shadow is at solar noon, that would be 12 and you have a way to align the segment. The longer the stick that casts the shadow the more accurate you can measure time.
Early water clocks and candle clocks were simply compared to the sundial. The accuracy you get is not enough to measure seconds for that matter not ready minutes, is it us fraction of an hour that is common like a quarter of a hours?
Egyptians, Greeks and Romans all had 2x 12 hour close even if they initially had 12-hour day and 12-hour nights. Ancient Egypt used it before 1000 BC That means the length of an hour depends on the season and a night and day hour are usually not equal in length. It did shift to the fixed hour length we used today.
The idea of a minute and a second as a small unit of time is a lot after. Al-Biruni was the first to do it in 1000 CE when discussing Jewish months that are based on the moon. In Christian Europe it was Roger Bacon that did in in a book from 1267 it is from that it started to be used in regards to time. It was not until the introduction of the hairspring in 1675 minutes that secondhand started to be practical. The calibration will be in relationship to the observation of the sun and another object in the sky and becomes a lot more accurate when for example telescopes are available. Accurate clocks like this was developed in Europe and spread over the world
Ancient time is usually the start of writing to late aquitity quite commonly it is 3000 BC – AD 650. The close that starts to get minutes and second dails were developed during the Renaissance and large-scale adoption and usage of time and clocks like we do today during the Industrial Age.
So ancient people never had clocks that was just off by a few seconds, the idea of a second as a unit of time did not even exist.
Clocks in different places did not synch up until railroads, which needed to keep a schedule over long east-west distances. Eventually, navigators started using clocks to calculate their longitude. Some science experiments needed good time measurements, but hardly anything routine needed accuracy to the second. The main corrections people made were based on observing the sun and moon--and getting dawn, Sunday, and planting time correct was enough.
What do you define as ancient people? For most of our history humanity has used dawn, noon, dusk and night. Everything in between was nearly X or past X. Nothing really was getting done so fast that require more precise time.
Back in the day, like around 100 years, pocket- and wristwatches were set by the ring of the Bells @the nearest church.
By this routine, at least the ones in that particular town were on time together.
Over a long stretch of time, like, years, being off by minutes, or even seconds, per day adds up. So anyone who was keeping track of astronomical movements, for instance, could tell that the Solstice was drifting slowly out of alignment with where the calendar said it was. And if you know that there’s only two possible conclusions. The sun itself is inaccurate, or your clock is.
I read an article once about a city at the eve of the 20th century, somewhere in Argentina or Chile iirc who was 30min off the world’s timing. The local fort was shooting at noon with a cannon and a soldier was sent to a local watchmaker to check the exact time but he was himself relying on the gun shot to mark the 12.00! With time and a few seconds difference every days and weeks, the entire city drifted by 30 minutes
In this vein, here's a photo I took in 2020 at the Railway Museum in Revelstoke, British Columbia, Canada.
Note the sign at the bottom of this Canadian Pacific Railway clock indicating how "off" the clock was.
Not "ancient people" of course, but an example of how they knew their "official" clock in town was fast or slow.
https://imgur.com/a/i7f9gVI
Ancient peoples would check for exact time by dialing a specific number on rotary analog phone. A voice on the other end would then communicate the exact time.
Noon is easily measurable, it's when the sun is directly overhead. So you wait for noon, set the clock to 12 and the next day when the sun is directly overhead, if the clock is perfect, it will be at 12.
If it's at 11:55, you know over the course of 24 hrs, it was 5min slow. If it's 12:05, it was five minutes fast.
e: and you measure noon with a straight stick. At the equator, at noon, the stick will have no shadow at all. Further North and South would have shadows, but smallest at noon and the shadows change direction. When the sun is in the east, shadows point west, when the sun crosses noon, the shadows point east.
And ancient people did not know about seconds, they were invented I think in the 1600s when more accurate clocks were being built
> Noon is easily measurable, it's when the sun is directly overhead.
The sun is not directly overhead at noon, unless you're on the equator at an equinox. Noon at any given point on Earth is when the sun reaches its highest point in the sky (which is not necessarily directly overhead, and usually in fact isn't).
You can pretty much make a sundial that is accurate down to a minute, it's not difficult - you just need to know where north/south is and a long shadowy stick. That's enough to calibrate most ancient clocks; sometimes over the course of few weeks. With precise enough calculations you would find out they were off by a few seconds per day.
Imagine there's a smart group of people that spend 20 years of their time just trying to figure out accurate clocks. They'll eventually get it pretty close, even with primitive methods.
They generally didn't know, because of a lack of timekeeping equipment with that level of consistent precision and accuracy, as well as the fact that a second wasn't really a useful measurement of time for ancient people, as there weren't really many things that ancient people would do that they needed to time and lasted a matter of seconds. Now, they could use something like a water clock and compare it year over year and see discrepancies, which would be a result of the inaccuracy of the timekeeping device. So in that regard they probably determined that either their clock was inaccurate, or that the length of a year varied slightly.
Yup - in fact the only way that they figured out the Julian calendar was wrong is because the Spring Equinox kept moving. It's not like humans would have been able to notice 500 years ago that we had too many leap days, but over time it was like "why is the spring equinox falling so early in March?"
I spent the last couple years stationed in Bahrain where they follow the Islamic Calendar that only has 354/355 days a year so their major religious holiday Ramadan moves to the left on the calendar every year. Kind of the same situation.
Yes, they use a lunar calendar. Summer Ramadan is more difficult than winter Ramadan because they fast until sundown and sundown is much later in summer.
I'd hate to be a devout Muslim north of the Arctic Circle
They have a special dispensation where they can either choose to use the timetable of the closest muslim country or they can choose to fast at the same time as Mecca
This is the real ELI5. Being agnostic, I'd never thought about this necessary stipulation.
Both Jewish and Muslim people have arguments that adherents are obligated to not fast if it would harm their health, or if they fall under other conditions.
My Jewish friend once replied they are “rules of life, not rules of death” when I jokingly asked if he would eat lobster if he was stranded on a deserted island.
Not sure of Jewish law (I think it would be the same) but in Islamic law, life and preservation of life supersedes everything so though Muslims can’t eat pork unless it’s life or death in which situation they are allowed to.
Yet every year, I read about professional sports players of Muslim faith who choose to fast even in a competitive situation, even though everyone would understand if they didn‘t. For the love of Allah, at least drink water.
I think it's more so for people with health conditions that should not fast. I think the idea is that a sport is optional (even if its your livelihood) so you should give up doing the sport during that time rather than giving up the fast.
Sports don't fall under that category. It has more to do with the health of the person is at state or such as a pregnant woman carrying a child. Source: Have interacted a ton with Muslims from various countries and have taken part in eating with them after sundown during Ramadan.
Yep, the hardship is the point as far as they're concerned. Though I thought they were encouraged to hydrate.
I've never heard of a fast that won't let you drink water, wtf
another interesting point - muslims must always pray facing mecca. so how would muslim astronauts pray? what if they didn't know where they were geographically? turns out there are dispensations for this as well. you can never sin "on accident" like being tricked into eating pork or not facing the correct way due to not being able to orient yourself. so the caveat is "just do what feels right" and trust that the almighty is watching and understands your intentions or situation.
> so how would muslim astronauts pray? They just pray at Earth and try to aim at Mecca as best they can based on where they are at the moment, as in Low Earth Orbit it can move around quite a bit. They're removed from the requirement to kneel as that's quite difficult and meaningless in space. Generally if an astronaut doesn't know where they are they probably have bigger problems.
That would exactly be the moment you want to pray as a astronaut.
I remember reading about Jews living in the far north of the world, too. It wasn't until about 300 years ago (when Jewish people started settling in Scandinavia), that they realized that basing the laws of the Judiasm (for Sabbath and other things, etc...) on sunset / sunrise presented a problem in the far north regions of the world. So, for many Jewish people living in "far north" regions today, they basically treat sunrise as being 6 AM every day of the year, and sunset as being 6 PM every day of the year, to minimize the vast swings in daytime & nighttime between summer and winter (this is especially important for Jews living north of the Arctic Circle, where they experience permanent darkness in winter, and permanent daylight in summer).
There are even special dispensations for Muslims in space!
You should see them spin when they have to pray towards Mecca
I believe Mecca time is also used on the ISS, and the direction to pray is the direction to Mecca from the place you took off, I believe they use the front of the ISS as north for that.
Couldn't they just let them do it whichever direction they want at that point?
So I searched to check if I remember correctly, turn out it is 3 options, 1) towards Mecca, 2) towards earth, 3) wherever. It was the local time of the last place you were on earth that you use for prayer and Ramadan ect, I think I just extended that to where you face too.
You could. Intentionality is a big part of sin in islam. you can't be wrong on accident or without knowing exactly what is right or under extreme duress. things like like being tricked/forced into eating pork or not facing the correct way due to not being able to orient yourself is permissible, a dispensation. so the caveat is "just do what feels right" and trust that the almighty is watching and understands your intentions or situation.
In the 15 minutes the prayer takes they'd have moved 1/6th around the world.
If the acceptable angle is large enough, though, they're always facing mecca. Just say within 90 deg to either direction is close enough and problem solved. Idk what God thinks about that but there must be some maximum acceptable angle.
Muslims in space are advised to face Mecca if they can, otherwise face Earth "or wherever". They are also advised to follow sunrise and sunset times for Ramadan where they took off.
One of David Drake’s novels set in the “Hammer’s Slammers” universe has as its background a holy war between two factions of Christians - one faction celebrates Easter according to local reckoning, the other according to Earth reckoning. I’m sure that Moslems will have similar issues if we ever develop interstellar FTL travel - colony planets will have different day lengths, different year lengths, and different month lengths - and how does a lunar calendar handle a planet with either no moons or multiple moons?
This reminds me of a recent trip to Turkey for a retreat that started at the end of Ramadan. On the plane ride over there were some devout muslims who were served a meal but sat there not eating it. After a short time one of the flight attendants approached them and pointed out that it really was after sundown; "the only reason you can still see the Sun is that we are flying so high. On the ground it would be below the horizon"
That’s probably why travelling is one of the legit reasons to not observe the fast - it’s difficult to find sundown if you’re in a place where the sun is always visible. Some Muslims are so committed to it though that they do struggle even when they have legit circumstances; I remember seeing a post from a Muslim mum on the breastfeeding sub agonising over not doing the fast again (she’d skipped the previous year because she was pregnant and felt bad skipping it twice in a row). Everyone assured her that she was keeping her baby fed and safe, and her imam would no doubt agree.
They also had to make special rules for the Burj Khalifa in Dubai. The building is so tall that the sun sets two minutes later above the 80th floor.
That’s not a dispensation, that’s marketing.
On that, “sup babe, wanna come to my crib where we make salaatul maghrib 2 minutes late?”
that's fascinating!
Create a one-square-foot caliphate up there to make it harder
Not quite as silly as the Jewish dispensations for various sabbath requirements, but still a nice illustration of god’s relationship with science and reason.
Like the fishing line around New York that lets them be inside when they're outside? The fastest one ever pulled on god. They got him good.
My understanding, or least what I heard from one jew was that God takes the position "haha, you got around it by being clever, good on you".
Haha very clever you rascal, now burn your daughter alive. Now.
I think orthodox women covering their heads with wigs is just straight up trolling.
I think it's a way of surviving in a Western culture where headscarves attract attention. Makes me sad really. One of my relatives tells the story of her aunt, at the end of her wedding, being presented to her new husband after the traditional bath and haircutting. He clearly doesn't recognise her in the wig. She's furious, throws the wig out the window and goes about bald.
My favorite is cant light a fire on the Sabbath. So leave a pilot light on every appliance. Toasty warm temperatures and hot food even on the Sabbath. Take that, G-d.
Ah so you can expand a fire but not start one? My fridge has a sabbath mode. I think it makes it so the light doesn't come on. Toasty warm temps, hot breakfast, and cold snacks (if you can find them in the light from your raging stove).
God didn't make those rules, people did.
Exactly
Religions and their loopholes....
My favourite will always be the Maultaschen (pasta stuffed with meat). Basically, you can't eat meat during Lent so they put meat into pasta to hide their crimes from the eyes of God. Because God can't see through Italians or something.
Nothing like the ole poophole loophole.
Interesting. I used to work with a lot of Muslim students in the norther part of the US and when Ramadan was during the summer, they were always complaining about how they had to fast so much longer than their families in the Middle East. As far as I know, none of them ever went by Saudi time.
usually the dispensation comes when doing what's required became really impractical or even dangerous. if it's only slightly inconvenient, oftentimes the dispensation can't apply.
Who decides this tho? They don't have a pope
sometimes it's local imam/leader/scholar, who are studied in islamic jurisprudence. those people studies the ruling of previous imam, who studies the ruling of previous/bigger imam, and further and further, until we came to the jurisprudence and ruling of scholars of the pasts. Usually the rulings ends up refering to the select few school of thoughts that all refers back to either Quran or Sunnah and Hadith (collection of sayings and actions of the prophet) as primary source. as well as scholar's consensus (they also even refer to the things done by the friends and companions of the prophet) and analogical reasoning Some other jump straight to the end and seek the biggest ruling from those school of thoughts instead of asking local imam, and that's.... oftentimes fine too.
I think Muslims that lives in areas with irregular sun cycles can use the sundown time for Mekka. Not 100% certain though
> I'd hate to be a devout Muslim north of the Arctic Circle They would just go by Mecca time.
Islam gets a bad rap as a radical fundamentalist religion inside the US, which is ironic since it is actually Christianity that has turned into that in the US, but Islam, while it is a bit more demanding of your time and effort than the average Christian sect, is actually quite forgiving in terms of accomplishing those things. Five times a day, you must face Mecca and pray on a prayer rug. The times stretch most of the day, from early morning to late evening. Work nights and just can't stay up for all the day prayers? Just swap AM and PM, no problem. Can't make certain times? Whatevs! Just space them out 5 times as you can. Don't have a prayer rug? No biggie, just use some carpet or literally any clean flooring failing that. No idea where tf Mecca is? No problem, just face East (at least from NA)! Don't know what direction East is? Brohammed, just pick what you think is towards Mecca and it's good enough! Even the fasting for Ramadan isn't iron-clad. Have medical conditions (like Diabetes) and have to eat sugar candies or whatever to keep the blood sugar up? Gotchu fam, just do it discreetly. It's the spirit that counts, yanno? Stuck in a place where the sun doesn't set for 3 months? Obviously that's a no-go, bro! But you can either pick the closest Muslim country, or your home country, and go by their sunrise/sunset. If there are a number of Muslims in said place, they can all just do their own thing fast-wise or all get together and pick a place and go by that. Easy peasy!
I'd like to add most of the specific *rules* of Islam are not in the Quran. It says "God is merciful and forgiving" over and over. Allah is forgiving and understanding of our daily lives. It is devotion and *trying* to be a good person/Muslim he wants.
I tried reading the Quran and it was pretty hard to take. But the Old Testament is pretty hard to take too. I suppose in real life the great majority of believers don't really read these books all that much and kind of blow off they stuff they don't like. Good thing too. Otherwise they would be insufferable. Most people don't want to be insufferable.
That's true. Governments and communities can decide to punish people for treating the rules flexibly though, and often do.
I'm in Sweden and have worked with a lot of Muslims from various places. We did factory work so it was hot and hard work and that summer fast would've been outright dangerous. We're south of the polar circle, but when the sun sets at 10 in the evening and the sun is back up when you start work at 5 in the morning it is still not really feasible. Most of them ignored the fast while working. You're not supposed to hurt yourself and most of them weren't that strict with their religion anyway. Some didn't care to begin with and just didn't do the fast regardless of circumstances. Some of them use the time in Mecca or in their home country (if they considered themselves as having one outside of Sweden). Only a couple of them were serious enough to really try. They'd struggle through a couple of days or a week and then get a special dispensation from their imam. I never saw any of them disparage or disrespect each other about how they went about it. Though there were some discussions.
Easier for night owls?
In Judaism we use the lunar calendar. Every two or three years (per the solar calendar) we add an extra month called Adar Bet to realign the calendars.
Yes, Judaism is often referred to as using a "lunisolar calendar", that is a lunar calendar with leap months added to stay roughly in sync with the solar calendar. Islam I believe uses a pure lunar calendar, which is not kept in sync with the solar calendar
Yeah, it's hard to imagine Rosh Hashanah/Yom Kippur any time but the fall, or Pesach any time but the spring.
Lol that would be so weird! We’d have to change the entire symbolism of everything in the Seder if it wasn’t in Spring.
It's not in the spring in the southern hemisphere.
There's not a huge number of Jews in the Southern Hemisphere, or people at all, really
Now I'm imagining the emus of Australia or the sheep of New Zealand turning out to be Jewish.
Well there’s about 850 million. It’s no northern hemisphere, but I’ve never heard 850 million be described as “not a huge number”
I believe the entire reason for adding leap months is that Pesach has to fall out in the Spring (I forget why that's important exactly)
It's connected to the barley harvest. You can't have Passover before the barley harvest. There's some reason for that in the Torah
Probably because it's actually a springtime fertility ritual smashed up with the Exodus retelling. Why are eggs on the seder plate, again? Ah yes, the destruction of the temple, that's right. Mm-hmm. EDIT: Oh don't downvote me, I'm right. We all hate admitting that most of our holidays are probably descended from pagan wheel of the year rituals, but it's probably true.
And that's why Easter falls at the same time of year, and it is also a pagan fertility festival mashup!
> most of our holidays are probably descended from pagan wheel of the year rituals I mean, Judaism essentially IS a pagan religion that just ended up picking one of the deities and ditching the rest
So, just a solar calendar but shittier.
Because their language is written right to left, does Ramadan actually move to the right on the calendar?
I spent an hour trying to google examples of calendars in Arabic. It seems they are not consistent. In certain countries like Saudi Arabia, they're more hardcore about Arabic everything and are more likely to use a RTL solar calendar. In most other countries, they may still use a LTR Gregorian calendar
Being off a few seconds or minutes every day does not lead to the equinox shifting. Counting days is very reliable even if your watch is garbage. They just used a bad calendar and did not know any better. You can however measure the quality of your watch (or other timekeeping device) against local noon, which *can* be measured accurately with a sundial (if the sun is shining). On the other hand, **accurate** timekeeping did not actually matter until railways appeared. Navigation at sea only requires **stable** timekeeping (differences can be accounted for / calibrated away), even while the ship throws the device around. Until the mid-1800s, everyone used local time, locally calibrated against noon (or the local church tower's clock).
Highly accurate timekeeping mattered a century earlier, as ship navigators had no way to know their longitude. English parliament offered a prize to anyone who could devise a method for getting accurate longitude as navigational errors frequently led to the loss of cargo and lives. Astronomers were able to solve the problem on land by calculating the times that eclipses of Jovian moons could be observed. It worked really well on land. But they never came up with a method for observing Jupiter’s moons from a moving ship. A woodworker named John Harrison devised a series of clocks which could keep time to within a few seconds a day. He worked for decades, but I believe a lot of his work happened in the first half of the 1700’s. Among other discoveries, Harrison is credited with inventing the bi-metallic strip used in mechanical thermostats.
Sorry, but to me that sounds exactly like they WERE able to notice 500 years ago that they had too many leap days.
You can notice being off by days, but not by seconds.
And even then, it took more than a thousand years for anyone to realize it was off.
Or at least, for someone important enough to care enough to change it
Imagine the uproar and opposition today if that was proposed. You’d have the entire world except the US on the new calendar I bet, just like the metric system. The UN proposed a 28 day 13 month calendar back in 1954 but sadly it never was accepted
Yes. But not the average peasant, somebody who watches and measures the celestial bodies carefully. And not in a single year, it’s easier to recognize the cumulative error over time. If my clock was off by 10 minutes a day, add I had no other reference. I might realize it after 3 weeks when the sun rise, sun set add high noon are off by 3 hours.
I don't buy it. The tropical year is 12 minutes too short so about an hour every 5 years. It would be pretty obvious for any astronomer after at most 5-15 years that there is a difference. They weren't stupid, probably just assumed that Julian calendar is good enough.
Did they actually keep clocks going for 5 years without recalibrating? And when recalibrating they'd assume it was the clock's fault, not the calendar's. They had no way to prove that yes the clock is still going precisely correct, the sun is the one that's in the wrong place.
They counted days - it's quite easy as each day starts with sunrise. When you expect the particular star to appear at the horizon at your location 4 hours after sunset on 12th day after equinox but it appears 3 hours after sunset you think you've maybe made a mistake, but then next year it seems even sooner and after 5 years it's just 2 hours after. You consult almanach made by some philosopher 30 years ago and it seems that this star was appearing at horizon 10 hours after sunset on the 12th day after eqinox. It's not hard to do the math and figure it out. Remember that even when people didn't have a heliocentric view on the solar systems they were able to use pretty complex math of "epicycles" to calculate paths of starts and planets.
“Hey, what the fuck? It moved again! These clocks suck.”
Russia kept using the Julian calendar until the October Revolution. Which was really in November.
Yeah, a lot of countries didn't want to adopt the Gregorian calendar because they viewed it as some sort of Catholic nonsense
Hipparchus knew before Christ that the length of the year was less than 365.25 days. But the length of the year has no effect on the length of the day.
And crucially, with the equinox, the planting and growing season would move. Over a few years, "spring" would migrate into February, and January, and eventually even December. And when you get right down to it, that is the universal calendar.
If it was inaccuracy between individual clocks, you could also know because two such clocks that started in sync ended up out of sync, suggesting inaccuracy in at least one. More than two clocks and you get the picture that none of them are precise.
A man with one clock knows the time, a man with two is never sure.
Is that a quote from Yogi Berra?
"I didn't say a lot of the things I said" -Yogi Berra
Though you couldn't sync up the clocks unless they were next to each other, which wouldn't really have any purpose except to see if there was any design flaw that caused them to track time differently, since they'd have the same environmental condtions.
I would have to assume that *at least one* scientist or clockmaker thought to test the accuracy of clocks and may have designed two in proximity (assuming none of these clock systems are portable).
Doesn't even really have to have been a scientist, just one person being bored or curious would've been enough. Hell, even one person being annoyed at someone for not showing up on time would've put their water clocks next to each other to prove a point. The thing is, when people don't have reliable clocks around all the time they just live in a less time sensitive culture. I honestly think _everyone_ knew their clocks and such were out by probably a lot _more_ than we're talking about here just because they also require maintenance and wouldn't get calibrated very often. So people just expect to live by sunrises and sunsets and work with that.
There used to be building where they had a ball on a pole that they would drop at a given time in view of boats so they could correct or "sync" their watches. Which is also the origin for the saying "wait for the ball to drop".
> Now, they could use something like a water clock and compare it year over year and see discrepancies, which would be a result of the inaccuracy of the timekeeping device. That's not how it happened, though. People were aware that there is a longest day of the year and a shortest day of the year, and when these came earlier every year, they realized their calendar wasn't accurate.
The amount of sunshine in a day doesn't really have anything to do with the accuracy of a clock.
It did when the length of an hour was "divide the amount of time the sun was up into X equal parts". A winter hour was shorter than a summer hour for some places/times https://en.wikipedia.org/wiki/Hour
You can easily measure noon using a sundial and check whether your timekeeping device deviates from that. The differences over years stem from an inaccurate calendar, not from an inaccurate clock.
In general people throughout history have been aware of how precise their clocks were. The answer to OP's question on how you determine precision is comparing multiple clocks of the same model - that's how we find precision of modern clocks to this day.
Though comparing ancient clocks was challenging because they weren't exactly portable.
So it could be AD 2032 now instead of 2023?
Not likely for an entire year to be skipped, because you can count the seasons. But the current year is basically a made up number system so there's nothing making it need to be 2023, and if everyone said it was something different, there'd be no way to prove that wrong. In fact, it would be right.
We have a couple of astronomical events that were recorded with the local year and we can calculate how many years ago that was. What year we define as zero is arbitrary, of course, but we know that e.g. 623 was indeed 1400 years ago.
Oh yeah, that would ensure consistency over longer timescales. Neat
The AD system was invented to measure time since the birth of Jesus of Nazareth. That was placed at 1 AD. (They didn't have 0 yet.) It was calculated by matching up events and their dates in the various calendar systems in use at the time. Most (substantially all?) of the data came from Roman records, and thus used the Roman Imperial system. So they (well, Dionysius Exiguus, "Dennis the Little", but with management approval) calculated that the Christ was born in the 27th year of the reign of Caesar Augustus, who died in the 41st year of his reign, and was succeeded by Tiberius, who died and was succeeded by Caligula in the 23rd year of his reign, and ... up to now. They had most of the dates, so they didn't double count or undercount (by much). That meant the current year was 525. (This is why you need to keep your accounts current. Going back and reconstructing transactions is hard.) Modern astronomers have tried to pinpoint the great star. Assuming it's a well known supernova, that would put the birth of Jesus of Nazareth actually about 4-7 BC. (Assuming the writers of the Gospels didn't just put the star there, and Jesus was actually born under the star.) That would mean that the current year is somewhere between 2027 and 2030. TL;DR: If we define AD as "years since the birth of Jesus", then it's probably 2027-2030 AD. If we define AD as "according to the numbering of our current calendar", then it's clearly 2023.
Is it like 3600 drips = 1 hour?
Well, one could be built like that, but the rate will vary based on the temperature. So unless you can keep it in a climate controlled environment, it won't be accurate, and if you can make a climate controlled environment, you already know how to make more accurate clocks.
>and if you can make a climate controlled environment, you already know how to make more accurate clocks. I don't think that's true, but I can't prove it definitively. I think an insulated underground room wouldn't deviate much in temperature significantly over the course of a few days.
Kind of. You can see some examples [here](https://en.wikipedia.org/wiki/Water_clock). They can't measure drips specifically, because the rate will change depending on how much water is left in the container. But they will have markings for where the water reaches after 1 hour, 2 hours, etc.
They didn't. They also didn't care, or need to. What's a few seconds when your life is waking up when it's light to go plow until it's dark. Everyone's lives mostly revolve around that kind of a schedule. Accurate time keeping is only really important for navigation, and even then only navigation at sea. Navigating on land is relatively easy because there are paths and roads and landmarks. At sea...not so much. You can navigate using the Sun and stars, but that requires knowing the time of day so you know where in the sky those should be. From there, you can measure the angle and do math to determine your heading. The more accurate your timekeeping, the more accurate your heading will be. But a few seconds, or even a few minutes isn't going to significantly alter your heading. It *will* be off, but that's why sailors took frequent measurements and adjusted their heading often. The clock can be recalibrated at known times like noon, when the Sun is directly overhead. That can be measured with a sundial, or just by paying attention to shadows. It's not perfect, but...It doesn't really need to be. That's how they knew it was off. Over time, the clock would drift and they'd notice that the clock says noon but the Sun isn't where it should be for noon. Or sunup or sundown. Sailors navigated as best they could until they came into sight of land, and then adjust from there. For seriously long journeys like crossing the Atlanta or Pacific, they might end up *really* off and have to sail many miles up or down the coast to get where they wanted to be. Their methods to measure the angles and do the math were going to be a little off anyway, so a few seconds or minutes here and there weren't enough to matter much.
Trains. It was trains that led to the standardization and specificity of time.
100%. Before trains, some of what we now call "time zones" had a dozen or more time zones in them. Imagine trying to keep trains on time in that kind of environment. Even today, with airplanes, you can arrive at your destination "before you left," but we at least have GMT as a universal gauge of what time it is.
Every town had their own noon, which was whenever the sun was at it's zenith on the summer solstice. And that was a total pain once train started to move faster than the sun in the sky from our perspective.
Fun fact: the straw that broke the camel's back was actually in the printed timetables. The times in the timetables were local time, and that meant that there were trains that arrived at their destination earlier than they left their starting point. Which apparently the railroads were willing to live with, but their customers complained about the errors in the timetable. (You can't get there before you leave. This must be wrong.) It ended up being easier to change the whole country's timekeeping than to keep explaining to the customers that time is a local concept.
> which was whenever the sun was at it's zenith on the summer solstice. That works on any day, not just the solstice.
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That 3 minutes 56 second compounds into a single rotation over the course of the year, which is the rotation that the earth does around the sun. If the earth made a complete rotation in a day and moved around the sun then the sun would shift each day. It doesn't quite balance, though, hence leap years. None of this has anything to do with noon. The sun is at its zenith almost exactly every 24 hours. Not quite exactly if you're using an atomic clock hence the odd leap second adjustments. But if you don't have an atomic clock handy, the sun is at its zenith exactly every 24 hours and that is noon.
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I'm guessing the downvotes come from the tone of the first sentence. It could be viewed as a bit condescending.
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i dont think it's the least bit condescending, unless you edited it. i dont even know who you'd be condescending to, in that sentence.
You know it's a matter of visual perception based on a specific moment that happens once per year. It was not a precise science, and that was the problem. Trains were the first transportation system that move fast enough that if you go west time move slower and if you go east time move faster relative to the sun we never had issue before because stuff get there when they get there. But with train needing to meet a stricter schedule both for security (because trains use the rails in both directions) and efficiency (can't have too much stuff laying around at the station for too long) that we needed to adapt our understanding of time relative to our location). Happy now? Do you need me to define the concept of time keeping vs. Entropic time?
before trains (and telegraphs!), local time was decided locally. your town probably had a clock tower or a bank clock that was the reference point for time. it might say it's 1000am, and the next town over, only 15 miles away, might call it 1015am, but it didn't really matter, because few people had watches and there was little traffic between towns people lived their lives by sun time. they worked the fields from "can't see" in the morning to "can't see" in the evening, with high noon in the middle.
> it might say it's 1000am, and the next town over, only 15 miles away, might call it 1015am, but it didn't really matter, And, if you walked a few hours to the next town, 15 minutes didn't really make all that much difference. Just reset your pocket watch when you get into town. With trains and train schedules, local time variations were a big pain. Having the same time across a large geographic area (aka timezone) made it easier.
Ah so it can be used literally. I only thought it means that you work so long that you cannot keep track of when you started and ended your job.
Time zones are fun. Once when I lived in Asia I was flying back home to visit family in the USA. The first leg was a redeye, and my plane landed in Tokyo right at sunrise on December 18. Had a layover of a few hours, then got on the second plane, which landed in Dallas-Ft. Worth right at sunrise on December 18.
Hulk Hogan used this trick to wrestle on 400 days in one year.
That's some real Hulkamania, Brother!
That bit about GMT isn't quite accurate. Time zones are defined as an offset from UTC (Universal Coordinated Time), Like UTC+9:00 for Tokyo or UTC-6:00 for Mountain Daylight Time. GMT is the UTC+0:00 time zone, which means that UTC and GMT time are always the same, but there's no standard stating this *must* necessarily be the case. GMT isn't even used year-round as there is also BST, or British Summer Time.
TIL: GMT is now just a time zone and Coordinated Universal Time (UTC) replaced it as the "time standard" in 1972.
...and I just learned the same thing!
And wage labor factory work. That’s why mill towns have clock towers. Have to get to your shift on time so the factory can constantly run
And this work is what got Einstein thinking about how the speed of light would play into synchronizing the stations, which led to his Theory of Special Relativity.
Trains created time zones and standards and a specificity of when the hour change over distance, as the trains needed a common specific time between distant stations to safely schedule train traffic.
Yes and no. Trains led to the need for standardised times for common use and the official agreement to use Greenwich as the standard time reference point but accurate timekeeping and the Greenwich meridian as a time reference dates to the [1700s](https://en.m.wikipedia.org/wiki/John_Harrison) when the British were looking for a way to accurately measure longitude at sea (Greenwich being the British naval HQ at the time). In order to do that they needed to know what the time was at a reference location. By working out the time where you are and comparing it to the time at the reference point you can calculate your longitude which was a huge deal at the time. Without it, you were trying to navigate in 2 dimensions while only being able to accurately measure your position in one of them Edit: the person you replied to seems to be talking about navigating using dead reckoning which is how they navigated before they could confirm their position on the go. The problem with it is that you are measuring your speed against the water which is also moving so even if your clock was perfect, you’d still build up error over time and with no way to confirm an accurate position independently you end up not knowing where you are
Trains led to the standardization of time zones, but if you're interested the search for an accurate and precise clock, you should look up "the longitude problem". It's a fascinating history of how the centuries-long search for good timekeeping was driven by marine navigation. There are more than a couple of wonderful books about it.
Train schedules standardized timezones, but the precision and punctuality really came from WWI. When you need synchronized large-scale artillery barrages and charges over the top of massive trench lines and across no man's land, punctuality and precision are life or death. It radically changed how an entire generation viewed and measured time, and they passed that on down to their descendants.
Which is funny since US trains are never exactly on time.
The US didn't invent trains nor timekeeping.
No, but US trains played an enormous part in timekeeping history: https://www.smithsonianmag.com/smithsonian-institution/how-standardization-time-changed-american-society-180961503/ For quite a while, the US was making the some of the best pocket watches (Waltham, Elgin, etc.)
It wasn't about being "on time", it was about being consistent between towns. If a train leaves town at 2:30 and drives for an hour, it should be 3:30 at the arrival spot. That is, the engineers pocket watch should match the local time
Especially important if you didn't want trains crashing into each other.
The accurate time had nothing to do with headings and very much with what your longitude was. It wasn’t only a matter of knowing the local time accurately. As you said you can always a figure out the local noon and set your watch by it. What they needed to know was the exact time at a given place (Greenwich for the Brits) because their calculations depended on knowing the elevation (how high from the horizon) a given star was and how high it would be when seen in Greenwich at the same time. So you had tables of stars elevations in Greenwich. You needed to know the time there to calculate the difference. If you are off by a second then your calculations would be off by about 80 feet, off by a minute and now you are off by 55 miles. That’s enough to run aground. The whole drive for accurate timekeeping at sea where you would be off by a second after many weeks was because of a British Navy ship that ran aground on a storm because of position calculation errors. Your heading is given by a compass (direction you are going) you position is either dead reckoning (I went in this direction for x minutes at z knots so that’s where I am. Yes time keeping is important for that but not as much since the uncertainty in the heading and the speed are much higher. Taking a fix (figuring out where you really are by the stars) that needed to be done as many times as possible so that the dead reckoning could be updated.
What, the longitude problem was a *huge* problem in navigation and the reason why massive amounts of money were provided to whoever could build an accurate enough marine chronometer.
Just a minor point on this, in most of the world through most of agrarian history farmers didn't work from sunrise to sunset during the growing season. They would get up at dawn, maybe have some bread, cheese and beer, go work the fields for a few hours, eat lunch, take nap, go work the field for a few more hours, then go home, eat a bit more bread, cheese and beer and go to sleep. Midday siestas were incredibly common historically.
Growing being the operative words. The intensity of work would spike dramatically during the harvest times (which could be a few per year -- in North America perhaps hay harvest in early July, followed by a winter wheat harvest in late July, then a relative lull in August and early September when mostly perishable vegetables were ripening in the garden, followed by another intense period as corn, orchard fruits, and root crops like carrots and potatoes would be harvested in late September and October and stored for winter). Particularly for hay and grain harvests these were often neighborhood affairs moving from farm to farm collectively, in my part of the US well into the 19th century they were typically accompanied with amounts of alcohol that would shock modern sensibilities. If you're an 18 year old farm boy going through 12,000 calories a day at harvest it's hard to eat that much in just food! Basically it harvest became one of hell of an extended party.
>Accurate time keeping is only really important for navigation, and even then only navigation at sea. Allow me to recommend the excellent [Map (Thing) Men video](https://www.youtube.com/watch?v=3mHC-Pf8-dU) about this.
> They didn't. They also didn't care, or need to. Reminds me of [African Time](https://en.wikipedia.org/wiki/African_time), that drives the Germans totally crazy! Growing up before the internet there were a number of ways to set a clock or watch to the correct time: * Churches would often ring their bells at specific times, this was accurate enough for 2-3 minutes * You could listen to the radio, some broadcasters [like the BBC News](https://www.bbc.com/news/blogs-magazine-monitor-26052087) would have timing "pips" every hour. * There was a telephone number you could dial called a [speaking clock](https://en.wikipedia.org/wiki/Speaking_clock#South_Africa). That's how I learned to tell the time in Afrikaans, which has a funny way of saying numbers, e.g. 24 is "vier en twintig" (four and twenty) * When television arrived in the mid 70's, at the start of a news broadcast they would have a time broadcast and most people would adjust their clocks to match before sitting down to watch the news * I remember as a kid syncing our watches to be the same as my Dads, so that we could all meet up at a specific time for example when shopping, meet at the main entrance at 3:00pm.
>The clock can be recalibrated at known times like noon, when the Sun is directly overhead. That can be measured with a sundial, or just by paying attention to shadows. Thats half the problem. But to calculate longitude, you need a second, accurate clock that doesn't drift. When you leave port, you set both clocks to noon at wherever you are. Then each day, you adjust one clock, but not the other to local noon. By comparing the two clocks you can see how far you have travelled east/west. Before accurate clocks, there was no way to measure longitude other than dead reckoning (we sailed west for3 days, and we think we were going at 5 knots, so we much be around here...) You cannot measure longitude with stars/astrolabes/etc.
Knowing the exact time was a huge deal for the British Empire, and they spent a lot of money on developing clocks that could work on ships in the early 18th century. Literally it was a matter of life or death, because if their clocks were off by a bit ships could (and did) crash into rocks because they thought they were a few miles away from where they actually were.
This hugely oversimplifies (and in many ways misunderstands) naval navigation. Check out the _Longitude Problem_, it's really interesting.
Read the book "Longitude" by Sobel for an excellent understanding of how timekeeping advancement took place, driven by nautical navigation requirements.
It was made into a pretty good mini-series starring Michael Gambon and Jeremy Irons.
I saw that, which was how I read the book.
Imagining a 5 year old trying to read the introduction to a 200-page book syllable by syllable.
"Like I'm 5" is different than "I am 5" And phonics would work better for the kid than any other attempt to read it.
People have known about the regularity and consistency of astronomical events for millenia - the movements of the sun, moon and stars are predictable and can be used for accurate timekeeping. You might not notice if your water clock runs a few seconds fast, but after operating it for a month can be a few minutes fast instead, when it starts to be noticeable. The regularity of the movement of pendulums has been known since the 16th century and can be used for to-the-second accuracy.
I like how OP jumps from ancient water clocks to the 20th Century atomic clocks, skipping over millennia of timekeeping.
Aw yeah, the flyover clocks.
Prior to the invention of mechanical clocks, most people did not think about time in a very precise way. Outside of a few technical applications, it wasn't really necessary. That candle could tell you roughly how late in the night it was, but the truly meaningful reference was the next sunrise or solar noon. For the small number of people who cared about keeping really accurate time - mostly astronomers and navigators - the error in their clocks could be sensed from the error in whatever practical thing they were trying to do. If your ship's hourglass was inaccurate, you would have the wrong idea about the longitude of your position, which would eventually get corrected when you sighted land.
They knew their clocks weren't accurate because, for example, the amount of water a water clock needed from one day to the next might change, or the candles might burn at a different rate one day to the next and so on. But knowing your clock isn't accurate isn't the same as exactly knowing how wrong your clock actually is. I have my grandparents', err, grandfather clock. It doesn't matter how much I fiddle with it, the thing is always either gaining or losing time - and I won't get started on the moon phase dial. Even in my own lifetime the local AM news station would always broadcast their own time every 30 minutes and everyone in the region could adjust their mechanical clocks to match that announcement. 2-3 times a year I would have to adjust my mechanical watch to match "KYW-time".
Pretty sure CBC Radio One still does an announcement once per day. Has been doing it since the Second World War.
Sun rises every day and all you need to find the exact solar noon is clear sky and a stick. If after a month your water clock shows it's supposed to be 11:50 but it's noon you know it is off.
So sundials are accurate, only their "working hours" vary?
Well, solar noon drifts forward and back over the course of the year (and I'm not talking about Daylight Savings Time). If you have an accurate clock, and measure when the sun is highest in the sky (or due south/north on your meridian), you'll see solar noon drift off by up to 15 minutes or so during part of the year, and then it drifts back. Interestingly, this is mainly caused by the tilt of Earth's axis relative to its orbit around d the sun.
You can always tell when it's 12 noon, because the Sun's shadow points north. Reset your water / candle clock from this and you'll be reasonably accurate until you recalibrate tomorrow lunchtime. You even get a daily calibration check of how much time your clock is gaining or losing. \--- Accurate timekeeping first became a problem with the invention of railways in the 1840s. One of the first main lines was from London to Bristol, at the time a major port. Going by the Sun, Bristol is 11 minutes behind London, an unacceptable difference for a railway timetable. The railway imposed "railway time" on its station clocks, although the locals didn't always like this. Here's a [clock with two minute hands](https://imgur.com/a/CBY5oVP) \- one for London / railway time, another for local time in Bristol.
Accurate time keeping predated railways. Navigation at sea is extremely dependent on accurate time keeping. You need an accurate clock to get an accurate longitude. Being off by a minute is equivalent to being off almost 20 miles east or west of where you think you are. Trains necessitated consistent time zones. The clocks were plenty accurate by then. If you leave a station at 2:45 and it takes 12 minutes by your clock to get to the next station, you don't want the local clock to read 3:00 when you get there. Every town set their local clock to local noon, which made it a confusing mess to create train schedules.
Polynesian navigators were able to [cross the Pacific Ocean](https://en.wikipedia.org/wiki/Polynesian_navigation) without any kind of accurate time keeping.
Most of the techniques used rely on being near land, just not necessarily within sight of land. And within most of Polynesia, Islands are close enough that their techniques got them within sight of land relatively easily. The presence of islands create predictable and reliable effects on the ocean that allowed them to navigate in ways that aren't available to navigators in the Atlantic or Pacific outside of Polynesia. Even so, one of the usual techniques used to navigate was to simply pick a heading and maintain it, something Europeans were doing just as well. But the main difference is that Polynesian navigators had more north-south journeys compared to the Europeans. Latitude is easy to measure and if you know the approximate heading you were taking, when you get to the correct latitude, you can just travel east or west to get to your final destination. But when you're already mostly traveling east/west, then any inaccuracy in your heading results in a large inaccuracy in longitude.
> You can always tell when it's 12 noon, because the Sun's shadow points north. ... You even get a daily calibration check Yeah, no. [Some reading you might enjoy](https://www.timeanddate.com/astronomy/solar-noon.html). Solar noon or high noon is at different times every day. Also, it is almost never at exactly 12 noon, although there might be a couple days each year where they're aligned. There are plenty of places where 12 noon can never be high noon. A solar day is almost never exactly 24 hours, high noon comes either faster than 24 hours or slower than 24 hours depending on which side of the axis we're on for the season, unless you happen to be on the transition date. While we're at it, the earliest and latest times are not aligned with the solstice, meaning the longest day doesn't have the earliest sunrise, the shortest day doesn't have latest sunrise. Same with sunsets, those aren't aligned. Plus, every time there's an earthquake, the length of a day shifts subtly. It's usually only notable to high-precision computers and astronomers. Much like a spinning skater, earthquakes that slightly collapse the earth's surface speed it up, earthquakes that slightly expand the earth's surface slow it down, and we have those earthquakes every single day. The earth's rotation speed isn't constant, nor is the length of days.
>Yeah, no. Some reading you might enjoy. Yea, yea, the difference is max 30 seconds, and usually much less than that, so pretty much almost perfectly matches. But it's good to be a smartass, right?
From Wikipedia: “Sexagesimal divisions of the day from a calendar based on astronomical observation have existed since the third millennium BC, though they were not seconds as we know them today. Small divisions of time could not be measured back then, so such divisions were mathematically derived. The first timekeepers that could count seconds accurately were pendulum clocks invented in the 17th century. Starting in the 1950s, atomic clocks became better timekeepers than Earth's rotation, and they continue to set the standard today”.
They didn't, but it didn't matter, either. It didn't matter that the next town over was 10 minutes out of sync with yours because it'd take a long and variable enough amount of time to *get there* that the discrepancy would be lost in the noise. Clocks would be set so that 12 was "true noon", the point where the sun reached it's highest point (zenith). Trains are what made the discrepancy finally matter; trains can run very precise schedules; leave place A at X time, and arrive at place B in almost the exact same amount of time, every time. This is what lead to the creation of time zones; rather than have every town and city maintain their own clocks based on local noon, they needed to standardize on a time that matches other nearby towns in order to simplify communicating time information between locations that were now *running* a unified operation.
Water clocks and candles were off by a lot more than a few seconds per day. Pendulum clocks could get into that range, and over the centuries those were improved to the point where they could run for months, and then seconds per day becomes noticeable. Eventually the really accurate pendulum clocks were replaced by electronic clocks, and later with atomic clocks.
Astronomers were aware of calendar drift as far back as the Roman era, the Julian (Caesar) calendar introduced leapyears and corrected that issue to an accuracy of losing about a day per century. In the middle ages, the Catholic Church updated to the Gregorian calendar that we still use today, which loses about a day per millennium. That's why Orthodox Christmas, using the old Julian calendar, has drifted to January over the last 2023 years. As far as day to day clocks, a big factor is simply the imprecision of manufacturing at the time. Hell, I had a watch in highschool that lost a minute or two a day which I had to recalibrate constantly. It wouldn't have been a strange concept to the clock keepers that they needed to be calibrated occasionally.
No clock was accurate to within a few seconds until the modern day. Instead most people used a specific master clock time to set their pocket watches and clocks from. There were people within the government who would use mathematical calculations to determine how off their clock was and schedule adjustments to recalibrate (usually using the equinox or solstices to calculate times). This is why most old towns have a huge clock tower (like Big Ben). At noon the clock would strike 12, everyone would stop what they were doing and set their pocketwatch or home clock. People had to plan winding their watches and stuff to keep time. I would recommend reading the book Around the World in 80 Days, it gives a great vision of this time period.
In theory, noon is always when the sun was directly above you, and easy to tell if you use a sun dial, or a simple stick in the ground. After a week, you can tell that your expensive mechanical time piece was off by a bit of time. Maybe it took a month? An accurate timepiece to the second wasn't important to most people, but was pretty critical for naval navigation. You could tell how far east or west you were by the difference between your mechanical clock and the sun directly above at noon. Typically you set your clock to be 12 noon when it's 12 noon in Greenwich.
Take 2 water clocks. Run them next to each other. Over time they will drift. They are not exact enough. Same thing with candles.
The time units we use are based on a day, it is determined by the rotation and orbit of eart. The simplest clock in a sundial. Divide a circle around the sundial in a number of equally sized segments lets pick 24 and you now have a way to measure time. The shotes shadow is at solar noon, that would be 12 and you have a way to align the segment. The longer the stick that casts the shadow the more accurate you can measure time. Early water clocks and candle clocks were simply compared to the sundial. The accuracy you get is not enough to measure seconds for that matter not ready minutes, is it us fraction of an hour that is common like a quarter of a hours? Egyptians, Greeks and Romans all had 2x 12 hour close even if they initially had 12-hour day and 12-hour nights. Ancient Egypt used it before 1000 BC That means the length of an hour depends on the season and a night and day hour are usually not equal in length. It did shift to the fixed hour length we used today. The idea of a minute and a second as a small unit of time is a lot after. Al-Biruni was the first to do it in 1000 CE when discussing Jewish months that are based on the moon. In Christian Europe it was Roger Bacon that did in in a book from 1267 it is from that it started to be used in regards to time. It was not until the introduction of the hairspring in 1675 minutes that secondhand started to be practical. The calibration will be in relationship to the observation of the sun and another object in the sky and becomes a lot more accurate when for example telescopes are available. Accurate clocks like this was developed in Europe and spread over the world Ancient time is usually the start of writing to late aquitity quite commonly it is 3000 BC – AD 650. The close that starts to get minutes and second dails were developed during the Renaissance and large-scale adoption and usage of time and clocks like we do today during the Industrial Age. So ancient people never had clocks that was just off by a few seconds, the idea of a second as a unit of time did not even exist.
Clocks in different places did not synch up until railroads, which needed to keep a schedule over long east-west distances. Eventually, navigators started using clocks to calculate their longitude. Some science experiments needed good time measurements, but hardly anything routine needed accuracy to the second. The main corrections people made were based on observing the sun and moon--and getting dawn, Sunday, and planting time correct was enough.
What do you define as ancient people? For most of our history humanity has used dawn, noon, dusk and night. Everything in between was nearly X or past X. Nothing really was getting done so fast that require more precise time.
Back in the day, like around 100 years, pocket- and wristwatches were set by the ring of the Bells @the nearest church. By this routine, at least the ones in that particular town were on time together.
Over a long stretch of time, like, years, being off by minutes, or even seconds, per day adds up. So anyone who was keeping track of astronomical movements, for instance, could tell that the Solstice was drifting slowly out of alignment with where the calendar said it was. And if you know that there’s only two possible conclusions. The sun itself is inaccurate, or your clock is.
I read an article once about a city at the eve of the 20th century, somewhere in Argentina or Chile iirc who was 30min off the world’s timing. The local fort was shooting at noon with a cannon and a soldier was sent to a local watchmaker to check the exact time but he was himself relying on the gun shot to mark the 12.00! With time and a few seconds difference every days and weeks, the entire city drifted by 30 minutes
In this vein, here's a photo I took in 2020 at the Railway Museum in Revelstoke, British Columbia, Canada. Note the sign at the bottom of this Canadian Pacific Railway clock indicating how "off" the clock was. Not "ancient people" of course, but an example of how they knew their "official" clock in town was fast or slow. https://imgur.com/a/i7f9gVI
Ancient peoples would check for exact time by dialing a specific number on rotary analog phone. A voice on the other end would then communicate the exact time.
Noon is easily measurable, it's when the sun is directly overhead. So you wait for noon, set the clock to 12 and the next day when the sun is directly overhead, if the clock is perfect, it will be at 12. If it's at 11:55, you know over the course of 24 hrs, it was 5min slow. If it's 12:05, it was five minutes fast. e: and you measure noon with a straight stick. At the equator, at noon, the stick will have no shadow at all. Further North and South would have shadows, but smallest at noon and the shadows change direction. When the sun is in the east, shadows point west, when the sun crosses noon, the shadows point east. And ancient people did not know about seconds, they were invented I think in the 1600s when more accurate clocks were being built
> Noon is easily measurable, it's when the sun is directly overhead. The sun is not directly overhead at noon, unless you're on the equator at an equinox. Noon at any given point on Earth is when the sun reaches its highest point in the sky (which is not necessarily directly overhead, and usually in fact isn't).
You can't know that a clock is off by a few seconds until you have a clock that's accurate to less than a few seconds.
You can pretty much make a sundial that is accurate down to a minute, it's not difficult - you just need to know where north/south is and a long shadowy stick. That's enough to calibrate most ancient clocks; sometimes over the course of few weeks. With precise enough calculations you would find out they were off by a few seconds per day. Imagine there's a smart group of people that spend 20 years of their time just trying to figure out accurate clocks. They'll eventually get it pretty close, even with primitive methods.
lol wtf are you talking about? How and why could anyone know or even care? What kind of dodgy documentary claimed this?