Since this is I’m gonna explain my question the same way.
Imagine there is a time-hating wizard who magically removes all time-keeping instruments like atomic clocks, phones and watches, so there is no way of knowing the time right now. If then we were asked to ‘bring back’ the old time that we used (e.g. so that we start again measuring 12:00 in London exactly when it was 12:00 in London before the wizard) could this be done? Is there something physical constant (like kg or meter) that determines what time of day it is? Or, did someone just say “we start measuring time from now, and I say that it is exactly 14:32…”?
Also, if there is this constant that allows us to know exactly when a certain time is, doesn’t that mean we don’t need atomic clocks and can just compare ourselves to this constant? Idk what this would be but perhaps when the sun is absolutely highest in the sky somewhere?
In: 40
To answer your question about whether we could create a correlation between the “old time” and the “new time” if we somehow had a “gap” in between the two (a not totally impossible idea, if you had a total civilizational collapse and much later rebirth) — astronomical records can be used to make such correspondences. This is how we can figure out what the dates of some very old events are in our modern system, because in the past there were people who kept very good records of things like eclipses that we can, with modern astronomical models, very precisely date.
There is no “constant” for time in the universe of the sort that you mean. But if we define some sort of event as the “beginning,” we can certainly say that some measure of time (say, rotations of the Earth around the Sun, or Earth rotations on its axis, or the vibration of piezoelectric atoms at a given frequency of electricity, etc.) has passed since that moment. So we could say, “ah, it is day X since that wizard cast the spell.”
When we started measuring time like everyone said it started with measuring 12:00 or the time when there was the least shadow, but due to seasons and the earths rotation that changed daily. Then sundials we’re invented and kept more consistent time but they were to heavy and couldn’t be carried with you. So then clocks were invented and if you only did business or met up with people from your area this was fine, everyone had their clocks set by the same or a similar 12:00. But once people started to travel and do business with others further away meeting times or delivery time ect were confusing and a wizard decided we need a standard time, and each country/region set their own standard time. Then at some point this still got confusing because it would still change from region to region so another wizard decided there would be a universal standard time around the world and since it benefits everyone it’s one of the few things all humans agreed on. So this wizard for some reason (the reason was that it benefits the largest number of people and puts the end of the day in the middle of the Pacific Ocean meaning that no country is forced to be on two dates at once) picked Greenwich, England as 12:00 or in this case 00:00. This means that all time zones are measured from that starting point and why we have a + or – on our time zones, for example, Sydney australia is +10 meaning 10 hours before Greenwich, and LA, USA is -7 meaning 7 hours after Greenwich. So this means that sunrise is always about 6am and sun set is about 6pm at the equator but varies because of seasons and the tilt of the earth. Like I’m australia we have daylight savings time with sets the clocks 1 hour back so the sun still rises about 6am but then extends the day so sun set is approximately 8pm, making better use of daylight rather than having a 5am – 7pm day when most people rise about 7am essentially “wasting” two hours of daylight
Edit* after reading I realised I didn’t really answer the question;
So to answer your question, yes we could, it would just be measured by the sun, the most and least consistent time keeper we have (inconsistent in the sort term, more consistent in the long term) but we have been measuring the sun and starts since the start of history and probably before and we still haven’t really nailed it down 100%. To be honest if we started from scratch we would people have a whole new system for keeping time but it would be at the essence the same thing, a way for anyone anywhere to communicate a period of time before they want something done, weather that’s to meet for lunch or to have a product/service made and delivered.
Iirc, the railroads made time aligned between locations. Until then, it didn’t really matter if the city 50km down the road had the *exact* same time on their clocks.
But when railroads were built and cities connected, they wanted to run “on time” and give schedules, so all the clocks needed to be aligned.
Before that, you could use the sun and get close enough.
Assuming we remember the units, we could end up with something quite comparable.
Broadly:
Find high-noon (eg: The middle of the day)
Then with any device that can keep a steady count (a metronome and a lot of patience would do it, though if you can automate it in any way that’d be great) you count until you get to the next high-noon.
That’s your basic metro-second count of the day. A Metronome isn’t exactly a second-per-tick, but it’s close enough. You probably have slightly less metro-seconds than there were real seconds because a metronome generally runs slower. This is a good thing because counting seconds would be mind-numbing.
Lets call it 80,000 metro-seconds between two high-noons, it’s probably a more annoying number, but the math is the same.
Now divide that into 24 blocks of 3,333 metro-seconds.
Divide that further into 60 blocks of around 55.5 metro-seconds and you’ve got your Metro-minutes.
55.5 metro-seconds is a minute. Which you know is 60 seconds.
Basic math says that a metro-second averages out at 0.925 seconds.
So now you have a standard for a second, you can use that to build out all your time-keeping infrastructure.
The question then arises for “what year is it?”
That’s a bit harder because all our date-keeping is based on an agreed-upon starting date.
Most of the western world agrees on a date 2,022 years ago as the start of the “Common Era”. You may even see the abbreviation CE sometimes. This is the non-religious direct equivalent of AD and pretty much the same thing.
In computing, we derive our date from Unix-Time. Which takes 01/01/1970 as an arbitrary starting date and counts in milliseconds from that point.
Given the massive upheaval of the Time Wizard’s actions, we might as well restart on 01/01/01 ATW (After Time-Wizard)
I’ve seen some good answers, but in addition to that, we’d be able to calculate the time back pretty easily and quickly based on previous records. We know what time the sun rises and sets. There’s 2 data points and if you can get the clock running so both of those line up as intended, your clock is accurate.
Time, both present and future, is all about synchronization and coordination of efforts.
Time, past, is all about cateloguing those previous efforts.
So as long as we have a system capable of cateloguing the synchronization of our efforts, your question will remain irrelivent.
We would probably come up with a lot of the same stuff that the ancient Babylonians did, just with a higher degree of specificity.
~360 days in a year because the position of the sun changes ~1 degree in the sky every day, months being ~28 days long (probably 4 weeks of 7 days and a catch-up period at the end for ease of accounting going forward) we would probably define the hour/minute/second out of a base 10 system as opposed to a base 60 system, so it would probably be 100 seconds to a minute 100 seconds to an hour (like it was 10 seconds to a minute 10 minutes to an hour for the Babylonians)
It would be some astronomical way, using the sun or other stars passing in front of some optical device. You’d also have to align that device somehow, probably using gravity. Hard to tell how precise you could get like that, but for one second resolution it would have to be able to differentiate angles as small as a “cake” devided into 86400 pieces. Maybe even the gravity of a mountain near you could distort your measurement, because the device would be misaligned(?)
We’d use the sun like we used to. Other commenters have pointed out that noon is the easiest point of the day to measure. That’s because the sun reaching it’s highest point in the sky is not subtle and easy to measure.
You wouldn’t even need anything complicated. Jab a stick in the ground, and you can trace the shadow throughout the day. Noon is when it’s the shortest and points straight towards the nearest pole. if you’re not in the tropics. From there, you mark the arc into hours. Now you have a reference to build your mechanical clock around.
That’s how clocks began in the first place. They were mechanical sundials with the hour hand simulating the shadow of a sundial. In the Northern Hemisphere where they were invented, a sundial’s shadow starts in the west, swings north, and then to the east. The same direction we now call clockwise (and used to call sunwise).
So there are 3 things to consider.
Time and time measurement. There is no objective time. There is a difference between time and measures of time. Think of it this way, it is possible to measure the height of a person. To do so, there needs to be a measure of height – meters, centimeters, feet and inches etc. But does “height” exist? It is merely a measure assigned to a person.
Time measurement. In modern times, the standard for time measurement is the count of the vibrations of a certain atom. A second in time is defined (by humans). This measure is universal so, as long as the right atom is measured and a counter available, it is possible to figure out what one “second” is.
Reference time. This is the division of passing time into things like days, weeks, months, dates. This is also human created and the nearly universally agreed upon major division is the day because there is a very obvious noon (sun overhead, short shadow) that is common to anyone on earth. It is very easy to measure the difference between one noon and the next. Other things like the period of a year are also observable, if we use telescopes. But the other references like month, day, year (2022AD, lunar etc) are not. If this knowledge were erased from everyone, there would be no way to recover it. It would be guesswork.
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