What is hammer time?

Hey there Dr. Johnston and thanks for doing the AMA!

I do feel the need to ask, why was the Great Pyramid considered as the source for the Prime Meridian?

Hi Dr. Johnston!

Without sounding too stereotypically Reddity, what are or were time guns? How did they come about and how widespread were they?

I'm definitely interested in the "Indigenous communities that used timekeeping to fight for autonomy" story, and wondering what the interactions were like between various imperial powers and Indigenous people when it came to communicating/forcing compliance with concepts of time. What sorts of pushback/promotion of alternative/indigenous timekeeping occurred, and how have they survived?

Thank you for taking questions Dr Johnson.

My question is this: Time services, such as those based out of Halifax, initially used syncing processes with a local clock at a known time to help adjust the clocks kept on the ships. In the case if Halifax specifically, money was provided by the British to support and maintain the time adjustment, but the local government chose to not spend those funds, and instead chose to allow a single private clockmaker to make the adjustments for arriving ships (at a nice profit of course). (This anecdote is recounted in "The Beginning of the Long Dash" by Thompson) Somewhat consequently the Dominion/Canadian government eventually helped establish their own time service through the Dominion Observatory. Are there, to your knowledge, other examples internationally of this kind of "privatisation" during the establishment of time services? Were there any other regions where the adjustments were made by private entities rather than scientific or military departments of government? Most importantly, did these entities actively try slow or disrupt the Standardization of time for profit?

It’s easy enough to conventionally understand the concept of days, but why did we divide days into 24 hours of 60 minutes of 60 seconds? Why are weeks 7 days and not 9 or 12 or whatever?

Good afternoon from the UK, Dr!! If you were asked to invent your own system of time measurement in a completely fantastical setting, what do you think it might look like?

Thanks for this AMA.

Could you talk about daily life impacts of time zones, particularly on the edges? I'd guess if you're someone working outside of railroads or other jobs that need precise hours and minutes living on the border of a zone had a different impact on how you adopted zones and experienced time.

How is time kept on the moon or Mars? Just by reference to Earth time or do they have their own time zones etc.

Maria Belville, who sold the time door to door in Victorian London

I'm sorry, what? What does it mean to sell the time? I take it to mean she went door to door telling people what time it is for a fee, but that seems ridiculous in light of older, much more practical methods of keeping time.

Are there accounts of scammers or other dishonest actors in the history of timekeeping?

Hello! I'd love to hear about timekeeping in schools! One thing I've always been curious about is the feedback loop between changes in schools and commercial products. For example, the NEA Committee of Ten reports recommended 40 to 50 minute periods for high schools in the late 1890s based on patterns they were seeing across the country. I'm curious if schools got to that particular time chunking on their own or if there were school bell and alarm manufactures advertising systems set to that timeframe. That is, what came first - the bell or the end of the class period?

(Also, if you've come across anything about Wirth's Platoon Plan and timekeeping that you'd like to share, I'm all ears!)

Thanks for doing this AMA!

Thank you for a great AMA. When the French adopted the metric system I understand they also had a metric calendar and metric hours/minutes system. Given the success of the other systems, why didn't the timekeeping metric system catch on?

I've always been really curious if there are any differences regarding perception of time for cultures that developed near the equator vs near the poles.

For example, right on the equator, seasonal changes are virtually nonexistent and days are near equal all the time, but at the arctic circle, you've got very dramatic and very regular cycles of change in the environment. Does it seem like that had any impact on how time is understood, especially over longer spans?

Vienna, and later Paris, had pneumatic clock networks, that connected a master clock with many slave clocks by puffs of air going through pipes. It was around this time (1850s to 1900s) that precision started to become important on a local level. What technological or societal advancements lead to the need of these centrally synchronised clock systems, which followed from them, and what other technologies achieved the goal of precise local time synchronisation? Thanks for the Ama :)

Hello Dr Scott and thank you for this great AMA! As someone lucky enough to go to a college named after Sandford Fleming himself, this is a subject I heard a fair bit about going to school! Just how influential was Fleming in getting standard time adapted? And what were some of the alternatives that were suggested?

Hello Dr. Johnston,

What has been, in your opinion, been the most creative form of timekeeping you've encountered in your career?

I once read that the rigor of the stagecoach system in Britain "horologically prepared" people for days measured and divided into minutes. What can you tell us about changing notions of punctuality over time?

Hello! Thanks for posting, Dr. Johnson.

I am curious if there has been anything unexpectedly dramatic happening in the more recent history of timekeeping (post atomic clocks and computerized timekeeping and the advent of “ticks” for timekeeping in the 70s). I am a computer programmer, and timekeeping is a tricky thing in some senses, and in others it is “solved.” We all have devices that call the various time servers on the net and so seem to be exactly in sync. But even so, as a developer I can’t rely on the time being correct on someone’s machine, and even if it is, it’s not precise under 200ms or so.

I spend so much time next to and around this stuff, and in the last 20 years it seems like things have generally been smooth sailing. I’m curious if there were any big struggles or intrigues or whatnot more like 40-60 years ago.

I am fascinated by the intersection of cartography and time keeping. I know that reliable timekeeping is necessary for surveys of coastlines because of its importance in navigation. When did chronometers become reliable enough and more importantly, how did they make sure they were reliable enough?

What, if any, role did timekeeping play in cartography ashore?

Were there areas which maintained a legacy timekeeping system for cultural or political reasons? I'm thinking of Russia's late adoption of the Gregorian calendar and the Russian Orthodox Church's refusal to consider the Gregorian calendar even until today. Were there similar holdouts when it came to timezones?

What role did colonialism and the resistance to colonialism play in the adoption of current timekeeping methods?

Can you please explain the medieval concept of 'unequal hours'?

Hi Dr. Johnston!

I would like to ask if there have there been instances of timezone political shenanigans or preparation for some?

For example, North Korea could choose to run it's timezone 15 minutes faster just to have its own timezone for purely political reasons. Or the west of China could argue for a timezone separate from the Beijing zone as it's population grows. Have timezones changed significantly or have countries refused to recognize a chosen timezone?

Hi Dr. Johnston!

I'm aware that an anarchist accidentally blew himself up on the way to Greenwich Observatory in the late 1800s, having intended to explode in the building itself (some debate on this point as it seems such an odd target, especially for such a small device). What impact (if any) would he have had on global timekeeping if he'd managed to blow it up completely?

How old are you?

Hi Scott, to what extent has Henri Bergson and his concept of duration influenced your research?

Hello Dr. Johnston,

I just finished reading Chasing Venus by Andrea Wulf which focused around one of the first global efforts by astronomers to measure an astronomical event in the 1760s when Venus passed across the Sun. The critical role of timekeeping was briefly mentioned a competition for the Longitude Prize between astronomer Nevil Maskelyne and clockmaker John Harrison.

Do you have more information worthy of sharing about this competition, the Longitude Prize, or the difficulty of transporting pendulum clocks across the oceans at the time? Anything on any of these topics would be interesting.

Also, a bonus if you're so inclined, I've also read A Geography of Time by Robert Levine and found what he shared about how different cultures view time differently pretty fascinating. I was wondering if you could share at least one unique cultural view of time that the average American or westerner might not understand but might have touched you as profound.

Thank you!

the debates about adopting the metric system

Why isn't most of the world using metric time the same way they use metric everything else? Seems odd to me.

As I understand it, with the increasing interval between leap seconds it looks like UTC might soon need negative leap seconds, potentially causing problems in systems that use it, to the point where there has been discussion of switching GPS-delivered time from UTC to International Atomic Time. Was the possibility of negative leap seconds contemplated when UTC was standardized? If so, was it thought to be a problem?

I'm familiar with the debate on the numeral IIII on clocks vs. the more traditional IV - you got anything really definitive on this?

Thank you for doing this AMA and the heads up about your new book!

As I understand it, before the telegraph was introduced, transferring time between different locations was no easy feat. Did different cities even attempt to synchronize with each other, or was timekeeping in each community its own enterprise? Were there attempts by governments to synchronize timing across a country or empire? How would this be done?

How much do you know about quantum physics and time? I was wondering if you've heard of Roger Penrose's Conformal Cyclic Cosmology theory. One of the more fascinating things he suggested was that, if there is a heat death of the universe where all massed particles decay, there would no longer be any means by which to create a clock (where lightspeed particles register a tick against something with mass), meaning time itself would end (or be meaningless).

Have any thoughts on the notion?

My understanding is that China uses one time zone, even though it spans five time zones. That's somewhat similar to the idea we all follow UTC instead of local time zones. Seems it could be convenient because it's the same time everywhere. But the idea of 7am being morning and noon being midday is gone. Do you know how that works out in practice?

There's an historical account of an eclipse happening over a thousand years ago that appearantly helped modern day astronomers refine their orbital model of the earth. I've tried without success to track this story down, do you have any more details? How many such historical records have actually proven useful in calibrating our orbital "clock"? Are there tantalizing events that astonomers predict should have been noticed, but somehow did not get successfully recorded?

Do you have any information on the creation of the unix timestamp, and the general hell that is dealing with timelines in modern devices?

There will be multiple timezones in other planets, like mars?

Can you explain TimeCube theory please?

I think you should also consider doing an AMA over at r/watches or r/Horology ... the real geeks are found over there.

Dr. Johnston,

Thank you for doing this AMA, I just have one question:

How often does someone send you the "time is a construct" .gif from Black Mirror: Bandersnatch?

Hello, as I understand GMT occurred as a result of British weight politically and economically. What is less unclear is when other nations accepted this as 'the central timezone' and why it did not change post ww2?

Is there an international legal treaty that governs time?

How do you think relativity will affect human timekeeping in the future?

How widespread is the cultural idea that time has a beginning or could conceivably stop? Are there any notable cultures that believe the opposite?

How have attitudes towards tardiness changed over time?

How would you feel about adopting a metric time system? Something like 100 seconds in a minute, a 100 minutes in an hour or similar?

What purpose does daylight savings have if any now days?

Were there any radical or outlandish claims when it came to time keeping?

I love the craziness of Anatoly Fomenko's New Chronology, and would be curious if there was any kind of outlandish pseudo science that timekeeping had to push back against when they were trying to organize, or maybe there was some pseudo science traps they fell into?

Hi, thanks for doing this! I’ve always wondered about the process for non European/North American countries adopting the UTC standardized clock. For instance, when and how did China or other East Asian countries adopt this new standard?

astronomy and timekeeping

I have always found it strange that the second is defined as 9,192,631,770 "oscillations" of a caesium atom. This seems to me we were looking for a physical phenomena "close" to our pre-existing definition of the second.

One thing I am curious about is if there was any effort to more precisely tie the second to the angular rotation of the earth. More specifically - there are 360 degrees in a circle - 60 minutes per degree - 60 seconds per minute. Was there effort to tie the second of rotation to the measured second of time keeping? If so - what prevented its adoption?

Newfoundland's time zone is unusual because it's 3 hours and 3 minutes later than GMT, as opposed to being based on hours difference. So at noon GMT it's 8:30am in Newfoundland.

That's always seemed really odd to me because almost all other time zones are based on the hour, not a fraction of it. Do you know how Newfoundland decided to do that? Does it cause problems for them? Did other places try that originally and then go to the hour difference?

The book costs over 47 euro on Bookdepository, and what's more it's already sold out.

When will it be available as a paperback, hopefully at a more reasonable price?

This question is a bit silly but how important were roosters in timekeeping for an average peasant?

Will there be an audio version of your book?

What do you mean by 'selling the time'?

I’m very impressed by this thread and the Dr. Johnston. Until this day the words time and historian never entered my mind consecutively. I’m now intrigued and will be getting your book!

Does political and/or economic ideology change how one might perceive or relate to time?

Is it true that the widespread availability of fairly-precise clocks in the 19th century was due in part to the rise of capitalism and the Industrial Revolution? That is, that Labor needed a way to measure their exchange with Capital, and vice-versa? Or is it just one of those things that seems like a tidy, convenient theory in hindsight and wasn't actually a motivating factor?

I've never understood how Asian countries (and especially anti-western countries like the DPRK) came to adopt the western calendars. When/why did they adopt the solar calendar with 12 months? The 7 day work-week plus weekends? 60 minute hours? etc.

OK... The metric system? I'm familiar with decimal time / the French revolutionary calendar - is that what you're talking about?

How much of your book do you get into the social construct of time and things like the difference between polychronic and monochronic time systems/cultures?

Why do some societies use a twenty-four hour clock and others use a twelve hour clock? For example: french and english Quebec.

Are there any implications to negative leap seconds that impact anything people might notice? We are in the early part of a trend, that if it continues, rather than adding leap seconds as we have always done, we may need to remove one (10+ years from now).

Time is a human contruct, most useful to people because it allows us to coordinate activities, to work together. That's what makes us such a powerful species. (Well, we had to have the intelligence to abstractly reason, to generate the idea of time, to begin with. I imagine that we're the only species that thinks it lives in time. That time is something to live in.)

The odd thing is, most people think it's some kind of force, that it causes or allows things to happen. But, the fact is, unless motion/change happens, time means nothing. Thus, it's all motion/change, and time is just the way we measure it. One change against another, until we standardized one change - clocks, which would change at a pretty stable rate. Then Newton came along and hypothesized that time is some absolute...something that happens whether or not any other change in the universe is happening. But, if you ask where the evidence for that is, it turns out that there isn't any. From this perspective, it's absolutely amazing how often peole talk about time as though it's some real...force? Dimension? WTF?

Do you think civilization will eventually start using a time system with measurements of 10, like the metric system?

If time is constructed, can it be deconstructed. If so, how? Please. I promise I won't deconstruct time. I just want to know how.

Hi Dr. Johnston, are you aware of societies through history with no concept or a very foreign (e.g. non-linear) concept of time and if so, how that has shaped their culture?

Great AMA!

In the 60s when Canada switch to metric the CBC Punk'd people by pretending that they would also switch to metric time. It may have been April fools.

Supposedly they had news broadcast where they said for example, hello everyone the time is 8:17 a.m. or 12.72 metric time.

I always thought this was purely a joke but you said the metric system was important for the adoption of time.

Was there ever such thing as metric time?

Thank you!

Moraviantown and other Indigenous communities that used timekeeping to fight for autonomy

Which time system is the most alien a modern westerner?

Have you ever read Thief of Time by Terry Pratchett?

Do you think humankind is better off with a universal time system (supply chain, broadcasting, transportation, etc.) or without one (sleeping properly, less schooling and working in the dark, more natural light, etc.)?

Do you get many Rocky Horror references, Dr. Scott?

I'm probably too late for this AMA, but:

Why is IST (India) half a time zone away? What was the argument that this was preferred over a simpler calculation?

When was the emergence of the 7 day week? What almost prevailed instead? Within the 7 day framework, any record of the regional time keepers missing a day and having to reconsile the particular day of the week with other regions?

Can you share any particularly interesting or unique historical methods for keeping time that you've come across?

How does the modern exchange of the highest precision time information work, like how does TAI coordinate globally? Is it all satellite based or do they use fiberoptics too?

We're about to start a pilot project with our national metrological institute and some interested parties to transport precicse time information through our country and we'll use WhiteRabbit in our fibers, but I imagine that's not good enough for TAI, so I'm curious.

What are the origins of the Swiss watch making industry? (Apologies If this has already been asked)

Why do we have 24 hours in a day? Why 2*12 hours? And why 60 min and 60 secs. in a hour/min.?

Can you explain, like I'm five years old, how marine chronometers were developed and how they work?

have seconds, minutes, and hours always been the default units for time? did other/ancient civilizations use different ones?

How lucky are we that our day is close to 24 hours and our year is close to 360 days? This almost perfectly fits a circular model. Was this helpful to ancient time keepers?

I’m curious what do you think of the labour issues related to the development and spread of time? Do you think they are central to the spread of the global time? I’m thinking the Taylor system

You mentioned that the metric system and timekeeping are surprisingly close. Can you explain that more?

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On another note, I grew up in Arizona, US, where we don't do daylights savings. I now live in Bern, Switzerland, where they do daylights savings. How can I escape my twice-yearly existential crisis of "right now it's four o'clock, but yesterday right now it was five o'clock"?

Time is the original Matrix. What are your thoughts on the recent BLC-1 radio signal that turned out to be "common clock oscillator frequencies"?

When time was first created and implemented, idk when that was or how universal it was from the jump but i assume it started with one place, a town, city, tribe whatever, when we first began to record actual time, did we start at zero? Did we just start off at midnight one day? Or 6 or zero hundred or whatever?

Was there a way to measure longitude at sea without clocks?

What made us choose this highly arbitrary way of cutting up time in base systems that don’t convert into each other nicely?

In other words, when will the metric system drop an album concerning time?

George Carlins stand up about Time is what made me originally even think about it. Everyone just accepts that it's this time.

"Excuse me, do to have the time?"

"Uhh, let me check real quick, I can tell you I certainly didn't have it this morning. Oh, that's right, I think the navy got it, in a lab somewhere, and everyday they let out a little bit...."

"Think about it, what time is it?! I don't mean, what time is it? I mean, WHAT TIME IS IT!! WHEN THE HELL IS IT!! We think we know where we are but we really don't know when we are. It could be the middle of last week for all we know!"

Do you believe in the fact that people slept in two phases before artificial light was abundant and did it have an effect on peoples perception of time?

Is this going to be available in an audiobook?

Hi! I've ways wondered why Swiss clocks have the number 4 wrong in Roman numerals. Never managed to find an answer that made sense.

I've heard that Dec 21 2012 still hasn't happened as our current time is wrong and only the Ethiopians hold the true untouched time. It's this true?

I've heard about incense clocks before. I think they're neat, and impressive but how reliable were those? Additionally what would a person back then when they forgot to maintain their clock of choice (grandfather clock, water clock, incense clock, etc.), and had to reset the clock to the correct time again? How would they know what the correct time is?

Hi Dr. Johnston, can you give us a sense for how various cultures subdivided time? Like 60 minutes and 24 hours...how did other cultures subdivide a day?

Not a history question, more of a future question.

When society eventually takes to the stars and inhabits multiple planets, space stations, moons and asteroids, how will universal time be organized? What is your best proposal for how we can record 'when something happened' for multiple observers, when the speed of light is a factor?

My cousin lives in 0gmt and I live in gmt+8. How do I trick her into calling me at 12 noon more often?

How in the world could you ever justify selling the Kindle version of your book for $37? I was interested until I saw the price. You can keep it. I'm not that interested...

I took a graduate class back around 2000, and we read a book that dealt with the history of time including how the ancients would tell time. I can't remember the name, but I thought it was pretty good.

What is the meaning of life?