5 ms·

There's a clock using French Revolutionary Time exposed at Musée des Arts et Métiers if you happen to be in Paris and want to see one. I've been using centiday

by vinc 7y ago

There's a clock using French Revolutionary Time exposed at Musée des Arts et Métiers if you happen to be in Paris and want to see one. I've been using centidays (and dimidays) for a few years now and it works well for me as a personal time keeping system in combination with local time (at local noon the sun is at its highest point in the sky and the clock shows 50:00) and a lunisolar calendar. More on that here: https://geodate.org https://geodate.org A centiday is precisely 864 seconds, and 4 centidays is almost equivalent to 1 hour (3456 seconds) so it's not too hard to make rough conversions. I made a little Fitbit app so my watch could display the time (with the longitude given by the GPS of my phone) and I have a sundial in the garden that works just as well. It's quite fun to play with time keeping systems.

phicoh 7y ago
In the context of the metric system, the problem is that the second and the 'day' don't line up. From a human time keeping point of view, days and fractions of days would be ideal. However, actual days are nowhere close to a fixed amount of time. And for historical reasons we are stuck with a very precisely defined second that is based on 24 hours in a day. So the obvious approach would be to define a new unit of time that is roughly equivalent to a milli- or microday. But the chance of that happening is close to zero. So we are stuck with the second as the fundamental unit of time. Having a 'centiday' as 864 seconds would be even more removed from the principles of the metric system than a 3600 second hour.
- vinc 7y ago
  Indeed, using the day as the fundamental unit may be a nice choice for humans on this planet as a personal system, it's equivalent to looking up and telling the time by the position of the sun in the sky, but it's not accurate nor regular due to celestial mechanics, so the second used by the metric system is much more universal and unlikely to change anytime soon. Thanks to our computers that keep track of every seconds elapsed since Unix Epoch, I can use them when I want to convert from my personal system to any other system or vice versa: $ geodate 51.1789 -1.8262 $(date +%s --date "12:00 +0100") --format "%c:%b" 45:33 hours:seconds => timestamp => centidays:dimidays
- WorldMaker 7y ago
  Sci-fi writers, most notably Vernor Vinge, have played with Metric Time [1] of the modern sort of being entirely second-based. It's interesting because it particularly exposes interesting flaws in using metric prefixes (that are sometimes also talked about in the world of grams where kilograms are the closer unit to most "human applicability" and that a more human scale would possibly have more prefixes near kilogram than gram). Particularly the magnitude jump from a kilosecond (16.7 minutes, about a quarter hour) to megasecond (11.6 days, nearly a fortnight). I've heard fun proposals that if Metric Time based on seconds were to be more useful on human timescales to bring back the deceased Metric prefix myria- [2]. A myriasecond is 167 minutes or just less than three hours (2.78). Maybe a prefix for the next digit as well (10^5) which would be just more than a day, by about an eighth of a day (27.8 hours). [1] https://en.wikipedia.org/wiki/Metric_time https://en.wikipedia.org/wiki/Metric_time [2] https://en.wikipedia.org/wiki/Myria- https://en.wikipedia.org/wiki/Myria-
  - phicoh 7y ago
    It is mainly what we are used to. For power we have kilowatt, megawatt, gigawatt, no problem. For gram, meter and second, we have milli, micro, nano, etc. no problem. But we don't have megagram, megameter because we not used to it. Just like you can easily talk about 10 km, 20 km, etc. you could easily talk about 10 ks, 20 ks, etc. no need for a special name. We are just not used to it.
    - WorldMaker 7y ago
      It's not just about what we are used to. The argument about where the "central" point in the scale matters (for seconds and for grams) because the prefixes are by their very nature logarithmic, with "easier" distinctions made close to the center point/0-point on the scale axis than further away in the scale. milli-, centi-, deci-, deca-, hecto-, kilo- are all six very close surrounding the 0-point/origin. Everything else gets logarithmically further out. Using second as the 0-point is great for computation, as milliseconds and even microseconds can matter to a computer, but it isn't great for the human perception of time where people are bad at even granulizing events that happen in deciseconds, leaving nearly all of the decimal prefixes almost useless in human timescales. Which is why you see the French Decimal Time system mentioned in the article here and used by the poster above in this thread centered around the day as its 0-point. milliday, centiday, deciday, decaday, hectoday, and even kiloday are all relatively useful units in a human timescale. While you are correct that we don't "need" that kind of vocabulary, the argument is that it would be useful in conversation and in day-to-day (fig. and lit.) math. Having additional prefixes serves as mental anchors/frames for the conversation. If I give a number of seconds to you as hundreds of milliseconds versus deciseconds, that gives you additional context about my methodology and/or focus in whatever that benchmark was. Sure, you can easily convert between the two prefixes, but that context can be useful. Just as the difference between if I tell you something is happening in hundreds of minutes from now versus threes of hours from now. There's probably a useful contextual distinction there. That's why people play with solutions like Decimal Time changing the scale altogether away from seconds to something more like an Earth day, or in the other direction explore ideas with more prefixes to fill in some of the logarithmic "gaps" such as myria- and hebdo-.
rakoo 7y ago
There is also the (Swatch) internet time (https://en.m.wikipedia.org/wiki/Swatch_Internet_Time https://en.m.wikipedia.org/wiki/Swatch_Internet_Time) that divides a day into 1000 units. I haven't used either system, but I can see a few advantages: - the .beat (a 1/1000th of a day) is equal to 1m26.4s, so it's enough to point at various points in time, rather than have 2 numbers - if more precision is needed, "centibeats" (1/100th of a .beat) exist, and are very close to a second so it's easier to grasp (0.864s) - taking a 1/1000th of a unit is the standard way of going up and down in units, rather than going 1/100th twice - I don't know if the French decimal time has ever been adopted beyond amateurs, but internet time has been (for a very short time at least)

by vinc 7y ago

phicoh 7y ago

In the context of the metric system, the problem is that the second and the 'day' don't line up. From a human time keeping point of view, days and fractions of days would be ideal. However, actual days are nowhere close to a fixed amount of time. And for historical reasons we are stuck with a very precisely defined second that is based on 24 hours in a day. So the obvious approach would be to define a new unit of time that is roughly equivalent to a milli- or microday. But the chance of that happening is close to zero. So we are stuck with the second as the fundamental unit of time. Having a 'centiday' as 864 seconds would be even more removed from the principles of the metric system than a 3600 second hour.

vinc 7y ago
Indeed, using the day as the fundamental unit may be a nice choice for humans on this planet as a personal system, it's equivalent to looking up and telling the time by the position of the sun in the sky, but it's not accurate nor regular due to celestial mechanics, so the second used by the metric system is much more universal and unlikely to change anytime soon. Thanks to our computers that keep track of every seconds elapsed since Unix Epoch, I can use them when I want to convert from my personal system to any other system or vice versa: $ geodate 51.1789 -1.8262 $(date +%s --date "12:00 +0100") --format "%c:%b" 45:33 hours:seconds => timestamp => centidays:dimidays
WorldMaker 7y ago
Sci-fi writers, most notably Vernor Vinge, have played with Metric Time [1] of the modern sort of being entirely second-based. It's interesting because it particularly exposes interesting flaws in using metric prefixes (that are sometimes also talked about in the world of grams where kilograms are the closer unit to most "human applicability" and that a more human scale would possibly have more prefixes near kilogram than gram). Particularly the magnitude jump from a kilosecond (16.7 minutes, about a quarter hour) to megasecond (11.6 days, nearly a fortnight). I've heard fun proposals that if Metric Time based on seconds were to be more useful on human timescales to bring back the deceased Metric prefix myria- [2]. A myriasecond is 167 minutes or just less than three hours (2.78). Maybe a prefix for the next digit as well (10^5) which would be just more than a day, by about an eighth of a day (27.8 hours). [1] https://en.wikipedia.org/wiki/Metric_time https://en.wikipedia.org/wiki/Metric_time [2] https://en.wikipedia.org/wiki/Myria- https://en.wikipedia.org/wiki/Myria-
- phicoh 7y ago
  It is mainly what we are used to. For power we have kilowatt, megawatt, gigawatt, no problem. For gram, meter and second, we have milli, micro, nano, etc. no problem. But we don't have megagram, megameter because we not used to it. Just like you can easily talk about 10 km, 20 km, etc. you could easily talk about 10 ks, 20 ks, etc. no need for a special name. We are just not used to it.
  - WorldMaker 7y ago
    It's not just about what we are used to. The argument about where the "central" point in the scale matters (for seconds and for grams) because the prefixes are by their very nature logarithmic, with "easier" distinctions made close to the center point/0-point on the scale axis than further away in the scale. milli-, centi-, deci-, deca-, hecto-, kilo- are all six very close surrounding the 0-point/origin. Everything else gets logarithmically further out. Using second as the 0-point is great for computation, as milliseconds and even microseconds can matter to a computer, but it isn't great for the human perception of time where people are bad at even granulizing events that happen in deciseconds, leaving nearly all of the decimal prefixes almost useless in human timescales. Which is why you see the French Decimal Time system mentioned in the article here and used by the poster above in this thread centered around the day as its 0-point. milliday, centiday, deciday, decaday, hectoday, and even kiloday are all relatively useful units in a human timescale. While you are correct that we don't "need" that kind of vocabulary, the argument is that it would be useful in conversation and in day-to-day (fig. and lit.) math. Having additional prefixes serves as mental anchors/frames for the conversation. If I give a number of seconds to you as hundreds of milliseconds versus deciseconds, that gives you additional context about my methodology and/or focus in whatever that benchmark was. Sure, you can easily convert between the two prefixes, but that context can be useful. Just as the difference between if I tell you something is happening in hundreds of minutes from now versus threes of hours from now. There's probably a useful contextual distinction there. That's why people play with solutions like Decimal Time changing the scale altogether away from seconds to something more like an Earth day, or in the other direction explore ideas with more prefixes to fill in some of the logarithmic "gaps" such as myria- and hebdo-.

rakoo 7y ago

There is also the (Swatch) internet time (https://en.m.wikipedia.org/wiki/Swatch_Internet_Time https://en.m.wikipedia.org/wiki/Swatch_Internet_Time) that divides a day into 1000 units. I haven't used either system, but I can see a few advantages: - the .beat (a 1/1000th of a day) is equal to 1m26.4s, so it's enough to point at various points in time, rather than have 2 numbers - if more precision is needed, "centibeats" (1/100th of a .beat) exist, and are very close to a second so it's easier to grasp (0.864s) - taking a 1/1000th of a unit is the standard way of going up and down in units, rather than going 1/100th twice - I don't know if the French decimal time has ever been adopted beyond amateurs, but internet time has been (for a very short time at least)