## A Case For Decimal Time

Centuries ago, the metric system was devised to unify varying local or cultural measuring systems and to simplify their use by utilizing a decimal, or base-ten, system of divisions. Curiously, while the originators of the metric system and subsequent supporters used it to measure and define nearly everything on earth and in space, the only quantifiable concept that was not subjected to decimalization was time.

The only real attempt to decimalize time was made by the French two years before their adoption of the metric system, but for some reason, when the French officially adopted metrics, time was left off the list. It could be that decimal time was dropped because the French public was not very accepting of its imposition two years earlier. But, since the French government subsequently imposed the new decimal system of measuring nearly everything else to replace previous cultural units, it is strange that time was not included as well.

Of course, to be factually correct, the second was adopted as the metric unit of time, but was only decimalized in its subdivision, not in its greater units, which remained the minute, the hour, and the day. While every other unit of measurement under the System International was decimalized both above and below, the second glaringly stands out as the only unit not treated so. I could find no reason or rationale for this action. It would seem that since those who developed the metric system went to so much trouble to decimalize every other conceivable unit of measurement that they would do the same with time. But they didn’t.

Therefore, in order to finish what they started but failed to complete, and to finally bring all units into compliance with the base-ten system, I propose the adoption of decimal time.

The problem is where to begin. That is, what should be our base unit upon which to build. Technically, the second, as a metric unit of time, was originally defined as 1/86,400 of a mean solar day. Since those who conceived of the metric system in the first place were obsessed with everything being based on units of ten, why they chose 1/86,400 of a mean solar day as their base unit, instead of 1/100,000 or 1/10,000, I do not know, unless it was intentionally done to keep the second as close to its traditional length as possible.

Thus, a decimal system of time could be built upon the second as its base unit, increasing in units of ten, just as it already is defined to decrease. Conforming to already established metric prefixes for all other units then, ten seconds would become a decasecond and 1/6th of an hour. Ten decaseconds or a hundred seconds would become a hectosecond, one minute and forty seconds or 1 2/3 hours. A kilosecond, 1,000 seconds, would become 16 minutes and 40 seconds or 0.27778 hours. And a megasecond, a million seconds, would be about 16,666.667 minutes or 277.778 hours, about 11.57 days. Of course, under this system, the concept of a minute and an hour would lose all definition. But there would be no way to discount the day, which would then be defined as 86,400 seconds, and would convert to 864 hectoseconds, 86.4 kiloseconds, and 0.086 megaseconds. An earth year would come out to be about 31.547 megaseconds.

Faced with the tediousness of system based on the second, I would propose using the full earth day, which would be more easily defined and would cross all cultures on the planet, all of whom would be familiar with that concept. Using the metric system’s base-ten, the earth day would be divided into ten equal units called an hour. Again using already established metric prefixes, each hour would be divided into ten decihours, 14.4 minutes long, using the present time units. A centihour, or hundredth of our new hour, would be 1.44 minutes long and a millihour would be .144 minutes long, or 8.64 seconds.

Continuing with the present conventions of metrics, the next smaller unit would be a microhour, 0.000144 minutes or 0.00864 seconds long. A unit of time this short would be of use only to scientist and researchers and not suited to everyday life. There would be no unit close to the interval of a second under this system, with the exception of what could be called a tenth millihour, 0.864 seconds long—fairly close to the current second.

The only real attempt to decimalize time was made by the French two years before their adoption of the metric system, but for some reason, when the French officially adopted metrics, time was left off the list. It could be that decimal time was dropped because the French public was not very accepting of its imposition two years earlier. But, since the French government subsequently imposed the new decimal system of measuring nearly everything else to replace previous cultural units, it is strange that time was not included as well.

Of course, to be factually correct, the second was adopted as the metric unit of time, but was only decimalized in its subdivision, not in its greater units, which remained the minute, the hour, and the day. While every other unit of measurement under the System International was decimalized both above and below, the second glaringly stands out as the only unit not treated so. I could find no reason or rationale for this action. It would seem that since those who developed the metric system went to so much trouble to decimalize every other conceivable unit of measurement that they would do the same with time. But they didn’t.

Therefore, in order to finish what they started but failed to complete, and to finally bring all units into compliance with the base-ten system, I propose the adoption of decimal time.

The problem is where to begin. That is, what should be our base unit upon which to build. Technically, the second, as a metric unit of time, was originally defined as 1/86,400 of a mean solar day. Since those who conceived of the metric system in the first place were obsessed with everything being based on units of ten, why they chose 1/86,400 of a mean solar day as their base unit, instead of 1/100,000 or 1/10,000, I do not know, unless it was intentionally done to keep the second as close to its traditional length as possible.

Thus, a decimal system of time could be built upon the second as its base unit, increasing in units of ten, just as it already is defined to decrease. Conforming to already established metric prefixes for all other units then, ten seconds would become a decasecond and 1/6th of an hour. Ten decaseconds or a hundred seconds would become a hectosecond, one minute and forty seconds or 1 2/3 hours. A kilosecond, 1,000 seconds, would become 16 minutes and 40 seconds or 0.27778 hours. And a megasecond, a million seconds, would be about 16,666.667 minutes or 277.778 hours, about 11.57 days. Of course, under this system, the concept of a minute and an hour would lose all definition. But there would be no way to discount the day, which would then be defined as 86,400 seconds, and would convert to 864 hectoseconds, 86.4 kiloseconds, and 0.086 megaseconds. An earth year would come out to be about 31.547 megaseconds.

Faced with the tediousness of system based on the second, I would propose using the full earth day, which would be more easily defined and would cross all cultures on the planet, all of whom would be familiar with that concept. Using the metric system’s base-ten, the earth day would be divided into ten equal units called an hour. Again using already established metric prefixes, each hour would be divided into ten decihours, 14.4 minutes long, using the present time units. A centihour, or hundredth of our new hour, would be 1.44 minutes long and a millihour would be .144 minutes long, or 8.64 seconds.

Continuing with the present conventions of metrics, the next smaller unit would be a microhour, 0.000144 minutes or 0.00864 seconds long. A unit of time this short would be of use only to scientist and researchers and not suited to everyday life. There would be no unit close to the interval of a second under this system, with the exception of what could be called a tenth millihour, 0.864 seconds long—fairly close to the current second.

Due to this shortcoming, I would further propose that the starting unit be based on the terrestrial day as defined by one complete rotation of the earth around its axis. Previous attempts at decimal time, not based on the second, have used the day as a basis. Because we divided the day into ten hours in the above scenario, basing our new system on the day makes it very similar, but more workable with smaller intervals of time.

Each day would be divided into ten subunits, again using our already established prefixes, called a deciday, and 144 minutes long, just like our metric hour in the previous example. The next divisions of the day would be the centiday, 1/100 day or 14.4 minutes long, and the milliday, 1.44 minutes long. The next unit on the list would be the microday, 0.00144 minutes or 0.0864 seconds long. Still too short to be of much use, but one could use ‘ten microdays’ as an approximation of one of the old units called a second, instead of a ‘tenth millihour.’ Still, it would be six to one, half a dozen to the other.

If we project ourselves even further out into the future when mankind has colonized other worlds with wildly varying periods of rotation, I don’t suppose it would matter much what the system was based on since the earth day would not mean much to someone on a planet with a thirty-six-hour day, or a ten-hour day, other than a standard. You could conceivably use almost any arbitrary unit of time, including the current definition of a second as “9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom.”

While decimal time has never really been tried in the real world, it has been used in the world of fiction, mainly science-fiction. In popular culture, probably its most prominent use was in the original Battlestar Galactica television series of the late ‘70s. The show’s creators used a base-ten system for time units, starting with the ‘centon,’ the show’s equivalent for our minute. A ‘micron’ was the show’s equivalent of a second, although it was 1/100th of a centon, and thus technically 0.6 seconds. The Colonial equivalent of an hour was called a ‘centar,’ and being 100 centons would actually be an hour and forty minutes. A week on the show was called a ‘secton’ and, using the base-ten system, would be 100 ‘centares,’ in our time, about 167 hours or 6.958 of our earth days, an amazingly close convergence. A ‘sectar,’ or Colonial month, was 10 sectons, about 70 of our earth days. The Battlestar Galactica year equivalent, was a ‘yahren.’ Though not specifically defined in the series, continuing the previous system, a yahren would likely be at least 10 sectars, or 700 of our days, a little less than two of our years. Their ‘millennium,’ or 1000 of their yahrens, would then be about 1,918 of our years and, just like the yahren, nearly double our earth millennia. As you can see, the system is not quite perfectly decimal, since sectars and yahrens are multiples of 10, not 100, but that was probably intentional for convenience sake to make the Colonial units approximate our standard months and years.

While it would seem more convenient, more intuitive, and more logical to have decimalized time above the second when the metric system was originally conceived, the current system of 60/60/24 seems now to be too entrenched to ever be dislodged. Who would want to go to the trouble of going back and converting all of the previous work and research done in the old system to the new one? The labor costs would be so enormous as to make it a waste of time to even consider changing our measurement of time to the base-ten system—which makes it all the more puzzling why the designers of the System International so long ago declined to include time in their original plan. That was their mistake and it is too late now to go back and undo it.

Despite its advantages over the uneven and unorthodox current division of time into seconds, minutes, and hours, the concept of a decimal or base-ten time system, for the present, seems to be confined to the realm of speculative science fiction. That is, until mankind breaks free from the shackles that bind us to this planet and is able to begin again somewhere else, or after an apocalypse that allows us to hit the reset button and start over.

Jeff Vanderslice

Each day would be divided into ten subunits, again using our already established prefixes, called a deciday, and 144 minutes long, just like our metric hour in the previous example. The next divisions of the day would be the centiday, 1/100 day or 14.4 minutes long, and the milliday, 1.44 minutes long. The next unit on the list would be the microday, 0.00144 minutes or 0.0864 seconds long. Still too short to be of much use, but one could use ‘ten microdays’ as an approximation of one of the old units called a second, instead of a ‘tenth millihour.’ Still, it would be six to one, half a dozen to the other.

If we project ourselves even further out into the future when mankind has colonized other worlds with wildly varying periods of rotation, I don’t suppose it would matter much what the system was based on since the earth day would not mean much to someone on a planet with a thirty-six-hour day, or a ten-hour day, other than a standard. You could conceivably use almost any arbitrary unit of time, including the current definition of a second as “9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom.”

While decimal time has never really been tried in the real world, it has been used in the world of fiction, mainly science-fiction. In popular culture, probably its most prominent use was in the original Battlestar Galactica television series of the late ‘70s. The show’s creators used a base-ten system for time units, starting with the ‘centon,’ the show’s equivalent for our minute. A ‘micron’ was the show’s equivalent of a second, although it was 1/100th of a centon, and thus technically 0.6 seconds. The Colonial equivalent of an hour was called a ‘centar,’ and being 100 centons would actually be an hour and forty minutes. A week on the show was called a ‘secton’ and, using the base-ten system, would be 100 ‘centares,’ in our time, about 167 hours or 6.958 of our earth days, an amazingly close convergence. A ‘sectar,’ or Colonial month, was 10 sectons, about 70 of our earth days. The Battlestar Galactica year equivalent, was a ‘yahren.’ Though not specifically defined in the series, continuing the previous system, a yahren would likely be at least 10 sectars, or 700 of our days, a little less than two of our years. Their ‘millennium,’ or 1000 of their yahrens, would then be about 1,918 of our years and, just like the yahren, nearly double our earth millennia. As you can see, the system is not quite perfectly decimal, since sectars and yahrens are multiples of 10, not 100, but that was probably intentional for convenience sake to make the Colonial units approximate our standard months and years.

While it would seem more convenient, more intuitive, and more logical to have decimalized time above the second when the metric system was originally conceived, the current system of 60/60/24 seems now to be too entrenched to ever be dislodged. Who would want to go to the trouble of going back and converting all of the previous work and research done in the old system to the new one? The labor costs would be so enormous as to make it a waste of time to even consider changing our measurement of time to the base-ten system—which makes it all the more puzzling why the designers of the System International so long ago declined to include time in their original plan. That was their mistake and it is too late now to go back and undo it.

Despite its advantages over the uneven and unorthodox current division of time into seconds, minutes, and hours, the concept of a decimal or base-ten time system, for the present, seems to be confined to the realm of speculative science fiction. That is, until mankind breaks free from the shackles that bind us to this planet and is able to begin again somewhere else, or after an apocalypse that allows us to hit the reset button and start over.

Jeff Vanderslice