The measurement of earth orbiting for one revolution around the sun (a unit of time we refer to as a year) isn’t arbitrary. It’s clearly defined. You’ve either made one complete revolution or not. It’s just that the original starting point for the first measurement was arbitrary because you’d have to start somewhere.
Many forms of measurement are based on absolutes, like temperature, measured from absolute zero, or time, measured against the cesium standard (atomic clock). You’d have to break physics in order to be able to define them as arbitrary.
The modern definitions of units feel even more arbitrary because they are inextricably tied to more organic origins. Consider the often made fun of fahrenheit scale which was the first to define a reasonably repeatable degree size by using two widely available reference points as the 100 and 0 ends of the scale, human body temperature for the high end and an ammonium chloride ice water mix for the low end.
The definition of a second was a bit jankier. Etymologically the name comes from a second hand added to a watch face to give some kind of indicator that the minutes are passing by. NIST has an excellent writeup on this subject. Over time different repeatable ways to measure a second have been determined all with the goal of having some action a human could use to calibrate their device’s second measurement to so their seconds are as long as everyone else’s.
The point is, we didn’t choose a second to be defined as some number of atomic oscillations. We had an already agreed upon definition of a second that used less precise methods than modern technology demanded and used a natural phenomenon that could be very accurately measured to make a less arbitrary definition.
Yeah and second is a 60th of a 60th of a 24th of a day. We just found the number of times cesium vibrates in that amount of time. 60 and 24 seem arbitrary to us now, but in addition to giving nice and useful chunks of time, they’re numbers that wouldn’t feel as arbitrary to ancient folks
Which is why I said define arbitrary earlier. I believe it had to do with accuracy of measurement equipment in the 1950’s as well as the ephemeral time scale, which was based on the observed movements of astronomical entities. So you can kinda argue either way. The selection of units can be influenced by an older system like you said, but that still is a system that was based on an observable or measurable phenomenon, which doesn’t fit the definition of arbitrary.
Maybe those planets/stars in the cartoon were aware of their own non-linear travel, as well as red/blue-shift effects, and that we earthlings based our original systems of measurement on them without prior knowledge of those factors, thus making them inconsistent and arguably arbitrary haha
I believe that was because at the time of its discovery, that was the most accurately we could measure it. It’s still based on a stable, constant, absolutely measurable phenomenon though. You can divide it into whatever arbitrary or non-arbitrary units you want, but that system of measurement is still based on an absolute standard.
It’s like saying that we now define one year as 1.234 earth revolutions around the sun. Or 2. Or whatever. Arbitrary units perhaps, but still based on an absolute phenomenon.
If you really want to throw a wrench into this whole concept though, mention that the earth’s rotation is slowing ever so slightly over time… so we have to add time on to the atomic clock to attempt to sync it better with the earth’s non-linear rotational velocity. Who’s arbitrary now?! 😀
But divisions of time are arbitrary, no? 60 seconds per minute, 60 minutes per hour, 24 hours per day, 30(ish) days in a month, 12 months in a year. There were other ways to divide all that up. There’s reasons they were divided that way, but the fact that we have to add a day every 4 years just because it’s not perfect says a lot haha
If there were reasons that it was divided that way, as you said, then that would make it non-arbitrary, as it was based on a system of logic. Define arbitrary, I guess.
Perhaps it would appear to be arbitrary though to those who aren’t aware of those reasons/logic, like the astronomical objects in the cartoon 🤷♂️😀
January 1st is defined, but it’s still pretty arbitrary. It would make more sense if it were the solstice 10 days earlier or the spring equinox or summer solstice etc. because at least that’s the start/end of “something”
The Julian calendar, the predecessor to the modern Gregorian calendar, didn’t quite fully account for leap year shenanigans, and so drifted be about 1 day every century. The Gregorian calendar changed the way leap year works, but didn’t reset the beginning of the year. It just froze the drift where it was at the time.
Aren’t all forms of measurement (in this case it’s a measurement of time) completely arbitrary?
The measurement of earth orbiting for one revolution around the sun (a unit of time we refer to as a year) isn’t arbitrary. It’s clearly defined. You’ve either made one complete revolution or not. It’s just that the original starting point for the first measurement was arbitrary because you’d have to start somewhere.
Many forms of measurement are based on absolutes, like temperature, measured from absolute zero, or time, measured against the cesium standard (atomic clock). You’d have to break physics in order to be able to define them as arbitrary.
There’s still a ton of non-absolute values though. Like the difference between absolute zero and absolute zero + 1.
Choosing one second to be 9192631770 transitions of a caesium atom seems quite arbitrary.
The modern definitions of units feel even more arbitrary because they are inextricably tied to more organic origins. Consider the often made fun of fahrenheit scale which was the first to define a reasonably repeatable degree size by using two widely available reference points as the 100 and 0 ends of the scale, human body temperature for the high end and an ammonium chloride ice water mix for the low end.
The definition of a second was a bit jankier. Etymologically the name comes from a second hand added to a watch face to give some kind of indicator that the minutes are passing by. NIST has an excellent writeup on this subject. Over time different repeatable ways to measure a second have been determined all with the goal of having some action a human could use to calibrate their device’s second measurement to so their seconds are as long as everyone else’s.
The point is, we didn’t choose a second to be defined as some number of atomic oscillations. We had an already agreed upon definition of a second that used less precise methods than modern technology demanded and used a natural phenomenon that could be very accurately measured to make a less arbitrary definition.
Yeah and second is a 60th of a 60th of a 24th of a day. We just found the number of times cesium vibrates in that amount of time. 60 and 24 seem arbitrary to us now, but in addition to giving nice and useful chunks of time, they’re numbers that wouldn’t feel as arbitrary to ancient folks
Which is why I said define arbitrary earlier. I believe it had to do with accuracy of measurement equipment in the 1950’s as well as the ephemeral time scale, which was based on the observed movements of astronomical entities. So you can kinda argue either way. The selection of units can be influenced by an older system like you said, but that still is a system that was based on an observable or measurable phenomenon, which doesn’t fit the definition of arbitrary.
Maybe those planets/stars in the cartoon were aware of their own non-linear travel, as well as red/blue-shift effects, and that we earthlings based our original systems of measurement on them without prior knowledge of those factors, thus making them inconsistent and arguably arbitrary haha
I believe that was because at the time of its discovery, that was the most accurately we could measure it. It’s still based on a stable, constant, absolutely measurable phenomenon though. You can divide it into whatever arbitrary or non-arbitrary units you want, but that system of measurement is still based on an absolute standard.
It’s like saying that we now define one year as 1.234 earth revolutions around the sun. Or 2. Or whatever. Arbitrary units perhaps, but still based on an absolute phenomenon.
If you really want to throw a wrench into this whole concept though, mention that the earth’s rotation is slowing ever so slightly over time… so we have to add time on to the atomic clock to attempt to sync it better with the earth’s non-linear rotational velocity. Who’s arbitrary now?! 😀
But divisions of time are arbitrary, no? 60 seconds per minute, 60 minutes per hour, 24 hours per day, 30(ish) days in a month, 12 months in a year. There were other ways to divide all that up. There’s reasons they were divided that way, but the fact that we have to add a day every 4 years just because it’s not perfect says a lot haha
If there were reasons that it was divided that way, as you said, then that would make it non-arbitrary, as it was based on a system of logic. Define arbitrary, I guess.
Perhaps it would appear to be arbitrary though to those who aren’t aware of those reasons/logic, like the astronomical objects in the cartoon 🤷♂️😀
January 1st is defined, but it’s still pretty arbitrary. It would make more sense if it were the solstice 10 days earlier or the spring equinox or summer solstice etc. because at least that’s the start/end of “something”
In this case I might argue that there are more “natural” points of reference (eg. solstices/equinoxes).
We use political/religious markers instead which are completely irrelevant to the planet’s orbit.
I mean, winter solstice is a little more than a week away, I’d say that was probably a significant influence on the designation of end of the year.
The Julian calendar, the predecessor to the modern Gregorian calendar, didn’t quite fully account for leap year shenanigans, and so drifted be about 1 day every century. The Gregorian calendar changed the way leap year works, but didn’t reset the beginning of the year. It just froze the drift where it was at the time.
https://en.m.wikipedia.org/wiki/Gregorian_calendar