Anyone here know the Time? No.
December 11, 2023 7:29 AM Subscribe
In Search of Lost Time. "If I’d gone to Boulder [NIST] expecting to find some unassailable master clock, surrounded by druidic time lords reverently conveying its results—the sacred source that had so captured my childhood imagination—what I found instead was rather disconcerting: Time, it would seem, is quite often out of joint."
A lovely essay on the delicate measurement of time and other things.
Years ago I had a coworker who had a couple atomic clocks of varying capabilities, sensitive enough that he could do amusing experiments like sync two, then take one up a high mountain pass in a truck and show how they were now different.
...anyway, his favorite quote was: "Someone with an atomic clock always knows exactly what time it is. Someone with TWO atomic clocks is never quite sure."
posted by aramaic at 7:47 AM on December 11, 2023 [32 favorites]
...anyway, his favorite quote was: "Someone with an atomic clock always knows exactly what time it is. Someone with TWO atomic clocks is never quite sure."
posted by aramaic at 7:47 AM on December 11, 2023 [32 favorites]
As a child, before gps receivers/mobile phone networks were widely available, I believed the new years eve broadcast, with it's large, friendly display of (seemingly) authoritative time, more than any other source to which I had access. I would eagerly try to sync my Casio wristwatch to the tv, usually trying several times to smash the tiny button at just the right instant, until I could perceive no difference between the two.
I wonder now how accurate that time was, especially when we were watching a rebroadcast of things that had happened in the eastern time zone.
I have occasionally been tempted to buy a rubidium oscillator reference, just because they are shockingly compact and (in a relative sense) affordable, but I have to many hobbies as it is.
posted by Pemdas at 8:09 AM on December 11, 2023 [5 favorites]
I wonder now how accurate that time was, especially when we were watching a rebroadcast of things that had happened in the eastern time zone.
I have occasionally been tempted to buy a rubidium oscillator reference, just because they are shockingly compact and (in a relative sense) affordable, but I have to many hobbies as it is.
posted by Pemdas at 8:09 AM on December 11, 2023 [5 favorites]
In the mid-80's I recall listening to the woman on the shortwave radio station WWV, tell us what time it was.
At that time, me and two others were tracking a comet (Giacobini-Zinner) across the sky as part of an Astronomy summer program. We needed the time to accurately track the position of G-Z across the night sky. And this fed into the calculation of the orbital elements.
Thinking about Time quickly descends into philosophical wells. How do we know an atomic clock keeps regular time? How do we measure its accuracy? We compare it against other clocks. It all works because it works.
But what if the physical constants involved are changing? What if Time is slowing down or speeding up? It can certainly do so locally. Time is affected by Gravity and by relative velocity. GPS clocks require corrections both for Special Relatitivy, which makes them tick slower than ground clocks and General Relativity, which makes them tick faster as they are higher in the Earth's gravity well.
posted by vacapinta at 9:00 AM on December 11, 2023
At that time, me and two others were tracking a comet (Giacobini-Zinner) across the sky as part of an Astronomy summer program. We needed the time to accurately track the position of G-Z across the night sky. And this fed into the calculation of the orbital elements.
Thinking about Time quickly descends into philosophical wells. How do we know an atomic clock keeps regular time? How do we measure its accuracy? We compare it against other clocks. It all works because it works.
But what if the physical constants involved are changing? What if Time is slowing down or speeding up? It can certainly do so locally. Time is affected by Gravity and by relative velocity. GPS clocks require corrections both for Special Relatitivy, which makes them tick slower than ground clocks and General Relativity, which makes them tick faster as they are higher in the Earth's gravity well.
posted by vacapinta at 9:00 AM on December 11, 2023
“We’ve dematerialized all of our units,”
It's about time.
Between 1967 and 1971, I worked in a windowless little room in northern Japan. Three shifts worked in that room, and at the beginning of every shift, the shift chief calibrated our clock. We invoked a signal from one or other sources that were continuously calibrated. The time from the source was expressed in UTC. In fact, our whole operation there ran on UTC, entirely disregarding local time.
Unlike the lady on the telephone our signals were a secession of clicks that terminated in a complex tone. The instrument we used to calibrate our clock identified the source of the signal and then presented an image on an oscilloscope that corrected for the time delay from the source to our clock, which we then adjusted to the nanosecond. This accuracy was needed by the geeks back at Fort Meade to deep-dive into the precise coordinates of the various things on the tapes we sent them. Our birds flew in a widely spread flock of four (we had ten flocks assigned to our site), so their accuracy, I presume, was pretty good. Well, it was at least close enough in case we wanted to send one of our ICBMs over there for a proper look-see. (haha)
Anyhow, nothing in this article even came close to discussing time dilation. I'm bereft.
posted by mule98J at 9:35 AM on December 11, 2023 [8 favorites]
It's about time.
Between 1967 and 1971, I worked in a windowless little room in northern Japan. Three shifts worked in that room, and at the beginning of every shift, the shift chief calibrated our clock. We invoked a signal from one or other sources that were continuously calibrated. The time from the source was expressed in UTC. In fact, our whole operation there ran on UTC, entirely disregarding local time.
Unlike the lady on the telephone our signals were a secession of clicks that terminated in a complex tone. The instrument we used to calibrate our clock identified the source of the signal and then presented an image on an oscilloscope that corrected for the time delay from the source to our clock, which we then adjusted to the nanosecond. This accuracy was needed by the geeks back at Fort Meade to deep-dive into the precise coordinates of the various things on the tapes we sent them. Our birds flew in a widely spread flock of four (we had ten flocks assigned to our site), so their accuracy, I presume, was pretty good. Well, it was at least close enough in case we wanted to send one of our ICBMs over there for a proper look-see. (haha)
Anyhow, nothing in this article even came close to discussing time dilation. I'm bereft.
posted by mule98J at 9:35 AM on December 11, 2023 [8 favorites]
Wibbly wobbly, timey wimey is about the extent with which I'm ready to consider the parameters of time at the moment. I mean it's Monday for God's sake.
(Or at least we've all agreed that this unit of time shall be measured as 'Monday'. Or so says my boss anyway.)
posted by BigHeartedGuy at 9:48 AM on December 11, 2023
(Or at least we've all agreed that this unit of time shall be measured as 'Monday'. Or so says my boss anyway.)
posted by BigHeartedGuy at 9:48 AM on December 11, 2023
The band Chicago once asked the question...
As I was walking down the street one day
A man came up to me and asked me
What the time was that was on my watch
Yeah, and I said
does anybody really know what time it is?
(Care) does anybody really care?
(About time) you know, I can't imagine why
(Oh no, no) we've all got time enough to cry
And I was walking down the street one day
A pretty lady looked at me
And said her diamond watch had stopped cold dead
And I said
does anybody really know what time it is?
(Care) does anybody really care?
(About time) you know, I can't imagine why
(Oh no, no) we've all got time enough to cry
And I was walking down the street one day
Being pushed and shoved by people
Trying to beat the clock, oh, no
I just don't know, I don't, I don't, oh
And I said yes, I said
does anybody really know what time it is?
(Care) does anybody really care?
(About time) you know, I can't imagine why
(Oh no, no) we've all got time enough to die
Everybody's working
(I don't care) I don't care
(About time)
(Oh no, no) oh no, no
posted by njohnson23 at 9:49 AM on December 11, 2023 [4 favorites]
As I was walking down the street one day
A man came up to me and asked me
What the time was that was on my watch
Yeah, and I said
does anybody really know what time it is?
(Care) does anybody really care?
(About time) you know, I can't imagine why
(Oh no, no) we've all got time enough to cry
And I was walking down the street one day
A pretty lady looked at me
And said her diamond watch had stopped cold dead
And I said
does anybody really know what time it is?
(Care) does anybody really care?
(About time) you know, I can't imagine why
(Oh no, no) we've all got time enough to cry
And I was walking down the street one day
Being pushed and shoved by people
Trying to beat the clock, oh, no
I just don't know, I don't, I don't, oh
And I said yes, I said
does anybody really know what time it is?
(Care) does anybody really care?
(About time) you know, I can't imagine why
(Oh no, no) we've all got time enough to die
Everybody's working
(I don't care) I don't care
(About time)
(Oh no, no) oh no, no
posted by njohnson23 at 9:49 AM on December 11, 2023 [4 favorites]
Fascinating article that blew some of my assumptions apart. Gotta admit though that I record-scratched at the example of FM radio transmissions. Should have used AM.
posted by achrise at 9:53 AM on December 11, 2023
posted by achrise at 9:53 AM on December 11, 2023
As a child, before gps receivers/mobile phone networks were widely available, I believed the new years eve broadcast, with it's large, friendly display of (seemingly) authoritative time, more than any other source to which I had access.
You only got it once a year? Here in Canada we'd get it once a week in the middle of the day on Saturday, "The beginning of the long dash following ten seconds of silence..." on CBC radio.
posted by clawsoon at 11:10 AM on December 11, 2023 [2 favorites]
You only got it once a year? Here in Canada we'd get it once a week in the middle of the day on Saturday, "The beginning of the long dash following ten seconds of silence..." on CBC radio.
posted by clawsoon at 11:10 AM on December 11, 2023 [2 favorites]
The beating heart of the nation’s time is the NIST-F1, one of the cesium fountain clocks that help maintain the standard tick. It has a steampunk vibe, all copper and aluminum and wires and tubes; a joking sign nearby it reads no playing in or around the fountain. As Elizabeth Donley, the chief of NIST’s Time and Frequency Division, described it, a ball of cesium atoms, introduced into a vacuum and cooled with lasers, are tossed up and fall back down through a tubular chamber, as in a fountain, while being “interrogated” at the midpoint of their journey by a series of microwaves.This is definitely going on the list of "things which will not survive the apocalypse."
posted by clawsoon at 11:11 AM on December 11, 2023 [1 favorite]
Wonderful article, thank you for posting!
Clocks and time are often really difficult to cope with, especially in the computing world where things happen very quickly and clocks can easily get out of sync. Many of my more maddening experiences with large computer services have involved clocks that were just a hundred milliseconds apart resulting in things that seemed to happen out of order…
Two interesting rabbit holes for clock nerdery include:
Clocks and time are often really difficult to cope with, especially in the computing world where things happen very quickly and clocks can easily get out of sync. Many of my more maddening experiences with large computer services have involved clocks that were just a hundred milliseconds apart resulting in things that seemed to happen out of order…
Two interesting rabbit holes for clock nerdery include:
- Google’s TrueTime service (in section 3 of the Spanner paper), which uses atomic clocks and GPS to provide not a single point in time to their servers, but a time range guaranteeing that the current time is within a certain number of nanoseconds
- The concept of logical clocks, for when you give up on knowing the current time and you just try to establish an order of events
Big fan of the JILA - which uses laser tweezers to suspend a handful of individual atoms which it then excites with other lasers and then uses the speed of light to snap a picture to get, and I'm quoting, an "exquisite" level of time resolution/frequency.
posted by zenon at 12:09 PM on December 11, 2023
posted by zenon at 12:09 PM on December 11, 2023
It is day. It is night. Usually close enough for me.
Apart from appointments with the doctor or dentist, of course. For which purposes my $80 Timex watch does the job.
Context matters.
posted by Pouteria at 12:33 PM on December 11, 2023
Apart from appointments with the doctor or dentist, of course. For which purposes my $80 Timex watch does the job.
Context matters.
posted by Pouteria at 12:33 PM on December 11, 2023
It is day. It is night. Usually close enough for me.
Yeah, yeah, but tell it to fucking pitch-dark 4:30pm NYC this time of year.
posted by The Bellman at 12:46 PM on December 11, 2023 [3 favorites]
Yeah, yeah, but tell it to fucking pitch-dark 4:30pm NYC this time of year.
posted by The Bellman at 12:46 PM on December 11, 2023 [3 favorites]
→
There have been a lot of seconds of silence. The CBC NRC time signal was discontinued as of October 10, 2023 because it was running 10 or more seconds late due to digital network latency
posted by scruss at 2:02 PM on December 11, 2023
The beginning of the long dash following ten seconds of silence..."
There have been a lot of seconds of silence. The CBC NRC time signal was discontinued as of October 10, 2023 because it was running 10 or more seconds late due to digital network latency
posted by scruss at 2:02 PM on December 11, 2023
It is day. It is night. Usually close enough for me.
I lost faith in clocks when I was in the 6th grade, and our teacher was explaining about time zones. I had a sudden brain fart and said to him, "But isn't it the same time all the time everywhere?" He hemmed and hawed about farmers and their crops and how we saved time...(This is where he tried to explain Daylight Savings Time, but by then, I had tuned him out.)
Only a few short years later, I had submitted to this nonsense, but then I found out about time and space, how they were not only two parts of the same thing, but that time was flexible and varied according to speed, and how you could determine how fast you were going, or where you were, but you couldn't do both at the same time. All this time, I thought space was there to have someplace to put your stuff, and time was just how long it took to get it there.
Whoooee!
Any how I gave up and got a watch like everybody else. But once I quit school and got unfettered, I got to leave all that shit behind, but then I got married and, well, hell. But I finally got that straight, although it took me three wives and a couple of short stints in jail to figure it out.
For several years, I observed time by the season--not the calendar season, but how soon the snow melted enough to let me get my mare and Jasper the Flying Mule back into the high country. Months mattered a little, but twelve to twenty-day supply drops were about as close as I got until the first post-Labor Day snows. Sometimes, I could ignore that until mid-November.
Nowadays, I work in 28-day cycles. That's when I refill my pill caddy. I usually watch the dawn break from my bedroom window--I can see the ridges of the Gila Mountains about twenty miles from here. That seems like a good time to get up and make some coffee. It still gets dark right after sunset. So far, I'm okay with how that works.
posted by mule98J at 2:14 PM on December 11, 2023 [2 favorites]
I lost faith in clocks when I was in the 6th grade, and our teacher was explaining about time zones. I had a sudden brain fart and said to him, "But isn't it the same time all the time everywhere?" He hemmed and hawed about farmers and their crops and how we saved time...(This is where he tried to explain Daylight Savings Time, but by then, I had tuned him out.)
Only a few short years later, I had submitted to this nonsense, but then I found out about time and space, how they were not only two parts of the same thing, but that time was flexible and varied according to speed, and how you could determine how fast you were going, or where you were, but you couldn't do both at the same time. All this time, I thought space was there to have someplace to put your stuff, and time was just how long it took to get it there.
Whoooee!
Any how I gave up and got a watch like everybody else. But once I quit school and got unfettered, I got to leave all that shit behind, but then I got married and, well, hell. But I finally got that straight, although it took me three wives and a couple of short stints in jail to figure it out.
For several years, I observed time by the season--not the calendar season, but how soon the snow melted enough to let me get my mare and Jasper the Flying Mule back into the high country. Months mattered a little, but twelve to twenty-day supply drops were about as close as I got until the first post-Labor Day snows. Sometimes, I could ignore that until mid-November.
Nowadays, I work in 28-day cycles. That's when I refill my pill caddy. I usually watch the dawn break from my bedroom window--I can see the ridges of the Gila Mountains about twenty miles from here. That seems like a good time to get up and make some coffee. It still gets dark right after sunset. So far, I'm okay with how that works.
posted by mule98J at 2:14 PM on December 11, 2023 [2 favorites]
it left me with a gnawing inquiry: How does she know what time it is? I imagined that time emanated, like the Emergency Alert System, from some secure government facility, possibly underground.No, it comes out of the Greenwich time transmitter via the Marillion Line. It's hours old by the time NIST gets ahold of it.
posted by flabdablet at 8:03 PM on December 11, 2023 [1 favorite]
logical clocks, for when you give up on knowing the current time and you just try to establish an order of events
I like to think of the current time as an emergent statistical property of countless ordered events, in much the same way that gas pressure is an emergent statistical property of countless collisions between molecules and temperature is an emergent statistical property of their individual kinetic energies.
It amuses me to assume that if we had the wherewithal to look at stuff really closely, it would turn out to be logical clocks all the way down.
posted by flabdablet at 8:34 PM on December 11, 2023
I like to think of the current time as an emergent statistical property of countless ordered events, in much the same way that gas pressure is an emergent statistical property of countless collisions between molecules and temperature is an emergent statistical property of their individual kinetic energies.
It amuses me to assume that if we had the wherewithal to look at stuff really closely, it would turn out to be logical clocks all the way down.
posted by flabdablet at 8:34 PM on December 11, 2023
Philomena Cunk tells us about time.
posted by Multicellular Exothermic at 8:36 PM on December 11, 2023 [1 favorite]
posted by Multicellular Exothermic at 8:36 PM on December 11, 2023 [1 favorite]
jinx
posted by flabdablet at 8:48 PM on December 11, 2023
posted by flabdablet at 8:48 PM on December 11, 2023
Jinx! I owe you a beverage, flabdablet!
posted by Multicellular Exothermic at 8:50 PM on December 11, 2023
posted by Multicellular Exothermic at 8:50 PM on December 11, 2023
I love this so much. The first I learned about NIST and the world of standards and measurements was in the mid 90s after I had just moved to DC. I was having beers at the Big Hunt right off DuPont Circle when I struck up a random conversation at the bar with a physicist who worked there. I’m still blown away by the concept.
posted by slogger at 5:13 AM on December 12, 2023 [1 favorite]
posted by slogger at 5:13 AM on December 12, 2023 [1 favorite]
This is definitely going on the list of "things which will not survive the apocalypse."
Quite the opposite, really. Having a correct and exact measurement of time is one of those Very Important Things that the U.S. military, especially the Air Force, depend upon. (See also, the GPS network, another one of those "can't fail" services, which gets its own independent line of funding for satellite launches.) So ever since the Cold War they put a lot of effort into hardening it in case of calamity.
posted by The Pluto Gangsta at 9:17 AM on December 12, 2023
Quite the opposite, really. Having a correct and exact measurement of time is one of those Very Important Things that the U.S. military, especially the Air Force, depend upon. (See also, the GPS network, another one of those "can't fail" services, which gets its own independent line of funding for satellite launches.) So ever since the Cold War they put a lot of effort into hardening it in case of calamity.
posted by The Pluto Gangsta at 9:17 AM on December 12, 2023
As it was published yesterday, some might even say it's...
...timely.
posted by a non mouse, a cow herd at 10:18 AM on December 14, 2023 [1 favorite]
...timely.
posted by a non mouse, a cow herd at 10:18 AM on December 14, 2023 [1 favorite]
Some years ago I came to believe that there needs to be a conceptual separation between the base unit of time used for civil, business and political purposes and that used for scientific purposes.
Scientific time ought to be measured in secs, where a sec matches the current SI definition of the second. Scientific timestamps would be kept in the format of secs since epoch at 1 Jan 1977 00:00:00 TAI. Timestamps would be strictly monotonic and not separable into date and time-of-day parts, so there would be no need for anything like a leap second.
Timestamps would not label a point in time, on the basis that there is anyway no such thing; rather, a timestamp would label a semi-open interval that begins exactly at the hypothetical point-in-time that the timestamp naively appears to specify, and ends before a succeeding timestamp quoted to the same precision. Such intervals could be made arbitrarily short by means of arbitrary increases in the precision with which a timestamp is recorded and/or quoted.
Civil time ought to be measured in seconds, where a second is nominally 1/86400 of a day, and the actual duration of a second in secs is varied as smoothly as possible so as to make 06:00:00 happen at sunrise every day in every place that has sunrises, or at the time when the nearest sunrise in the direction of the equator is occurring in polar regions that don't.
The adjustment that fixes the time of day for sunrise would make twice-yearly daylight-saving time jumps inherently redundant, and the latitude dependency it introduces would make longitude-based time zones impractical. All civil dates and times would thereby become hyper-local; exactly how hyper would depend on the required accuracy of coordination across geographical distance. For almost all purposes, specifying a city name alongside a date and time would be accurate enough.
The only nod in the direction of time zones would be retention of the International Date Line.
NTP, GPS, broadcast media systems, filesystem timestamps etc that rely on tight time coordination across geography should all work on the basis of sec-based scientific timestamps, or at least in task-specific sec-based timestamps whose only difference from the standard is in choice of epoch; clock displays for human consumption should derive the wall time to be displayed in any given locale from the scientific timestamp and the applicable geographic coordinates.
So there you have it: Flabdablet Aggressively Universally Local Time. Everybody thinks I'm joking when I propose this but ha ha, only serious. Would adopting it cause you more headaches than it saves? Bug reports welcomed.
posted by flabdablet at 3:44 PM on December 14, 2023 [2 favorites]
Scientific time ought to be measured in secs, where a sec matches the current SI definition of the second. Scientific timestamps would be kept in the format of secs since epoch at 1 Jan 1977 00:00:00 TAI. Timestamps would be strictly monotonic and not separable into date and time-of-day parts, so there would be no need for anything like a leap second.
Timestamps would not label a point in time, on the basis that there is anyway no such thing; rather, a timestamp would label a semi-open interval that begins exactly at the hypothetical point-in-time that the timestamp naively appears to specify, and ends before a succeeding timestamp quoted to the same precision. Such intervals could be made arbitrarily short by means of arbitrary increases in the precision with which a timestamp is recorded and/or quoted.
Civil time ought to be measured in seconds, where a second is nominally 1/86400 of a day, and the actual duration of a second in secs is varied as smoothly as possible so as to make 06:00:00 happen at sunrise every day in every place that has sunrises, or at the time when the nearest sunrise in the direction of the equator is occurring in polar regions that don't.
The adjustment that fixes the time of day for sunrise would make twice-yearly daylight-saving time jumps inherently redundant, and the latitude dependency it introduces would make longitude-based time zones impractical. All civil dates and times would thereby become hyper-local; exactly how hyper would depend on the required accuracy of coordination across geographical distance. For almost all purposes, specifying a city name alongside a date and time would be accurate enough.
The only nod in the direction of time zones would be retention of the International Date Line.
NTP, GPS, broadcast media systems, filesystem timestamps etc that rely on tight time coordination across geography should all work on the basis of sec-based scientific timestamps, or at least in task-specific sec-based timestamps whose only difference from the standard is in choice of epoch; clock displays for human consumption should derive the wall time to be displayed in any given locale from the scientific timestamp and the applicable geographic coordinates.
So there you have it: Flabdablet Aggressively Universally Local Time. Everybody thinks I'm joking when I propose this but ha ha, only serious. Would adopting it cause you more headaches than it saves? Bug reports welcomed.
posted by flabdablet at 3:44 PM on December 14, 2023 [2 favorites]
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WHAT
posted by Halloween Jack at 7:35 AM on December 11, 2023 [1 favorite]