Long before most of you were born there was a special number you could call to get the time here in the USA. It would give you a localized time every 10 seconds. It was considered an authoritative value, but I knew that normal analog clocks drifted a fair amount, and I was fascinated by the Time voice.
There was also a special number to dial that was called Information. When I was about 12, I suddenly thought that’s amazing, you can just call and get information. What I didn’t know at the time was that it only applied to phone numbers.
One day, I called Information and asked them how accurate the time number was and what mechanism was used to deliver it. Incredibly, they connected my preadolescent self to a public relations person at AT&T. That person somehow took me seriously and hooked me up with another party. And that person told me about the cesium atomic clock used to keep track of the time.
Later, I would call Information to find out the acreage occupied by the Los Angeles Zoo, and it was then that they brusquely explained to me that the number was not for general knowledge.
> Today’s best atomic clocks are billions of times more accurate and precise than any other type of clock. If they had been running since the Big Bang, 13.8 billion years ago, they would have lost or gained less than a second.
Absolutely incredible, but then confused by the next assertion that is made without context:
> New kinds of clocks may soon open up capabilities that previous generations could only dream about.
What is possible by pushing past that incredibly narrow margin of 1s in 13b years? What dreamy capabilities do we get that we don’t enjoy today?
Edit: I’d assumed they were talking about new approaches to making these clocks more accurate, but I wonder if they’re referring to power and form factors? I.E. an atomic clock the size of a grain of rice: https://www.nist.gov/noac/success-story-chip-scale-atomic-cl...
> What is possible by pushing past that incredibly narrow margin of 1s in 13b years? What dreamy capabilities do we get that we don’t enjoy today?
You can measure speed (via special relativity) and altitude (via gravity/general relativity) with atomic clocks [0], so with a more accurate clock, you should be able to calculate your speed/altitude more accurately.
GPS is already pretty good at measuring speed/altitude, but its not always very accurate, and it only works if you can receive the satellite's signal. In theory, a more accurate atomic clock would solve both of these problems (as long as you had an equally-accurate clock at a fixed location to compare to).
In radio astronomy, more precise clocks can directly improve the quality/resolution of observations.
> Data received at each antenna in the array include arrival times from a local atomic clock, such as a hydrogen maser. At a later time, the data are correlated with data from other antennas that recorded the same radio signal, to produce the resulting image. The resolution achievable using interferometry is proportional to the observing frequency.
There are still big leaps, like their optical lattice clock that's sensitive to the gravitational difference caused by tidal effects on the earth's crust.
It can detect gravitational differences of a few cm!
Pretty sure you can rig something far better than radar if you have the ability to detect extremely tiny gravitational waves via an array of hyper-accurate clocks.
> detect extremely tiny gravitational waves via an array of hyper-accurate clocks.
I wonder how tiny is feasible. Would it get to a level of accuracy where you could detect neutrinos? We know they have some (v tiny) mass, so it should in theory be detectable that way?
What, Exactly, Is a Clock?
To understand atomic time, we must first understand something about clocks.
A clock is, at its core, a marriage of two components: a mechanism that oscillates, or ticks with a steady beat, and a device that counts those beats and displays the time
Yeah but more deeply time is a property of the universe that the clock including atomic clocks are tracking. Kant said it is 'schema' i.e. without understanding time we wouldn't even understand causality so it is the purest possible a-priori concept that doesn't rely on sensory input to learn about
This is why I like using my Alphadec system that splits the year into 26 chunks from A-Z <https://github.com/firasd/alphadec> as my working dir; eg. right now the current Alphadec is '2026_P5M7_200286' so my working dir is Documents/work/2026_P. That way there is a folder system automatically imposed on various .js or .py stuff without having to pre-create a taxonomy since 'time is schema'--I can estimate "that ffmpeg project was in Spring so it must be around 2026_F.."
Not sure I get what is better about this than simply using the month, like Documents/work/202606 (which also sorts nicely and does not need a conversion in my head to know what time of the year that must be)
Yup as far as the folder taxonomy thing ISO YYYYMM works fine too
Alphadec is just a timezone free UTC encoding that works down the millisecond so I also use it for snapshots eg
myscript.py.backup.2026_P5G6_328054_Aug06.txt
So then when I'm doing multiple revisions I don't have to worry about which revision of 20260806's day it was etc. Unix time in ms would work too but Alphadec is a little bit nicer to me than saying myscript.py.backup.1786086462604.txt
Also, has anyone else ever used their Randomness Beacon? I once used it to settle an argument in a book club over which book to read next. It's basically a very fancy and high tech coin flip.
Fun fact, two (very expensive) wristwatches have actual atomic timekeeping in them, instead of just receiving a radio time signal: the Bathys Hawaii Cesium 133, and a few different shaped from Hoptroff London.
All released 2013-2015. Not sure what happened then for there to be suddenly two.
Symmetricom (now owned by Microchip) released the first Chip Scale Atomic Clocks in 2011. It probably took some time for them to become available to watch designers and for them to be integrated into watch designs.
Sadly, no major miniaturization breakthroughs since. And those CSACs still eat up a lot of power (as do good OCXOs), making them rough for battery powered wearables.
There was also a special number to dial that was called Information. When I was about 12, I suddenly thought that’s amazing, you can just call and get information. What I didn’t know at the time was that it only applied to phone numbers.
One day, I called Information and asked them how accurate the time number was and what mechanism was used to deliver it. Incredibly, they connected my preadolescent self to a public relations person at AT&T. That person somehow took me seriously and hooked me up with another party. And that person told me about the cesium atomic clock used to keep track of the time.
Later, I would call Information to find out the acreage occupied by the Los Angeles Zoo, and it was then that they brusquely explained to me that the number was not for general knowledge.
Absolutely incredible, but then confused by the next assertion that is made without context:
> New kinds of clocks may soon open up capabilities that previous generations could only dream about.
What is possible by pushing past that incredibly narrow margin of 1s in 13b years? What dreamy capabilities do we get that we don’t enjoy today?
Edit: I’d assumed they were talking about new approaches to making these clocks more accurate, but I wonder if they’re referring to power and form factors? I.E. an atomic clock the size of a grain of rice: https://www.nist.gov/noac/success-story-chip-scale-atomic-cl...
You can measure speed (via special relativity) and altitude (via gravity/general relativity) with atomic clocks [0], so with a more accurate clock, you should be able to calculate your speed/altitude more accurately.
GPS is already pretty good at measuring speed/altitude, but its not always very accurate, and it only works if you can receive the satellite's signal. In theory, a more accurate atomic clock would solve both of these problems (as long as you had an equally-accurate clock at a fixed location to compare to).
[0]: https://news.ycombinator.com/item?id=16473776
> Data received at each antenna in the array include arrival times from a local atomic clock, such as a hydrogen maser. At a later time, the data are correlated with data from other antennas that recorded the same radio signal, to produce the resulting image. The resolution achievable using interferometry is proportional to the observing frequency.
https://en.wikipedia.org/wiki/Very-long-baseline_interferome...
It can detect gravitational differences of a few cm!
I wonder how tiny is feasible. Would it get to a level of accuracy where you could detect neutrinos? We know they have some (v tiny) mass, so it should in theory be detectable that way?
The next gen will have an alarm with snooze button.
[0]: https://en.wikipedia.org/wiki/International_Atomic_Time
https://www.nist.gov/pml/owm/metric-si/metric-kitchen/metric...
A clock is, at its core, a marriage of two components: a mechanism that oscillates, or ticks with a steady beat, and a device that counts those beats and displays the time
Yeah but more deeply time is a property of the universe that the clock including atomic clocks are tracking. Kant said it is 'schema' i.e. without understanding time we wouldn't even understand causality so it is the purest possible a-priori concept that doesn't rely on sensory input to learn about
This is why I like using my Alphadec system that splits the year into 26 chunks from A-Z <https://github.com/firasd/alphadec> as my working dir; eg. right now the current Alphadec is '2026_P5M7_200286' so my working dir is Documents/work/2026_P. That way there is a folder system automatically imposed on various .js or .py stuff without having to pre-create a taxonomy since 'time is schema'--I can estimate "that ffmpeg project was in Spring so it must be around 2026_F.."
Alphadec is just a timezone free UTC encoding that works down the millisecond so I also use it for snapshots eg
So then when I'm doing multiple revisions I don't have to worry about which revision of 20260806's day it was etc. Unix time in ms would work too but Alphadec is a little bit nicer to me than saying myscript.py.backup.1786086462604.txtAlso, has anyone else ever used their Randomness Beacon? I once used it to settle an argument in a book club over which book to read next. It's basically a very fancy and high tech coin flip.
https://csrc.nist.gov/projects/interoperable-randomness-beac...
All released 2013-2015. Not sure what happened then for there to be suddenly two.
https://www.nist.gov/noac/success-story-chip-scale-atomic-cl...
I'm guessing the watches sold poorly and the chip packages are still large compared to a watch movement, so no new designs.