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Atomic Clocks

nist.gov

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Re: Atomic Clocks

#61

Post by inigyou »

wildzzz wrote: post #60
r3trohack3r wrote: post #4

> 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…

Cost, size, weight, and power are definitely things that can be improved on. The atomic clocks you can buy for a lab are big 3U boxes but shrinking it down to something portable is the future. I actually work with one of those chip scale atomic clocks. The goal is to put it in space. If you need precise timing in space, the current state is to lock to a GPS reference clock (just for timing, don't care about position)…

Where are you getting GPS receivers that work in space?

Re: Atomic Clocks

#62

Post by cogogo »

globular-toast wrote: post #23
tomcam wrote: post #15

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…

That's brilliant. Sometimes talking to real humans is great. It reminds me of two things. When I was a child I was given a postage stamp and wrote a letter to "Wallace and Gromit Ltd" and posted it. Remarkably, I got a reply from Aardman Animations with a card signed by Nick Park himself. Someone at Royal Mail obviously understood and looked up the real address of the studio. Later as a teen I noticed the clock on ou…

My GE microwave has a whole damn button the same size as the start button for AM/PM. Has to be one of the dumbest design wastes I have seen. I have always wished the 24 hr clock had taken off in the US. I use it on any clock that supports it.

Re: Atomic Clocks

#63

Post by AlotOfReading »

inigyou wrote: post #61
wildzzz wrote: post #60

Earlier quoted context omitted.

Cost, size, weight, and power are definitely things that can be improved on. The atomic clocks you can buy for a lab are big 3U boxes but shrinking it down to something portable is the future. I actually work with one of those chip scale atomic clocks. The goal is to put it in space. If you need precise timing in space, the current state is to lock to a GPS reference clock (just for timing, don't care about position)…

Where are you getting GPS receivers that work in space?

Probably one of the numerous companies making qualified receivers? E.g. [0]. There's even a published table comparing basically all of them [1].

[0] https://www.aac-clyde.space/what-we-do/space-products-compon...

[1] https://www.mdpi.com/1424-8220/23/17/7648#app1-sensors-23-07...

Re: Atomic Clocks

#64

Post by EA »

svennidal wrote: post #54

It's still relative. I think... If you could have a atomic wristwatch and you travel around the world with it, you will have a very precise time for you, but you'll end up out of sync with almost every other atomic clock. If you sync two atomic clocks and put one at the surface of the arctic ocean and another one on top of Mount Nevado in Peru, and leave them there for one million years, the clock in Peru will be 1.8…

You are off by a factor of the speed of light.

The clocks would be off by less than a quarter second over a million years.

Re: Atomic Clocks

#65

Post by rammy1234 »

I wish we had books for kids at school that explains in this fashion. Even a beginner can grasp the idea behind it and dive deeper if interested. Loved it.

Re: Atomic Clocks

#66

Post by alnwlsn »

svennidal wrote: post #54

It's still relative. I think... If you could have a atomic wristwatch and you travel around the world with it, you will have a very precise time for you, but you'll end up out of sync with almost every other atomic clock. If you sync two atomic clocks and put one at the surface of the arctic ocean and another one on top of Mount Nevado in Peru, and leave them there for one million years, the clock in Peru will be 1.8…

You mean everyone else would have the "wrong" time whereas your clock is still bang-on correct for you. So you have become a time traveler.

Re: Atomic Clocks

#68

Post by alnwlsn »

tomcam wrote: post #15

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…

You actually can still call NIST and hear the signal broadcast from WWV[0], though that's probably different from the telephone time of day you're thinking of, which might have come from one of these machines [1] in a local telephone exchange.

[0] https://www.nist.gov/pml/time-and-frequency-division/time-di...

[1] https://en.wikipedia.org/wiki/Audichron

Re: Atomic Clocks

#69

Post by alnwlsn »

atypeoferror wrote: post #34

I recently bought my first not-super-cheap watch, and found out that all around the world there radio stations which broadcast the atomic clock time that a lot of clocks/watches listen to. After setting the time zone (I guess this also changes the frequency that it listens on) it starts to sync itself using that signal. It is also solar-charging - so this basically means that I never have to touch it. Although it's a…

In the US, those are radio stations WWVB for clocks and watches, and WWV/WWVH for shortwave.

One thing I think is interesting is that not only are the digital formats these carry synced to an atomic clock, but the radio carrier wave is too. So if you need a very precise 10 MHz signal in the lab, you can hook up a shortwave antenna and a filter, and receive the precisely-on-frequency signal broadcast from WWV.

Re: Atomic Clocks

#70

Post by [deleted] »

Schlagbohrer wrote: post #13

NIST is a great example of a true Public Good. 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. https://csrc.nist.gov/projects/interoperable-randomness-beac...

[deleted]
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