New Atomic Fountain Clock Joins Elite Group That Keeps the World on Time (nist.gov) 17
NIST: Clocks on Earth are ticking a bit more regularly thanks to NIST-F4, a new atomic clock at the National Institute of Standards and Technology (NIST) campus in Boulder, Colorado. This month, NIST researchers published a journal article establishing NIST-F4 as one of the world's most accurate timekeepers. NIST has also submitted the clock for acceptance as a primary frequency standard by the International Bureau of Weights and Measures (BIPM), the body that oversees the world's time.
NIST-F4 measures an unchanging frequency in the heart of cesium atoms, the internationally agreed-upon basis for defining the second since 1967. The clock is based on a "fountain" design that represents the gold standard of accuracy in timekeeping. NIST-F4 ticks at such a steady rate that if it had started running 100 million years ago, when dinosaurs roamed, it would be off by less than a second today.
By joining a small group of similarly elite time pieces run by just 10 countries around the world, NIST-F4 makes the foundation of global time more stable and secure. At the same time, it is helping to steer the clocks NIST uses to keep official U.S. time. Distributed via radio and the internet, official U.S. time is critical for telecommunications and transportation systems, financial trading platforms, data center operations and more.
NIST-F4 measures an unchanging frequency in the heart of cesium atoms, the internationally agreed-upon basis for defining the second since 1967. The clock is based on a "fountain" design that represents the gold standard of accuracy in timekeeping. NIST-F4 ticks at such a steady rate that if it had started running 100 million years ago, when dinosaurs roamed, it would be off by less than a second today.
By joining a small group of similarly elite time pieces run by just 10 countries around the world, NIST-F4 makes the foundation of global time more stable and secure. At the same time, it is helping to steer the clocks NIST uses to keep official U.S. time. Distributed via radio and the internet, official U.S. time is critical for telecommunications and transportation systems, financial trading platforms, data center operations and more.
Nice!!! (Score:3)
Interesting time geek link to the first true atomic wristwatch.
http://leapsecond.com/pages/at... [leapsecond.com]
I Will Stick With The Sun (Score:2)
But you do you. Since you are so smarter than the Sun.
As long as DOGE doesn't screw wirh it (Score:2, Interesting)
How long until this administration kills off NIST? Any bets?
Re: (Score:2)
Re:As long as DOGE doesn't screw wirh it (Score:4, Informative)
Good news (Score:2)
Journalists ... (Score:2)
Clocks on Earth are ticking a bit more regularly thanks to NIST-F4, ...
NIST-F4 measures an unchanging frequency in the heart of cesium atoms, ...
So, the unchanging frequency is more regular? (*sigh*)
Re: (Score:3)
To elaborate on the other guy's comment, the second is defined in terms of "the unperturbed ground-state hyperfine transition frequency" of cesium-133, but the tricky part is measuring that accurately. https://www.nist.gov/pml/time-... [nist.gov] explains how NIST-F3 and NIST-F4 do that.
if it had started running 100 million years ago... (Score:4, Funny)
It would probably have been destroyed 35 million years later when the asteroid hit Chicxulub .
Extrapolating to millions of years (Score:2)
if it had started running 100 million years ago, when dinosaurs roamed, it would be off by less than a second today.
This extrapolation is not valid. Sure, the match is (probably) right. But we have no way to know what external factors, over 100 million years, might affect the speed of this timekeeping method. We know, for example, that the accuracy of orbiting Cesium clocks is affected by the topography of the earth. https://www.vice.com/en/articl... [vice.com] Over 100 million years, it wouldn't take much interference from, say, passing asteroids, to potentially affect the accuracy, leading to more than a second of discrepancy at
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I think you are referring to general relativistic effects. However, I don't think we would say this reduces its accuracy - it is correctly keeping time within its reference frame.
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My issue is with the extrapolation, not the specific effect that might impact the timekeeping. If a timekeeping mechanism is shown to be extremely accurate over a period of a few years or even decades, it does not necessarily follow that it will be just as accurate over a period of millions of years. That has yet to be proven.
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We know, for example, that the accuracy of orbiting Cesium clocks is affected by the topography of the earth.
No the accuracy is not affected by gravity. The relative time differences between clocks are affected due to relativistic effects. The clock's accuracy is determined in its own reference frame when compared to that of the hyperfine transition of the caesium atom, and gravity doesn't influence this.
Just because one clock reads differently to another due to gravity and motion doesn't mean that one clock is less accurate than the other. When dealing with these kinds of precise measurements you really need to p
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While that's all true, it's kind of like saying that computers always do exactly what they are told to do. And yet, we have bugs everywhere, because what we told them to do, differs from what we expected it to do. In the case of relativistic effects on timekeeping pieces, it's true that the clocks keep time in exactly the way they experience time, and yet will end up differing from each other because of those effects. The result is that different clocks can accurately keep time, and yet not be in sync with
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it's true that the clocks keep time in exactly the way they experience time, and yet will end up differing from each other because of those effects.
The first part of this is false because a major cause of timekeeping error is errors in clocks' counting mechanisms; these errors make them not keep time in exactly the way they experience time. The second part is a red herring because serious clock people don't count relativistic effects as part of clock error.
If someone is surprised by this difference, they don't know enough to productively use a clock (or frequency reference) this accurate.
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None of your arguments refute the fact that it's a fallacy to extrapolate accuracy over a few seconds or minutes, to millions of years.