5 ms·

Maybe this is the disaster plan: There's not a smouldering hole where NIST's Boulder facility used to be, and it will be operational again soon enough. There'

by ssl-3 11mo ago

Maybe this is the disaster plan: There's not a smouldering hole where NIST's Boulder facility used to be, and it will be operational again soon enough. There's no present need for important hard-to-replace sciencey-dudes to go into the shop (which is probably both cold, and dark, and may have other problems that make it unsafe: it's deliberately closed) to futz around with the the time machines. We still have other NTP clocks. Spooky-accurate clocks that the public can get to, even, like just up the road at NIST in Fort Collins (where WWVB lives, and which is currently up), and in Maryland. This is just one set. And beyond that, we've also got clocks in GPS satellites orbiting, and a whole world of low-stratum NTP servers that distribute that time on the network. (I have one such GPS-backed NTP server on the shelf behind me; there's not much to it.) And the orbital GPS clocks are controlled by the US Navy, not NIST. So there's redundancy in distribution, and also control, and some of the clocks aren't even on the Earth. Some people may be bit by this if their systems rely on only one NTP server, or only on the subset of them that are down. And if we're following section 3.2 of RFC 8633 and using multiple diverse NTP sources for our important stuff, then this event (while certainly interesting!) is not presently an issue at all.

Balgair 11mo ago
There are many backup clocks/clusters that NIST uses as redundancies all around Boulder too, no need to even go up to Fort Collins. As in, NIST has fiber to a few at CU and a few commercial companies, last I checked. They're used in cases just like this one. Fun facts about The clock: You can't put anything in the room or take anything out. That's how sensitive the clock is. The room is just filled with asbestos. The actual port for the actual clock, the little metal thingy that is going buzz, buzz, buzz with voltage every second on the dot? Yeah, that little port isn't actually hooked up to anything, as again, it's so sensitive (impedance matching). So they use the other ports on the card for actual data transfer to the rest of the world. They do the adjustments so it's all fine in the end. But you have to define something as the second, and that little unused port is it. You can take a few pictures in the cramped little room, but you can't linger, as again, just your extra mass and gravity affects things fairly quickly. If there are more questions about time and timekeeping in general, go ahead and ask, though I'll probably get back to them a bit later today.
- ronjakoi 11mo ago
  Will the time it takes you to answer depend on the mass of the person asking?
- Workaccount2 11mo ago
  >The actual port for the actual clock, the little metal thingy that is going buzz, buzz, buzz with voltage every second on the dot? Yeah, that little port isn't actually hooked up to anything, as again, it's so sensitive (impedance matching). So they use the other ports on the card for actual data transfer to the rest of the world. Can you restate this part in full technical jargon along with more detail? I'm having a hard time following it
  - pas 11mo ago
    it sounds like there's some kind of coupling, inductive or optoelectronic but yes, I also want the juicy details! so this is the clock https://en.wikipedia.org/wiki/NIST-F1 https://en.wikipedia.org/wiki/NIST-F1 or this https://en.wikipedia.org/wiki/NIST-F2 https://en.wikipedia.org/wiki/NIST-F2 or there's already F4 too, but it doesn't have a Wikipedia article yet https://www.nist.gov/news-events/news/2025/04/new-atomic-fountain-clock-joins-elite-group-keeps-world-time https://www.nist.gov/news-events/news/2025/04/new-atomic-fou... but maybe they are talking about the new non-microwave clocks that use Ytterbium-based optical combs ... or about the Aluminum ion clock https://www.nist.gov/news-events/news/2025/07/nist-ion-clock-sets-new-record-most-accurate-clock-world https://www.nist.gov/news-events/news/2025/07/nist-ion-clock... mind blown
  - lisper 11mo ago
    These claims are bullshit. You can get technical details about the clock first-hand at this link: https://www.nist.gov/pml/time-and-frequency-division/time-realization/cesium-fountain-atomic-clocks https://www.nist.gov/pml/time-and-frequency-division/time-re... and you can see a photo of the actual installation here: https://www.denver7.com/news/front-range/boulder/new-atomic-clock-in-boulder-ensures-the-rest-of-the-world-is-on-time https://www.denver7.com/news/front-range/boulder/new-atomic-... As you can see, the room is clearly not filled with asbestos. Furthermore, the claim is absurd on its face. Asbestos was banned in the U.S. in March 2024 [1] and the clock was commissioned in May 2025. The rest of the claims are equally questionable. For example: > The actual port for the actual clock ... isn't actually hooked up to anything ... they use the other ports on the card for actual data transfer It's hard to make heads or tails of this, but if you read the technical description of the clock you will see that by the time you get to anything in the system that could reasonably be described as a "card" with "ports" you are so far from the business end of the clock that nothing you do could plausibly have an impact on its operation. > You can't put anything in the room or take anything out. That's how sensitive the clock is. This claim is also easily debunked using the formula for gravitational time dilation [2]. The accuracy of the clock is ~10^-16. Calculating the mass of an object 1m away from the clock that would produce this effect is left as an exercise, but it's a lot more than the mass of a human. To get a rough idea, the relativistic time dilation on the surface of the earth is <100 μs/day [3]. That is huge by atomic clock standards, but that is the result of 10^24kg of mass. A human is 20 orders of magnitude lighter. --- [1] https://www.mesotheliomahope.com/legal/legislation/asbestos-bans/ https://www.mesotheliomahope.com/legal/legislation/asbestos-... [2] https://en.wikipedia.org/wiki/Gravitational_time_dilation https://en.wikipedia.org/wiki/Gravitational_time_dilation [3] https://tf.nist.gov/general/pdf/3278.pdf https://tf.nist.gov/general/pdf/3278.pdf
mcculley 11mo ago
> And the orbital GPS clocks are controlled by the US Navy, not NIST. I thought it was US Space Force / Air Force. Was the Navy previously or currently involved?
- icegreentea2 11mo ago
  Direct control is by Space Force. However the US Navy Naval Observatory is responsible for (amongst other things) providing timekeeping for the DoD. In this context, they feed timing updates to the GPS operators https://www.cnmoc.usff.navy.mil/Our-Commands/United-States-Naval-Observatory/Precise-Time-Department/Global-Positioning-System/ https://www.cnmoc.usff.navy.mil/Our-Commands/United-States-N...

by ssl-3 11mo ago

Balgair 11mo ago

There are many backup clocks/clusters that NIST uses as redundancies all around Boulder too, no need to even go up to Fort Collins. As in, NIST has fiber to a few at CU and a few commercial companies, last I checked. They're used in cases just like this one. Fun facts about The clock: You can't put anything in the room or take anything out. That's how sensitive the clock is. The room is just filled with asbestos. The actual port for the actual clock, the little metal thingy that is going buzz, buzz, buzz with voltage every second on the dot? Yeah, that little port isn't actually hooked up to anything, as again, it's so sensitive (impedance matching). So they use the other ports on the card for actual data transfer to the rest of the world. They do the adjustments so it's all fine in the end. But you have to define something as the second, and that little unused port is it. You can take a few pictures in the cramped little room, but you can't linger, as again, just your extra mass and gravity affects things fairly quickly. If there are more questions about time and timekeeping in general, go ahead and ask, though I'll probably get back to them a bit later today.

ronjakoi 11mo ago
Will the time it takes you to answer depend on the mass of the person asking?
Workaccount2 11mo ago
>The actual port for the actual clock, the little metal thingy that is going buzz, buzz, buzz with voltage every second on the dot? Yeah, that little port isn't actually hooked up to anything, as again, it's so sensitive (impedance matching). So they use the other ports on the card for actual data transfer to the rest of the world. Can you restate this part in full technical jargon along with more detail? I'm having a hard time following it
- pas 11mo ago
  it sounds like there's some kind of coupling, inductive or optoelectronic but yes, I also want the juicy details! so this is the clock https://en.wikipedia.org/wiki/NIST-F1 https://en.wikipedia.org/wiki/NIST-F1 or this https://en.wikipedia.org/wiki/NIST-F2 https://en.wikipedia.org/wiki/NIST-F2 or there's already F4 too, but it doesn't have a Wikipedia article yet https://www.nist.gov/news-events/news/2025/04/new-atomic-fountain-clock-joins-elite-group-keeps-world-time https://www.nist.gov/news-events/news/2025/04/new-atomic-fou... but maybe they are talking about the new non-microwave clocks that use Ytterbium-based optical combs ... or about the Aluminum ion clock https://www.nist.gov/news-events/news/2025/07/nist-ion-clock-sets-new-record-most-accurate-clock-world https://www.nist.gov/news-events/news/2025/07/nist-ion-clock... mind blown
- lisper 11mo ago
  These claims are bullshit. You can get technical details about the clock first-hand at this link: https://www.nist.gov/pml/time-and-frequency-division/time-realization/cesium-fountain-atomic-clocks https://www.nist.gov/pml/time-and-frequency-division/time-re... and you can see a photo of the actual installation here: https://www.denver7.com/news/front-range/boulder/new-atomic-clock-in-boulder-ensures-the-rest-of-the-world-is-on-time https://www.denver7.com/news/front-range/boulder/new-atomic-... As you can see, the room is clearly not filled with asbestos. Furthermore, the claim is absurd on its face. Asbestos was banned in the U.S. in March 2024 [1] and the clock was commissioned in May 2025. The rest of the claims are equally questionable. For example: > The actual port for the actual clock ... isn't actually hooked up to anything ... they use the other ports on the card for actual data transfer It's hard to make heads or tails of this, but if you read the technical description of the clock you will see that by the time you get to anything in the system that could reasonably be described as a "card" with "ports" you are so far from the business end of the clock that nothing you do could plausibly have an impact on its operation. > You can't put anything in the room or take anything out. That's how sensitive the clock is. This claim is also easily debunked using the formula for gravitational time dilation [2]. The accuracy of the clock is ~10^-16. Calculating the mass of an object 1m away from the clock that would produce this effect is left as an exercise, but it's a lot more than the mass of a human. To get a rough idea, the relativistic time dilation on the surface of the earth is <100 μs/day [3]. That is huge by atomic clock standards, but that is the result of 10^24kg of mass. A human is 20 orders of magnitude lighter. --- [1] https://www.mesotheliomahope.com/legal/legislation/asbestos-bans/ https://www.mesotheliomahope.com/legal/legislation/asbestos-... [2] https://en.wikipedia.org/wiki/Gravitational_time_dilation https://en.wikipedia.org/wiki/Gravitational_time_dilation [3] https://tf.nist.gov/general/pdf/3278.pdf https://tf.nist.gov/general/pdf/3278.pdf

mcculley 11mo ago

> And the orbital GPS clocks are controlled by the US Navy, not NIST. I thought it was US Space Force / Air Force. Was the Navy previously or currently involved?

icegreentea2 11mo ago
Direct control is by Space Force. However the US Navy Naval Observatory is responsible for (amongst other things) providing timekeeping for the DoD. In this context, they feed timing updates to the GPS operators https://www.cnmoc.usff.navy.mil/Our-Commands/United-States-Naval-Observatory/Precise-Time-Department/Global-Positioning-System/ https://www.cnmoc.usff.navy.mil/Our-Commands/United-States-N...