You Keep Using That Word…

It’s time for another installment of “That’s Not A Clock (it’s a stopwatch)”

New Clock May End Time As We Know It. This is the same technology that I’d linked to back in January, and NPR did something back then, too. I thought maybe this was prompted by a new paper, but the story may have just been motivated by our daylight saving shift last weekend.

I completely agree with Tom O’Brian — time is a human construct, in that it’s abstraction we came up with (but then, so is length). But I have an issue with saying that NIST has America’s master clock, while ignoring the one that resides in Washington DC, run by the navy, and that Tom O’Brian is America’s official timekeeper (i.e. singular). Sins of omission.

This new clock can keep perfect time for 5 billion years.

…if it ran continuously. But it doesn’t. Jun Ye gave a talk on this at DAMOP this past summer, and someone asked him if/when any of these optical lattice devices were going to run as actual clocks, and how long they could run. The answer was (paraphrasing here) “about 24 hours, because people need to sleep.” NIST isn’t going to be pushing very hard to extend that, because that’s not their job. As he put it, once you get to the noise limit of the device, they sort of lose interest in running it any longer.

The rest of it is pretty good for a pop-sci piece, aside from the observation that (as Matthew Francis tweeted at me) “end time as we know it” seems a trifle hyperbolic. In other words, what do you mean, “we”? The issues of trying to synchronize clocks are not going to affect the vast majority of people. It’s a very interesting technical challenge, for reasons described in the article, and once people come up with applications that require picosecond-ish level of timing or better, it’s something we’ll have to solve. But it’s not going to affect whether you’re late for work or what time the game comes on.