A behind-the-scenes look at the work of Canada’s timekeepers - video

Dr. Louis Marmet reveals how official time is calculated

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Transcript:

Time is omnipresent. It wakes us in the morning, gets us to work on time (most days), and runs our mobile devices and our stock markets. But how can we make sure all of these clocks are on time? Exact time, to be precise. There’s a lab in Ottawa where you can find Canada’s official timekeepers. It’s from this building that the official time signal is broadcast. It sounds like this: NRC Eastern Standard Time... Eleven hours, fifty-six minutes, and ten seconds... BEEP. Here’s a rare, behind-the-scenes look at how Canada’s time is kept.

Interviewer: So what does a timekeeper actually do?

Dr. Marmet: So we do maintain the atomic clocks, we provide the most accurate time, and we make sure to disseminate it to all our customers. Accurate time is very important, because it’s used in all the electronic devices, the GPS systems, and telecommunications, for example.

Interviewer: So how is time actually kept? I see there are a lot of devices behind you, there are clocks… There are more than one clock, right?

Dr. Marmet: That’s right, there are actually about a dozen clocks, and all their signals are sent up here in this Control Room. The signals are prepared with all these electronic circuits, and digitized, and the time differences are recorded numerically on the screen. Then, once we have all these numbers, there’s an algorithm that we can use to calculate very stable time, which makes this the official Canadian time.

Interviewer: So how precise can you say we are on time?

Dr. Marmet: Each atomic clock varies by a few nanoseconds, and then when you calculate the average, taken over a period of one year for example, the difference won’t be larger than about one microsecond.

Interviewer: So you’re talking about cesium atomic clocks, so what is that? Dr. Marmet: That’s right, so it’s called an atomic clock because it uses atoms, and the atoms are specifically cesium, which are used for the definition of the second.

Interviewer: And I heard there’s a rumor that there’s a clock here in a copper box or something?

Dr. Marmet: Yes, so, we have an older clock in a copper room, which needs to be placed there because it’s a very sensitive clock.

Interviewer: It doesn’t really look like a traditional clock…

Dr. Marmet: Well, more precisely it’s the internal mechanism of a clock. Essentially that’s where the oscillations of the cesium atoms are measured. So at this end, you have the source of cesium atoms, which travel along the tube, with various electronics which are measuring the oscillations, and at the end, the signal comes and controls the electronics and generates the second signal.

Interviewer: So, I’ve always been fascinated at what actually happens here in this lab when we change time...

Dr. Marmet: So, we don’t actually touch the atomic clocks, but we do change the time we broadcast to our customers. So in the fall, the clocks are set back, and in the spring they are set an hour forward, on early Sunday morning.

One thing you can be sure of is that timekeepers will keep working around the clock, because time never stops. Beep, beep, beep.

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