Elements: Caesium
Business Daily
BBC
4.4 • 816 Ratings
🗓️ 24 September 2014
⏱️ 38 minutes
🧾️ Download transcript
Summary
The atomic clock runs on caesium, and has redefined the very meaning of time. But it has also introduced a bug into timekeeping that affects everything from computerised financial markets to electricity grids, to satellite navigation, to the Greenwich Meridian. Justin Rowlatt travels to the birthplace of modern time, the National Physical Laboratory in Teddington, England, to speak to Krzysztof Szymaniec, the keeper of the 'Caesium Fountain', and Leon Lobo, the man charged with disseminating time to the UK.
He also hears from Felicitas Arias, director of Time at the Bureau International des Poids et Mesures in Paris, about plans to abolish the “leap second”. And the Astronomer Royal, Martin Rees, explains why even the atomic clock can never hope to provide an absolute measure of time.
Transcript
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| 0:00.0 | Welcome to the latest special edition in the Elemental Economics series from the BBC. |
| 0:11.6 | I am Justin Rowlat. |
| 0:14.5 | And today, we're exploring the role of an element we would be lost without. |
| 0:19.9 | It helps lubricate the equipment that drills the wells |
| 0:23.1 | that provides the world with oil and gas, |
| 0:25.7 | but that is not the main reason why it helps us get around. |
| 0:30.4 | That's down to its role in keeping time. |
| 0:34.2 | In fact, you could say this element is the source of time itself, as we will be |
| 0:40.7 | discovering on Business Daily from the BBC. |
| 0:51.7 | Today I have come to somewhere really rather special. |
| 0:55.9 | You could describe this as the place where time began, or at least modern time, |
| 1:01.8 | because I'm at the National Physical Laboratory in Tettington, |
| 1:04.9 | and this is where the most accurate clocks of their day were developed back in the 1920s. |
| 1:10.0 | And here in the lobby of the building, they've got an example of those first quartz clocks, developed by a horologist called Louis Essen, which was at that time, the most accurate timepiece in the world. |
| 1:22.0 | And it's actually a lot smaller than I expected. It's about 10 centimetres in diameter. It's round. |
| 1:32.3 | And actually, you can see inside the ring of courts, though quite how it works. I don't understand. But of course, new developments have superseded the quartz clock, as I'm going to discover. |
| 1:51.3 | Well, I've come down into the heart of the building to meet Leon Lovar, and you have the most wonderful title. |
| 1:57.4 | You are in charge of disseminating time here at the National Physical Laboratory, which is a wonderful title. |
| 2:00.1 | I have to ask you, what on earth does it mean, Leon? |
| 2:01.9 | So I work on distributing the UK's times scale to the UK. So your job is to tell Britain the time, yeah? That's correct. |
| 2:07.5 | Accurate timekeeping for the nation. That's correct. That's entrusted to you. How accurate |
| 2:12.0 | were those early courts clocks, like the Essen clock that I saw in the lobby here? The ring |
... |
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