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BEHOLD, the beating heart of a time machine! Or 鈥渃lock鈥�, as most people call them, but this one is nothing like your grandfather鈥檚. This super-accurate timekeeper is an optical atomic clock built by the UK鈥檚 National Physical Laboratory (NPL) and its tick is governed by a single ion of the element strontium.
The ion is trapped in an electromagnetic field within the small cube at the centre and cooled with lasers to just a fraction above absolute zero. The lasers are fired through three of the glass shafts emanating from the cube, but must be carefully directed out of the other side to prevent them scattering within the clock, which is why there are six shafts in total.
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Once the ion is cooled, another laser makes it resonate between two energy states with an incredible regularity governed by quantum mechanics. It gives off a regular pulse of optical radiation exactly 444,779,044,095,485 times per second.
Don鈥檛 be fooled by the orange light, it has nothing to do with the ion. It鈥檚 just the hot glow of a wire that measures the quality of the vacuum within the cube. 鈥淵ou can see a bright spot in the middle, I hesitate to say whether that is fluorescence from an ion, but that鈥檚 where it is located,鈥� says NPL鈥檚 Patrick Gill.
Despite its sophistication, the clock鈥檚 round face and equally spaced arms give it a familiar look. Gill, though, sees something totally different. 鈥淲hat with the arms coming off,鈥� he says, 鈥淚 always call it the Buddha.鈥�
When this article was first published, it gave the strontium ion鈥檚 pulse rate as 429,228,004,229,952 per second. This has been updated to reflect the even rapider reality.