杏吧原创

TIME stood still in Britain last week鈥攕o still that some had to be imported from the US. The reason? The government-run atomic clock that acts as Britain鈥檚 official timekeeper had to be taken off the air for more than a week.

The Department of Trade and Industry pays the National Physical Laboratory 拢500,000 a year to create and broadcast Britain鈥檚 official time signal 24 hours a day, from a radio station in Rugby, Warwickshire. Called MSF鈥攖he abbreviation鈥檚 meaning has been lost in the depths of history鈥攖he signal is used by hundreds of thousands of businesses, broadcasters and self-correcting clocks.

Last week, the steel cables holding up a transmitter mast next to the 250-metre-high MSF mast began to weaken. So British telecommunications company BT, which broadcasts the ultra-accurate time signal for NPL, decided to close both masts down while repairs were made. Repairs would have been too dangerous with power still being sent to the MSF mast, says John Laverty at NPL, because the weakened one could have fallen onto nearby power cables.

As the signal went down, complaints from MSF users began. 鈥淲e were very, very busy with calls and emails in the first two days after the signal was turned off,鈥� says Laverty. To stay on time, users had to switch to the American GPS network, which broadcasts a time signal from an atomic clock in its positioning data.

So why is there no back-up mast for the time signal? NPL risk assessments carried out in 1995 didn鈥檛 foresee that a stand-in would ever be needed, says a spokeswoman. And despite last week鈥檚 signal loss, no back-up is being planned. Given the low chance of needing it again, it would not be a cost-effective use of taxpayers鈥� money, says the Department of Trade and Industry.