Welcome to daylight-saving time. You’ve just lost an hour and you get to set every single clock and watch in the house to the new time (which means trying to remember the tricky combination of button pushing to advance your digital wristwatch).
Oh if only you had atomic timekeeping devices. Well, not actual atomic clocks (those are about 10 feet tall), but clocks and watches that communicate directly with THE atomic clock in Boulder, Colo. Then you’d never have to set a clock or watch again.
Yes, we have the technology! Clocks exist that obediently update the time based on the atomic clock’s precise time. And they reset after the power goes off or if the time changes. It’s all done via the magic of microchips, radio signals and an atomic clock that marks the passing of time right down to nanoseconds.
But before we delve into that, let’s take a little walk through time. The following historical time tidbits are from the Web site of the National Institute of Standards and Technology (NIST) – keepers of the atomic clock.
Seems there have always been some among us preoccupied with tracking time. Early man scratched lines and gouged holes into sticks and bones to mark changes observed in the night sky.
Eventually things got a bit more precise. Some 5,000 to 6,000 years ago, cultures began making “clocks.” Early versions were sundial contraptions, candles with marked increments and sandfilled hourglasses. By about 350 B.C. the Greeks were using water clocks – stone vessels that allowed water to drip at a nearly constant rate from a small hole.
Fast-forward to the first pendulum clock invented in 1656. Quartz clocks entered the picture in the 1930’s and 1940’s. And the first atomic clock – based on the ammonia atom – was built in 1949. It was replaced by the much more accurate cesium atomic beam device in 1957.
How does such an atomic clock work?
To best understand the intricacies of this ultimate timekeeping device, go get a master’s degree in physics. If a rudimentary explanation will suffice, read on.
The device that carefully keeps track of time in Boulder is officially known as: The Frequency Standard. It’s OK, however, to call it an atomic clock.
Don’t confuse atomic with radioactive. There are no mushroom clouds involved. “It’s electromagnetic radiation as opposed to ionized radiation,” said Collier Smith, a spokesman for NIST in Boulder.
To make sense of the atomic clock, it’s important to have a grip on basic clock function.
“All clocks have three essential parts: something that repeats itself at a regular pace, something that counts those regular events and some way to display that count,” Smith explained.
For example, he said, a grandfather clock has a regularly swinging pendulum. Gears translate the swinging into circular motion that displays the time on the clock face.
The atomic clock uses a vacuum chamber and lasers to create conditions for recording the frequencies of the cesium atom. The transitions of the cesium atom as it moves back and forth between two energy levels are counted to keep time, according to the NIST. The clock is so accurate that it will neither gain nor lose a second in 20 million years.
But that’s not good enough.
Smith said researchers are constantly working on developing even more accurate devices. “We are working one or two generations ahead almost all the time.”
As the world gets more high-tech, so does the need for accurate time. Precise time is used to synchronize high-speed communications systems, track space probes, transmit sonar signals, regulate power grids and for television feeds and bank transfers.
The atomic clock’s time is continuously sent out by radio signal from towers north of Fort Collins, Colo., to those requiring split-second accuracy.
Does that include the typical person trying to get the kids to the school bus stop at 7:15 a.m. or watch “Survivor” at 8 p.m.?
Well, no.
“There is no need for the atomic level of accuracy (in the home) that we are talking about here,” Smith said.
But the convenience offered by a clock synchronized to the atomic clock, is another matter. It’s certainly nice not to have to reset a clock after a power outage or the switch to daylight-saving time, said Bridget Haggerty, a spokeswoman for Chaney Instrument Co. in Lake Geneva, Wis., which makes radio-controlled clocks linked to the atomic clock (its clocks and watches are sold through mail-order stores, large retailers and www.klockit.com).
The technology has been available for years, but it wasn’t until recently that the clocks became more affordable, she said.
“Until a couple years ago, the signal that we were sending was not powerful,” Smith said. “We about tripled the power a couple of years ago. Before that, the sensitivity of the clock had to be pretty high, which made it expensive.”
Radio-controlled wall clocks are approximately $25 to $50, Haggerty said. Wristwatches sell for $50 to $300, she said. The quartz clocks and watches have tiny receivers and microchips that prompt them to seek – at certain times – the radio signal from the atomic clock and synchronize to it. The time zone must be initially set by the owner. A clock or watch will not automatically adjust if it is taken to a different time zone.
Smith said he owns one of the clocks. “It’s nice to have at least one clock in the house that you know is right,” he said.