Video Description
The video features Dr. Steve Jefferts, a staff physicist at the National Institute of Standards and Technology (NIST) in Boulder, Colorado. He is an expert on how we measure time and has co-developed one of the world’s most accurate atomic clocks. The video explores the importance of atomic clocks in our everyday lives.
Video Transcription
Here that that’s a second or is it how do we know what a second really is here’s someone you should know Steve Jeffords. I’m a staff physicist at the National Institute of Standards and Technology (NIST) in Boulder, Colorado. He’s also an expert on how we measure time. Nature provides a bunch of clocks if you will automatically. For example, the Sun rising and setting marks a day, the moon waxing and waning marks a month.
In the past, we measured time using these natural clocks but then we adopted more sophisticated technology whether it’s a water drip clock or a pendulum clock or finally a quartz crystal oscillator. All these clocks have one thing in common; they measure periodic events, how long it takes for say a pendulum to swing back and forth or the earth to move around the Sun.
And today we’re using this same idea to build something even more accurate. If you want to talk about atomic clocks, we just in some sense go then they stamp. Atomic clocks are clocks that measure the oscillations of atoms. This is pretty complicated stuff but the basic idea is that all atoms of a given element vibrate or tick the same number of times per second. For example, nine billion 9,192,631,770 to be exact.
And that number is pretty important since today the international standard for what a second is, is based on that many vibrations or ticks of a cesium atom. Part of Jeffords’ job is to make sure that time in the U.S. is calibrated to those ticks. Simply count how many ticks the cesium atom says have gone by and when I reached this nine billion number that’s one second.
Unlike a normal clock which might lose or gain a second, commercial atomic clocks are accurate to something like one second in three million years. And to calibrate U.S. time, Jefferts uses a cesium clock at NIST that is accurate to a second in almost a hundred million years. If you’d had two of these clocks in the dark ages and you kept in ticking until now, they’d be within a microsecond of each other. And a microsecond is is so small.
But why should we care about atomic clocks at all? Why do we need clocks this accurate? If you don’t have atomic clocks a whole bunch of things that we do everyday don’t work. Lots of the high-speed protocols for data transmission on the Internet, the GPS navigational system goes away, cellphone towers probably quit working, even the electric grid would stop working.
Our high-speed interconnected world works because we can synchronize different pieces of technology using accurate time. And Jeffords says whenever we build a better clock, engineers find some new way to use it. Sort of a Field of Dreams analogy, if you build it the technology will come. So in the future, who knows where better atomic clocks might lead us, only time will tell you.