The Hydrogen Maser A High-Precision Clock

In running water, also in the sleep Of winter seeds, where time to come has tensed Itself, enciphering a script so fine Only the hourglass can magnify it, only The years unfiold its sentence to the root. 

Early in a child s life, he or she discovers the facts of birth and 

Einstein s theories of relativity were created during the early years of the twentieth century. The desire to confirm the many predictions of relativity has been one motivation in the search for ever more accurate clocks. The hydrogen maser clock is a part of that tradition. 

Quartz clocks are accurate to about 0.0001 seconds per day. Such accuracy is more than adequate for everyday affairs. Suppose, however, the challenge is to measure the difference in clock rate between sea level and the top of Mount Everest The answer is that a clock on the top of Everest loses about 0.000030 second 

Atomic clocks have their roots in Rabi s magnetic resonance 

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