Time and frequency activities at NIST include maintaining standards, providing official time to the U.S., and carrying out a broad program of research and service activities in time and frequency metrology.
Philosophically, what is "time"? Even if we don’t completely understand what time is, we can precisely measure what time it is, thanks to the atomic clock, humankind’s most accurate measurement device. Atomic clocks have revolutionized navigation. Only time will tell us its future applications.