Atomic clocks have grown so precise that timekeeping itself may be redefined. Optical clocks lose less than a second over the age of the universe. Metrologists are preparing to base the second on them.
Optical precision
Frequencies are higher. Optical transitions tick far faster than microwave ones. Precision soars.
Astonishing stability
Errors are tiny. The best clocks err by parts in a billion billion. Records keep falling.
Redefining the second
Standards may shift. The unit could be tied to an optical transition. Committees are deliberating.
New sensing
Uses multiply. Such clocks probe gravity and fundamental constants. Science benefits.
Comparison challenge
Linking is hard. Distant clocks must be compared precisely. Networks are being built.
A careful process
Change is deliberate. Redefinition requires broad agreement. The timeline is measured.
The bottom line
Optical atomic clocks are so precise that the second may be redefined around them. Their stability enables new tests of physics. Metrologists are preparing a careful transition.
