3 ms·
I thought a second was a SI base unit: (from Wikipedia) The second, symbol s, is the SI unit of time. It is defined by taking the fixed numerical value of the
by hackbinary 8y ago
I thought a second was a SI base unit: (from Wikipedia)
The second, symbol s, is the SI unit of time. It is defined by taking the fixed numerical value of the caesium frequency {\displaystyle \Delta \nu _{\text{Cs}}} {\displaystyle \Delta \nu _{\text{Cs}}}, the unperturbed ground-state hyperfine transition frequency of the caesium-133 atom, to be 9192631770 when expressed in the unit Hz, which is equal to s−1.
- matt4077 8y agoI believe they are referring to the relativistic drift experienced when comparing two observers moving with high relative speed.
- jldugger 8y agoThis is true, but does not compensate for relativistic time dilation.
- mdavidn 8y agoYes, but that frequency depends on the caesium-133's frame of reference. In a deep gravity well or at "high" speed, caesium-133 emits at a lower frequency relative to caesium-133 in deep space moving at "low" speed.