Do you know what a second is, actually? Scientifically?
Michigan’s army of researchers no doubt know: “The second [...] is defined by taking the fixed numerical value of the cesium (Cs) frequency, ΔνCs, the unperturbed ground-state hyperfine transition frequency of the Cs-133 atom, to be 9,192,631,770 when expressed in the unit hertz, which is equal to s^−1.”
