5 ms·
A second is the period of a pendulum with a length of one meter. :-) (But not really; that was originally considered as a way to standardize the meter, IIRC, b
by saalweachter 3y ago
A second is the period of a pendulum with a length of one meter. :-)
(But not really; that was originally considered as a way to standardize the meter, IIRC, but the period of a pendulum varies too much even over the area of France to be used as a concrete standard.
But the relationship is remarkably close for a coincidence, like the way a rod is almost exactly five meters.)
- ninju 3y agoThe calculation of a second has been updated in 2019 The second is defined by taking the fixed numerical value of the cesium frequency ∆ν, the unperturbed ground-state hyperfine transition frequency of the cesium 133 atom, to be 9 192 631 770 when expressed in the unit Hz, which is equal to s−1. https://www.npl.co.uk/si-units/second https://www.npl.co.uk/si-units/second
- runlevel1 3y agoThe conference where this was made official was quite a beautiful, upbeat demonstration of people from around the world coming together to agree upon a change: https://www.youtube.com/live/qA67T7FPBME?t=498 https://www.youtube.com/live/qA67T7FPBME?t=498