2 ms·

Thanks for that clarification. After this, I was able to find the International System of Units Wikipedia page which clearly defines a second as per your summar

Thanks for that clarification. After this, I was able to find the International System of Units Wikipedia page which clearly defines a second as per your summary. It's a relief to see that it's a constant formula like that of the Kilogram.

craftyguy 8y ago
I was suprised to learn (from the wiki page) that the kelvin, mole, and ampere do not have exact numerical definitions yet, though I guess that's expected to change in May of this year. And then there's the candela, still basically defined by how luminous whale blubber is when it is burning: > Current (1979): The luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 5.4×1014 hertz and that has a radiant intensity in that direction of 1 / 683 watt per steradian. > Note: both old and new definitions are approximately the luminous intensity of a whale blubber candle burning modestly bright, in the late 19th century called a "candlepower" or a "candle".
- kevingrahl 8y ago
  What happens in May?
  - craftyguy 8y ago
    World Metrology Day, where acceptance of these standards will be voted on. https://www.nist.gov/news-events/news/2018/11/historic-vote-ties-kilogram-and-other-units-natural-constants https://www.nist.gov/news-events/news/2018/11/historic-vote-...