The duration of 9,192,631,770 periods of the radiation corresponding to the transition between two hyperfine levels of the ground state of the cesium-133 atom.
This definition was adopted in 1967 by the International System of Units (SI).
BUT that is just a construct devised to consistently measure the second using the constant of that particular cesium isotope. It doesn't define the second any more than a precise ruler defines the inch or the foot. Saying an atomic clock invented the second is about as true as saying my tape measure invented the inch.
Well sure! But I'm not saying "an atomic clock invented the second". I'm just giving you a textbook definition of a "second". What else is there? Do you know of a better way? Or standard? Not being argumentative I just don't know.
The second is defined as:
The duration of 9,192,631,770 periods of the radiation corresponding to the transition between two hyperfine levels of the ground state of the cesium-133 atom.
This definition was adopted in 1967 by the International System of Units (SI).
BUT that is just a construct devised to consistently measure the second using the constant of that particular cesium isotope. It doesn't define the second any more than a precise ruler defines the inch or the foot. Saying an atomic clock invented the second is about as true as saying my tape measure invented the inch.
Well sure! But I'm not saying "an atomic clock invented the second". I'm just giving you a textbook definition of a "second". What else is there? Do you know of a better way? Or standard? Not being argumentative I just don't know.