A second via atomic decay?

[JeffCyr]

I recall hearing somewhere that the official length of a second was now kept by the measure of how much an atom of a certain material or isotope decays, such as "When X decays by Y it equals one second"

For the novel I'm writing I need a means to measure seconds that would be completely universal no matter where one would be in the universe, so recalling this I figured the decay of some element would be the best way to measure it.

Am I recalling it right that some element's decay is the official measurement of a second? Whether it is or not, is there such an element that could be used for it?

 

[Vanadium 50]

See http://physics.nist.gov/cuu/Units/second.html

 

[JeffCyr]

Thank you, although that's a bit of unknown for me. Does that mean that 1 second is the span of 9 192 631 770 change in energy levels of a cesium atom at 0 kelvin?

 

[DaveC426913]

Thank you, although that's a bit of unknown for me. Does that mean that 1 second is the span of 9 192 631 770 change in energy levels of a cesium atom at 0 kelvin?

Pretty much, yes.

 

[JeffCyr]

Ah thank you!