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B A second via atomic decay?

  1. May 19, 2017 #1
    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?
  2. jcsd
  3. May 19, 2017 #2

    Vanadium 50

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  4. May 19, 2017 #3
    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?
  5. May 19, 2017 #4


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    Pretty much, yes.
  6. May 19, 2017 #5
    Ah thank you!
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