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Why is the kilogram standard mass changing?

  1. Sep 23, 2011 #1
    from the current Physicsworld newsletter:

    ???
     
  2. jcsd
  3. Sep 23, 2011 #2
    Much to my surprise, wikipedia has quite a bit on this subject!!


    But:
    http://en.wikipedia.org/wiki/Kilogram#Stability_of_the_international_prototype_kilogram
     
  4. Sep 23, 2011 #3

    Maroc

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    Gold Member

    This can change so many things...
     
  5. Sep 23, 2011 #4
    I heard this one before, as well as several other articles related to various constants that were thought to be reliable showing slight changes over time. Wish I kept a link of those articles. One was the rate of atomic decay not being consistent ,slowing down faster in the past than now today by a small amount, the other was light speed being faster in the past than now today. Neither article has been able to understand why and therefore have not been able to prove it conclusively. Those articles I read around one year ago haven't seen anything since on either article. may or may not be related
     
  6. Sep 23, 2011 #5
    Last edited: Sep 23, 2011
  7. Sep 23, 2011 #6

    Drakkith

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    Staff: Mentor

    The reason for the change is that it is a better idea to use something that is constant to the best of our measurements instead of something that is known to vary. The other measurements, such as the second and the meter are all based on constants that don't change according to our current understanding.
     
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