Oof Arted Posted November 7, 2011 Report Share Posted November 7, 2011 <_< We are all in serious trouble chaps read this link http://uk.news.yahoo.com/kilogramme-faces-quantum-diet-weight-gain-131735537.html The French can't be trusted with our most treasured S.I. Quote Link to comment Share on other sites More sharing options...
kenberg Posted November 7, 2011 Report Share Posted November 7, 2011 First the neutrino, now the kilogram, is nothing safe!!! However:The idea that they can know it changed by 50 microgrammes , but they are not sure whether it is +50 or -50, strikes me as very odd. Or maybe I read it wrong? Maybe E = mc^(2.0000003)? Quote Link to comment Share on other sites More sharing options...
barmar Posted November 8, 2011 Report Share Posted November 8, 2011 Wikipedia has a section about this: http://en.wikipedia.org/wiki/Kilogram#Stability_of_the_international_prototype_kilogram There are a bunch of copies of the standard distributed to different countries around the world, and periodically they compare the primary one with them. They're all fluctuating over time, but since there's nothing else to compare to, all they can actually tell is that the prototype has dropped relative to the rest. If they've all lost mass, the prototype has lost more; if they've all gained mass, the prototype has gained less. It's theoretically possible that the prototype has actually stayed stable, and only the copies have changed, but this would be quite a coincidence. Quote Link to comment Share on other sites More sharing options...
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