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Latest SI base units Stories

6ed60629f44cb8b9fd715d1c2ad82b4b1
2008-02-28 18:53:08

Change should have little impact on nuclear weapons complexThe kilogram is losing weight and many international scientists, including some at Sandia National Laboratories, agree that it's time to redefine it.Scientists are hoping to redefine the kilogram by basing it on standards of universal constants rather than on an artifact standard.The International Prototype Kilogram (IPK) or "Le Grand K," made in the 1880s, is a bar of platinum-iridium alloy kept in a vault near Paris."The idea is to...

6b6a393fe3a9962291d5b99c201176911
2007-09-12 19:35:00

PARIS -- A kilogram just isn't what it used to be. The 118-year-old cylinder that is the international prototype for the metric mass, kept tightly under lock and key outside Paris, is mysteriously losing weight - if ever so slightly. Physicist Richard Davis of the International Bureau of Weights and Measures in Sevres, southwest of Paris, says the reference kilo appears to have lost 50 micrograms compared with the average of dozens of copies. "The mystery is that they were all made of the...