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Physics, Astronomy & Cosmology / Why is NIST basing the new kilogram (kg) definition on gravity?
« on: 02/12/2017 01:38:15 »
So NIST are redefining the kg next year : instead of a lump of plat in Paris, a kg will be defined using a formula based on fundamental constants.... and Earth's surface gravity. And there's the prob I see with this definition. Earth's surface gravity is known to vary slightly over time in every place where its tested. Why base a constant on something that is known to vary? Or has Veri got it wrong when he states g is a part of definition? Will the watt balance give the same definition value of 1kg when performed under different gravitys?