A replica of the International Prototype Kilogram. The golf ball-sized metal cylinder at the heart of the world’s system for measuring mass is now in retirement. Photo: AP

Chunk of metal known as ‘Grand K’ is now officially retired as the world’s only true kilogram

  • About 50 nations vote to overhaul the international system of measurements
  • New formula for the kilogram seen as more accurate when measuring very small or very large masses
Topic |   Science

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A replica of the International Prototype Kilogram. The golf ball-sized metal cylinder at the heart of the world’s system for measuring mass is now in retirement. Photo: AP
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