“On the outskirts of Paris, eight metres below ground in a climate-controlled vault, sits a 143-year-old platinum alloy cylinder. Standing just 39 mm tall, it has never been touched by human hands. Like a delicate Russian doll, the cylinder is caged inside three nested glass bells in a room that can be accessed only with three keys kept by three different people. Surrounding the mysterious object are ‘the witnesses’: six ‘identical’ cylinders cast from the same platinum alloy.
“Though preservation efforts rival those of the Turin Shroud, the cylinder is not a sacred religious object. It is the International Prototype Kilogram (IPK), the one and only true kilogram against which all others are measured. Housed in the Pavillon de Breteuil – home to the International Bureau of Weights and Measures (BIPM) – the IPK will soon lose its unique status and become a relic of a bygone age. It will then be as quaint as the International Prototype Metre (IPM) – a platinum alloy bar also housed at the BIPM – that served as the world’s official metre until 1960.”
Benjamin Skuse, SI gets a makeover
Good article about the history of the kilogram and the new definition that was officially adopted yesterday (November 16th).
About the vote, another article: “Scientists for whom the update represents decades of work clapped, cheered and even wept as the 50-plus nations one by one said “yes” or “oui” to the update in the French city of Versailles on Friday (local time).
Nobel prize winner William Phillips called it “the greatest revolution in measurement since the French revolution”, which ushered in the metric system of metres and kilograms. “
#oh look an update #the power of science