Scientists met in Versailles on 16 Nov and the vote re-defined the metric system for the first time since 1983. The new system completely upends the historical methods for setting standards using physical objects. Previous systems have used things like the notches on a metal rod to set a distance standard. Up until the vote, the kilogram had been based on a platinum-iridium cylinder stored under lock and key in France.
this is it
“Perhaps the biggest change was in the definition of the kilogram, which was the last remaining unit to be based on a physical artifact: the International Prototype Kilogram, also known as Le Grand K, locked in a vault in a Paris suburb. While scientists will still monitor and study Le Grand K, it no longer has its former scientific significance. Now, it’s just a cylinder with a lot of history. Starting in May, the kilogram will be defined in terms of Planck’s constant, a number that relates a radio wave’s energy to its frequency.”
this is the new authoratative gadget for measuring the standard kilo..