In between coffee breaks and presentations on quantum physics, scientists today voted to redefine the kilogram, the unit that underpins the world’s system of weights. Instead of basing the kilogram’s value on a physical artifact, as has been the case for more than 100 years, it will now be defined using a constant of nature.
Its weight, handily, will not change.
The vote has been centuries in the making, with scientists describing it as the biggest revolution in measurement since the French Revolution. Now, they say, the metric system will fulfill the guiding ideology of metrology established in that period: to create units of measurement “A tous les tempes, a tous les peuples” — for all time and for all people.