Elusive Quest for One True Kilogram Finally Pays Off
The international system of measurement has a weight problem—and a crystal ball could provide the solution.
For over a century, a golf-ball sized cylinder locked in a vault in Sèvres, France, has defined the true mass of a kilogram (2.2 pounds) for the entire planet.
The International Prototype of the Kilogram, a gleaming object of platinum and iridium otherwise known as Le Grand K or Big K, is the last of its kind. All other standardized units of measurement have been redefined in terms of a fundamental natural constant. For instance, the meter, which was originally represented by a metal bar, was redefined in 1983 as the distance light travels in a vacuum during 1/299,792,458 of a second.
An international cohort of scientists hopes to do the same for the kilogram and, once and for all, toss out
