The Hunk of Metal | The Last Artifact

The kilogram, the base unit of mass in the International System of Units, helped send humans to the moon and satellites into space. This small hunk of metal is the object against which all others are measured. Yet over time, its mass mysteriously eroded by the weight of an eyelash.  A change that, unbeknownst to most, unleashed a crisis with potentially dire consequences.

Learn about the challenges of using an artifact to define the standard of measurement.