Silicon sphere

This sphere was produced as part of an international project known as the Avogadro project. The goal of the Avogadro Project is to measure the value of the Avogadro constant to extreme precision, thereby allowing the mass of the kilogram to be defined in terms of the Avogadro constant. This would do away with the current physical artefact (a cylinder made of an alloy of platinum and iridium) and allow the kilogram to be reproduced in any laboratory by following a prescribed procedure.