Sphere Made to Redefine Kilogram Has Purest Silicon Ever Created – Scientific American

Credit: Enrico Massa and Carlo Sasso

The perfect sphere that will be used to redefine the kilogram in terms of the Planck constant in 2018 has been shown to consist of the purest silicon ever made.

The kilogram is the only unit still based on a physical object. The ‘big k’ is a platinum–iridium cylinder stored in an underground vault in France. However, over time this artefact can gain or lose atoms, which is why the International Committee for Weights and Measures decided to redefine the unit using the Planck constant. This fundamental physical constant relates to mass through Einstein’s formula E = mc2


Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s

%d bloggers like this: