Perfect Silicon Sphere to Redefine the Kilogram

MrCreosote writes "The Age reports optical specialists at CSIRO are helping create a new standard for the kilogram, based on a precise number of atoms in a perfect sphere of silicon. This will replace the International Prototype, a lump of metal alloy in a vault in Paris."

Comments

Re:alternate theories

[jmv]

I personally wouldn't put too much trust into a measurement that depends on gravitational acceleration for several reasons.
1) It means you can't move the setup somewhere else easily because gravity is location-dependent
2) Events like the 2004 tsunami has a slight (but measurable) effect on the Earth's rotation and hence on the acceleration (because of centrifugal force) ... and most importantly
3) Your measurement will (*literally*) depend on the phase of the moon (just like tides)