http://www.physicsweb.org/article/news/7/9/9From the seven basic SI-units, the kilogram is the only one that is not yet defined in terms of fundamental constants. Instead, it is defined as the mass of a prototype. Scientists want to change this.
(For those who are not familiar with the SI-system: the SI-system is the international standard for units of measure. It has seven base units:
Kilogram for mass
Meter for length
Second for time
Ampère for electrical current
Mole for amount of substance
Kelvin for temperature
and a unit for brilliance, IIRC.
All other units are derived from the base units; for instance, speed is measured in meters/second.)
Difference in opinions hath cost many millions of lives: for instance, whether flesh be bread, or bread be flesh; whether whistling be a vice or a virtue; whether it be better to kiss a post, or throw it into the fire... (from Gulliver's Travels)
