On Monday, May 20 - World Metrology Day - the definition for the kilogram, the base unit of mass, will change following a decision late last year by the General Conference on Weights and Measures to fundamentally reform the International System of Units (SI). Going forward, all SI units will be based on the values laid down for seven selected natural constants - eliminating all man-made objects from these definitions.
The new definition for the kilogram, say researchers, could have positive implications for areas where extremely precise measurements are required - such as with the use of nanodevices, when concocting the correct dose of compounds used in a medicine, or when calculating the weight of a newly discovered subatomic particle.
Professor Wolfgang Ketterle , the 2001 Nobel laureate in physics, will present a special lecture at MIT exploring the new standards of measurement and why this is such a historic shift for scientists around the world. The lecture will delve into how, for the first time ever, the definition for the kilogram - as well those for the base units of charge, temperature, and mole - will shift from being based on physical objects that can change over time, to fundamental constants that scientists around the world will be able to reproduce.
"This seemingly insignificant alteration to the underpinnings of our measurement system could not only help reduce uncertainty when calculating values using the international standards of measurement," say MIT researchers, "but also help democratize access to the system of weights and measures so that it is no longer tied to a specific country or place."
Ketterle's lecture - World Metrology Day Special Lecture: The New Kilogram - will be held at MIT's Huntington Hall at 4 PM on Monday, May 20, 2019.
Scientists create scales for the new kilogram