Wow! The Kilogramm just got redefined!!! π€©
Originally shared by Eli Fennell
Kilogram Redefined for 21st Century (and Beyond)
Ever since the 1800’s, the kilogram has been defined by a literal, physical object: a platinum iridium cylinder, locked away in a vault and France and only rarely removed for reweighing.
On the one hand, there is a very imprecise way to define a unit of weight that often needs to be very precise. For example, the Earth is not a perfect sphere, and therefore very slight gravitational differences on different parts of our planet mean the relation between weight and mass is less than perfect. On the other hand, objects lose mass over time no matter how well preserved from the elements, and this cylinder is no exception, and has been losing mass.
The new measure of a kilogram will be based on an application of Planck’s constant, which thus should be valid across time and space. The cylinder will no doubt be retired now to some museum, a relic of how we once measured the universe little more sensible in retrospect than the arbitrary measures in the English measuring systems which the new metric measurements eventually replaced (everywhere, at least, except in the United States).
#BlindMeWithScience #Physics #Kilogram
https://www.sciencealert.com/it-s-official-the-definition-of-a-kilogram-has-changed//cdn.embedly.com/widgets/platform.js