Share the knowledge!
Key Facts In This Video
In 1899, the International Bureau of Weights and Measures created an iridium cylinder as the worldwide standard for the kilogram. 00:32
30 years ago, scientists realized that the masses of the original kilogram and its copies are drifting apart. Nobody knows why. 01:03
The BIPM has already redefined other measures using universal constants. A meter, for example, is the distance light travels in 1/299,792,458 of a second. 01:39
Wake up with the smartest email in your inbox.
Our best articles a few times a week.