NIST-F4: the new atomic clock to mark the passage of time with maximum precision. It also gives the time

The NIST-F4 is the name of the new atomic caesium source clock of the National Institute of Standards and Technology of the United States (NIST). It has an accuracy of 2.2 parts in 1016, which means that, if it had started to work 100 million years ago, today it would be diverted less than a second. The technology on which it is based is a source of caesium: a cloud of atoms cooled with lasers up to almost absolute zero and thrown vertically, wh…