WHAT:
Caesium-133 Primary Standard Atomic Clock
WHERE:
NPL, Hampton Rd, Teddington, TW11 0LW, UK
LOCATION:
WHEN:
1955
WHO:
Louis Essen
DETAILS:
In 1955, the National Physical Laboratory built the world’s first caesium‑133 atomic clock, designed by physicist Louis Essen. This groundbreaking achievement provided an unprecedented level of accuracy in measuring time and became the basis for defining the international standard second. The clock marked a turning point in science and technology, influencing fields such as global navigation, telecommunications, and space exploration. NPL’s work on the atomic clock remains one of its most celebrated contributions, shaping the way time is measured worldwide.
LINKS:
The National Physical Laboratory Teddington – Garden Party 13th September 2025
The National Physical laboratory was set up 125 years ago. It has gone on to nurture an incredible array of scientists and researchers with some world changing inventions to their names. On the 13th of September there will be no fewer than FOUR World Origin Site plaques on display before they are put up permanently. Four is an incredible achievement but there are more already in discussion. Here are their first four plaques fresh from the foundry. See link to book for this event
