What's in an hour....

For would it not by any other name be as long?
Turns out that an hour has not always been an hour...
The division of day into 24 hours dates back to Mesopotamia and Egypt. With basis in the moons 12 cycles in a year, the day and night was each given 12 hours. The only problem is of course that an hour was dramatically different in Mesopotania than in England or Norway. An hour was also very different in summer and in winter.
Today, we have defined an hour as 60minutes times 60 seconds, where 1 second is 9 192 631 770 oscillations of the Cesium atom 133Cs.