Time scales

Category:Time scales - Wikipedia

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Time zones

Hafele and Keating flew caesium clocks around the world in 1971 and the two directions were wrong in opposite ways Why physics needed a second that does not depend on the rotation of the Earth Why servers log in UTC while every bug report arrives in local time Astronomy forced the world to standardise time long before any other science did Who is legally responsible when a national time signal goes wrong? Flight plans run on UTC while the departure board shows local time Why the same list of dated events can support two defensible orderings Spanner's TrueTime buys causality with atomic clocks and an explicit uncertainty window What happens to software that assumes every minute has exactly 60 seconds? How is a leap second inserted and who signs off on it? There is no global now in a distributed system and NTP cannot manufacture one Why do timestamps in logs sometimes jump backwards? What makes an atomic clock wrong by only one second in a hundred million years? How do you calibrate a clock against a reference you are not allowed to touch? Why is UTC a time scale rather than a time zone?

Seasons Horology Time measurement systems History of timekeeping Time Management Future Timeline Calendars Time in life Historical eras