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  2. Doomsday Clock - Wikipedia

    en.wikipedia.org/wiki/Doomsday_Clock

    The Doomsday Clock is a symbol that represents the estimated likelihood of a human-made global catastrophe, in the opinion of the members of the Bulletin of the Atomic Scientists. [1] Maintained since 1947, the Clock is a metaphor, not a prediction, for threats to humanity from unchecked scientific and technological advances. That is, the time ...

  3. Atomichron - Wikipedia

    en.wikipedia.org/wiki/Atomichron

    The Atomichron was the world's first commercial atomic clock, built by the National Company, Inc. of Malden, Massachusetts. It was also the first self-contained portable atomic clock and was a caesium standard clock. More than 50 clocks with the trademarked Atomichron name were produced. [1] [2] [3] [4]

  4. Atomic clock - Wikipedia

    en.wikipedia.org/wiki/Atomic_clock

    A caesium atomic clock from 1975 (upper unit) and battery backup (lower unit) [15] ... the National Radio Company sold more than 50 units of the first atomic clock, ...

  5. International Atomic Time - Wikipedia

    en.wikipedia.org/wiki/International_Atomic_Time

    TAI is a weighted average of the time kept by over 450 atomic clocks in over 80 national laboratories worldwide. [3] The majority of the clocks involved are caesium clocks; the International System of Units (SI) definition of the second is based on caesium. [6] The clocks are compared using GPS signals and two-way satellite time and frequency ...

  6. Mengenlehreuhr - Wikipedia

    en.wikipedia.org/wiki/Mengenlehreuhr

    The Mengenlehreuhr displaying 10:31 Clock displaying time from 16:50 to 17:05 (4:50 pm to 5:05 pm) in time lapse. The clock at its original location in May 1979, displaying 17:54 (5:54pm). The Mengenlehreuhr (German for "Set Theory Clock") or Berlin-Uhr ("Berlin Clock") is the first public clock in the world that tells the time by means of ...

  7. History of timekeeping devices - Wikipedia

    en.wikipedia.org/wiki/History_of_timekeeping_devices

    The first clock known to strike regularly on the hour, a clock with a verge and foliot mechanism, is recorded in Milan in 1336. [96] By 1341, clocks driven by weights were familiar enough to be able to be adapted for grain mills, [97] and by 1344 the clock in London's Old St Paul's Cathedral had been replaced by one with an escapement. [98]

  8. Atmos clock - Wikipedia

    en.wikipedia.org/wiki/Atmos_clock

    The first clock powered by changes in atmospheric pressure and temperature was invented by Cornelis Drebbel in the early 17th century. Drebbel built as many as 18 of these, the two most notable being for King James VI & I of Britain, and Rudolf II of Bohemia. The King James clock was known as the Eltham Perpetuum, and was famous throughout Europe.

  9. List of largest clock faces - Wikipedia

    en.wikipedia.org/wiki/List_of_largest_clock_faces

    A list of permanent working clocks with the largest faces in the world. Entries include all clocks with faces at least 4 m (13 ft) in diameter. Clocks can be located on the exterior or interior of buildings, and towers as well as on the ground as is the case with floral clock faces.