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  2. Atomic clock - Wikipedia

    en.wikipedia.org/wiki/Atomic_clock

    In addition to increased accuracy, the development of chip-scale atomic clocks has expanded the number of places atomic clocks can be used. In August 2004, NIST scientists demonstrated a chip-scale atomic clock that was 100 times smaller than an ordinary atomic clock and had a much smaller power consumption of 125 mW .

  3. History of timekeeping devices - Wikipedia

    en.wikipedia.org/wiki/History_of_timekeeping_devices

    The invention of the verge and foliot escapement in c.1275 [87] was one of the most important inventions in both the history of the clock [88] and the history of technology. [89] It was the first type of regulator in horology. [6] A verge, or vertical shaft, is forced to rotate by a weight-driven crown wheel, but is stopped from rotating freely ...

  4. Timeline of time measurement inventions - Wikipedia

    en.wikipedia.org/wiki/Timeline_of_time...

    c. 3500 BC - Egyptian obelisks are among the earliest shadow clocks. [1] c. 1500 BC - The oldest of all known sundials, dating back to the 19th Dynasty. [2] c. 500 BC - A shadow clock is developed similar in shape to a bent T-square. [3] 3rd century BC - Berossos invents the hemispherical sundial. [4] 270 BCE - Ctesibius builds a water clock.

  5. Doomsday Clock - Wikipedia

    en.wikipedia.org/wiki/Doomsday_Clock

    The Doomsday Clock is a symbol that represents the likelihood of a human-made global catastrophe, in the opinion of the members of the Bulletin of the Atomic Scientists. [1] Created by J. Robert Oppenheimer [ citation needed ] and maintained since 1947, the Clock is a metaphor , not a prediction, for threats to humanity from unchecked ...

  6. List of atomic clocks - Wikipedia

    en.wikipedia.org/wiki/List_of_atomic_clocks

    View history; Tools. Tools. move to sidebar hide. Actions Read; Edit; View history; General ... This is a list of some experimental laboratory atomic clocks worldwide.

  7. Doomsday clock moves to 90 seconds to midnight – the ... - AOL

    www.aol.com/doomsday-clock-moves-90-seconds...

    In 2020, the clock was set at 100 minutes to midnight, and remained unchanged for the next three years. Although originally intended to warn of the threat of nuclear Armageddon, the Doomsday Clock ...

  8. International Atomic Time - Wikipedia

    en.wikipedia.org/wiki/International_Atomic_Time

    The United States Naval Observatory began the A.1 scale on 13 September 1956, using an Atomichron commercial atomic clock, followed by the NBS-A scale at the National Bureau of Standards, Boulder, Colorado on 9 October 1957. [9] The International Time Bureau (BIH) began a time scale, T m or AM, in July 1955, using both local caesium clocks and ...

  9. Time signal - Wikipedia

    en.wikipedia.org/wiki/Time_signal

    One sort of public time signal is a striking clock. These clocks are only as good as the clockwork that activates them, but they have improved substantially since the first clocks from the 14th century. Until modern times, a public clock such as Big Ben was the only time standard the general public needed.