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  2. Primary Atomic Reference Clock in Space - Wikipedia

    en.wikipedia.org/wiki/Primary_Atomic_Reference...

    The mission, to have been funded by NASA, involved a laser-cooled caesium atomic clock, and a time-transfer system using Global Positioning System (GPS) satellites. PARCS was to fly concurrently with the Superconducting Microwave Oscillator (SUMO) [ 2 ] a different type of clock that was to be compared against the PARCS clock to test certain ...

  3. Caesium standard - Wikipedia

    en.wikipedia.org/wiki/Caesium_standard

    This also linked the definitions of the derived units relating to force and energy (see below) and of the ampere, whose definition at the time made reference to the newton, to the caesium standard. Before 1967 the SI units of time and frequency were defined using the tropical year and before 1960 by the length of the mean solar day [5]

  4. NIST-F2 - Wikipedia

    en.wikipedia.org/wiki/NIST-F2

    NIST physicists Steve Jefferts (foreground) and Tom Heavner with the NIST-F2 cesium fountain atomic clock, a civilian time standard for the United States. NIST-F2 is a caesium fountain atomic clock that, along with NIST-F1, serves as the United States' primary time and frequency standard. [1] NIST-F2 was brought online on 3 April 2014. [1] [2]

  5. NIST-F1 - Wikipedia

    en.wikipedia.org/wiki/NIST-F1

    NIST-F1, source of the official time of the United States. NIST-F1 is a cesium fountain clock, a type of atomic clock, in the National Institute of Standards and Technology (NIST) in Boulder, Colorado, and serves as the United States' primary time and frequency standard. The clock took fewer than four years to test and build, and was developed ...

  6. Atomic clock - Wikipedia

    en.wikipedia.org/wiki/Atomic_clock

    BeiDou Time (BDT) is a continuous time scale starting at 1 January 2006 at 0:00:00 UTC and is synchronised with UTC within 100 ns. [139] [140] BeiDou became operational in China in December 2011, with 10 satellites in use, [141] and began offering services to customers in the Asia-Pacific region in December 2012. [142]

  7. A data company has figured out which airlines fly on time ...

    www.aol.com/data-company-figured-airlines-fly...

    Atlanta-based Delta achieved an on-time rate of more than 83%, good enough to rank third worldwide. The next-best U.S. carriers were United Airlines , at nearly 81%, and Alaska Airlines, at just ...

  8. Here's when you'll need REAL ID to go through US ... - AOL

    www.aol.com/heres-youll-real-id-us-205309390.html

    Once the REAL ID requirements take effect after the new deadline of May 7, 2025, travelers boarding flights in the U.S. – whether domestic or international – will be required to have a REAL ID ...

  9. Unit of time - Wikipedia

    en.wikipedia.org/wiki/Unit_of_time

    The Jiffy is the amount of time light takes to travel one femtometre (about the diameter of a nucleon). The Planck time is the time that light takes to travel one Planck length. The TU (for time unit) is a unit of time defined as 1024 μs for use in engineering. The svedberg is a time unit used for sedimentation rates (usually