Atomic Time

Some articles on time, atomic time, atomic:

Second - History - Modern Measurements
... As a unit of time, the second (meaning the second division by 60 of an hour) entered English in the late 16th century, about a hundred years before it was measured ... In 1832, Gauss proposed using the second as the base unit of time in his millimeter-milligram-second system of units ... agreed to use the second of mean solar time as the unit of time." BAAS formally proposed the CGS system in 1874, although this system was gradually replaced over the next 70 years by MKS units ...
Tropical Year - Time Scales
... As mentioned in History, advances in time-keeping have resulted in various time scales ... One useful time scale is Universal Time (especially the UT1 variant), which is the mean solar time at 0 degrees longitude (the Greenwich meridian) ... This time scale is known to be somewhat variable ...
Theoretical Astronomy - Theory of Astronomical Time Keeping - Atomic Time
... is required that attempts to produce the SI second (s) such as an atomic clock ... the Atomic Time TAI ... From the General theory of relativity the time measured depends on the altitude on Earth and the spatial velocity of the clock so that TAI refers to a location on sea level that rotates ...
Time Zone - Definition
... Before 1972, all time zones were specified as an offset from Greenwich Mean Time (GMT), which was the mean solar time at the meridian passing through the ... Since 1972 all official time services have broadcast radio time signals synchronized to UTC, a form of atomic time that includes leap seconds to keep it within 0.9 seconds of ... Many countries now legally define their standard time relative to UTC, although some still legally refer to GMT, including the United Kingdom itself ...

Famous quotes containing the words time and/or atomic:

    Our fathers water’d with their tears
    This sea of time whereon we sail,
    Their voices were in all men’s ears
    Who pass’d within their puissant hail.
    Still the same ocean round us raves,
    But we stand mute, and watch the waves.
    Matthew Arnold (1822–1888)

    Take adultery or theft.
    Merely sins.
    It is evil who dines on the soul,
    stretching out its long bone tongue.
    It is evil who tweezers my heart,
    picking out its atomic worms.
    Anne Sexton (1928–1974)