atomic second การใช้

• An atomic second is equal to 9, 192, 631, 770 oscillations.
• Within the limits of observing accuracy, ephemeris seconds are of constant length, as are atomic seconds.
• Unfortunately, some finagling is needed to synchronize the atomic second with the less accurate and slightly mismatched rotation of the Earth.
• This publication allowed a value to be chosen for the length of the atomic second that would work properly with the celestial laws of motion.
• The atomic second, often called the SI second, was intended to agree with the ephemeris second based on Newcomb's work, which in turn makes it agree with the mean solar second of the mid-19th century . ( McCarthy & Seidelman, 2009, pp . 81 & ndash; 2, 191 & ndash; 7)