López J M, Lombardi M A
Divisíon de Metrología de Tiempo y Frecuencia, Centro Nacional de Metrología (CENAM), km 4.5 Carretera a los Cues, El Marques, Querétaro, C.P. 76241, México.
Time and Frequency Division, National Institute of Standards and Technology (NIST), Boulder, CO, USA.
Rev Mex Astron Astrofis. 2015;46:1-6.
Time and its measurement belong to the most fundamental core of physics, and many scientific and technological advances are directly or indirectly related to time measurements. Timekeeping is essential to everyday life, and thus is the most measured physical quantity in modern societies. Time can also be measured with less uncertainty and more resolution than any other physical quantity. The measurement of time is of the utmost importance for many applications, including: global navigation satellite systems, communications networks, electric power generation, astronomy, electronic commerce, and national defense and security. This paper discusses how time is kept, coordinated, and disseminated in the Americas.
时间及其测量属于物理学最基本的核心内容，许多科技进步都直接或间接地与时间测量相关。计时对日常生活至关重要，因此是现代社会中测量最多的物理量。与其他任何物理量相比，时间的测量也能做到不确定性更小、分辨率更高。时间测量对许多应用都至关重要，包括：全球导航卫星系统、通信网络、发电、天文学、电子商务以及国防与安全。本文讨论了美洲地区时间的保持、协调和传播方式。
