TAI

International Atomic Time

A time standard that is based on the average time elapsed between two specific points in the orbits of Earth’s moon. TAI is one of the most accurate and stable time scales available, and it is maintained by the International Bureau of Weights and Measures. TAI is used for many scientific, technical, and engineering applications that require accurate and stable timekeeping, such as the GPS system, the Internet, and many other technologies.

TAI was first implemented in 1958 as a way to provide a more precise and uniform time standard for scientific and technical purposes. Before TAI, the standard for timekeeping was based on the rotation of the Earth, which is irregular and subject to small variations. TAI is based on a network of atomic clocks that are used to measure the time elapsed between two specific points in the orbits of Earth’s moon and it is kept within 0.1 microseconds of the atomic time scale.

TAI is used as the basis for many timekeeping systems, including Coordinated Universal Time (UTC), which is used for civil timekeeping and legal purposes.

• Abbreviation: TAI