The International Earth Rotation and Reference Systems Service is the body responsible for maintaining global time and reference frame standards, notably through its Earth Orientation Parameter (EOP) and International Celestial Reference System (ICRS) groups. 8:17 am, August 6, 1945, Japanese time. ... A frame of reference in physics is a set of axes which enable an observer to measure the aspect, position and motion of all points in a system relative to the reference frame. ... The J2000. ...

Among its other functions, the IERS is responsible for announcing leap seconds. A leap second is a one-second adjustment to civil time in order to keep it close to the mean solar time. ...

The organization was formerly known as International Earth Rotation Service until April 2, 2002 when it formally changed its name. The organisation chose to retain the acronym IERS. 2 April is the 92nd day of the year (93rd in leap years) in the Gregorian calendar, with 273 days remaining. ... 2002 is a common year starting on Tuesday of the Gregorian calendar. ...

The Sub-bureau for Rapid Service and Predictions of Earth Orientation Parameters of the IERS, located at the United States Naval Observatory, monitors the Earth's rotation. Part of its mission involves the determination of a time scale based on the current rate of the rotation of the Earth. UT1 is the non-uniform time based on the Earth's rotation. Aerial view of USNO. The United States Naval Observatory (USNO) is one of the oldest scientific agencies in the United States. ... Earth, also known as the Earth, Terra, and (mostly in the 19th century) Tellus, is the third planet outward from the Sun. ... Universal Time (UT) is a timescale based on the rotation of the Earth. ...

See also

• International Atomic Time
• Coordinated Universal Time
• International Terrestrial Reference System
• International Celestial Reference System
• ΔT

Temps Atomique International (TAI) or International Atomic Time is a very accurate and stable time scale. ... Coordinated Universal Time or UTC, also sometimes referred to as Zulu time, is an atomic realization of Universal Time or Greenwich Mean Time, the astronomical basis for civil time. ... The International Terrestrial Reference System (ITRS) describes procedures for creating reference frames suitable for use with measurements on or near the Earths surface. ... The J2000. ... Delta T and delta-T are ASCII substitutes for the formal ΔT, which is Terrestrial Time minus Universal Time. ...

External link

• Official website